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This study investigates the effect of chloride levels on the mode of action of palladium complexes for the activation of propargyl- and allene-protected fluorophores and chemotherapeutic drugs through uncaging reactions. Four Pd(II) complexes were synthesized and characterized using various spectroscopic techniques to confirm their structure and electronic properties. Kinetic studies and density functional theory calculations revealed that chloride ions in phosphate buffered saline (PBS) significantly enhance catalytic efficiency, particularly for allenyl-protected substrates compared to propargylic counterparts. This enhancement is attributed to the neutral charge nature of the Pd complex. The data suggest that neutral complexes are less prone to chloride exchange by water molecules. Additionally, chloride ligands counterbalance the unusually high stability of the key σ-bound η 1 -Pd intermediates in the aquo complexes in PB, leading to an overall higher reactivity. These results highlight the impact of fine-tuning the electronic properties of the metal center through both designed ligands and environmental factors. Bench evaluations and tests with living breast cancer cells demonstrated that a Pd catalyst complex with a bidentate ligand effectively activates the prodrugs propargyl-5-fluorouracil (Prop-5FU) and allene-5-Fluorouracil (Alle-5FU), the latter being a novel prodrug. The Pd catalyst successfully released the active drug, inducing significant cytotoxicity, especially with Alle-5FU, which operates at lower catalyst concentrations than Pro-5FU., (© 2024 Wiley-VCH GmbH.)

Cancer is a leading cause of death worldwide. Glioblastoma (GBM) is a major challenge in oncology due to its highly invasive nature and limited treatment options. GBM's aggressive migration beyond tumor margins and rapid tumor growth hinders success in patient treatment. Localized therapeutic delivery, such as the use of transition metals like copper, is highlighted as a novel therapeutic agent for many potential biomedical applications. Herein, it is aimed to study the effects of Cu release on the proliferation and invasiveness of cancer cells. To this end, novel copper‐based nanostructures with different release patterns are designed. Using a complex 3D cell culture model to mimic the tumor microenvironment, it is shown that different patterns of copper ion release have a strong impact on GBM progression and invasiveness. The findings highlight the importance of optimizing localized copper release patterns to tailor different tumor treatment strategies. They also show the potential and suitability of 3D microchips as instruments to study the behavior of tumor spheroids. In spite of their limitations, these 3D microdevices enable a controlled and close monitoring of the influence of environmental factors (such as the presence of Cu ions) on the proliferation and invasiveness of the cells, with a better approach to reality compared to 2D models and with a more controlled environment, compared to an in vivo model. [ABSTRACT FROM AUTHOR]

Bioorthogonal chemistry has inspired a new subarea of chemistry providing a powerful tool to perform novel biocompatible chemospecific reactions in living systems. Following the premise that they do not interfere with biological functions, bioorthogonal reactions are increasingly applied in biomedical research, particularly with respect to genetic encoding systems, fluorogenic reactions for bioimaging, and cancer therapy. This Minireview compiles recent advances in the use of heterogeneous catalysts for bioorthogonal reactions. The synthetic strategies of Pd-, Au-, and Cu-based materials, their applicability in the activation of caged fluorophores and prodrugs, and the possibilities of using external stimuli to release therapeutic substances at a specific location in a diseased tissue are discussed. Finally, we highlight frontiers in the field, identifying challenges, and propose directions for future development in this emerging field., (© 2022 The Authors. Angewandte Chemie International Edition published by Wiley-VCH GmbH.)

