Functionalized Silver Nanoparticles Research Articles

Functional silver nanoparticles as broad-spectrum antimicrobial agents

Indole-functionalized silver nanoparticles were prepared by a simple one-pot method, which exhibited efficient antibacterial activity against Gram-positive and Gram-negative bacteria.

Investigation of antibacterial properties of polyacrylonitrile fibers modified by new functional groups and silver nanoparticles.

This work reports the surface modification of polyacrylonitrile (PAN) fibers by graft copolymerization to ensure the decoration of homogenous and dense Ag nanoparticles. Two facile and subsequent modification processes resulted in a PAN fiber composite with an intact fibrous structure, sufficiently conductive for antistatic application and antibacterial activity. In the first step, some chemically attractive monomers and monomer mixtures, such as acrylic acid (AA), AA-itaconic acid (AA-IA), AA-acrylamide (AA-AAm), were introduced to the fiber surface by grafting. The grafting process was evidenced by FTIR, 1H-NMR, and SEM techniques. The second step aimed to form a chelate structure by Ag+ ions with the coordination centers imparted to the PAN structure, and then, Ag nanoparticles (AgNPs) were decorated on the copolymer fiber surfaces by reducing with the NaBH4. The presence, distribution, and changes that occurred after the AgNPs decoration were also monitored by the SEM technique. It was obtained that the AgNPs could not be easily removed from the composites, which presented an appearance as if they were dyed with Ag. It was determined that the composite fibers gained a certain degree of conductivity with the surface resistivity value of 109-102 Ω/cm2. The antibacterial activity of the composites against E. coli and S. aureus was examined by the zone of inhibition test compared to their detergent-washed samples.

Functionalized silver nanoparticles for SERS amplification with enhanced reproducibility and for ultrasensitive optical fiber sensing in environmental and biochemical assays.

Plasmonic sensors have broad application potential in many fields and are promising to replace most bulky sensors in the future. There are various method-based chemical reduction processes for silver nanoparticle production with flexible structural shapes due to their simplicity and rapidity in nanoparticle fabrication. In this study, self-assembled silver nanoparticles (Ag NPs) with a plasmon peak at 424 nm were successfully coated onto -NH2-functionalized glass and optical fiber sensors. These coatings were rapidly produced via two denaturation reactions in plasma oxygen, respectively, and an APTES ((3-aminopropyl)triethoxysilane) solution was shown to have high strength and uniformity. With the use of Ag NPs for surface-enhanced Raman scattering (SERS), excellent results and good stability with the detection limit up to 10-10 M for rhodamine B and 10-8 M for methylene blue, and a signal degradation of only ∼20% after storing for 30 days were achieved. In addition, the optical fiber sensor with Ag NP coatings exhibited a higher sensitivity value of 250 times than without coatings to the glycerol solution. Therefore, significant enhancement of these ultrasensitive sensors demonstrates promising alternatives to cumbersome tests of dye chemicals and biomolecules without any complicated process.

Development of Functionalized silver Nanoparticles from Allamanda neriifolia Hook and their In Vitro Cytotoxic Effect on MCF-7 Cells

The present work demonstrates the influence of plant extract composition (antioxidant and total phenolic content) on the size and morphology of the produced AgNPs. In this study, silver nanoparticles (AgNPs) were synthesized using aqueous flower extract of Allamanda neriifolia plant. The biosynthetic procedure was rapid and simple and was easily monitored via colour changes and examined AgNPs (AN-AgNPs) by ultraviolet-visible spectroscopy, Fourier transform infrared (FTIR) spectroscopy and scanning electron microscope (SEM). The results obtained from various characterizations revealed that average size of synthesized AgNPs was 50 nm and in spherical structure. The anticancer potential of AN-AgNPs was investigated against human breast cancer cells (MCF-7). The cytotoxic response was assessed by 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide (MTT), and morphological changes by apoptosis. The biosynthesized AgNPs-induced cell death in MCF- 7 cells suggested the anticancer potential of AN-AgNPs. Therefore, they may be used to treat the breast cancer cells.

