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Light is indispensable to every aspect of our life. It is also a very important component of photodynamic therapy to cure cancer. Photodynamic therapy is a modern and effective technique among all these prevailing anticancer therapies because of its uniqueness in selectivity. Organometallic complexes are seen to be better candidates for photodynamic therapy. Cyclometalated complexes have been developed for targeting cellular organelles with remarkable photoactivity. Different types of metal complexes can display PDT activity. Considering its photophysical characteristics, the iridium complex is the most effective alternative to use as a PDT agent. Iridium-based cyclometalated complexes have shown decent results as a PDT-active anti-cancer agent. Reactive oxygen species (ROS) and singlet oxygen with high singlet oxygen quantum yield are both extremely capable of being produced by complexes. High cytotoxicity has been exhibited by various Iridium-based cyclometalated complexes in the presence of light and negligible cytotoxicity in dark conditions. These complexes are considerably fluorescent with the capability of cellular imaging and have displayed very significant potency against HeLa, A549, MCF-7, and other various cell lines. Complexes can arrest the different paths of the cell cycle through different mechanisms and help to force cellular apoptosis. Hence, a galore of organelle-targeted cyclometalated iridium complexes has been showcased in this review article. • Summarizing Current Research: This review papers provide an overview of existing literature on a particular topic. It summarizes the current research and advancements in the field of photodynamic therapy using cyclometalated iridium complexes. • Identifying Trends and Gaps: By analyzing various studies, the review can identify trends in research, such as the most effective types of complexes or promising targeting strategies. It highlights gaps in knowledge or areas where further research is needed. • Consolidating Information: Research in the field of photodynamic therapy using cyclometalated iridium complexes may be scattered across various journals and publications. This review paper consolidates this information into one place, making it easier for researchers and clinicians to access and understand. • Informing Future Research Directions: This review paper can suggest future research directions or areas that warrant further investigation. This can help guide researchers in their studies and experiments. • Educational Resource: This review paper serves as a valuable educational resource for students, researchers, and practitioners. It provides an in-depth understanding of this specific topic and can be used as a reference in academic settings. • Impact on Clinical Practice: Ultimately, the goal of research in this area is to develop more effective treatments for various diseases, such as cancer. This review paper highlights the promising cyclometalated iridium complexes for photodynamic therapy that could have a direct impact on clinical practice by informing the development of new therapeutic strategies. [ABSTRACT FROM AUTHOR]

Nitroreductase (NTR) is overexpressed in hypoxic tumor cells, which is closely related to inflammation, tumorigenesis, tumor invasion and metastasis. Therefore, developing fluorescence probes for detecting intracellular NTR sensitivity has great significance for diagnosis and treatment of tumors. Therefore, we designed a novel fluorescent probe (Pro-CN) based on julolidine skeleton for the detection of NTR. The probe could discriminate rapidly NTR from other biological species like sulfhydryl compounds and some ions. Meanwhile, a fine linear relationship between fluorescence intensity of the probe and NTR consistence has been observed with a very low detection limit of 4.4 ng/mL. In addition, Pro-CN was successfully applied in imaging endogenous NTR in Hela cells and living zebrafish. The excellent performance of the probe makes it have great potential for monitoring NTR in complex biological systems, and it also provides the possibility of its application in human health, disease diagnosis and treatment. [Display omitted] • Probe Pro-CN exhibits a turn-on fluorescence for sensing NTR. • Pro-CN is highly sensitive to sense NTR with a very low detection limit of 4.4 ng/mL. • Pro-CN was successfully applied for imaging endogenous NTR in living Hela cells and zebrafish. [ABSTRACT FROM AUTHOR]

Ferroptosis is a distinctive iron-dependent and GSH-related cell death form, and has been demonstrated to closely relate with Golgi apparatus (GA). Exploring the fluctuations of GSH level in GA during ferroptosis is of great importance for the deep research of biological functions of GA in ferroptosis. Herein, we reported a novel GA-targeting probe (NA-G) for the detection of GSH in GA during ferroptosis. The probe NA-G utilized N-oxidized pyridine sulfonyl as a responsive site for GSH, with tetradecanoyl amide serving as GA-targeting moiety. NA-G exhibited remarkable sensitivity and selectivity, manifesting a heightened response to GSH and effectively visualizing GSH through bright green fluorescence under UV light. By fluorescence imaging of cellular GSH, NA-G was demonstrated to serve as a GA-targeting probe, and could successfully monitor the dynamic changes in intracellular GSH. Further experimentation revealed that NEM stimulation resulted in the removal of a significant amount of endogenous GSH in GA, and erastin-induced ferroptosis significantly reduced GSH levels in GA. Notably, we discovered that Fer-1 and VE effectively inhibited the substantial depletion of GSH in GA during ferroptosis. [Display omitted] • A Golgi apparatus-targeting probe (NA-G) for revealing the fluctuations of GSH during ferroptosis was developed. • The probe NA-G could be used to image endogenous GSH in Golgi apparatus of living cells. • Erastin-induced ferroptosis could decrease GSH level in Golgi apparatus of living cells. • Fer-1 and VE were demonstrated to efficiently inhibit the depletion of GSH during ferroptosis. [ABSTRACT FROM AUTHOR]

• A single-shot 3D epi-fluorescence microscope based on the transport of intensity equation (3DFM-TIE) using two synchronized image sensors is proposed. • The proposed microscope is utilized to monitor the volumetric cell division process of tobacco BY-2 suspension cells including the dynamics of microtubule. • The system is a prominent option for live cell imaging owing to real-time single-shot 3D fluorescence imaging capability. The dynamic activity of the microtubule cytoskeleton is critical to cellular organization, including structural support, intracellular transport, and engagement in processes such as cell division and cell motility. In this work, we monitor the volumetric cell division process of tobacco BY-2 suspension cells including the dynamics of microtubule in a single-shot by using a 3D epi-fluorescence microscope based on the transport of intensity equation (3DFM-TIE) with two synchronized image sensors. The technique makes it possible to recognize and track cell mobility by examining the fluorescently tagged proteins and studying their behavior and dynamics during the cell division process. In light of experimental findings, the 3DFM-TIE system could be a favored option for live cell imaging and analysis because of its real-time 3D imaging capability and simple and compact optical design, and it has the potential to be employed in both basic and clinical investigations. [ABSTRACT FROM AUTHOR]

• The bidirectional phase retrieval (BPR) was proposed. • Simulation and experimental results prove that the BPR provides more accurate phase results compared to conventional phase retrieval. • The BPR will be a valuable tool in the field of biological imaging. Quantitative phase imaging plays a crucial role in biological imaging, with many phase retrieval technologies being particularly important. However, cells and tissues must be placed on certain carriers during imaging, such as glass slides, cell culture dishes, and cell culture boxes. Therefore, current unidirectional phase retrieval technologies are not suitable for biplane samples, causing the phase of the object to always be coupled with the phase of noise. As a solution, this study proposes bidirectional phase retrieval to independently analyze the phase of both planes in the sample. Considering that most biological samples can be treated as two planes: one representing the object and the other serving as noise. By decoupling the phase of the two planes, this approach protects biplane biological samples from interference caused by the noise plane, leading to more accurate phase retrieval. This innovation holds significant value for the advancement of biological imaging. [ABSTRACT FROM AUTHOR]

A fluorescent probe (probe 1) with selectivity and sensitivity for H 2 S and N 2 H 4 has been developed. Probe 1 exhibits dual-excitation and dual-emission fluorescence response to H 2 S and fluorescence enhancement toward N 2 H 4 with distinct naked-eye color changes. Moreover, probe 1 displayed low detection limits for H 2 S and N 2 H 4 of 0.90 nM and 23.6 nM, respectively. The reaction mechanism of probe 1 toward H 2 S and N 2 H 4 was established using 1H NMR and HR-MS spectroscopy. Additionally, probe 1 was used for monitoring and differentiating H 2 S and N 2 H 4 in HeLa cells and displays good biocompatibility and low cytotoxicity. • Probe 1 exhibits dual-emission fluorescence-enhanced detection of H 2 S in mitochondria. • Probe 1 exhibits a turn-on response for the detection of N 2 H 4 in mitochondria. • Probe 1 exhibits rapid response, good optical performance, high selectivity, and high sensitivity in solution. • Probe 1 displays multi species detection in the mitochondria of HeLa cells and zebrafish. • Detection using Probe 1 can be achieved using a smartphone with a chromaticity APP. [ABSTRACT FROM AUTHOR]