The copper-catalyzed azide-alkyne cycloaddition (CuAAC) has heralded a new era of chemical biology and biomedicine. However, caveats of the CuAAC include formation of reactive oxygen species (ROS) and other copper-related toxicity. This limits utility in sensitive biological samples and matrices. Towards addressing these caveats, we synthesized and fully characterized two air and water stable trinuclear Cu(I) dimer complexes. The complexes were stable to oxidation in the presence of hydrogen peroxideand other chelators, which was reasoned to be due to the linear benzimidazole-Cu-benzimidazole geometry. Computational investigations of the catalytic cycle implicated two of the three coppers in the trimer complex as the active metal centers. The complexes were shown to catalyze the reaction at far below sub-toxic concentrations for intracellular click reactions to label triple negative breast cancer cells and compared to the current CuSO 4 -THPTA standard., (© 2024 Wiley-VCH GmbH.)

The field of bioorthogonal chemistry has revolutionized our ability to interrogate and manipulate biological systems at the molecular level. However, the range of chemical reactions that can operate efficiently in biological environments without interfering with the native cellular machinery, remains limited. In this context, the rapidly growing area of photocatalysis offers a promising avenue for developing new type of bioorthogonal tools. The inherent mildness, tunability, chemoselectivity, and external controllability of photocatalytic transformations make them particularly well-suited for applications in biological and living systems. This minireview summarizes recent advances in bioorthogonal photocatalytic technologies, with a particular focus on their potential to enable the selective generation of designed products within biologically relevant or living settings., (© 2024 The Authors. Angewandte Chemie International Edition published by Wiley-VCH GmbH.)

The term "in vivo ("in the living") chemistry" refers to chemical reactions that take place in a complex living system such as cells, tissue, body liquids, or even in an entire organism. In contrast, reactions that occur generally outside living organisms in an artificial environment (e.g., in a test tube) are referred to as in vitro. Over the past decades, significant contributions have been made in this rapidly growing field of in vivo chemistry, but it is still not fully understood, which transformations proceed efficiently without the formation of by‐products or how product formation in such complex environments can be characterized. Potential applications can be imagined that synthesize drug molecules directly within the cell or confer new cellular functions through controlled chemical transformations that will improve the understanding of living systems and develop new therapeutic strategies. The guiding principles of this contribution are twofold: 1) Which chemical reactions can be translated from the laboratory to the living system? 2) Which characterization methods are suitable for studying reactions and structure formation in complex living environments? [ABSTRACT FROM AUTHOR]

Graphene quantum dots (GQDs) possess potential properties for the targeted transport and tracking of anticancer medication to tumor cells. For this purpose, the synthesized GQDs were decorated with folic acid (FA) and methoxy polyethylene glycol (mPEG2000), and finally loaded with tamoxifen (TMX) drug. The synthesized nano‐drug was characterized using FTIR, XRD, UV‐Vis, PL, HRTEM, FESEM, and DLS analytical devices. Based on the obtained data, the average hydrodynamic diameter of particles dissolved in water was 294.7 nm and the size of dehydrated particles was between 53 and 210 nm. PL data showed that prepared nanoparticles have an emission wavelength of 438 nm, which is in the blue fluorescent wavelength range, thus making these nanoparticles suitable for cell imaging. The encapsulation efficiency and loading percentage of tamoxifen in nanoparticles were calculated at about 52.5 % and 30 %, respectively, and cumulative drug release reached 89 % within 42 hours. The cytotoxicity effects of nanoparticles were investigated. According to IC50 results, the targeted mPEG‐GQDs‐FA/TMX (TMX‐FPGs) nano‐drug was more toxic than free TMX on MCF‐7 cells and had reduced side effects on healthy HDF cells. TMX‐FPGs induced apoptosis cell death, significantly. The confocal imaging experiments showed that TMX‐FPGs are appropriate for monitoring and targeting MCF‐7 cells. [ABSTRACT FROM AUTHOR]