Simple smartphone merged rapid colorimetric platform for the environmental monitoring of toxic sulfide ions by cysteine functionalized silver nanoparticles

Herein, we have proposed a new, highly specific and simple colorimetric assay for the chemosensing of sulfide ions (S2−) in environmental water samples, by using cysteine-functionalized colloidal silver nanoparticles (Cys-AgNPs). As prepared Cys-AgNPs and their interface with S2− ions were demonstrated using absorption, high resolution transmission electron microscopy (HR-TEM), dynamic light scattering (DLS) and Zeta potential measurements. The colour of Cys-AgNPs altered from vivid-yellow to colourless in two minutes after the mixing of S2− ions, resulting the suppression of surface plasmon resonance (SPR) band. The relative absorption intensity was inversely proportional to the concentrations of S2− ions in the ranges from 4 × 10−7 mol dm−3 to 48 × 10−7 mol dm−3 and lowest detection limit was computed as 28 × 10−9 mol dm−3. Furthermore, the current tactic illustrates a highly specific towards S2− ions over fifteen other potentially interfering inorganic anions investigated. Furthermore, visually measurable colour changes of Cys-AgNPs have been well incorporated with a RGB colour value of smartphone to construct it consistent indicator for immediate testing of S2− ions with the limit of detection attributable to 90 × 10−9 mol dm−3. An analytical practicability of the present approaches were (colorimetric and RGB colour value based tactics) applied for the chemosensing of S2− ions in real samples including drinking, tap and sea water samples with reasonable recoveries (90.1–101.4%). Finally, the current colorimetric method is rapid, very simple, very sensitive with highly specific and this effortless nanosensor was practicable for environmental screening of toxic S2− ions.

Fluorescence microscopy and photodielectric characterization studies of the composite films of polyvinyl alcohol and tryptophan functionalized silver nanoparticles

Fluorescent nanocomposite films were prepared by solution mixing of polyvinyl alcohol (PVA) and tryptophan functionalized silver (AgTrp) nanoparticles. Synchrotron excitation deep-ultraviolet (DUV) fluorescence imaging was used to follow the distribution of AgTrp nanoparticles within the polymer matrix. Pronounced growth of dendrite-like structures in the presence of AgTrp nanoparticles was confirmed by bright field and fluorescence imaging as well as with atomic force microscopies. Both tryptophan and AgTrp nanoparticles influence thermal properties of the matrix. Differential scanning calorimetry measurements showed that they reduce crystallinity and significantly increase the glass transition temperature of PVA (in the case of PVA-AgTrp film the Tg increases by ~20 °C). Dielectric properties of the films were studied under two different conditions (dark and illumination). The illumination with 250 nm light induces a significant increase in conductance of the PVA-AgTrp nanocomposite. The relative changes, with respect to the conductance measured in the dark, were almost ~200%.

Arginine-Glycine-Aspartic-Modified Silver Nanoparticles Improve the In Vitro Anti-Cancer Efficacy of Adriamycin for Prostate Cancer Treatment

Prostate cancer (PC) is the most frequently diagnosed cancer in men and it is difficult to achieve the desired therapeutic effect through traditional chemotherapy. Thus, it is necessary to develop advanced strategies to treat PC. Functionalized nanoparticles have been developed as a unique tumor-targeted delivery platform for PC therapy. In this study, tumor-targeted RGD-silver nanoparticles (RGD-Ag NPs) were prepared, in which RGD could specially bind with its receptor αvβ3 integrin over-expressed on LNCaP cells. RGD-Ag NPs were adopted to load adriamycin (Am) to prepare functionalized silver nanoparticles (RGD-Ag@Am). The average particle size of RGD-Ag@Am was about 65 nm and kept under 90 nm during the 8-day trial period. LNCaP cells showed greater uptake in RGD-Ag@Am group compared to Ag@Am group, indicating active targeting of carrier RGD-Ag NPs could effectively enhance the uptake of Am in LNCaP cells. RGD-Ag@Am entered LNCaP cells in a clathrin-mediated energy-dependent manner and demonstrated an excellent pH-response release of Am under the acidic condition, which was conducive to enhancing the distribution of Am in the tumor microenvironment. RGD-Ag@Am inhibited the proliferation and invasion of LNCaP cells and induced LNCaP cell apoptosis which probably promotes the production of reactive oxygen species (ROS). It was noteworthy that RGD-Ag@Am exhibited greater anti-cancer activity in comparison with free Am and Ag@Am in the LNCaP cell model, indicating that RGD-Ag NPs had the ability to enhance the anti-cancer efficacy of Am. These findings showed that RGD-Ag@Am has promising potential for use in PC therapy.