• Promising G-quadruplex binders: chroman derivatives ligands & their BF2-complexes. • These compounds stabilize parallel and mixed hybrid G-quadruplex structures. • In vitro and cellular studies: biophysical analyses demonstrate binding affinity in both contexts. • Molecular docking: computational study supports binding of chroman complexes to G-quadruplex. • Potential fluorescent ligands: these compounds offer new options for G-quadruplex targeting ligands. Currently, G-quadruplex structure targeting strategies are considered as a promising anticancer approach. The purpose of this research is to expand the options for G-quadruplex targeting ligands, particularly emphasizing fluorescent ligands. Our study contributes to the field by providing additional choices for G-quadruplex binders with a notable focus on selectivity towards G-quadruplex topology over duplex DNA. In the search of selective and potent G-quadruplex binders, here we discuss an analysis of a few chroman derivatives ligands named A and C and their respective borondifluoride complexes B and D as a quadruplex targeting compounds which found to stabilize G-quadruplex structure. To investigate the binding characteristics of these molecules with G-quadruplex vs. duplex selectivity, In vitro biophysical studies were performed by steady-state fluorescence, UV–visible titration, fluorescent TO displacement assay, CD thermal melting, circular dichroism spectroscopy, and cellular imaging by employing both telomeric and PRCC G-quadruplex forming sequences. Our investigation shows that these chromam ligands and their complexes are able to selectively bind and stabilize parallel and mixed hybrid topology of G-quadruplex both In vitro and in cellular conditions. A molecular docking and MD simulation study also suggests the binding of these compounds with G-quadruplex conformation. Collectively our study suggests these chroman complexes for the first time as a potentially useful fluorescent chemical product for G-quadruplex specific ligands and expands an option for G-quadruplex targeting ligands. [Display omitted] [ABSTRACT FROM AUTHOR]

[Display omitted] • Summarization of recent progress in the biomedical applications of water-soluble polythiophenes, covering biosensing, cell imaging, gene delivery, drug delivery, cancer therapy, and tissue engineering. • Emphasis on polymerization methods of water-soluble polythiophenes. • Description of the mechanisms underlying the biomedical applications of water-soluble polythiophenes. • Outlining of challenges and future developments in the use of water-soluble polythiophenes for biomedical applications. Water-soluble polythiophenes (PTs) have gained attention for their potential in medical uses. PTs have strong electrical and optical properties and are sensitive to outside influences. Recently, they have been widely applied for detecting nucleic acid, adenosine triphosphate, antibiotics, cancer biomarkers, and metal ions. They are also used for imaging cells, delivering genes and drugs, photodynamic, photothermal, sonodynamic treatments, and tissue engineering. However, there is still no comprehensive review covering these applications. This review briefly outlines the medical uses of water-soluble PTs, including biosensing, cell imaging, gene and drug delivery, cancer treatment, and tissue engineering. It also discusses the significant challenges and future directions for water-soluble PTs. [ABSTRACT FROM AUTHOR]

[Display omitted] • A dual-locked fluorescence probe (TPA-DNP) for LDs and HClO was designed. • TPA-DNP could detect LDs and HClO simultaneously by "turn-on" fluorescence singal. • TPA-DNP had successfully been applied in imaging HClO within LDs accumulation environments. • The real-time dynamic imaging of LDs and HClO by TPA-DNP under the LPS-induced inflammatory system. Inflammation is a key factor leading to the occurrence and development of many diseases, both lipid droplets (LDs) and hypochlorous acid (HClO/ClO-) are regarded as the important biomarkers of inflammation. Therefore, it is of great significance to develop an efficient single chemical sensor that can simultaneously detect these two biomarkers. To achieve the goal, we developed a dual-locked fluorescence probe (TPA-DNP) by fusing two targets activated reporting system, its implementation was achieved by turning-on the fluorescence of TPA-DNP through LDs and HClO/ClO- simultaneously. In simulated LDs environment, TPA-DNP displayed excellent selectivity to HClO/ClO-, high sensitivity (LOD = 0.527 μM) and strong anti-interference ability. In addition, cell and zebrafish imaging experiments showed that TPA-DNP could be utilized to visualize exogenous/endogenous HClO/ClO- in LDs environment, and could also be used to observe the impact of LDs changes on the HClO/ClO- detection. On the basis, TPA-DNP served as a favorable tool to achieve visualization of inflammatory dynamic changes. [ABSTRACT FROM AUTHOR]

• Constructing a complex (1) with precise structures by introducing luminescent groups triphenylphosphine (TPA), is used for treatment and imaging. • Within 0.5 h, 1 can be distributed into cells, performing effective cell imaging. • 1 can be used for CDT, promoting oxidative stress and causing cell apoptosis. The combination of imaging and treatment is the fundamental strategy for achieving precise anticancer treatment. This article constructs a copper(I) complex (1) by aminourea derivative containing triphenylamine (TPA). 1 with precise structure, can be used for cell imaging and chemodynamic therapy (CDT). Within 0.5 h, 1 can be distributed into the mitochondria of T24 cells, performing effective cell imaging and then promoting oxidative stress and causing cell apoptosis. A precise complex with luminescent triphenylphosphine (TPA) group, is used for the effective cell imaging, promoting oxidative stress and causing cell apoptosis. [Display omitted] [ABSTRACT FROM AUTHOR]

• Novel indium(III) phthalocyanines baring mercaptopyridine groups and their quaternized derivatives were synthesized. • Singlet oxygen generation and photostability of these phthalocyanines were investigated. • Electrochemical biosensing assay conducted with disposable pencil graphite electrodes. • Interaction of phthalocyanines with AS1411 examined by electrochemical impedance spectroscopy as well as spectroscopic techniques. • The developed targeted PDT agent has the potential for breast cancer treatment in the future. In the study, the novel indium(III) phthalocyanines containing 4-mercaptopyridine groups as substituents on the peripheral (Pc3) or non-peripheral (Pc8) tetra-and peripheral octa (Pc13) positions were synthesized. After then, the synthesized phthalocyanines were converted to their water-soluble derivatives that are Pc5, Pc10, and Pc15 by the quaternization of the nitrogen atoms on the substituents. These new phthalocyanines have been characterized by various spectroscopic methods such as FT-IR, 1H NMR, elemental analysis, UV–vis, MALDI-TOF mass spectra. Photochemical properties were also investigated for the synthesized phthalocyanines. In this study; quaternized derivatives were studied in DMSO and aqueous solutions, while non-quaternized derivatives were studied only in DMSO. The interaction between AS1411 and three phthalocyanines (Pc5, Pc10 , and Pc15) was investigated using spectroscopic methods and electrochemical impedance spectroscopy technique combined with pencil graphite electrodes (PGEs). The cytotoxic activity of AS1411 and each phthalocyanine was investigated in the MCF-7 and doxorubicin (Dox) resistant MCF-7/DOX-R cell lines in the presence and absence of Dox. The photodynamic therapy (PDT) activity of Pc5, Pc10 , and Pc15 and their AS1411 conjugates was investigated on MCF-7, MCF-7/DOX-R and MCF-10A cells. The IC 50 values for MCF-7 cells were found as 1.1, 0.46, and 0.46 mM for Pc5 and 0.58, 0.34, and 0.32 mM for Pc5 -AS1411 conjugate in the absence of irradiation and radiation with 7 J and 20 J. The values for MCF-7/DOX-R cells were found 0.81, 0.30, and 0.11 mM for Pc5 and 0.39, 0.12, and 0.15 mM for Pc5 -AS1411 conjugate without irradiation and radiation with 7 J and 20 J, respectively. Apoptosis and cell imaging studies showed that conjugation of the phthalocyanines with AS1411 induced apoptosis in both cell lines and increases the intracellular entry of phthalocyanine Pc5. [ABSTRACT FROM AUTHOR]

Micro- and nanoplastics (MNPs) are ubiquitous in the environment, resulting in the uptake of MNPs by a variety of organisms, including humans, leading to particle-cell interaction. Human macrophages derived from THP-1 cell lines take up Polystyrene (PS), a widespread plastic. The question therefore arises whether primary human macrophages also take up PS micro- and nanobeads (MNBs) and how they react to this stimulation. Major aim of this study is to visualize this uptake and to validate the isolation of macrophages from peripheral blood mononuclear cells (PBMCs) to assess the impact of MNPs on human macrophages. Uptake of macrophages from THP-1 cell lines and PBMCs was examined by transmission electron microscopy (TEM), scanning electron microscopy and live cell imaging. In addition, the reaction of the macrophages was analyzed in terms of metabolic activity, cytotoxicity, production of reactive oxygen species (ROS) and macrophage polarization. This study is the first to visualize PS MNBs in primary human cells using TEM and live cell imaging. Metabolic activity was size- and concentration-dependent, necrosis and ROS were increased. The methods demonstrated in this study outline an approach to assess the influence of MNP exposure on human macrophages and help investigating the consequences of worldwide plastic pollution. [Display omitted] • Human monocyte-derived macrophages as novel in vitro model to study effects of MNP. • Concentration-dependent cytoplasmic uptake of PS MNBs visualized by TEM and SEM. • Uptake of PS MNBs by primary human macrophages is visible in live cell imaging. • Effects of different sized, non-fluorescent PS-MNBs in physiological concentration. • PS MNBs induce nitric oxide formation and cytotoxic effects in human macrophages. [ABSTRACT FROM AUTHOR]