Soft hydrated permeable surfaces of hydrogels exhibit unique lubrication behaviors, including frictional hysteresis found in tribo-rheometry measurements. A hydrogel lubrication model that describes the transient behavior was previously developed using the structure kinetics model in the field of rheology and rate-and-state friction model, where the friction change is described as a competition between buildup and breakdown rates. In this study, the model is further modified to include the effect of hydrophilicity of a countersurface. Ultraviolet (UV)/ozone treatment on an aluminum surface significantly removes organic materials, resulting in extremely hydrophilic surface. Friction response of a polyacrylamide hydrogel against untreated and UV/ozone-treated aluminum exhibited noteworthy difference in the trajectory of hysteresis. Model fits were conducted using the modified lubrication model on both hystereses, and the fitting parameters of both hystereses are compared with each other to identify a parameter addressing hydrophilicity. Based on the model fits, we suggest that the hydrophilicity of the countersurface initially prevents the adsorption on the hydrogel surface because it holds water better. However, once water goes out of the contact due to contact pressure, a stronger adsorption occurs, which increases friction and decreases the speed dependence of friction. [ABSTRACT FROM AUTHOR]

Prodrugs have emerged as a major strategy for addressing clinical challenges by improving drug pharmacokinetics, reducing toxicity, and enhancing treatment efficacy. The emergence of new bioorthogonal chemistry has greatly facilitated the development of prodrug strategies, enabling their activation through chemical and physical stimuli. This "on-demand" activation using bioorthogonal chemistry has revolutionized the research and development of prodrugs. Consequently, prodrug activation has garnered significant attention and emerged as an exciting field of translational research. This review summarizes the latest advancements in prodrug activation by utilizing bioorthogonal chemistry and mainly focuses on the activation of small-molecule prodrugs and antibody–drug conjugates. In addition, this review also discusses the opportunities and challenges of translating these advancements into clinical practice. [ABSTRACT FROM AUTHOR]

Bioorthogonal reactions that enable switching molecular functions by breaking chemical bonds have gained prominence, with the tetrazine-mediated cleavage of trans-cyclooctene caged compounds (click-to-release) being particularly noteworthy for its high versatility, biocompatibility, and fast reaction rates. Despite several recent advances, the development of highly reactive tetrazines enabling quantitative elimination from trans-cyclooctene linkers remains challenging. In this study, we present the synthesis and application of sulfo-tetrazines, a class of derivatives featuring phenolic hydroxyl groups with increased acidity constants (pK a ). This unique property leads to accelerated elimination and complete release of the caged molecules within minutes. Moreover, the inclusion of sulfonate groups provides a valuable synthetic handle, enabling further derivatization into sulfonamides, modified with diverse substituents. Significantly, we demonstrate the utility of sulfo-tetrazines in efficiently activating fluorogenic compounds and prodrugs in living cells, offering exciting prospects for their application in bioorthogonal chemistry., (© 2024 The Authors. Angewandte Chemie International Edition published by Wiley-VCH GmbH.)

Despite the promise of activatable chemotherapy, the development of a spatiotemporally controllable strategy for prodrug activation in deep tissues remains challenging. Herein, a proof-of-concept is proposed for a gold nanocluster-based strategy that utilizes X-ray irradiation to trigger the liberation of platinum (Pt)-based prodrug conjugates, thus enabling radiotherapy-directed chemotherapy. Mechanistically, the irradiated activation of prodrugs is achieved through direct photoelectron transfer from the excited-state gold nanoclusters to the Pt(IV) center, resulting in the release of cytotoxic Pt(II) agents. Compared to the traditional combination of chemotherapy and radiotherapy, this radiotherapy-directed chemotherapy strategy offers superior antitumor efficacy and safety benefits through spatiotemporal synergy at the tumor site. Additionally, this strategy elicits robust immunogenic cell death and yields profound outcomes for combined immunotherapy of breast cancer. This versatile strategy is ushering in a new era of radiation-mediated chemistry for controlled drug delivery and the precise regulation of biological processes., (© 2024 Wiley‐VCH GmbH.)