Synthesis and Photonics Applications of Afzelechin Conjugated Silver Nanoparticles

The silver nanoparticles were synthesized, functionalized with afzelechin and characterized using UV-Visible spectroscopy. A difference of 20 nm was observed in surface plasmon resonance of bare and functionalized silver nanoparticles which indicates afzelechin conjugation with silver nanoparticles. The atomic force microscopy (AFM) technique was used for the determination of the size and morphology of synthesized silver nanoparticles. The afzelechin conjugated silver nanoparticles were spherical and their sizes ranged from 3 to 10 nm with an average size of 8 nm while the bare silver nanoparticles were also spherical and their sizes ranged from 3 to 10 nm with an average size of 6 nm. The average sizes were also calculated by fitting their UV-Visible absorption spectra. Fitting is based on the Mie and Mie Gans models, which deduced that afzelechin conjugated silver nanoparticles were 96.5% spherical and 3.5% spheroidal with an average size of 5 nm while bare silver nanoparticles were 100% spherical with an average size of 4 nm. Both the fitting model as well as the AFM results showed a difference of 3 nm between the sizes of afzelechin conjugated silver nanoparticles while 2 nm differences was observed for bare silver nanoparticles. The band gap energy of afzelechin conjugated silver nanoparticles and bare silver nanoparticles were calculated via Tauc’s equation and were found to be 5.1 eV and 5.4 eV, respectively. A difference of 0.3 eV was observed in band gap energies of afzelechin conjugated silver nanoparticles and bare silver nanoparticles.

Functionalized Silver Nanoparticles Enhance Therapeutic Effect of Paclitaxel for Prostate Cancer Therapy by Arresting the Cellular Cycle and Producing ROS

Chemotherapy has been proven to be an efficient strategy for the treatment of prostate cancer (PC). However, the insufficient cellular uptake of drugs is the biggest challenge for PC therapy. Therefore, in order to address the above concern, we developed tumor-targeted hyaluronic acid-silver nanoparticles (HA-Ag NPs), in which hyaluronic acid can specially bind with its receptor CD44 overexpressed on LNCaP cells. HA-Ag NPs have been used to load paclitaxel (PTX) to prepare functionalized silver nanoparticles (HA-Ag-PTX). The average particle size of HA-Ag-PTX was about 70 nm and kept under 120 nm for eight days. androgen-sensitive prostate cancer cells (LNCaP) cells show good uptake of HA-Ag-PTX, and HA-Ag-PTX enters LNCaP cells in a clathrin-mediated energy-dependent manner. HA-Ag-PTX exhibits an excellent pH response release of PTX under the acidic condition, which is beneficial to enhance the distribution of PTX in the tumor microenvironment. HA-Ag-PTX effectively suppresses the migration and proliferation of LNCaP cells probably by arresting the cellular cycle at [Formula: see text]0/[Formula: see text]1 phase and enhancing the production of the reactive oxygen species. It is worth mentioning that HA-Ag-PTX exhibits greater anticancer activity in comparison with free PTX in the LNCaP cell model, indicating that HA-Ag NPs can effectively enhance the anticancer efficacy of PTX. As a whole, these findings suggest that HA-Ag-PTX has promising potential for PC therapy.

DNA mediated graphene oxide (GO)-nanosheets dispersed supramolecular GO-DNA hydrogel: An efficient soft-milieu for simplistic synthesis of Ag-NPs@GO-DNA and Gram + ve/-ve bacteria-based Ag-NPs@GO-DNA-bacteria nano-bio composites

The proposition of bio-material based soft hydrogel scaffold formation is one of the pivotal triggers to have the functionally suitable nano-bio composite. In this work, calf-thymus DNA (CT-DNA) and water-exfoliated 2D graphene oxide (GO) nanosheets have been executed towards the formation of nano and bio-material based flexible supramolecular hydrogel structure to achieve nano-bio functionality. Herein, calf thymus DNA and 2D GO nanosheets meditated a supramolecular hydrogel has been employed for the sun-ray directed synthesis of supramolecular hydrogel capped functional silver nanoparticles through a green synthetic protocol by reducing Ag(I) to Ag(0) without applying any added reducing agents. The CT-DNA and 2D GO nanosheets meditated a supramolecular hydrogel capped well-designed Ag-NPs (Ag-NPs@GO-DNA) have been employed for the production of smart ultrafine bacteria-mediated nano-bio composites. In this presentation, Gram + ve bacteria (Bacillus subtilis) and Gram -ve bacteria (Escherichia coli) have been chosen as the competent living ingredients for offering new class of Ag-NPs with considerable stability through exploiting the catalytic effects of the bacteria on Ag-NPs@GO-DNA.

In vitro study on the immunomodulatory effects of differently functionalized silver nanoparticles on human peripheral blood mononuclear cells.