Cryopreserved cell banks are fundamental for off-the-shelf mesenchymal stromal cell (MSC) therapies. However, cryopreserved MSCs are functionally impaired after thaw. Since metabolic fitness is linked to the functional potency of MSCs, we tested whether cultured (fresh) and thawed MSCs exhibit metabolic differences. Donor- and age-matched cultured and cryopreserved human umbilical cord or bone marrow MSCs were lifted or thawed respectively, suspended in xeno-free media, and cultured at 37C, 5% CO2. Mitochondrial morphology was assessed by live cell imaging of Mitotracker-stained cultures. Cellular energetics were quantified using a Seahorse metabolic analyzer after 6-, 24-, and 48-hours post-thaw. Thawed cells exhibited mitochondrial fusion and reduced networking, accompanied by reduced metabolic flux. These effects lasted 24-48 hours, depending on the donor. MSCs exposed to IFN-γ and TNF-α have increased potency, so we tested whether this strategy enhances MSC metabolism. Indeed, cytokine preconditioning shifted MSCs into glycolysis, independent of dose or time, and this effect was retained during cryopreservation and thaw. We next tested whether the glycolytic state of preconditioned MSCs improves their function. Fresh and thawed MSCs were challenged with IFN-γ and TNF-α and changes in functional biomarkers including IDO-1 quantified using RT-qPCR. Six and 24 hours after thaw, the preconditioned MSCs produced equivalent IDO-1 to fresh cells, suggesting that cytokine preconditioning may be a useful strategy to accelerate metabolic and functional recovery of cryopreserved MSCs. [ABSTRACT FROM AUTHOR]

[Display omitted] • An enzymatically activated biosensor was designed named E-MB-tFNA. • E-MB-tFNA was self-powered and self-recycled. • E-MB-tFNA showed excellent stability. • E-MB-tFNA can specific imaging APE1 in situ. • E-MB-tFNA can used for monitoring drug resistance and achieving guided surgical excision in vivo. Specific imaging of tumor cells with high sensitivity is urgently needed for evaluating the risk of tumor metastasis and progression. However, traditional tumor cell imaging strategies are still restricted by limited tumor specificity and sensitivity due to off-tumor signal leakage and a lower content of the targets. Therefore, a self-powered and self-recycled strategy based on molecular beacon (MB) hybridized on tetrahedral framework DNA (E-MB-tFNA) using the endogenous enzyme, apurinic/apyrimidinic endonuclease 1 (APE1), was rationally developed for tumor cell-specific molecular imaging with superior spatial specificity and improved sensitivity. The apurinic/apyrimidinic site (AP site) can be specifically recognized and cleaved by APE1, and was modified on the stem and loop region of E-MB-tFNA. The resultant E-MB-tFNA can be specifically recognized and cleaved by APE1 in the cytoplasm, which is overexpressed in tumor cells compared to normal cells. In particular, once APE1 cleaves the AP site on the stem region (double-stranded DNA) of E-MB-tFNA, the self-powered and self-recycled sequences modified on the stem region of E-MB-tFNA is freed to hybridize with the loop region of E-MB-tFNA, prompting APE1 to further hydrolyze the E-MB-tFNA loop region and generate fluorescence signals. In addition, the self-powered and self-recycled sequences can be hybridized with other E-MB-tFNA to continuously and cyclically amplify the fluorescence signal. The experimental results of this study showed that the E-MB-tFNA has the capability to monitor drug resistance and achieve guided precision surgical excision in vivo with superior spatial specificity and improved sensitivity. In particular, E-MB-tFNA can realize the risk classification of neuroblastoma patients in clinical plasma. [ABSTRACT FROM AUTHOR]

Fluorescent probes have revolutionized biological imaging by enabling the real-time visualization of cellular processes under physiological conditions. However, their size and potential perturbative nature can pose challenges in retaining the integrity of biological functions. This manuscript highlights recent advancements in the development of small fluorescent probes for optical imaging studies. Single benzene-based fluorophores offer versatility with minimal disruption, exhibiting diverse properties like aggregation-induced emission and pH responsiveness. Fluorescent nucleobases enable precise labeling of nucleic acids without compromising function, offering high sensitivity and compatibility with biochemistry studies. Bright yet small fluorescent amino acids provide an interesting alternative to bulky fusion proteins, facilitating non-invasive imaging of cellular events with high precision. These miniaturized fluorophores promise enhanced capabilities for studying biological systems in a non-invasive manner, fostering further innovations in molecular imaging. [ABSTRACT FROM AUTHOR]

Emerging studies demonstrates that mitochondrial G-quadruplex (G4) may be a prospective diagnostic and therapeutic target for cancer. Fluorescent probes targeting mitochondrial G4 are crucial for in-depth research on G4 function and mechanism and developing new diagnostic techniques. Here, we report a benzothiazole derivative named ThT-E, which can be prepared with high yield through only one step of reaction. ThT-E exhibits superior detection sensitivity compared to existing probes, and also demonstrates reliable performance for in situ characterization of mitochondrial G4 in living cells. Interestingly, ThT-E has been used to differentiate tumor cells from normal cells by quantifying the formation of mitochondrial G4s, implicating that ThT-E may have wide applications in tumor diagnosis. • A benzothiazole derivative for monitoring mitochondrial G-quadruplexes. • More pronounced fluorescence enhancement in tumor cells than normal cells. • More G-quadruplex formation in tumor mitochondria. • Mitochondrial G-quadruplex as a potential cancer biomarker. • New probe tool for tumor diagnosis. [ABSTRACT FROM AUTHOR]

[Display omitted] • Herein we constructed and synthesized turn-on fluorescent probe NSP based on simple condensation reaction. • Probe on incubating with triphosgene in presence of 1 % Triethylamine (TEA) show maximum emission at 586 nm within ≤3 s. • The probe displayed both colorimetric and fluorescence response with phosgene (0.01 ppm). • The probe-loaded paper strips, allowed for the direct visualization of phosgene vapour from household bleaching powder. • The probe detect phosgene in living cells. Phosgene is a vital industrial gas that might substantially imperil public safety in the case of an accident or terrorist attack due to its extreme toxicity and history of use as a chemical warfare agent. Herein we built a simple photoinduced electron transfer-intramolecular charge transfer based turn-on fluorescent probe for ultrafast detection of phosgene within ≤ 3 s. The probe provides low detection limit (0.01 ppm) with distinct colour and fluorescence changes only in the presence of phosgene. With the help of a readily available colour smartphone app, the probe-loaded paper strips allowed for the direct visualization and quantitative measurement of phosgene vapour. Using the probe-coated strips to detect phosgene that evolved from common household bleach. Finally, the probe was utilized to detect phosgene in living cells. [ABSTRACT FROM AUTHOR]

[Display omitted] • The probe P-1 can selectively detect H 2 O 2 with colorimetric change. • the P-1 can be used for on-site and visual detection of H 2 O 2. • The P-1 can image H 2 O 2 in cells and distinguish cancer cells and normal cells. • The P-1 probe was applied to monitor H 2 O 2 of tumor in mice. We designed and developed the probe P-1 for detecting H 2 O 2. The probe can selectively detect H 2 O 2 with colorimetric change. In addition, the combination of portable test strips with a smartphone platform provided great convenience for on-site and visual detection of H 2 O 2 with satisfactory sensitivity and reliability. The P-1 can image exogenous and endogenous H 2 O 2 in cells and distinguish cancer cells and normal cells by fluorescence image of H 2 O 2 and flow cytometry. Meanwhile, the P-1 probe has been successfully applied to monitor H 2 O 2 levels of tumor in mice, and the results showed the level of H 2 O 2 in tumor tissue increased significantly. Therefore, P-1 provided a potential chemical tool to understand pathological and physiological mechanisms of diseases by imaging H 2 O 2. [ABSTRACT FROM AUTHOR]

[Display omitted] • The new probes with AIE characteristic for cell imaging. • The probe has high sensitivity in the presence of solvent shielding effects. • The probe has good reversibility for environmental testing and could be recycled. A new fluorescent probe TPA-DAP with aggregation-induced emission (AIE) characteristic based on 2,6-pyridinedicarboxylic acid was synthesized for the detection of paramagnetic ions (Cu2+, Co2+, Ni2+). In the DMF/PBS (5:95, v/v, pH = 7.40) solvent mixture, the fluorescence intensity exhibited a notable enhancement of over 3-fold when compared to DMF alone. Concurrently, fluorescence quenching phenomena were observed in the presence of Cu2+, Co2+, and Ni2+, with corresponding detection limits measured at 56.4 nM, 22.4 nM, and 26.5 nM, respectively. These detection limits were found to be lower than the prescribed thresholds for Cu2+ in Class I groundwater and Co2+, Ni2+ in Class III groundwater, multi-functional detection was possible. The coordination constants were 9.07 × 105, 3.63 × 105 and 5.69 × 105, respectively. However, in the DMSO system, the probe will be highly selective in the presence of solvent shielding effects. The probe showed more than 10-fold enhancement of fluorescence intensity in DMSO/Tris-HCl (5:95, v/v, pH = 7.00) compared to DMSO and specific detection of Cu2+ with a detection limit of 36.7 nM and a coordination constant of 4.35 × 105, and was cyclically detectable in the presence of EDTA. TPA-DAP was applied for the detection of Cu2+ in actual water samples and showed good biocompatibility and recyclability, making it suitable for water testing and test paper experiments, and also for a wide range of applications in the identification of Cu2+, Co2+, Ni2+ and other bioassays in cells and zebrafish. Solvents could be selected according to actual test requirements. [ABSTRACT FROM AUTHOR]