Chemotherapy is crucial in oncology for combating malignant tumors but often encounters obatacles such as severe adverse effects, drug resistance, and biocompatibility issues. The advantages of degradable silica nanoparticles in tumor diagnosis and treatment lie in their ability to target drug delivery, minimizing toxicity to normal tissues while enhancing therapeutic efficacy. Moreover, their responsiveness to both endogenous and exogenous stimuli opens up new possibilities for integrating multiple treatment modalities. This review scrutinizes the burgeoning utility of degradable silica nanoparticles in combination with chemotherapy and other treatment modalities. Commencing the elucidation of degradable silica synthesis and degradation mechanisms, emphasis is placed on the responsiveness of these materials to endogenous (e.g., pH, redox reactions, hypoxia, and enzymes) and exogenous stimuli (e.g., light and high-intensity focused ultrasound). Moreover, this exploration delves into strategies harnessing degradable silica nanoparticles in chemotherapy alone, coupled with radiotherapy, photothermal therapy, photodynamic therapy, gas therapy, immunotherapy, starvation therapy, and chemodynamic therapy, elucidating multimodal synergies. Concluding with an assessment of advances, challenges, and constraints in oncology, despite hurdles, future investigations are anticipated to augment the role of degradable silica in cancer therapy. These insights can serve as a compass for devising more efficacious combined tumor treatment strategies., (© 2024 Wiley‐VCH GmbH.)

Semiconductor photocatalysis has become an increasing area of interest for use in water treatment methods. This review systematically presents the recent developments of emerging semiconductor photocatalysis system and their application in the removal of water pollutants. A brief overview of the semiconductor photocatalysis mechanism involved with the generation of reactive oxygen species (ROS) is provided first. Then a detailed explanation of the development of TiO2-based, g-C3N4-based, and bismuth-based semiconductor materials and their applications in the degradation of water pollutants are highlighted with recent illustrative examples. Furthermore, the future prospects of semiconductor photocatalysis for water treatment are critically analyzed. [ABSTRACT FROM AUTHOR]

The importance of transition metal catalysis is exemplified by its wide range of applications, for example in the synthesis of chemicals, natural products, and pharmaceuticals. However, one relatively new application is for carrying out new‐to‐nature reactions inside living cells. The complex environment of a living cell is not welcoming to transition metal catalysts, as a diverse range of biological components have the potential to inhibit or deactivate the catalyst. Here we review the current progress in the field of transition metal catalysis, and evaluation of catalysis efficiency in living cells and under biological (relevant) conditions. Catalyst poisoning is a ubiquitous problem in this field, and we propose that future research into the development of physical and kinetic protection strategies may provide a route to improve the reactivity of catalysts in cells. [ABSTRACT FROM AUTHOR]

The medicinal chemistry of gold has experienced an exponential development since the 2000s. For long, the mechanisms of action of gold complexes have been limited to direct coordination of the gold ion or supramolecular interactions of the whole gold complex with biomolecules. In the recent years, other modes of action of gold‐based drug candidates have emerged. Herein, we review these new modalities, including photo‐induced cytotoxicity, selective protein modification and in cellulo catalysis. [ABSTRACT FROM AUTHOR]

Photocatalysis is an emerging area of chemistry that takes advantage of light as the primary source of energy to carry out chemical transformations. In this context, organic photocatalysts appear as an alternative that has proven to be efficient in treating polluted effluents. Although organic photocatalysts are not able to generate hydroxyl radical, their photoactivated excited states generated using visible light can act as strong oxidants in most cases. In fact, pollutant photooxidation can be produced from an initial electron transfer between an excited state of an organic photocatalyst and the contaminant, generating their respective radical anion and cation (Type I mechanism). However, as most of the organic photocatalysts are able to generate singlet oxygen, pollutant degradation can also be initiated from this oxidative species (Type II mechanism). Moreover, the heterogenization of the photocatalysts seems the straightforward step to boost photostability and facilitate recovery after the reaction. In the present review, we chronicle our research progress and how interestingly, it cannot be assumed that the main reaction pathways of a photocatalyst are the same under homogeneous conditions as in heterogeneous media. Herein we have selected Rose Bengal (RB), Riboflavin (RF), and a perylene diimide derivative (PDI) to illustrate the different modes of action of these organic photocatalysts under homogeneous/heterogeneous conditions. [ABSTRACT FROM AUTHOR]