The interaction of silver nanoparticles (AgNPs) with the immune system has not yet been sufficiently elucidated even though they belong to the most investigated and exploited group of nanomaterials. This study aimed to evaluate immunomodulatory effect of four different AgNPs on human peripheral blood mononuclear cells (hPBMCs). Fresh hPBMCs were exposed to the small sized (~ 10 nm) AgNPs immediately after isolation from the whole blood of healthy volunteers. The study considered coating-, time- and dose-dependent response of hPBMSc and stimulation of both early and intermediate activation of lymphocytes and monocytes using flow cytometry. The AgNPs differed in surface charge and were stabilised with polyvinyl pyrrolidone (PVP), poly-L-lysine (PLL), bis(2-ethylhexyl) sulfosuccinate sodium (AOT) or blood serum albumin (BSA). Response of hPBMCs to coating agents and ionic Ag form was evaluated to distinguish their effect from the AgNPs action as they may be released from the nanosurface. There was no significant effect of any tested AgNPs on relative count of hPBMCs subpopulations. The T-cells and monocytes were not activated after treatment with AgNPs, but the highest concentration of PLL- and BSA-AgNPs decreased density of CD4 and CD8 markers on T-helper and T-cytotoxic cells, respectively. The same AgNPs activated B- and NK-cells. Ionic Ag activated T-, B- and NK-cells, but at very higher concentration, whereas only PLL exhibited immunomodulatory activity. This study evidenced immunomodulatory activity of AgNPs that may be fine-tuned by the design of their surface functionalization.Graphic abstract Supplementary InformationThe online version contains supplementary material available at 10.1007/s00775-021-01898-0.

A Sensitive SERS Method for Determination of Pymetrozine in Apple and Cabbage Based on an Easily Prepared Substrate.

Residual pesticides are one of the major food safety concerns around the world. There is a demand for simple and reliable methods to monitor pesticide residues in foods. In this study, a sensitive method for determination of pymetrozine in apple and cabbage samples using surface-enhanced Raman spectroscopy (SERS) based on decanethiol functionalized silver nanoparticles was established. The proposed method performed satisfactorily with the linear detection range of 0.01–1.00 mg/L and limit of detection (LOD) of 0.01 mg/L in methanol. In addition, it was successfully used to detect pymetrozine in apple and cabbage samples, the LOD was 0.02 and 0.03 mg/L, respectively, and the recoveries of spiked cabbage and apple ranged 70.40–104.00%, with relative standard deviations below 12.18% and 10.33% for intra-day and inter-day tests. Moreover, the results of the correlation test with real cabbage samples of liquid chromatography-tandem mass spectrometry showed that they were highly correlated (slope = 0.9895, R2 = 0.9953). This study provides a sensitive approach for detection of pymetrozine in apple and cabbage, which has great potential for determination of pymetrozine residues in food products.

Biomimetic synthesis of functional silver nanoparticles using hairy roots of Panax ginseng for wheat pathogenic fungi treatment

Presently, multifunctional silver nanoparticles (AgNPs) show a rapid growth in various commercial applications, leading to increasing demand for new eco-friendly manufacturing technologies. An array of genetic engineering tools can be used to increase the yield in the production of AgNPs using various biological systems. The present study reports a green chemistry approach for the biological synthesis of AgNPs using extracts from non-transformed callus, rolC-transgenic callus and hairy roots of Panax ginseng and an evaluation of their efficacy against crop-damaging fungal pathogens. All types of ginseng cell lines promote the reduction of silver nitrate and formation of spherical AgNPs with an average diameter of 50–90 nm. Notably, hairy root extract possessed the maximal reduction potential among the studied cell lines probably due to higher secondary metabolite content. The biosynthesized nanoparticles were highly toxic against several wheat fungal pathogens including Fusarium graminearum, F. avenaceum, F. poae, and F. sporotrichioides, which are associated with fusarium head blight disease in cereals. Furthermore, the antifungal activity of nanosilver was successfully utilized for surface sterilization of infected wheat kernels without any negative effect on seed germination capability.

