Site-Selective Photosynthesis of Ag-AgCl@Au Nanomushrooms for NIR-II Light-Driven O2- and O2•--Evolving Synergistic Photothermal Therapy against Deep Hypoxic Tumors.

Light-driven endogenous water oxidation has been considered as an attractive and desirable way to obtain O2 and reactive oxygen species (ROS) in the hypoxic tumor microenvironment. However, the use of a second near-infrared (NIR-II) light to achieve endogenous H2O oxidation to alleviate tumor hypoxia and realize deep hypoxic tumor phototherapy is still a challenge. Herein, novel plasmonic Ag-AgCl@Au core-shell nanomushrooms (NMs) were synthesized by the selective photodeposition of plasmonic Au at the bulge sites of the Ag-AgCl nanocubes (NCs) under visible light irradiation. Upon NIR-II light irradiation, the resulting Ag-AgCl@Au NMs could oxidize endogenous H2O to produce O2 to alleviate tumor hypoxia. Almost synchronously, O2 could react with electrons on the conduction band of the AgCl core to generate superoxide radicals (O2•-)for photodynamic therapy. Moreover, Ag-AgCl@Au NMs with an excellent photothermal performance could further promote the phototherapy effect. In vitro and in vivo experimental results show that the resulting Ag-AgCl@Au NMs could significantly improve tumor hypoxia and enhance phototherapy against a hypoxic tumor. The present study provides a new strategy to design H2O-activatable, O2- and ROS-evolving NIR II light-response nanoagents for the highly efficient and synergistic treatment of deep O2-deprived tumor tissue.

Plasmon Coupling in DNA-Assembled Silver Nanoclusters.

Quantum-size metal clusters with multiple delocalized electrons could support collective plasmon excitation, and thus, theoretically, coupling of plasmons in the few-atom limit might exist between assembled metal clusters, while currently few experimental observations about this phenomenon have been reported. Here we examined the optical absorption of DNA-templated Ag nanoclusters (DNA-AgNCs) assembled through DNA hybridization and found their absorption peaks were sensitive to the assembled distances, which share common characteristics with classical plasmon coupling. Dipolar charge distribution, multiple transition contributed optical absorption, and strongly enhanced electric field simulated by time-dependent density functional theory (TDDFT) indicated the origin of the absorption of individual DNA-AgNCs is a plasmon. The consistency of the peak-shifting trend between experimental and simulation results for assembled DNA-AgNCs suggested the possible presence of plasmon coupling. Our data imply the possibility for quantum-size structures to support plasmon coupling and also show that DNA-AgNCs possess the potential to be promising materials for construction of plasmon-coupling devices with ultrasmall size, site-specific and stoichiometric binding abilities, and biocompatibility.

Novel Ag/cellulose-doped CeO2 quantum dots for efficient dye degradation and bactericidal activity with molecular docking study.

In the present study, the novel Ag/cellulose nanocrystal (CNC)-doped CeO2 quantum dots (QDs) with highly efficient catalytic performance were synthesized using one pot co-precipitation technique, which were then applied in the degradation of methylene blue and ciprofloxacin (MBCF) in wastewater. Catalytic activity against MBCF dye was significantly reduced (99.3%) for (4%) Ag dopant concentration in acidic medium. For Ag/CNC-doped CeO2 vast inhibition domain of G-ve was significantly confirmed as (5.25-11.70 mm) and (7.15-13.60 mm), while medium- to high-concentration of CNC levels were calculated for G + ve (0.95 nm, 1.65 mm), respectively. Overall, (4%) Ag/CNC-doped CeO2 revealed significant antimicrobial activity against G-ve relative to G + ve at both concentrations, respectively. Furthermore, in silico molecular docking studies were performed against selected enzyme targets dihydrofolate reductase (DHFR), dihydropteroate synthase (DHPS), and DNA gyrase belonging to folate and nucleic acid biosynthetic pathway, respectively to rationalize possible mechanism behind bactericidal potential of CNC-CeO2 and Ag/CNC-CeO2.

Cathode-Anode Spatial Division Photoelectrochemical Platform Based on a One-Step DNA Walker for Monitoring of miRNA-21.