An azobenzene-bearing N-heterocyclic carbene-based gold catalyst is reported of which the reactivity in a cyclization reaction depends on the isomeric state of the azobenzene. The configurations of the catalyst can be reversibly switched by light and are stable during the reaction, effectively leading to a switchable catalyst system. [ABSTRACT FROM AUTHOR]

The process of N-doping is frequently employed to enhance the properties of carbon quantum dots. However, the precise requirements for nitrogen precursors in producing high-quality N-doped carbon quantum dots (NCQDs) remain undefined. This research systematically examines the influence of various nitrogen dopants on the morphology, optical features, and band structure of NCQDs. The dots are synthesized using an efficient, eco- friendly, and rapid continuous hydrothermal flow technique. This method offers unparalleled control over synthesis and doping, while also eliminating convention-related issues. Citric acid is used as the carbon source, and urea, trizma base, beta-alanine, L-arginine, and EDTA are used as nitrogen sources. Notably, urea and trizma produced NCQDs with excitation-independent fluorescence, high quantum yields (up to 40%), and uniform dots with narrow particle size distributions. Density functional theory (DFT) and time-dependent DFT modelling established that defects and substituents within the graphitic structure have a more significant impact on the NCQDs' electronic structure than nitrogen-containing functional groups. Importantly, for the first time, this work demonstrates that the conventional approach of modelling single-layer structures is insufficient, but two layers suffice for replicating experimental data. This study, therefore, provides essential guidance on the selection of nitrogen precursors for NCQD customization for diverse applications., (© 2024 The Authors. Small published by Wiley‐VCH GmbH.)

The appeal of carbon dots (CDs) has grown recently, due to their established biocompatibility, adjustable photoluminescence properties, and excellent water solubility. For the first time in the literature, copper chlorophyllin-based carbon dots (Chl-D CDs) are successfully synthesized. Chl-D CDs exhibit unique spectroscopic traits and are found to induce a Fenton-like reaction, augmenting photodynamic therapy (PDT) efficacies via ferroptotic and apoptotic pathways. To bolster the therapeutic impact of Chl-D CDs, a widely used cancer drug, temozolomide, is linked to their surface, yielding a synergistic effect with PDT and chemotherapy. Chl-D CDs' biocompatibility in immune cells and in vivo models showed great clinical potential.Proteomic analysis was conducted to understand Chl-D CDs' underlying cancer treatment mechanism. The study underscores the role of reactive oxygen species formation and pointed toward various oxidative stress modulators like aldolase A (ALDOA), aldolase C (ALDOC), aldehyde dehydrogenase 1B1 (ALDH1B1), transaldolase 1 (TALDO1), and transketolase (TKT), offering a deeper understanding of the Chl-D CDs' anticancer activity. Notably, the Chl-D CDs' capacity to trigger a Fenton-like reaction leads to enhanced PDT efficiencies through ferroptotic and apoptotic pathways. Hence, it is firmly believed that the inherent attributes of Chl-CDs can lead to a secure and efficient combined cancer therapy., (© 2024 Wiley‐VCH GmbH.)