[Display omitted] • An azo-Schiff base (ASB) chemosensor was synthesized from salicylaldehyde and N, N-dimethyl-4,4′-azodianiline. • ASB exhibits turn-on fluorescence toward Al3+ due to the Al3+-promoted hydrolysis of imine bonds. • ASB can be used for qualitative and quantitative Al3+ sensing in three antacid tablets. • ASB can be applied to cell imaging of Al3+ in breast cancer cell MCF-7. The azo-Schiff base (ASB) chemosensor was designed and synthesized by the reaction of salicylaldehyde and N, N-dimethyl-4,4′-azodianiline. The ASB sensor can be used to detect Al3+ in antacid tablets and cell imaging applications. After adding Al3+ ions, the ASB sensor exhibits turn-on fluorescence performance because of the Al3+-promoted hydrolysis of the imine bond. The Al3+-promoted hydrolysis of the imine bond has been evidenced by FTIR, 1H NMR, and 13C NMR spectra analysis. The ASB sensor displayed a selective and sensitive recognition of Al3+ by turn-on fluorescence with the detection limit of 1.53 × 10−7 M, and a binding constant of 2.36 × 104 M−1 in an aqueous HEPES buffer/DMSO solution (2/8 v/v). The ASB sensor can be applied to the qualitative and quantitative detection of Al3+ in three antacid tablets (Gelusil, Macgel, Swellin). Besides, the ASB sensor shows low cell toxicity and good cell permeability. The cell-imaging test indicates that the ASB probe can detect Al3+ ions in breast cancer cell MCF-7 under optical fluorescence microscopy. [ABSTRACT FROM AUTHOR]

[Display omitted] • The high sensitivity of the probe with a detection limit of 58 nM. • Successful detection of endogenous and exogenous CO in living cells. • Capable of detecting CO in zebrafish. • NIR probe with a high signal-to-noise ratio for imaging CO in biological samples. Carbon monoxide (CO) is a highly emitted atmospheric pollutant that can pose a serious health risk when its concentration is too high. However, endogenous CO plays an important role in maintaining human health. The development of tools capable of detecting CO in environmental samples and biological samples is therefore essential. Although CO fluorescent probes have been reported, their further applications are limited by factors such as low sensitivity and emission wavelength. Here, we have constructed a CO probe with simple structure, high sensitivity, good selectivity and near-infrared (NIR) emission characteristics. The probe uses the dicyanoisophorone derivative as fluorophore and connects allyl moiety as the reaction site. After the response, the intramolecular charge transfer (ICT) process turns on and releases strong near-infrared fluorescence at 675 nm. The linear range of fluorescence intensity of the probe for CO concentration is 1–10 μM and the detection limit is as low as 58 nM. The high sensitivity and NIR emission give the probe excellent imaging of cellular exogenous and endogenous CO. Moreover, the probe can also be used to image CO in zebrafish. There is reason to believe that the probe can be a powerful tool for detecting CO concentrations in environmental samples and for analyzing the biological role of CO in organisms. [ABSTRACT FROM AUTHOR]

DNA-functionalized nanomaterials represent the cutting edge of the convergence between nanoscience and life sciences. The gold nanoparticles (AuNPs), with their versatile attributes, serve as multifunctional carriers in complex environments, supporting diverse physiological activities of DNA. Concurrently, DNA enhances the target specificity and stability of nanomaterials, significantly improving or fine-tuning their performance. This review explores key aspects of DNA-functionalized AuNPs, including their synthesis methods, properties, and biosensing applications. It starts by delving deeply into the interactions between DNA and AuNPs, emphasizing their role in material customization and highlighting the advantages and applicability of each technique. Furthermore, the review thoroughly evaluates the latest synthesis methods developed from shielding the charger repulsion and extremely compressing the physical space. It showcases the potential of DNA-functionalized AuNPs in addressing complex challenges for biosensing applications. This synergistic relationship has propelled advancements in nanotechnology, facilitating the integration of life sciences, medicine, and nanotechnology, and expanding the application domains of these novel biomimetic nanocomposite materials. Therefore, there is an urgent need for in-depth research into the synthesis, structure and function of DNA-functionalized nanomaterials to unravel their pivotal mechanisms. Illustration of the application of DNA-functionalized gold nanomaterials in the field of biosensing. [Display omitted] • Mechanisms behind those milestones during the evolution of synthesizing DNA-functionalized AuNPs have been extensively discussed. • Engineering DNA-AuNPs enables biosensing of biomolecules for more intuitive and accurate access to spatiotemporal information. • Continuous innovation of synthesis enhances the efficiency in designing more functionalized nanomaterials across diverse fields. [ABSTRACT FROM AUTHOR]

Ammonia is a common toxic gas in industrial and agricultural production, which will cause harm to the environment and human health in certain extent. Here, a novel fluorescent probe (R)- 1 based on 1,1′-binaphthol (BINOL) was synthesized for real-time, on-site and quantitative detection of ammonia. The mechanism study shows that the functional groups of –CHO and –OH on (R)- 1 interact with ammonia, which changes the electronic state of the probe molecule and excites strong fluorescence. A test strip for rapid detection of ammonia was developed, which changed from light yellow to reddish brown under natural light after interacting with ammonia, thus realizing the rapid detection and easy visualization of ammonia. Meanwhile, bioimaging experiments shows that probe (R)- 1 can detect exogenous ammonia in cells. [Display omitted] • Specific selective fluorescence recognition of ammonia. • Fast response time (300 s) and high sensitivity (0.96 ppm). • A test strip for real-time and visual detection of ammonia. • Exogenous ammonia fluorescence imaging of cells. [ABSTRACT FROM AUTHOR]

The biomechanical regulation of the cytoskeleton and cell adhesions underlies various essential cellular functions. Studying them requires visualizing their nanostructure and molecular dynamics with evermore precise spatio-temporal resolution. In this review we will focus on the recent advances in single molecule fluorescence imaging techniques and discuss how they improve our understanding of mechanically sensitive cellular structures such as adhesions and the cytoskeleton. We will also discuss future directions for research, emphasizing on the 3D nature of cellular structures and tissues, their mechanical regulation at the molecule level, as well as how super-resolution microscopy will enhance our knowledge on protein structure and conformational changes in the cellular context. [ABSTRACT FROM AUTHOR]

The Tubulin Code revolutionizes our understanding of microtubule dynamics and functions, proposing a nuanced system governed by tubulin isotypes, posttranslational modifications (PTMs) and microtubule-associated proteins (MAPs). Tubulin isotypes, diverse across species, contribute structural complexity, and are thought to influence microtubule functions. PTMs encode dynamic information on microtubules, which are read by several microtubule interacting proteins and impact on cellular processes. Here we discuss recent technological and methodological advances, such as in genome engineering, live cell imaging, expansion microscopy, and cryo-electron microscopy that reveal new elements and levels of complexity of the tubulin code, including new modifying enzymes and nanopatterns of PTMs on individual microtubules. The Tubulin Code's exploration holds transformative potential, guiding therapeutic strategies and illuminating connections to diseases like cancer and neurodegenerative disorders, underscoring its relevance in decoding fundamental cellular language. [ABSTRACT FROM AUTHOR]

A double 3D DNA walker nanomachine by DNAzyme self-driven positive feedback loop amplification for the detection of miRNA was constructed. This method uses two gold nanoparticles as the reaction core, and because of the spatial confinement effect the local concentration of the reactants increase the collision efficiency was greatly improved. Meanwhile, the introduction of positive feedback loop promotes the conversion efficiency. In presence of miRNA-21, a large amount of DNAzyme was released and hydrolyze the reporter probe, resulting the recovery of fluorescence signal. The linear range for miRNA-21 is 0.5–60 pmol/L, and the detection limit is 0.41 pmol/L (S/N = 3). This nanomachine has been successfully used for accurate detection of miRNA-21 expression levels in cell lysates. At the same time, it can enter cells for intracellular miRNA-21 fluorescence imaging, distinguishing tumor cells from normal cells. This combination of in vitro detection and imaging analysis of living cells can achieve the goal of jointly detecting cancer markers through multiple pathways, providing new ideas for early diagnosis and screening of diseases. A dual-core 3D DNA nanomachine based on DNAzyme positive feedback loop for highly sensitive MicroRNA imaging in living cells was constructed. [Display omitted] • A new double 3D DNA nanomachine uses the spatial confinement effect to improve the walking efficiency. • DNAzyme self-driven positive feedback loop amplification is introduced for sensitive analysis of miRNA. • This nanomachine was applied for the precise imaging of microRNA in living cells. [ABSTRACT FROM AUTHOR]

The in situ precise quantification and simultaneous imaging of low abundance microRNAs (miRNAs) within living cells is critical for cancer diagnosis, yet it remains a significant challenge. Leveraging the excellent sensitivity and spatiotemporal resolution of dark-field microscopy (DFM) and fluorescence imaging, we have successfully devised a novel detection approach using dual-signal reporter probes (DSRPs). These probes allow for highly sensitive detection of miRNA-21 in living cells via toehold-mediated strand displacement cascades. The DSRPs were constructed by Au nanoparticles and Ag nanoclusters core-satellite nanostructures. After the recognition of miRNA-21, the strand displacement cascades were triggered, inducing the disassembly of the Au/Ag core-satellite nanostructure with apparent scattering intensity decrease and peak wavelength shifts. Additionally, the fluorescence of Ag clusters could be recovered and further enhanced when in close proximity to specific guanine-rich strands. The dual-signal response capability enables the accurate detection of miRNA-21 from 1 fM to 1 nM, with a limit of detection reached 0.75 fM. DFM and fluorescent imaging of living cells efficiently confirms the applicable detection of miRNA-21 in complex detection media. The biosensor based on DSRPs represents a promising nanoplatform for visual monitoring and imaging of biomolecules in living cells, even at the single particle level. [Display omitted] • Dual-signal reporter probes was proposed based on core-satellite nanostructures. • Target microRNA triggered the strand displacement cascades on the probe surface. • The dual signals of LSPR shifts and fluorescence enhancement were induced. • Accurate detection and simultaneous imaging of intracellular microRNA were realized. [ABSTRACT FROM AUTHOR]