Determination of Chromium(VI), Chromium(III), Arsenic(V), Aluminum(III), Iron(II), and Manganese(II) by Colorimetry and Surface-Enhanced Raman Scattering (SERS) Using Ferulic Acid Functionalized Silver Nanoparticles

Plasmonic nanoparticles having localized surface plasmon resonance in the visible and infrared region are potential candidates for the fabrication of simple, rapid, selective and specific metal ion detection systems based on colorimetry and surface-enhanced Raman spectroscopy. The study describes simple approaches for selective colorimetric and surface-enhanced Raman scattering determination of aluminum(III), chromium (VI), chromiun(III), manganese (II), iron(II) and arsenic (V) ions in aqueous medium using ferulic acid functionalized silver nanoparticles (F-AgNPs) synthesized by chemical reduction and microwave assisted method. The analysis of photographs reveals that ferulic acid functionalized silver nanoparticles synthesized by chemical reduction (C-F-AgNPs) sensitively detect Al(III) ions in aqueous media while nanoparticles synthesized by microwave reduction method can be used to determine As(V), Mn(II) and Fe(II) ions. In addition, C-F-AgNPs also enhance the Raman spectral profile of the water samples spiked by Cr(III) ions giving a peculiar vibration spectral feature that assists in the detection of Cr(III) ion in aqueous medium. Moreover, ferulic acid functionalized silver nanoparticles synthesized by the microwave assisted method (M-F-AgNPs) increase the intensity of Raman bands in the spectral profile of the water samples spiked with Cr(VI) and Mn(II) ions. The specific and selective interactions of F-AgNPs with the Cr(VI), Cr(III), Mn(II), Fe(II), Al(III) and As(V) leading to the aggregation of the dispersed silver nanoparticles enable their determination in aqueous media . The results of the present study shows the potential of F-AgNPs based sensor probes toward conceptualizing and fabricating simple, rapid and cost effective detection tools onsite determination of metal ions in aqueous media.

Functionalized silver nanoparticles synthesized from marine algae: In vitro Evaluation of Antibacterial Potential

Natural antioxidants, in particular phenolic derivatives, are used efficiently to combat against oxidative induced tissue damages. The objective of the study is to determine the antioxidant potential of methanolic extracts obtained from eight marine algal species (Enteromorpha compressa, Chaetomorpha antennina, Caulerpa racemosa, Caulerpa taxifolia, Sargassum vulgare, Padina tetrastromatica, Amphiroa fragilissima and Gracilaria corticata) by assessing their total phenolic content, DPPH scavenging assay, FRAP assay, H2O2 radical and superoxide radical scavenging activities. Among them, P.tetrastromatica, S.vulgare, E.compressa, C.taxifolia display significant antioxidant activities. Further, the aqueous extracts of these four algae are used for bioreduction of silver nitrate to silver nanoparticles (AgNPs) by green synthesis method at room temperature. UV-Visible spectrum revealed the surface plasmon resonance at 430 and 440nm. The characterizations of AgNPs by Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD) studies revealed the bioreduction and capping of AgNPs. XRD analysis elucidated the synthesized nanoparticles having face centered cubic crystalline geometry, with a mean size of 17 nm. The nanoparticles have better antimicrobial activity against cocci shaped than the rod shaped bacteria. The minimum inhibitory concentration and minimum bactericidal concentration exhibit more activity against S.aureus and B.cereus rather than E.coli.

Counteraction of Biofilm Formation and Antimicrobial Potential of Terminalia catappa Functionalized Silver Nanoparticles against Candida albicans and Multidrug-Resistant Gram-Negative and Gram-Positive Bacteria.

Biofilms not only protect bacteria and Candida species from antibiotics, but they also promote the emergence of drug-resistant strains, making eradication more challenging. As a result, novel antimicrobial agents to counteract biofilm formation are desperately needed. In this study, Terminalia catappa leaf extract (TCE) was used to optimize the TCE-capped silver nanoparticles (TCE-AgNPs) via a one-pot single-step method. Varied concentrations of TCE have yielded different sized AgNPs. The physico-chemical characterization of TCE-AgNPs using UV-Vis, SEM, TEM, FTIR, and Raman spectroscopy have confirmed the formation of nanostructures, their shape and size and plausible role of TCE bio-active compounds, most likely involved in the synthesis as well as stabilization of NPs, respectively. TCE-AgNPs have been tested for antibiofilm and antimicrobial activity against multidrug-resistant Pseudomonas aeruginosa (MDR-PA), methicillin-resistant Staphylococcus aureus (MRSA), and Candida albicans using various microbiological protocols. TCE-Ag-NPs−3 significantly inhibits biofilm formation of MDR-PA, MRSA, and C. albicans by 73.7, 69.56, and 63.63%, respectively, at a concentration of 7.8 µg/mL, as determined by crystal violet microtiter assay. Furthermore, SEM micrograph shows that TCE-AgNPs significantly inhibit the colonization and adherence of biofilm forming cells; individual cells with loss of cell wall and membrane integrity were also observed, suggesting that the biofilm architecture and EPS matrix were severely damaged. Moreover, TEM and SEM images showed that TCE-AgNPs brutally damaged the cell wall and membranes of MDR-PA, MRSA, and C. albicans. Additionally, extreme ultrastructural changes such as deformation, disintegration, and separation of cell wall and membrane from the cells, have also been observed, indicating significant loss of membrane and cell wall integrity, which eventually led to cell death. Overall, the research revealed a simple, environmentally friendly, and low-cost method for producing colloidal TCE-AgNPs with promising applications in advanced clinical settings against broad-spectrum biofilm-forming antibiotic-resistant bacteria and candida strains.