Aptamer-modified Zr-MOFs (UiO-66-APT) were constructed as nanocatalysts for achieving specific hydrolysis of paraoxon. The conjunction mode of the aptamer on the Zr-MOFs affected the binding of the substrates with the catalytic sites, thus leading to different catalytic activities. This study provides a solution for achieving specific catalysis of nanocatalysts, just like that in natural enzymes. [ABSTRACT FROM AUTHOR]

Recent years have witnessed a considerable progress in research aimed at merging transition metal catalysis with chemical and cell biology. Therefore, a crescent number of metal‐catalyzed transformations have been shown compatible with biological media and even with living settings. Of the different transition metals used to build these biocompatible catalysts, ruthenium has demonstrated to be particularly powerful, in part because the resulting complexes exhibit a very good balance between reactivity and biological stability. Indeed, ruthenium complexes have demonstrated utility to promote a great variety of reactions in biologically relevant contexts, from deprotection and redox processes to cycloadditions or photocatalytic transformations. Many of these reactions may enable the development of new type of biological tools and pharmacological strategies. [ABSTRACT FROM AUTHOR]

Bioorthogonal chemistry has inspired a new subarea of chemistry providing a powerful tool to perform novel biocompatible chemospecific reactions in living systems. Following the premise that they do not interfere with biological functions, bioorthogonal reactions are increasingly applied in biomedical research, particularly with respect to genetic encoding systems, fluorogenic reactions for bioimaging, and cancer therapy. This Minireview compiles recent advances in the use of heterogeneous catalysts for bioorthogonal reactions. The synthetic strategies of Pd‐, Au‐, and Cu‐based materials, their applicability in the activation of caged fluorophores and prodrugs, and the possibilities of using external stimuli to release therapeutic substances at a specific location in a diseased tissue are discussed. Finally, we highlight frontiers in the field, identifying challenges, and propose directions for future development in this emerging field. [ABSTRACT FROM AUTHOR]

Due to rising resistance, new antibacterial strategies are needed, including methods for targeted antibiotic release. As targeting vectors, chelating molecules called siderophores that are released by bacteria to acquire iron have been investigated for conjugation to antibacterials, leading to the clinically approved drug cefiderocol. The use of small‐molecule catalysts for prodrug activation within cells has shown promise in recent years, and here we investigate siderophore‐linked ruthenium catalysts for the activation of antibacterial prodrugs within cells. Moxifloxacin‐based prodrugs were synthesised, and their catalyst‐mediated activation was demonstrated under anaerobic, biologically relevant conditions. In the absence of catalyst, decreased antibacterial activities were observed compared to moxifloxacin versus Escherichia coli K12 (BW25113). A series of siderophore‐linked ruthenium catalysts were investigated for prodrug activation, all of which displayed a combinative antibacterial effect with the prodrug, whereas a representative example displayed little toxicity against mammalian cell lines. By employing complementary bacterial growth assays, conjugates containing siderophore units based on catechol and azotochelin were found to be most promising for intracellular prodrug activation. [ABSTRACT FROM AUTHOR]

Gold catalysts exhibit poor compatibility with cellular components. We show that encapsulation of a gold catalyst within the cavity of a supramolecular cage improves the reactivity of the gold complex under biological conditions. The gold complex catalyzes an intramolecular hydroarylation to produce a fluorescent dye. The encapsulated gold is able to produce this dye in higher yields compared to the free gold under aqueous aerobic conditions and in the presence of biological additives. The substrate was found to be highly cytotoxic, meaning that a very low substrate concentration of 1 μM is required to carry its transformation inside living cells; however, catalysis in cell culture media carried out at micromolar range is found to be inhibited. Although this specific reaction cannot be applied inside living cells, we present a viable strategy to improve the reactivity of gold catalysts in vivo. [ABSTRACT FROM AUTHOR]

