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A novel supramolecular system based on calix[4]arene linked with rhodamine B was designed and synthesized, incorporating different alkoxy side chains. All four supramolecular compounds (3a–3d) synthesized using this approach exhibited nematic-type liquid crystalline properties. Detailed analyses using polarizing optical microscopy, differential scanning calorimetry, the X-ray diffraction technique, and thermogravimetry were performed to investigate the microscopic, molecular arrangement pattern, and thermal behavior of the compounds. The well-known Schlieren and threaded-type texture pattern was observed in all four bi-substituted calixarene derivatives. They displayed unique texture patterns supporting the idea of a well-organized supramolecular structure. Additionally, these materials demonstrated enantiotropy-type mesophase with a wide temperature range and good thermal stability. Notably, they exhibited light-emitting properties in both solution and solid thin film states, showing the intriguing aggregation-induced emission effect. All four compounds adopted a cone conformation with two side substitution on the calix[4]arene rigid core. Compound 3c was utilized to stain nematode samples using a solution-state aggregation approach. The fluorescent supramolecule effectively allowed visualization and tracking of the staining patterns within the nematode organisms. This methodology enabled the examination of cellular and subcellular structures, further offering valuable insights into the behavior and morphology of nematodes. [ABSTRACT FROM AUTHOR]

PEGylated 2-(2-(6-(dimethylamino)benzooxazol-2-yl)vinyl)quinolin-8-ol (BQ-mPEG) was synthesized, which exhibited strong fluorescence at 610 nm (φf = 0.11) and a large Stoke's shift (Δλ = 202 nm) in the aqueous solution. The fluorophore displayed a two-photon absorption characteristic and a strong red emission (λem = 625 nm) was observed with NIR (950 nm) irradiation. The feasibility of using BQ-mPEG as a fluorescent imaging reagent suggested that the fluorophore targets mitochondria, and with 950 nm excitation, bright fluorescence images in HeLa live cells were observed. Furthermore, the fluorophore exhibited some advantages of high photostability and pH stability, as well as low cytotoxicity. [ABSTRACT FROM AUTHOR]

In this paper, nitrogen-doped carbon dots (NCDs) were synthesized via a facile hydrothermal method using gum arabic (GA) and tris(hydroxymethyl)methyl aminomethane (tris) as precursors. The resultant NCDs show uniform size distribution and stable optical performance. Then a fluorescent signal quenching probe based on NCDs was proposed for the quantitative detection of mercury ions (Hg2+). The developed fluorescent nanoprobe based on NCDs demonstrated a good linear relationship in the range of 10 to 120 μM (R² = 0.99265) for toxic mercury(II), with a detection limit of 4.87 μM. Additionally, the present assay system could be efficiently used for the detection of Hg2+ in real water samples with a satisfactory recovery rate (96.11-104.04%). The metal-free NCDs, which exhibited little cytotoxicity, were successfully applied to in vitro fluorescence imaging of human triple negative breast cancer (TNBC) cells, achieving visualization of Hg2+ in cells. With good water solubility and biocompatibility, the nitrogen-doped carbon dots synthesized by this economical and ecologically friendly process are suitable for use in analytical testing and biological research. [ABSTRACT FROM AUTHOR]

Traditional chemotherapy faces challenges related to limited drug efficacy and adverse reactions. Intelligent nanocarrier drug delivery systems (INDDSs) promise improved treatment outcomes with reduced toxicity. However, several clinical challenges persist in achieving rapid drug release and real-time monitoring. Herein, a ROS-responsive amphiphilic copolymer was synthesized: polyethylene glycol (mPEG-TK-OH) with ROS-responsive thioketal (TK) as the macromolecular initiator, and enzymatic ring-opening polymerization of caprolactone was performed. Small molecules of tetraphenylethylene (TPE) with aggregation-induced emission (AIE) properties were added to the polymer's terminus to enable fluorescence imaging and the ROS-responsive amphiphilic copolymer mPEG-TK-PCL-TPE with AIE properties is formed and enhances drug release monitoring through fluorescence resonance energy transfer (FRET) between TPE and the hydrophobic anti-cancer drug DOX. Leveraging distinct ROS levels between tumor and normal cells, these ROS-responsive nanomicelles effectively respond to high intracellular redox-active species and release DOX. The mPEG-TK-PCL-TPE micelles displayed a suitable size, high drug loading, and excellent imaging quality. In vitro cell experiments confirmed their biocompatibility and efficacy in inhibiting 4T1 tumor cells. This ROS-responsive amphiphilic copolymer, incorporating the AIE structure, introduces new opportunities for cancer treatment, enabling real-time drug release tracking and improving therapeutic outcomes. [ABSTRACT FROM AUTHOR]