Specific staining of cancer cells is momentous for cancer research. Nanoprobe with multivalent recognition is emerging as powerful tools for bioimaging, but the nonspecific cell uptake and complex functional modification procedures are still obstacles for specific detection and convenient synthesis. Carbon dots (CDs) with an intrinsic targeting ability, excellent optical properties and biocompatibility acquired from an efficient one-step fabrication procedure were urgently desired in specific cancer cells visualization. Herein, inspired by the interrelationships between interface and biomolecular mechanisms, we suggested that it was possible to construct CDs with the desired characteristics for folate receptor (FR) positive-expressed cancer cell imaging via rich hydroxyl groups Tris-assisted one-step hydrothermal treatment of folate acid (FA) and l -Arginine (L-Arg) precursors. The prepared small-sized F-CDs were equipped with abundant hydroxyl, pterin and negative charge surface, and possessed environmental friendliness, outstanding photostability and biocompatibility. Moreover, F-CDs had an intrinsic FR positive-expressed cancer cell targeting ability without any post-modification of the ligands. Rich hydroxyl groups play a vital role in endowing the optical properties and biological effects of F-CDs. F-CDs could be used as a promising candidate for FR-expressed cancer cell labeling and tracking. In addition, the caveolae-mediated endocytosis pathway of F-CDs was ascertained. More importantly, experimental results confirmed that the combination of physicochemical properties may provide an efficient strategy to overcome non-specific cell uptake interactions for cell labeling. Our strategy put forward a promising alternative to design fluorescent CDs for extensive chemical and biomedical applications. Tris-assisted one-step fabrication of functional F-CDs for specific folate receptor positive-expressed cancer cell imaging. [Display omitted] • F-CDs were fabricated via rich hydroxyl groups Tris to mediate hydrothermal process of FA and L-Arg. • Rich hydroxyl groups of Tris play a vital role in the optical properties and intrinsic targeting ability for FR positive-expressed cancer cell for labeling and tracking. • This study provides an efficient strategy to design fluorescent CDs for extensive applications. [ABSTRACT FROM AUTHOR]

Perennial ryegrass (Lolium perenne) is a fructan-accumulating plant constituting one of the most important grassland species with high herbage production, nutritive value and digestibility for grazing cattle. Although fructans were reported to be involved in plant defense acting as antioxidants or stress signals, their contribution in root protection is still to be explored. In roots, atypical defense is provided by the "Root Extracellular Trap" or "RET" at the root-soil interface. The molecular composition and structural organization of the RET are essential to provide root defense against pathogen attacks and abiotic stresses. The RET was reported to be mainly composed of polysaccharides (homogalacturonan, xylogalacturonan, xyloglucan) and proteoglycans such as arabinogalactan proteins (AGPs). Our aim is to characterize the RET composition of L. perenne using cell imaging techniques and a wide range of monoclonal antibodies directed against epitopes from cell wall glycomolecules and to investigate the potential presence of fructans. Interestingly, we found that both mucilage and cell wall surface of border cells were enriched in AGP epitopes. An increased amount of the AGP-containing mucilage was produced by L. perenne root tip in response to both elicitor and osmotic stress. Fructan epitopes were also detected in root cap cells and appeared to be released in the RET under stress conditions. Taken together our findings suggest that AGPs together with fructans are involved in root response of L. perenne to environmental stresses. • The root tip of perennial ryegrass produced border cells of different morphologies. • The root extracellular trap (RET) of perennial ryegrass contained abundant mucilage rich in arabinogalactan protein (AGP). • Fructan epitopes are released within the RET in response to PEG-induced osmotic stress and flagellin 22 elicitation. • Fructans, together with AGPs are promising candidates in root response to environmental stress in perennial ryegrass. [ABSTRACT FROM AUTHOR]

Scheme 1 Illustration of the synthetic procedure of Br-CDs-AM and the application in sensing HClO in food matrices and lysosomal imaging. [Display omitted] • Br-CDs with excellent photostability were synthesized by self-doping strategy. • Br-CDs-AM as a probe was made of Br-CD and N -aminomorpholine by substitution reaction. • HClO in milk, yogurt and meat samples were detected accurately (96.5 %–108 %). • • Br-CDs-AM can be used to locate lysosome and visualize HClO in live cells. Hypochlorous acid (HClO) is used in food preservation. However, excessive HClO can deteriorate nutritional composition of food, compromise its quality, and potentially induce various diseases. Consequently, the development of multifunctional fluorescent probes for the sensitive and selective detection of HClO is highly anticipated for food safety. In this work, we designed a nanoprobe using N -aminomorpholine (AM)-functionalized bromine-doped carbon dots (Br-CDs-AM) for sensing HClO. This nanoprobe exhibits pH stability, strong resistance to photobleaching, superior long-term photostability (12 weeks), high sensitivity (19.3 nM), and an ultrarapid response (8 s) for detecting HClO residues in food matrices with percentage recovery (96.5 %–108 %) and RSDs less than 5.34 %. In addition, extremely low cytotoxicity and outstanding biocompatibility enable the nanoprobe to be used primarily for lysosome tracking and rapidly visualizing HClO in live cells. Thus, this study provides a new pathway to design unconventional nanoprobes for food safety assessment and subcellular organelle-specific imaging HClO. [ABSTRACT FROM AUTHOR]

Sulfur dioxide (SO 2) is a significant gas signaling molecule in organisms, and viscosity is a crucial parameter of the cellular microenvironment. They are both involved in regulating many physiological processes in the human body. However, abnormalities in SO 2 and viscosity levels are associated with various diseases, such as cardiovascular disease, lung cancer, respiratory diseases, neurological disorders, diabetes and Alzheimer's disease. Hence, it is essential to explore novel and efficient fluorescent probes for simultaneously monitoring SO 2 and viscosity in organisms. We selected quinolinium salt with good stability, high fluorescence intensity, good solubility and low cytotoxicity as the fluorophore and developed a highly sensitive ratiometric probe QQD to identify SO 2 and viscosity changes based on Förster resonance energy transfer/twisted intramolecular charge transfer (FRET/TICT) mechanism. Excitingly, compared with other probes for SO 2 detection, QQD not only identified HSO 3 −/SO 3 2− with a large Stokes shift (218 nm), low detection limit (1.87 μM), good selectivity, high energy transfer efficiency (92 %) and wide recognition range (1.87–200 μM), but also identified viscosity with a 26-fold fluorescence enhancement and good linearity. Crucially, QQD was applied to detect HSO 3 −/SO 3 2− and viscosity in actual water and food samples. In addition, QQD had low toxicity and good photostability for imaging HSO 3 −/SO 3 2− and viscosity in cells. These results confirmed the feasibility and reliability of QQD for HSO 3 −/SO 3 2− and viscosity imaging and environmental detection. We reported a unique ratiometric probe QQD for detecting HSO 3 −/SO 3 2− and viscosity based on the quinolinium skeleton. In addition to detecting HSO 3 −/SO 3 2− and viscosity change in actual water and food samples, QQD could also monitor the variations of HSO 3 −/SO 3 2− and viscosity in cells, which provided an experimental basis for further exploration of the role of SO 2 derivatives and viscosity in biological systems. [Display omitted] • A dual-function fluorescent probe was designed for detecting SO 2 and viscosity. • QQD had large Stokes shift of 218 nm and wide detection rang of 1.87–200 μM. • QQD showed high sensitivity and selectivity. • QQD achieved the dual colorimetric and ratiometric fluorescent strategy. • QQD achieved the application of foods, water samples and living cells. [ABSTRACT FROM AUTHOR]

Detecting and neutralizing Pd2+ ions are a significant challenge due to their cytotoxicity, even at low concentrations. To address this issue, various chemosensors have been designed for advanced detection systems, offering simplicity and the potential to differentiate signals from different analytes. Nonetheless, these chemosensors often suffer from limited emission response and complex synthesis procedures. As a result, the tracking and quantification of residual palladium in biological systems and environments remain challenging tasks, with only a few chemosensing probes available for commercial use. In this paper, a straightforward approach for the selective detection of Pd2+ ions is proposed, which involves the design, synthesis, and utilization of a propargylated naphthalene-derived probe (E)-N'-((2-(prop-2-yn-1-yloxy)naphthalen-1-yl)methylene)benzohydrazide (NHP). The NHP probe exhibits sensitive dual-channel colorimetry and fluorescence Pd2+ detection over other tested metal ions. The detection process is performed through a catalytic depropargylation reaction, followed by an excited state intramolecular proton transfer (ESIPT) process, the detection limit is as low as 11.58 × 10−7 M under mild conditions. Interestingly, the resultant chemodosimeter adduct (E)-N'-((2-hydroxynaphthalen-1-yl)methylene)benzohydrazide (NHH) was employed for the consecutive detection of CN− ions, exhibiting an impressive detection limit of 31.79 × 10−8 M. Validation of both detection processes was achieved through 1H nuclear magnetic resonance and density functional theory calculations. For real-time applications of the NHP and NHH probes, smartphone-assisted detection, and intracellular detection of Pd2+ and CN− ions within HeLa cells were studied. This research presents a novel naphthalene derivative for visually detecting environmentally toxic Pd2+ and CN− ions. The synthesized probe selectively binds to Pd2+, forming a chemodosimeter. It successfully detects CN− ions through colorimetry and fluorimetry, offering a low detection limit and quick response. Notably, it's the first naphthalene-based small molecule to serve as a dual probe for toxic analytes - palladium and cyanide. Moreover, it effectively detects Pd2+ and CN− intracellularly in cancer cells. [Display omitted] • Probe NHP selectively detects Pd2+ and forms chemodosimeter adduct NHH , showing a specific turn-on response to CN- ions. • The "off-on-off" ESIPT process led to the dual-channel detection of Pd2+ and CN− in an ethanol-H 2 O solution. • Consecutive detection, first of Pd2+ and then of CN-, showed naked-eye visibility, rapid response, and a low detection limit. • The study explored both on-site smartphone-based detection and intracellular detection of Pd2+ and CN- within HeLa cells. [ABSTRACT FROM AUTHOR]