Photoelectrochemical (PEC) biosensors carried out the whole reaction process in the same solution, which would limit the sensitivity and selectivity of detection in the sensing system. Herein, we reported a promising new cathode-anode spatial division PEC platform based on the two-electrode synergistic enhancement strategy. With the photoanode and photocathode integrated in the same current circuit, the platform exhibited an increased photocurrent response, as well as an improved anti-interference ability led by separating the two electrodes spatially. In this proposal, red light-driven AgInS2 nanoparticles (NPs) served as the photoanode to build biometric steps and amplify the signal, whereas p-type PbS quantum dots were selected as the photocathode to increase the signal. With the participation of alkaline phosphatase (ALP) labeled on Au NPs-DNA, ascorbic acid 2-phosphate was catalyzed to produce ascorbic acid as an electron donor, resulting in the enhancement of the PEC signal. Interestingly, in the presence of miRNA-21 and T7 Exo, the one-step DNA walker amplification can be triggered to reduce the PEC signal by releasing ALP-Au NP-DNA. The constructed PEC biosensor exhibited a detection limit of as low as 3.4 fM for miRNA-21, which was expected to be applied to early clinical diagnosis. Also, we believe that the proposed cathode-anode spatial division PEC platform can open up a new view for the establishment of other types of PEC biosensors.

Mussel-Inspired Immobilization of Photocatalysts with Synergistic Photocatalytic-Photothermal Performance for Water Remediation.

The serious problem of pharmaceutical and personal care product pollution places great pressure on aquatic environments and human health. Herein, a novel coating photocatalyst was synthesized by adhering Ag-AgCl/WO3/g-C3N4 (AWC) nanoparticles on a polydopamine (PDA)-modified melamine sponge (MS) through a facile layer-by-layer assembly method to degrade trimethoprim (TMP). The formed PDA coating was used for the anchoring of nanoparticles, photothermal conversion, and hydrophilic modification. TMP (99.9%; 4 mg/L) was removed in 90 min by the photocatalyst coating (AWC/PDA/MS) under visible light via a synergistic photocatalytic-photothermal performance route. The stability and reusability of the AWC/PDA/MS have been proved by cyclic experiments, in which the removal efficiency of TMP was still more than 90% after five consecutive cycles with a very little mass loss. Quantitative structure-activity relationship analysis revealed that the ecotoxicities of the generated intermediates were lower than those of TMP. Furthermore, the solution matrix effects on the photocatalytic removal efficiency were investigated, and the results revealed that the AWC/PDA/MS still maintained excellent photocatalytic degradation efficiency in several actual water and simulated water matrices. This work develops recyclable photocatalysts for the potential application in the field of water remediation.

[Drug Release System Controlled by Photothermal Effect of Gold Nanoparticles].

Controlled drug release in response to light irradiation is an important technique for focusing drug elution to specific sites and reducing the side effects of drugs in normal tissue. In one example, we used double-stranded DNA to modify gold nanorods. When the gold nanorods were heated by irradiation with near-infrared light, single-stranded DNA was released. Thus, we successfully prepared a controlled release system that responds to near-infrared irradiation by combining heat-labile linkers such as double-stranded DNA. However, the drug-loading capacity on the surface of the nanoparticles was limited. To improve the loading efficiency, we encapsulated gold nanorods in poly(lactic-co-glycolic acid) (PLGA) nanoparticles, where PLGA acted as a drug payload. When the gold nanorod-containing PLGA nanoparticles were irradiated with a near-infrared laser, the PLGA nanoparticles were destroyed and significant drug release was observed. In another example, silver nanoplates were used as a near-infrared responsive photothermal nanodevice. Silver nanoparticles show antimicrobial activity that we expected could be controlled by light irradiation. First, we coated the silver nanoplates with gold atoms to mask the antimicrobial activity. When the gold-coated silver nanoplates were irradiated with a near-infrared pulsed laser, the shape of the silver nanoplates changed from plate-like to spherical, and silver ions were released. As a result, the antibacterial activity of the silver nanoplates was recovered. In this review, we outline examples of controlled release systems that respond to light irradiation. We believe that this review will contribute to improving the efficiency and safety of chemotherapy.

Carbon quantum Dot@Silver nanocomposite-based fluorescent imaging of intracellular superoxide anion.