This study focuses on the use of carbon quantum dots (CQDs) from Syzygium cumini seeds prepared through hydrothermal synthesis for anti-oxidant, bioimaging, and anti-neoplastic activities. Syzygium cumini seeds were incorporated with various biomass-sourced precursors to enhance their physicochemical properties, and doping of folic acid was performed to create surface passivated folate receptors for better anti-neoplastic activity exhibiting minimal toxicity, excellent biocompatibility, outstanding luminosity, and optical features. The concentration of CQDs required to inhibit the proliferation of cells by 50% (at 500 μg mL−1 concentration) was calculated by applying the dose–response curve applied to the HeLa cell line, and the conclusion was computed by means of an augmented mimicking approach, leading to roughly identical inhibition by folic acid doped S. cumini seeds (40.926%) and doxorubicin (DOX) (43.39%) justifying better anti-neoplastic activity. The anti-oxidant potency of the prepared CQDs was assessed to be exceedingly excellent, with an index of up to 98.99%, implying resilient surface passivation. CQDs utilized for in vitro photoluminescence and live cell imaging of S. cerevisiae displayed green and blue fluorescence images with stabilized luminescence with extraordinary quantum yield (50.74%). [ABSTRACT FROM AUTHOR]

When designing sensors for optoelectronic devices, fluorescent materials are always the choice of material chemists. Among the existing fluorescent molecules, the most widely used sensing materials are colloidal nanocrystals, which are classified as quantum dots (QDs). Photoluminescence and tuning of the band gap are the two domains that are explored while engineering optically active crystals. The selection of dopants in a host lattice is the initial step towards achieving the material of choice and designing tailor-made stable materials. Among various QD materials, doped ZnS quantum dots have emerged as a fascinating class, showcasing distinctive characteristics resulting from both transition and non-transition metal doping. This work reviews recent developments in the synthesis, structural characterization, and applications of transition and non-transition metal-doped ZnS quantum dots. Transition metal doping, involving elements such as Mn, Co, and Cu, imparts remarkable photoluminescence properties to QDs, rendering them suitable for optoelectronic devices, such as light-emitting diodes and displays. Non-transition metal doping, involving elements such as Al, Mg, and Ga, facilitates bandgap engineering, paving the way for enhanced light absorption and utilization in photovoltaics and photocatalysis. Transition and non-transition metal-doped ZnS quantum dots exhibit diverse applications across multiple domains. In the field of biomedicine, their biocompatibility, tunable fluorescence, and ability to generate reactive oxygen species under light irradiation present opportunities for cellular imaging and photodynamic therapy. Moreover, their integration into composite materials holds the potential for enhanced electronic and optoelectronic device performance. Challenges in this field include achieving precise control over dopant concentrations, uniformity, and stability, while also addressing scalability issues for large-scale production. Future directions include exploring novel doping strategies, co-doping schemes, and surface functionalization techniques to further enhance the properties of doped ZnS quantum dots. In conclusion, transition and non-transition metal-doped zinc sulphide quantum dots showcase a realm of exciting possibilities for technological innovation. Their unique properties, enabled by judicious dopant incorporation, make them valuable materials for applications spanning optoelectronics, energy conversion, and biomedical sciences. As research in this field advances, these doped quantum dots are poised to significantly contribute to the progression of next-generation technologies. [ABSTRACT FROM AUTHOR]

Here, we report the design and synthesis of a Schiff base probe, DBNHC ((E)-2-(2,4-dihydroxybenzylidene)-N-(naphthalen-1-yl)hydrazine-1-carbothioamide), and its interaction with bovine serum albumin (BSA). In ∼100% PBS buffer, the probe DBNHC can self-assemble into nonfluorescent nanoaggregates due to the aggregation caused quenching (ACQ) effect. However, it becomes highly fluorescent (∼14 fold) in the presence of BSA which facilitates the disassembly of nanoaggregates into its monomer. The site-selective fluorescence displacement assay and molecular docking simulations reveal that mainly hydrogen bonding, π⋯sulphur and π⋯alkyl interactions are responsible for the disassembly of nanoaggregates leading to encapsulation of DBNHC monomer at site II in BSA, resulting in a cyan green emission. The detection limit determined by the 3σ/slope method was found to be 58 nM, and the lower dissociation constant [Kd = (1.506 ± 0.196) μM] value suggests strong binding between the probe and BSA. Further, DBNHC was used for cell incubation and in vitro fluorescence imaging of BSA. [ABSTRACT FROM AUTHOR]