[Display omitted] • Two rhodamine derivatives (L-Et and L-Pr) were developed without imine bond to avoid hydrolysis for Al3+ sensing with high selectivity. • There were significant increments in fluorescence at 555 nm and absorbance at 530 nm of with Al3+. • LOD values for Al3+ were determined ∼1.0 nM. • Both of these probes were used to image the cation in C6 cells. To address limitations like susceptibility to hydrolysis of an imine bond and low selectivity of rhodamine based chemosensors, we report here two rhodamine dyes, namely, L-Et i.e. 3′,6′-bis(ethylamino)-2′,7′-dimethyl-2-(2-morpholinoethyl)spiro[ isoindoline -1,9′- xanthen ]-3-one and L-Pr i.e. 3′,6′-bis(ethylamino)-2′,7′-dimethyl-2-(3-morpholinopropyl)spiro[ isoindoline -1,9′- xanthen ]-3-one for detection of Al3+ in 10 mM HEPES buffer in H 2 O/EtOH = 1:9 (v/v) (pH 7.4). Both the probes detect exclusively Al3+ among 16 different metal ions. The sensing ability has been achieved by noting color change (colorless to pink), increment in absorption intensity at 530 nm and fluorescence intensity at 555 nm. Opening of spirolactam ring of the chemosensors followed by complexation with Al3+ is responsible for such changes. A 1:1 complex is formed by both the probes with high association constant (1.14 × 105 M−1 for L-Et and 1.17 × 105 M−1 for L-Pr). The limit of detection values of L-Et and L-Pr towards Al3+ have been determined as 1.7 nM and 1.1 nM, respectively signifying very high sensitivity. These have been successfully applied in cell imaging studies in C6 cells. Introduction of a methylene group does not influence spectral properties vividly. As both the probes do not contain any imine bond, the possibility of hydrolysis in the presence of Al3+ has been avoided. [ABSTRACT FROM AUTHOR]

[Display omitted] In this study, we have developed an innovative pH-triggered nanomedicine delivery system, targeting HER2-positive breast cancer cells for effective low-cost, imaging-guided drug delivery and precise therapy. The key feature of this system lies in its unique tumor interstitial fluid microenvironment-responsive drug release behavior which achieved tumor site-specific drug delivery. Our in vitro experiments demonstrated that the carbon dot-integrated material achieves more efficient DTX release (96.13 % at 72 h) in the tumor interstitial fluid microenvironment (pH 6.5), thereby boosting drug concentration at the tumor site and enhancing therapeutic efficacy. Further cell experiments confirmed the system's significant inhibitory effect on HER2-positive tumor cells SKBR3 in a pH 6.5 environment, and apoptosis assays indicating a notable increase in early cell apoptosis (from 8.39 % to 24.61 % compared with pH 7.4). Furthermore, the integration of HER2 aptamer within the carbon dot-based system enables targeted recognition and binding to tumor cells, ensuring more precise delivery of DTX while minimizing potential side effects. Crucially, the carbon dots in this system emit superior red fluorescence (the QY = 47.64 % excited at 535 nm compared with Rodamine 6G), enabling real-time visualization of the drug delivery process. This feature provides valuable feedback on treatment effectiveness, facilitating necessary adjustments. The small size (1.88 ± 0.48 nm) of carbon dots significantly improved their ability to penetrate biological barriers, while their low toxicity (no significant cell toxicity under 350 μg/mL) contributed to the formulation's outstanding biocompatibility. Overall, this carbon dot-enhanced drug delivery system offers immense potential for enhancing drug efficacy, minimizing side effects, and providing real-time treatment monitoring, thus proposing a innovate strategy for breast cancer therapy. [ABSTRACT FROM AUTHOR]

[Display omitted] As essential subcellular organelles, lipid droplets (LDs) are involved in various the pathophysiological processes of metabolic diseases, including fatty liver and diabetes. Therefore, detecting LDs is conducive for studying the pathogeny and the early diagnosis of associated diseases. In this work, a series of fluorescent probes L1 - L3 based on triphenylamine derivatives were designed and synthesized for tracking LDs in living cells. Due to the different terminal moieties of the three probes, L1 and L3 are aggregation-induced emission (AIE)-active, while L2 is a dual-state emission (DSE) molecule. In addition, confocal cell imaging experiments showed that probes L1 - L3 specifically target intracellular LDs sites without the post washing. Importantly, probe L3 allows real-time monitoring of the dynamic processes and changes in the number of LDs. In summary, probe L3 is an ideal probe for studying LDs-related pathophysiological processes, and this work provides more ideas for the future design and synthesis of high-performance fluorescent probes for targeting LDs. [ABSTRACT FROM AUTHOR]

[Display omitted] • Plasmon-enhanced fluorescence-Raman scattering (PEF-SERS) sensors are reviewed. • Signal enhancement mechanisms for fluorescence/Raman probes are explained. • Construction strategies for plasmonic enhancement substrates are highlighted. • Several signal readout modes and advanced practical applications are overviewed. • The present challenges and perspectives are proposed. Plasmonic nanomaterials could improve various optical performance including fluorescence emission, Raman scattering, infrared absorption, etc. Among them, plasmon-enhanced fluorescence (PEF) can realize high-sensitivity sensing and super-resolution imaging quickly, but with inferior multiplexed detection capability. Surface-enhanced Raman scattering (SERS) can offer fingerprint-like spectra for multiplexing, but its imaging speed and resolution are limited. The PEF-SERS integrated sensors could congregate their individual strengths while overcoming inherent weaknesses. Specifically, they can use fluorescence signals to rapidly screen out "suspicious" locations within numerous samples or a broad area, and then conduct multi-peak SERS measurements there to gather more detailed information. Besides, cross-verification of PEF and SERS results is possible to realize self-correction. Hence, many existing issues could be addressed including sensitivity, accuracy, speed, and multiplexing. Attracted by these superior advantages, we review here the interaction between plasmonic nanomaterials and fluorescence/Raman probes to explain enhancement mechanisms, the construction strategies for plasmonic substrates with better PEF-SERS performance, different modes for transforming analyte's information into measurable optical signals, as well as the main application in substance research, disease diagnosis, cell imaging, drug delivery. We believe, a deeper understanding of the state-of-arts of multifunctional plasmonic platforms could provide a generic guideline for their future development and practical application. [ABSTRACT FROM AUTHOR]

Mercury (Hg) is one of the most widespread pollutants that pose serious threats to public health and the environment. People are inevitably exposed to Hg via different routes, such as respiration, dermal contact, drinking or diet. Hg poisoning could cause gingivitis, inflammation, vomiting and diarrhea, respiratory distress or even death. Especially during the developmental stage, there is considerable harm to the brain development of young children, causing serious symptoms such as intellectual disability and motor impairments, and delayed neural development. Therefore, it's of great significance to develop a specific, quick, practical and labor-saving assay for monitoring Hg2+. Herein, a mitochondria-targeted dual (excitation 700 nm and emission 728 nm) near-infrared (NIR) fluorescent probe JZ-1 was synthesized to detect Hg2+, which is a turn-on fluorescent probe designed based on the rhodamine fluorophore thiolactone, with advantages of swift response, great selectivity, and robust anti-interference capability. Cell fluorescence imaging results showed that JZ-1 could selectively target mitochondria in HeLa cells and monitor exogenous Hg2+. More importantly, JZ-1 has been successfully used to monitor gastrointestinal damage of acute mercury poisoning in a drug-induced mouse model, which provided a great method for sensing Hg species in living subjects, as well as for prenatal diagnosis. [Display omitted] • An activated probe JZ-1 for fluorescent detecion of Hg2+ was devised. • JZ-1 has dual NIR excitation and emission analysis wavelengths (both > 700 nm). • JZ-1 has a rapid response time and outstanding detection limit. • It was successfully used to in a drug-induced mouse of acute mercury poisoning. [ABSTRACT FROM AUTHOR]