Silver nanoparticle (Ag NP)-coated carbon quantum dot (CQD) core-shell-structured nanocomposites (CQD@Ag NCs) were developed for fluorescent imaging of intracellular superoxide anion (O2•-). The morphology of CQD@Ag NCs was investigated by transmission electron microscopy, and the composition was characterized by X-ray diffraction and X-ray photoelectron spectroscopy. CQDs display blue fluorescence with excitation/emission maxima at 360/440 nm, and the fluorescence was quenched by Ag NPs in CQD@Ag NCs. In the presence of O2•-, Ag NPs were oxide-etched and the fluorescence of CQDs was recovered. A linearity between the relative fluorescence intensity and O2•- solution concentration within the range 0.6 to 1.6 µM was found, with a detection limit of 0.3 µM. Due to their high sensitivity, selectivity, and low cytotoxicity, the as-synthesized CQD@Ag NCs have been successfully applied for imaging of O2•- in MCF-7 cells during the whole process of autophagy induced by serum starvation. In our perception, the developed method provides a cost-effective, sensitive, and selective tool in bioimaging and monitoring of intracellular O2•- changes, and is promising for potential biological applications. Graphical abstract Illustration of the synthesis of carbon quantum Dot@Silver nanocomposites (CQD@Ag NCs), and CQD@Ag NCs as a "turn-on" nanoprobe for fluorescent imaging of intracellular superoxide anion.

NaGdF4:Yb,Er-Ag nanowire hybrid nanocomposite for multifunctional upconversion emission, optical imaging, MRI and CT imaging applications.

The effect of novel silver nanowire encapsulated NaGdF4:Yb,Er hybrid nanocomposite on the upconversion emission and bioimaging properties has been investigated. The upconvension nanomaterials were synthesised by polyol method in the presence of ethylene glycol, PVP and ethylenediamine. The NaGdF4:Yb,Er-Ag hybrid was formed with upconverting NaGdF4:Yb,Er nanoparticles of size ~ 80 nm and silver nanowires of thickness ~ 30 nm. The surface plasmon induced by the silver ion in the NaGdF4:Yb,Er-Ag nanocomposite resulted an intense upconversion green emission at 520 nm and red emission at 660 nm by NIR diode laser excitation at 980 nm wavelength. The UV-Vis-NIR spectral absorption at 440 nm and 980 nm, the intense Raman vibrational modes and the strong upconversion emission results altogether confirm the localised surface plasmon resonance effect of silver ion in the hybrid nanocomposite. MRI study of both NaGdF4:Yb,Er nanoparticle and NaGdF4:Yb,Er-Ag nanocomposite revealed the T1 relaxivities of 22.13 and 10.39 mM-1 s-1, which are larger than the commercial Gd-DOTA contrast agent of 3.08 mM-1 s-1. CT imaging NaGdF4:Yb,Er-Ag and NaGdF4:Yb,Er respectively showed the values of 53.29 HU L/g and 39.51 HU L/g, which are higher than 25.78 HU L/g of the CT contrast agent Iobitridol. The NaGdF4:Yb,Er and NaGdF4:Yb,Er-Ag respectively demonstrated a negative zeta potential of 54 mV and 55 mV, that could be useful for biological application. The in vitro cytotoxicity of the NaGdF4:Yb,Er tested in HeLa and MCF-7 cancer cell line by MTT assay demonstrated a cell viability of 90 and 80 %, respectively. But, the cell viability of NaGdF4:Yb,Er-Ag slightly decreased to 80 and 78%. The confocal microscopy imaging showed that the UCNPs are effectively up-taken inside the nucleolus of the cancer cells, and it might be useful for NIR laser-assisted phototherapy for cancer treatment. Graphical abstract.

High-efficient and synergetic antibacterial nanocomposite hydrogel with quaternized chitosan/Ag nanoparticles prepared by one-pot UV photochemical synthesis.

Hydrogel dressings have significant advantages such as absorption of tissue exudate, maintenance of proper moist environment, and promotion of cell proliferation. However, facile preparation method and high-efficient antibacterial hydrogel dressings are still a great challenge. In this study, a facile approach to prepare antibacterial nanocomposite hydrogel dressing to accelerate healing was explored. The hydrogels consisted of quaternized chitosan and chemically cross-linked polyacrylamide, as well as silver nanoparticles (AgNPs) stabilized by chitosan. The synthesis of the hydrogels including the formation of AgNPs and polymerization of acrylamide was accomplished simultaneously under UV irradiation in 1 hour without adding initiator. The hydrogels showed favorable tensile strength of ∼100 kPa with elongation at break over 1000% and shear modulus of ∼104 Pa as well as suitable swelling ratio, which were appropriate for wound dressing. The combination of quaternized chitosan and AgNPs exhibited high-efficient and synergetic antibacterial performance with low cytotoxicity. In vivo animal experiments showed that the hydrogel can effectively prevent wound infection and promote wound healing. This study provides a facile method to produce antibacterial hydrogel wound dressing materials.

Mechanistic investigations into synergistically enhanced radiative-charge-transfer in Au-Ag bimetallic nanoclusters.