In this study, a novel functionalized graphene oxide (F‐GO) modified polyamide 6 (PA6) sizing agent is developed to improve the interfacial and mechanical properties of carbon fiber (CF) reinforced PA6 composites. To enhance compatibility between GO and sizing agent, PA6 molecular chains are covalently grafted onto the GO sheets in advance. The results show that the F‐GO modified sizing layer improves interfacial compatibility and wettability of the CF surface. Moreover, F‐GO nanoparticles retard crack propagation along the interface based on the reinforcement effect. Accordingly, the interfacial shear strength increases by 54.5% from 45.1 MPa for desized CF/PA6 composites to 69.7 MPa for F‐GO modified sizing agent treated CF/PA6 composites. Meanwhile, the average interlaminar shear strength, tensile strength, and flexural strength increase by 45.2%, 15.6%, and 19.3% from 45.7, 1307.4, and 792.2 MPa for desized CF/PA6 composites to 66.3, 1511.2, and 945.2 MPa for those reinforced with the CFs treated by the F‐GO modified sizing agent due to the effective stress transfer across the interface. The improvement in the mechanical properties is verified based on the cross‐section morphology and fracture surfaces. [ABSTRACT FROM AUTHOR]

N‐heterocyclic carbenes (NHCs) have become attractive ligands for functionalizing gold nanoparticle surfaces with applications ranging from catalysis to biomedicine. Despite their great potential, NHC stabilized gold colloids (NHC@AuNPs) are still scarcely explored and further efforts should be conducted to improve their design and functionalization. Here, the 'bottom‐up' synthesis of two water‐soluble gold nanoparticles (AuNP‐1 and AuNP‐2) stabilized by hydrophilic mono‐ and bidentate NHC ligands is reported together with their characterization by various spectroscopic and analytical methods. The NPs showed key differences likely to be due to the selected NHC ligand systems. Transmission electron microscopy (TEM) images showed small quasi‐spherical and faceted NHC@AuNPs of similar particle size (ca. 2.3–2.6 nm) and narrow particle size distribution, but the colloids featured different ratios of Au(I)/Au(0) by X‐ray photoelectron spectroscopy (XPS). Furthermore, the NHC@AuNPs were supported on titania and fully characterized. The new NPs were studied for their catalytic activity towards the reduction of nitrophenol substrates, the reduction of resazurin and for their photothermal efficiency. Initial results on their application in photothermal therapy (PTT) were obtained in human cancer cells in vitro. The aforementioned reactions represent important model reactions towards wastewater remediation, bioorthogonal transformations and cancer treatment. [ABSTRACT FROM AUTHOR]

Compared to inorganic quantum dots, fluorescent carbon nanomaterials (C-dots) have gained significant attention because of their unique optoelectrical properties and low toxicity. Although many review articles summarized the last research achievements, only a few of them are focusing on red/near-infrared C-dots. Due to their unique optical and optoelectrical properties in the red/near-infrared region, this interesting subclass of C-dots may be applied as important building blocks for several applications spanning from bioimaging and nano-thermometry, to luminescent solar concentrators (LSCs) and photoelectrochemical systems. Therefore, in this review the synthesis and the fluorescence mechanism together with the most important applications in thermometry, bio-imaging, LSCs and photocatalysis of red/near-infrared C-dots are considered. Furthermore, another aim is to highlight the available approaches to improve the carbonization degree and, additionally, to discuss the structure/composition correlated optical properties. Finally, outlooks, future perspectives and challenges are also discussed for these highly promising nanostructures. [ABSTRACT FROM AUTHOR]

High aspect-ratio gold nanostructures sustain Fabry–Perot-like surface plasmon responses from infrared to visible light energies. We show that some resonances can be tuned by means of laser irradiation, where low energy modes stay unperturbed. After laser irradiation, gold nanowires' tips are transformed into nanoparticles of various sizes joint to gold nanowires, producing high aspect-ratio half-dumbbells and dumbbells structures. The plasmonic behaviour of both the nanowires and the newly created nanostructures has been characterised by in-depth monochromated electron energy loss spectroscopy (EELS) developed in a transmission electron microscope (TEM) and state-of-the-art discrete dipole approximation (DDA) calculations. All these analyses serve as experimental proof of the selective tuning (or robustness) of the plasmonic modes of the nanostructures in a specific spectral range, which is of critical interest regarding applications for sensing devices, nano-sources or nanophotonic waveguide, as well as optical remote control. [ABSTRACT FROM AUTHOR]