[Display omitted] • A convenient approach to construct excimer emissive luminogens was established. • A double-bond linker between π-moiety and side-moiety is essential for AIE. • The structure-luminescence relationship was elucidated. • The high-resolution image of living Hela cells was observed. The excimer emission based on discrete π-stacked dimers of polycyclic π-systems has generated significant interest in the structure-luminescence relationship of excimers owing to their ultra-large Stokes shift. Herein, a series of excimer emissive luminogens were obtained by conjugating different polycyclic aromatic aldehydes (anthraldehyde, pyrenealdehyde and perylenealdehyde) with triphenylmethylamine. In crystalline states, all the molecules were arranged in the form of π-stacked arene dimers which were spatially isolated from each other by the bulky triphenylmethyl groups, and thus emitted bright excimer emission. The anthracene and pyrene derivatives showed fluorescence enhancement responses to grinding and the enhanced fluorescence could recover to the original state upon heating. The aggregation-induced emission (AIE) properties of them were dependent on the shapes and sizes of the polycyclic aromatic groups. The pyrene derivative showed the most excellent excimer-based AIE behavior among them. All of them were more apt to exhibit the excimer emission when formed nanoparticles with pluronic F-127 than that without pluronic F-127. Furthermore, PETP was utilized for bioimaging of living Hela cells and the high-resolution image was observed. [ABSTRACT FROM AUTHOR]

[Display omitted] • A novel NIR chemosensor BDDH based on isophorone was synthesized and characterized. • BDDH showed selectivity and sensitivity responses to Al3+ with fluorescence enhancement and color change. • The limit of detection (LOD) for Al3+ was reached the level of 10−8 M. • BDDH was applicated in identification of Al3+ in the different water samples. • BDDH was applicated in cell imaging in alive MCF-7 cells and plant imaging in soybean roots. In this paper, an isophorone-based NIR fluorescent and colormetric probe BDDH for Al3+ was synthesized and characterized, it showed highly selectivity and sensitivity through significant fluorescence enhancement and visible color change towards Al3+. The job plot confirmed that the binding ratio of BDDH with Al3+ was 1:1. Furthermore, the limit of detection (LOD) of Al3+ was determined to be 4.01 × 10−8 M. Moreover, BDDH was successfully applicated in identification of Al3+ in the different water samples, cell imaging in alive MCF-7 cells and plant imaging in soybean roots. [ABSTRACT FROM AUTHOR]

• Two thiazole-fused fluoran-based fluorescent probes for copper ions have been prepared. • The two probes show high selectivity and sensitivity for copper ions. • MTFH achieves red emission (632 nm) towards copper ions due to the methyl functionalization. • The two probes can be utilized for tracing intracellular copper ions. In this work, two thiazole-fused fluoran-based fluorescent probes 8′-(diethylamino)-2-((2-hydroxyethyl) amino)spiro[isoindoline-1,11′-xantheno[2, 1- d ]thiazol]-3-one (TFH) and (8′-(diethylamino)-2-((2-hydroxyethyl)amino)-3′-methyl-3-oxospiro[isoindoline-1,11′-xantheno[2,1- d ]thiazol]-3′-ium).BF 4 (MTFH) have been prepared for copper ions. It should be noted that MTFH achieves red emission (632 nm) compared with TFH in the presence of copper ion, which mainly can be attributed to the methylation of molecule MTFH that induced more stronger ICT effect. The two probes show selective fluorescence off-on signal changes towards copper ions with detection limits of 8.8 and 60.8 nM. Copper ion detection can be conducted in a wide pH range including the physiological pH environment. Both TFH and MTFH exhibit suitable cytotoxicity and have been used for copper ion tracing in living cells. However, no other significant improvements of MTFH in sensing performance can be observed when compared with TFH. Two thiazole-fused fluoran-based fluorescent probes have been prepared for selectively and sensitively sensing copper ions, in particular, the methyl functionalization probe achieves red emission mainly due to a stronger ICT effect. [Display omitted] [ABSTRACT FROM AUTHOR]

[Display omitted] • Nano gold functionalized ruthenium(III) complex of doxorubicin was prepared. • Particle size of Nano gold ruthenium(III)-DOX is less than 15 nm. • Anticancer activity of nano compound is higher against the cell lines. • Cell imaging of this complex is high fluorescence at 100 µg/mL. Metal-based drugs have attracted greater attention for cancer diseases because of biological relevance. However, some drawbacks are present in the metal complexes such as low stability and low bioavailability. Nanomaterials functionalized metal complexes can protect the stability and enhanced the bioavailability. In the present study, Nano gold functionalized ruthenium(III) complex from doxorubicin have been synthesized from ruthenium(III) complex and characterized using various spectrochemical techniques such as IR, UV, and NMR. In the metal complex, Doxorubicin (DOX) acts as a monobasic bidentate ligand and is coordinated through the carbonyl oxygen and phenolate oxygen of the anthracene ring. Based on spectral evidences, the complex [Ru(DOX)(PPh 3) 2 Cl 2 ] has an octahedral geometry. The Nano Au-Ru(III) DOX is analysed for their size, and morphology using XRD, SEM and HRTEM. X-ray diffraction pattern revealed that the complex has nanocrystalline in nature. The Nano Au-Ru(III) DOX is spherical shape and particle size is less than 15 nm. The DNA cleavage activity of [Ru(DOX)(PPh 3) 2 Cl 2 ] and Nano Au-Ru(III) DOX has been evaluated using pUC18 plasmid DNA and the results showed significant cleavage. The [Ru(DOX)(PPh 3) 2 Cl 2 ] and Nano Au-Ru(III) DOX have been tested against human breast cancer (MCF-7) and leukemia cancer cell lines (K-562) in vitro for its antitumor effects. The tumour activity of the Nano Au-Ru(III) DOX showed more promising activity than the [Ru(DOX)(PPh 3) 2 Cl 2 ]. The cell imaging of the Nano Au-Ru(III) DOX was examined against epithelial human breast cancer cell line (MDA-MB-231) using fluorescent microscopy. The fluorescence images showed high scattering light in tumour tissue at 100 µg/mL Hence, Nano Au-Ru(III) DOX can serve as a promising drug for cancer therapy and cellular imaging. [ABSTRACT FROM AUTHOR]

• CM exhibit "Turn-On" blue fluorescence response for Ca2+ in solution, which is free from interference of co-existing cations. • "Tyndall Effect" can be observed during chelation, blue emissive nanowires induced by aggregation were investigated. • The molecular docking result reveals CM can bind with receptor 1A of melatonin via hydrogen bond. • CM and its Ca2+ complex shows good cell permeability and low cytotoxicity, their localization in organelle were studied. Due to a physiological significant role of calcium ion, it is essential to develop ways of detecting and monitor the level of Ca2+ ions in living cell. Herein, we rationally designed and synthesized a functional blue fluorescent compound CM based on amide condensation of coumarin and melatonin. Interestingly, it could exhibit an "On-OFF" fluorescence response for Ca2+ in an aqueous environment with 80-fold enhancement in bright blue emission, which is also free from interference of other co-existing cations of high concentration. A detection limit of 0.28 ppm was obtained, and the binding ratio of CM and Ca2+ is further investigated by Job's plot. After coordination of CM with calcium ion, a significant "Tyndall Effect" can be observed, and blue emissive nanowires induced by aggregation of complex of CM and Ca2+ were further investigated by Dynamic Light Scattering, analysis of Zeta potential, and confocal imaging. The molecular docking of CM with melatonin receptor 1A is also conducted. MTT assay reveals that CM ligand and the corresponding Ca2+ complex are non-cytotoxic. Moreover, CM shows good membrane permeability, and the relative cellular uptake mechanism is mainly dominated by an energy-dependent process. CM and its complex of Ca2+ can be further used as intracellular luminescent imaging probes and their localization in cell organelles is also revealed. [ABSTRACT FROM AUTHOR]

To study the collaboration between lipid droplets (LDs) and lysosomes, and the lipid change in nonalcoholic fatty liver disease (NAFLD), herein two pH-triggered hydrophility-adjustable fluorescent probes (LD-Lyso and LD-Lyso 1) are designed. The mechanism is based on cyclization and ring-opening with thorough consideration of pH and hydrophilic differences between LDs and lysosomes. Both of the two probes exist in ring-opening form and emit red fluorescence in acidic environment, while they exist in cyclized form and the emission is blueshifted in alkaline environment due to reduced conjugate planes. Moreover, LD-Lyso exhibits near infrared fluorescence at 740 nm under ring-opening form, which facilitates further cell, tissue, and in vivo imaging. The cell imaging results show that LD-Lyso can simultaneously target LDs and lysosomes by two different colors. Impressively, LD-Lyso cannot only detect NAFLD tissues from the normal tissue, but also distinguish different degrees of NAFLD tissues and mice, which provides a very promising tool for timely diagnosis of early NAFLD. [Display omitted] [ABSTRACT FROM AUTHOR]

Mitophagy is a critical cellular self-protective mechanism involving the degradation and recycling of damaged or excessive mitochondria, which has been implicated in various diseases. In our study, we designed and synthesized two phenothiazine-based fluorescent probes, DPTZ and CMDP , specifically targeting mitochondria and lysosomes, respectively, to investigate mitophagy. H 2 S, a cell-protective agent, was chosen as the target molecule for both probes. Our findings demonstrate the selective localization of DPTZ to mitochondria and CMDP to lysosomes. Both probes exhibited rapid, selective, and highly sensitive recognition of H 2 S, enabling imaging of exogenous and endogenous H 2 S. By employing split-targeting and simultaneous detection, we were able to monitor changes in H 2 S levels in mitochondria and lysosomes, providing dynamic and visual imaging of the mitophagy processes. Upregulation of mitochondrial and lysosomal H 2 S was observed during mitochondrial autophagy. This work introduces valuable research methods and tools for investigating mitophagy, thereby enhancing our understanding of the molecular mechanisms underlying this process. [Display omitted] • Phenothiazine-based probes DPTZ and CMDP detect hydrogen sulfide. • DPTZ and CMDP target mitochondria and lysosomes for imaging in A549 cells. • Split-targeting and detection strategy reveals hydrogen sulfide fluctuations in autophagy. [ABSTRACT FROM AUTHOR]