Synergetic effects in Au-Ag bimetallic nanoclusters (BNCs) more favorably enhanced electrochemical redox induced electrochemiluminescence (ECL) over photoexcitation induced photoluminescence (PL); this not only led to Au-Ag BNCs with enhanced bandgap-engineered ECL compared to Au NCs, but it also generated surface-defect related ECL to enhance the total ECL intensity.

Ageing alters the physicochemical properties of silver nanoparticles and consequently compromises their acute toxicity in mammals.

Despite numerous investigations into AgNP-induced toxicity, little has been taken into consideration the potential health impacts of aged AgNPs in comparison to fresh AgNPs. In the current study, we scrutinized the potential effects of aged AgNPs in animals. We first found that AgNPs underwent morphological transformations after natural ageing in aqueous solution upon exposure to air and sunlight for 9 days, as characterized by significant aggregation with increase of particle size approximately by 2 fold. Meanwhile, dissolved Ag ions from aged AgNPs increased by 33% compared to fresh AgNPs. Strikingly, the acute exposure results showed that aged AgNPs induced lower toxicity in mice relative to fresh AgNPs. Aged AgNPs caused milder local inflammation in the peritoneal cavity of mice, as evidenced by 63% reduction of tumor necrosis factor α (TNF-α) than that induced by fresh AgNPs. The deposition mass of aged AgNPs in the liver, spleen, lung and kidney was diminished by 69%, 39%, 83% and 40%, respectively, compared to the distribution profiles in response to fresh AgNPs. Whereby, milder splenic hyperemia was observed, and no significant hepatoxicity was found. Additionally, aged AgNPs provoked milder increase of periphery leukocytes and malondialdehyde (MDA) in mice in comparison to fresh AgNPs. Taken together, this study unraveled that the ageing process elicited remarkable alterations to physicochemical properties and toxic effects as well. This study would provide new insights into the potential health impacts of AgNPs under transformation-determined exposure scenarios.

Silver nanoparticles doped TiO2 catalyzed Suzuki-coupling of bromoaryl with phenylboronic acid under visible light.

The formation of the carbon­carbon bond in the synthetic chemistry explored in many ways. Suzuki-cross coupling is one of the ways to make bonds between two carbon atoms of similar molecules or different molecules. CC bond was successfully formed between two aryl rings of aryl halides and phenylboronic acid at room temperature and atmospheric pressure under the visible illuminance. In this work we report, an in-situ synthesis of silver nanoparticles doped TiO2 nanoparticles (NPs) and studied its catalytic activity as an eco-friendly, simple, recyclable and efficient catalyst for one-pot Suzuki-coupling of bromoaryl with phenylboronic acid under visible light. Only, 45 mg of the catalyst resulted in a 98% conversion of p-ethyl bromobenzene with a 97% yield of p-ethyl biphenyl using toluene as the solvent in the presence of visible light at atmospheric pressure. The electron-donating groups (e.g., ethyl group) substituted bromobenzene resulted in the maximum yields than that of the substitution with the electron-withdrawing groups. The catalyst shown significant catalytic activity up to seven recycling runs without any loss. The doping of silver nanoparticles boosted the catalytic activity at titanium dioxide surface as well as inside the pores. The high surface area of the semiconductor support provides the sites for accommodated silver nanoparticles and shows enhanced reactivity towards the coupling reaction of bromoaryl with phenylboronic acid. The as-synthesized catalyst was thoroughly characterized by XRD, TEM, EDX, XPS, FTIR, TGA, UV-vis, Raman and BET analysis. The high recyclability of the photocatalyst remarked the footprints in the CC coupling reactions.

Silver nanoparticles in dye effluent treatment: A review on synthesis, treatment methods, mechanisms, photocatalytic degradation, toxic effects and mitigation of toxicity.

The current scenario of water resources shows the dominance of pollution caused by the draining of industrial effluents. The polluted waters have resulted in severe health and environmental hazards urging for a suitable alternative to resolve the implications. Various physical and chemical treatment steps currently in use for dye effluent treatment are more time consuming, cost-intensive, and less effective. Alternatively, nanoparticles due to their excellent surface properties and chemical reactivity have emerged as a better solution for dye removal and degradation. In this regard, the potential of silver nanoparticles in dye effluent treatment was greatly explored. Efforts were taken to unravel the kinetics and statistical optimization of the treatment conditions for the efficient removal of dyes. In addition, the role of silver nanocomposites has also experimented with colossal success. On the contrary, studies have also recognized the mechanisms of silver nanoparticle-mediated toxicity even at deficient concentrations and their deleterious biological effects when present in treated water. Hence, the fate of the silver nanoparticles released into the treated water and sludge, contaminating the soil, aquatic environment, and underground water is of significant concern. This review summarizes the current state of knowledge regarding the use of silver nanoparticles and silver-based nanocomposites in effluent treatment and comprehends the recent research on mitigation of silver nanoparticle-induced toxicity.