As a means to develop new tools to manipulate biological systems, transition metals have been looked upon as an area of high potential due to the bioorthogonality of new‐to‐nature reactions. To facilitate their incorporation into complex biological systems, researchers have mainly focused on the development of metal catalyst complexes, protein scaffolds, and nanocarriers to protect and preserve the biocatalytic activity of transition metals. The intent of this review is to summarize these structural scaffolds, which has steadily allowed researchers to push transition metal usage not previously thought possible within bacteria, mammalian cells, and higher‐level organisms. [ABSTRACT FROM AUTHOR]

Conventional wet electrodes, such as a silver/silver chloride electrode, are limited for electroencephalogram (EEG) sensors directly attached to the scalp with existing hair due to their incomplete contact and increased impedance. In this study, an all-solution-processed trapezoidal electrode array is demonstrated for highly sensitive and reliable detection of EEG signals even when in direct contact with the scalp. The proposed noninvasive EEG sensors based on nanocomposites consisting of single-wall carbon nanotube random networks incorporated into a gelatin matrix exhibited a relatively low contact impedance of 11.16 × 102 Ω and a high sensitivity of 14.81 dB regardless of existing hair for real-time EEG recording without conductive gels or electrolytes. Furthermore, the origin of such advances induced by the soft and conductive electrode array is investigated by analyzing the effective contact area and signal-to-noise ratio on different scalp positions from 20 different subjects. A trapezoidal EEG electrode penetrates the dense hair and bypasses the hair shaft owing to its deformable shape induced by the soft and flexible nanocomposite film. [ABSTRACT FROM AUTHOR]

One of the bottlenecks in realizing the potential of nanoporous graphene assemblies is the difficulty of engineering narrow pores and high surface density distributions, with a nanometer resolution across multilayer graphene assemblies using scalable approaches. Here, the authors develop a photocatalyzed perforation protocol to incorporate nanopores across modified graphene assemblies via localizing the oxidation during the photo‐excitation process between photo‐initiators and graphitic assemblies under the ultraviolet–visible stimuli. Nanopores are engineered across the graphene nanostructures with a pore size range varying from 20 to 100 nm depending on the irradiation duration, as well as tunable densities of 101–103 pores/µm2 on the same order of the loaded nanocatalysts to the graphene surfaces. By fine‐tuning the graphene chemistry and the physical dimension of photo‐initiators, as well as their concentrations across graphitic planes used during the perforation, the diameter, and the density distributions of generated nanopores across graphene, can be rationally confined, avoiding merging between pores during the nanopore formation. These porosity parameters engineered across graphene nanosieves are in the same order obtained by other nanolithographic techniques. Plus, this sustainable route may boost the potential of porous graphene assemblies in energy‐efficient nanotechnologies based on separation and catalytic processes. [ABSTRACT FROM AUTHOR]

Bioorthogonal chemistry is a powerful tool to site-specifically activate drugs in living systems. Bioorthogonal reactions between a pair of biologically reactive groups can rapidly and specifically take place in a mild physiological milieu without perturbing inherent biochemical processes. Attributed to their high selectivity and efficiency, bioorthogonal reactions can significantly decrease background signals in bioimaging. Compared with metal-catalyzed bioorthogonal click reactions, metal-free click reactions are more biocompatible without the metal catalyst-induced cytotoxicity. Although a great number of bioorthogonal chemistry-based strategies have been reported for cancer theranostics, a comprehensive review is scarce to highlight the advantages of these strategies. In this review, recent progress in cancer theranostics guided by metal-free bioorthogonal click chemistry will be depicted in detail. The elaborate design as well as the advantages of bioorthogonal chemistry in tumor theranostics are summarized and future prospects in this emerging field are emphasized. [ABSTRACT FROM AUTHOR]