[Display omitted] • Characterization of cresyl violet fluorescence in plant cells. • Cresyl violet can be used to distinguish acidic endosomes and vacuoles. • Cresyl violet is more reliable to maps endosomes populations in plant leaf and root cells. • Cresyl violet in plant cells is highly photostable and is devoid of cytotoxic properties. The advent of fluorescent probes and the characterization of their photochemical properties in the past years allowed significant advances in the studies of spatiotemporal cellular processes within complex and crowded systems. Dyes are indeed extremely useful tools for the visualization of cellular and subcellular structures present in living cells, as well as to study their dynamic and molecular composition or physiological changes. There are some areas of plant cell biology that have been more challenging to explore due to the physiology and organization of certain endomembrane compartments. In this study we characterize the labeling properties of cresyl violet as quick and inexpensive imaging agent for tracking endosomes, vacuole compartments which are usually very differentiated and categorized as more acidic as well as acidic plant compartments. Its photobleaching, labelling and cytotoxic properties are compared with other well-known and currently most used synthetic and molecular probes. [ABSTRACT FROM AUTHOR]

[Display omitted] • A new fluorescent chemosensor (SDAF) was developed for Al3+. • The SDAF has an ultralow detection limit (28 nM) and fast response time. • DFT studies were strongly confirmed the spectroscopy results. • The SDAF was successfully used to detect Al3+ in water samples, test-kits and living cells. A new fluorescent chemoprobe (SDAF) was successfully synthesized and utilized as a sensor for the recognition of Al3+ in EtOH:HEPES (3:2, v:v, pH: 7.0) media. The SDAF depicted a selective "turn–on" response at λ em = 467 nm to Al3+ over competitive cations, and the SDAF– Al3+ complex had a reversible response with F−. The limit of detection (LOD) was found about at nano–molar level (28.0 nM), demonstrating the sensitivity of the chemoprobe toward Al3+. The binding stoichiometry of SDAF –Al3+ was investigated by TOF–MS, Job's plot, 1H NMR and 13C NMR methods and found as 1:1. The recognition mechanisms of SDAF for the detection of Al3+ were the –C = N isomerization and photoinduced electron transfer (PET) mechanisms, and they were confirmed by density functional theory (DFT) computation. Furthermore, the SDAF was successfully employed in living–cell bioimaging and cytotoxicity, it was also utilized in Smartphone, test–kit and natural spring water (recovery values; 89.01 %– 96.33 %)applications. [ABSTRACT FROM AUTHOR]

[Display omitted] • The crystal structure of π–π stacking of red carbon nanosheets, and enhance the fluorescence properties of red carbon in aggregation state. • The fluorescence of red carbon can be quenched by the Fe3+ and recovered by ethylene diamine tetraacetic acid. • The red carbon can detect the Fe3+ with highly sensitive, rapid response, and anti-interference and cellular imaging. The subcarboxylated carbon (C 3 O 2) is a unique molecule that spontaneously polymerizes into highly conjugated fluorescence structures p(C 3 O 2) n , named "red carbon". This unique property, combined with its role as aggregation-induced emission luminogens, has allowed for a deeper exploration of their emission mechanism. Herein, both density functional theory calculations and experimental approaches to elucidate the crystal structure of π–π stacking in red carbon, thereby enhancing the fluorescence properties of p(C 3 O 2) n polymer in its aggregated state. The time-dependent density functional theory calculations and experimental observations indicate that the fluorescence of red carbon can be quenched by ferric ions (Fe3+) and subsequently restored by ethylenediaminetetraaceticacid (EDTA). This quenching process follows first-order reaction kinetics. On the basis of the coordination to metal ions from abundant heteroatoms on red carbon, the high sensitivity, quick responsive (1 min), sensitive detection (the lowest detection limit is 0.97 μM) for the Fe3+ were realized in red carbon, which provides inspirations for the design of new turn-on probes with high stability in detecting the Fe3+ in aqueous solution. Crucially, the red carbon as a light-up fluorescence probe can be employed for the Fe3+ sensing in living cells, which enlighten a new perspective for designing non-conjugated fluorescent polymers. This innovative approach opens up new avenues for developing probes that can detect Fe3+ with high precision and reliability in complex biological environments. [ABSTRACT FROM AUTHOR]

[Display omitted] • A framework nucleic acids (FNAs) fluorescent nanoprobe was constructed. • The detection of multiple DNA repair enzymes in living cells was realized. • This method exhibits good selectivity and high sensitivity. • The FNAs enter the cell autonomously and image UDG and APE1. DNA repair enzymes play pivotal roles in DNA damage repair. Imaging multiple DNA repair enzymes in living cells is significant for DNA damage repair-related biological study and disease diagnosis. Here, we constructed a framework nucleic acids (FNAs) fluorescent nanoprobe for imaging multiple DNA repair enzymes in living cells. Uracil DNA glycosylase (UDG) and human apurinic/apyrimidinic endonuclease 1 (APE1) were used as the target analytes. Two double-stranded DNA probes (dsDNA1 and dsDNA2) were designed. dsDNA1 contained four uracil (U) bases for UDG recognition and was labeled with black hole quencher2 (BHQ2) /cyanine5 (Cy5). dsDNA2 contained one apurinic/apyrimidinic (AP) site for APE1 recognition and was labeled with black hole quencher1 (BHQ1) /fluorophore carboxyfluorescein (FAM). To obtain the FNAs fluorescent nanoprobe, dsDNA1 and dsDNA2 were attached to two vertices of a DNA tetrahedron (a type of FNAs). Under the action of UDG and APE1, dsDNA1 and dsDNA2 were both dissociated, generating fluorescence of Cy5 and FAM. Among them, Cy5 indicated the activity of UDG and FAM indicated the activity of APE1. This method had good sensitivity to UDG and APE1, and the detection limits were 0.0012 U/mL and 0.057 U/mL, respectively. This method also exhibited high selectivity for UDG and APE1. When the FNAs fluorescent nanoprobe was endocytosed, it had little toxicity to normal and cancer cells. Furthermore, this method successfully achieved multiple imaging UDG and APE1 in cancer cells. This study provides a novel strategy for imaging multiple DNA repair enzymes and holds great potential in biological applications and clinical diagnosis. [ABSTRACT FROM AUTHOR]

[Display omitted] • Cyanide exhibits a dual nature, serving as an industrial asset and causing an environmental threat. • The focus on cyanide detection increases as micromolar cyanide levels create fatal risks. • Colorimetric and fluorescent chemosensors offer quick, affordable, and portable detection of cyanide. • This review highlights colorimetric and fluorescent probes' significance in monitoring cyanide ions. • The survey was executed utilizing published reports from 2021 to 2023. Anions, specifically cyanide, occupy crucial roles in various biological, physiological, and industrial contexts. While cyanide is indispensable as a raw material in the synthesis of herbicides, resins, synthetic fibers, and the gold-extraction process, its widespread presence causes a significant threat to both environmental and social systems. Cyanide abundance in the environment arises not just from industrial effluents but also from the natural biological processes of fungi and algae. The dual nature of cyanide, serving both as a useful industrial component and a potential environmental hazard, highlights the importance of responsible management and regulation in its production and application. The detection of cyanide has become a matter of paramount importance due to its extreme toxicity and potential environmental contamination, where even micromolar levels can prove fatal to humans. In addressing this critical concern, researchers have focused on developing simple, inexpensive, and rapid detection methods, with chemosensors emerging as among the most promising solutions. These chemosensors rely on colorimetric and fluorometric responses, offering a synergistic combination that enhances the versatility of cyanide detection methodologies. Through novel design and synthesis, researchers have constructed a diverse range of chemosensors with tailored properties, such as high selectivity, low detection limits, and rapid response times. Especially, efforts have been directed towards making these detection systems portable and user-friendly, facilitating their practical implementation in real-world scenarios. This comprehensive review provides a focused examination of colorimetric and fluorescent probes designed for the specific and sensitive recognition of cyanide anions. Emphasizing their applicability in on-site portable strips and cellular imaging, the review aims to enhance readers' understanding of the critical need for monitoring cyanide ions in the context of human health and disease. The discussed probes are categorized into various classes, including small molecules, metal complexes, metal–organic frameworks (MOFs), macrocyclic compounds, nanomaterials, and polymer-based probes, each classified based on their structural properties and functional groups. Encompassing advancements made in the field from 2021 to 2023, the review underscores the progress achieved in developing these probes. Finally, the review addresses the potential future applications of colorimetric and fluorescent probes in detecting cyanide ions, pointing towards the evolving landscape of analytical techniques and their significance in advancing our ability to monitor cyanide levels effectively. [ABSTRACT FROM AUTHOR]