Study of the intracellular nanoparticle-based radiosensitization mechanisms in F98 glioma cells treated with charged particle therapy through synchrotron-based infrared microspectroscopy.

The use of nanoparticles (NP) as dose enhancers in radiotherapy (RT) is a growing research field. Recently, the use of NP has been extended to charged particle therapy in order to improve the performance in radioresistant tumors. However, the biological mechanisms underlying the synergistic effects involved in NP-RT approaches are not clearly understood. Here, we used the capabilities of synchrotron-based Fourier Transform Infrared Microspectroscopy (SR-FTIRM) as a bio-analytical tool to elucidate the NP-induced cellular damage at the molecular level and at a single-cell scale. F98 glioma cells doped with AuNP and GdNP were irradiated using several types of medical ion beams (proton, helium, carbon and oxygen). Differences in cell composition were analyzed in the nucleic acids, protein and lipid spectral regions using multivariate methods (Principal Component Analysis, PCA). Several NP-induced cellular modifications were detected, such as conformational changes in secondary protein structures, intensity variations in the lipid CHx stretching bands, as well as complex DNA rearrangements following charged particle therapy irradiations. These spectral features seem to be correlated with the already shown enhancement both in the DNA damage response and in the reactive oxygen species (ROS) production by the NP, which causes cell damage in the form of protein, lipid, and/or DNA oxidations. Vibrational features were NP-dependent due to the NP heterogeneous radiosensitization capability. Our results provided new insights into the molecular changes in response to NP-based RT treatments using ion beams, and highlighted the relevance of SR-FTIRM as a useful and precise technique for assessing cell response to innovative radiotherapy approaches.

Tuning DNA electrical conductivity by silver photo-doping.

Photodoping of silver into bulk DNA is studied by measuring its ambient electrical conductivity. Mechanically pressed pellets of pure DNA and chemically modified Ag-DNA were prepared and were further coated with silver paste on either side of pellets to monitor the photodoping process. The electrical conductivity of these pellets was continuously measured under white light irradiation. The initial electrical conductivity of these pellets was smaller, that progressively increased with increase in number of current-voltage scan cycles under constant illumination of visible light. The change in electrical conductivity by photodoping is more in a pure DNA as compared to that of chemically modified Ag-DNA. The temperature dependent electrical conductivity exhibits the Arrhenius behavior. A detailed elemental depth profile was studied by core level x-ray photo-electron spectroscopy (XPS). The results clearly suggest that photodoping of silver can alter the DNA's starting electrical conductivity.

Plasmonic Ag decorated graphitic carbon nitride sheets with enhanced visible-light response for photocatalytic water disinfection and organic pollutant removal.

Photocatalytic disinfection with high performance is thought to be a promising way for water purification. Herein, plasmonic Ag doped urea-derived graphitic carbon nitride (g-C3N4) composites were fabricated via in-situ photo-deposition at room temperature as the visible-light photocatalyst. Scan electron microscopy and transmission electron microscopy images showed the uniform dispersion of Ag nanoparticles on the surface of g-C3N4 sheet, which facilitated the synergistic effect of antibacterial performance from Ag and photocatalytic property from Ag/g-C3N4 composites. Photocatalytic water disinfection against Escherichia coli with visible light was performed to demonstrate the improved photocatalytic property with assistance of Ag. The 3-Ag/g-C3N4 exhibited the best bactericidal performance by inactivating all bacteria within 120 min with damaged cell membranes of Escherichia coli observed by scan electron microscopy and transmission electron microscopy images. Photoluminescence spectra, steady-state surface photovoltage spectra, photocurrent response, and electrochemical impedance spectra results revealed that Ag nanoparticles inhibited the recombination of photo-generated e- and h+ pairs and further reinforced the photocatalytic performance of g-C3N4. Scavenger experiments indicated that h+ produced on valence band of g-C3N4 dominated the photocatalytic disinfection process against Escherichia coli. This work further proved Ag/g-C3N4 showed great potential in photocatalytic water disinfection under visible-light irradiation.

Photoelectrocatalytic degradation of Ag-cyanide complexes and synchronous recovery of metallic Ag driven by TiO2 nanorods array photoanode combined with titanium cathode.

A photoelectrocatalytic (PEC) system for the decomposition of Ag-cyanide complexes synchronously with Ag recovery was established using the titanium dioxide nanorods (TiO2 NRs) as photoanode and the titanium plate as cathode. The removal efficiency of total cyanide was 76.58%, and the recovery ratio of Ag achieved 84.48% at the applied bias potential of 1.0 V vs SCE in the PEC process. During the reaction, the surface variations and photo-electric properties of TiO2 NRs photoanode or titanium cathode were characterized by SEM-EDS, XPS, and photoelectronic analyses. It was indicated that Ag2O and metallic Ag were deposited onto the TiO2 NRs photoanode and titanium cathode, respectively. Specifically, the in situ generated Ag2O on the TiO2 NRs photoanode facilitated the separation of the photogenerated charge carriers and enhanced the visible-light response, thus improving its PEC catalytic activity toward cyanide destruction. Combined with the results of active species quenching experiments, the mechanism of Ag-cyanide complexes decomposition and metallic Ag recovery by the PEC process was proposed.

In Situ Generated Plasmonic Silver Nanoparticle-Sensitized Amorphous Titanium Dioxide for Ultrasensitive Photoelectrochemical Sensing of Formaldehyde.

Trace concentration of formaldehyde can damage human health and environment. Consequently, it is of great significance to develop an ultrasensitive sensor for its determination. Herein, an ingenious and efficient photoelectrochemical sensor for formaldehyde was constructed by amorphous TiO2 hollow spheres incorporated with Ag+ ions, which were brought about by silica template etching and then the exchange of Ag+/Na+ ions. The amorphous TiO2 acted the dual role of Ag+ ion probe carriers and photoelectric materials. Upon exposure to the increased concentration of formaldehyde, the Ag nanoparticles were produced in situ, and photocurrent amplification was then achieved in a proportional manner. It is attributed to the injection of hot electrons from plasmonic Ag nanoparticles into the conduction band of amorphous titanium dioxide and therefore enhanced the photocurrent. The linear relationship between 1 and 400 pmol L-1 resulted from the enhanced photocurrent and increased concentration of formaldehyde, and the detection limit was 0.4 pmol L-1. Benefiting from an in situ and unique sensitization strategy, this photoelectrochemical sensor exhibited many advantages such as sensitivity, selectivity, cost-effectiveness, convenience of fabrication, low power consumption, and stability.

Ag Nanoparticles/α-Ag2WO4 Composite Formed by Electron Beam and Femtosecond Irradiation as Potent Antifungal and Antitumor Agents.

The ability to manipulate the structure and function of promising systems via external stimuli is emerging with the development of reconfigurable and programmable multifunctional materials. Increasing antifungal and antitumor activity requires novel, effective treatments to be diligently sought. In this work, the synthesis, characterization, and in vitro biological screening of pure α-Ag2WO4, irradiated with electrons and with non-focused and focused femtosecond laser beams are reported. We demonstrate, for the first time, that Ag nanoparticles/α-Ag2WO4 composite displays potent antifungal and antitumor activity. This composite had an extreme low inhibition concentration against Candida albicans, cause the modulation of α-Ag2WO4 perform the fungicidal activity more efficient. For tumor activity, it was found that the composite showed a high selectivity against the cancer cells (MB49), thus depleting the populations of cancer cells by necrosis and apoptosis, without the healthy cells (BALB/3T3) being affected.

Turn-on fluorescence detection of cysteine with glutathione protected silver nanoclusters.

In this work, we report a sensitive and selective turn-on fluorescence detection of cysteine with glutathione protected silver nanoclusters (GSH-Ag NCs). The glutathione stabilized silver nanoclusters were synthesized by the boiling water method. When excited at 380 nm, the GSH-Ag NCs exhibited a weak emission at about 680 nm, which could be enhanced by cysteine. The proposed method allows evaluation of cysteine in the range of 2-3000 µM with a detection limit of 0.51 µM. The recoveries were found to be 95.07%-101.38% when detecting cysteine contents in fetal bovine serum samples. In addition, we also discussed the possible mechanism for the fluorescence enhancement of GSH-Ag NCs by addition of cysteine. It might be the formation of cysteine and glutathione co-capped Ag NCs. This work reported a fluorimetric method for the assay of cysteine and provided a strategy for the synthesis of dual ligand-protected Ag nanoclusters.