A label-free SERS sensor for the detection of Hg2+ based on phenylacetylene functionalized Ag nanoparticles

The development of a facile, rapid, precise, and ultrasensitive assay for the detection of mercury ions (Hg2+) is an urgent problem to be solved because excessive Hg2+ poses a great threat to human health and the ecological environment. Herein, a novel surface-enhanced Raman scattering (SERS) sensor which employed phenylacetylene (PA) as a label-free probe was established. The PA functionalized silver nanoparticles (PA-AgNPs) produced an intense SERS signal in the Raman-silent region, which effectively avoided the interference of solvent and overcame the signal overlap problem. In the presence of Hg2+, the PA molecules separated from the Ag surface due to the strong coordination between the alkynyl group and Hg2+, which resulted in a significant SERS signal attenuation. Basing on the proposed SERS platform, a linear relationship with a wide range from 10–10 to 10–8 M and a low detection limit of 87.6 pM were obtained. Besides, the selectivity and reproducibility of the SERS system were also investigated. What’s more, we applied the SERS sensor to analyze Hg2+ in lake water with high accuracy and excellent recovery. The obtained results demonstrated that the established SERS platform is expected to be a promising alternative tool for the determination of Hg2+ in practical application.

Simultaneous Colorimetric Sensing of Anion (I−) and Cation (Fe2+) by Protein Functionalized Silver Nanoparticles in Real Samples

Simultaneous Colorimetric Sensing of Anion (I−) and Cation (Fe2+) by Protein Functionalized Silver Nanoparticles in Real Samples

Biodegradable hydrogel with thermo-response and hemostatic effect for photothermal enhanced anti-infective therapy

Massive bleeding and infectious complication remain the leading cause of worldwide trauma deaths. To tackle this issue, a platelet-inspired degradable antibacterial hydrogel (Gel/PP-TA-Ag) is synthesized based on gelatin methacrylate (GelMA), tannic acid (TA), polyphosphate (PolyP) and gallic acid functionalized silver nanoparticles (Ag NPs) via a facile photopolymerization process. Accompanied by the degradation of the hydrogel, the released PolyP can activate the coagulation pathway, resulting in a better hemostatic effect than commercial gauze in the mice-bleeding model. Simultaneously, benefiting from hyperthermia originated from Ag NPs and photothermal accelerated release of TA and Ag+, 97.57% of methicillin-resistant Staphylococcus aureus (MRSA) and 95.99% of E. coli are eliminated in vitro. Moreover, in vivo experiments reveal that 91.76% of MRSA in wounds is removed, and the wound healing is effectively improved with more angiogenesis and collagen deposition. The level of inflammation in the wounds is also significantly reduced. As a result, Gel/PP-TA-Ag hydrogel possesses great potential in achieving satisfactory efficacy in infected wound healing.

Metal enhanced chemiluminescence nanosensor for ultrasensitive bioassay based on silver nanoparticles modified functional DNA dendrimer

A novel metal enhanced chemiluminescence (MEC) nanosensor was developed for ultrasensitive biosensing and imaging, based on functional DNA dendrimer (FDD), proximity-dependent DNAzyme and silver nanoparticles (AgNPs). The FDD containing two split G-quadruplex structures was prepared through an enzyme-free and step-by-step assembly strategy, and then reacted with AgNPs and hemin molecules to form the FDD/hemin/AgNPs facilely. Such a MEC nanosensor consisted of three modules: FDD (scaffold), the generated G-quadruplex/hemin DNAzyme (signal reporter) and AgNPs (chemiluminescence enhancer). The MEC effect was achieved by controlling the length of DNA sequences between AgNPs on the periphery of FDD and DNAzymes inside it. Such nanosensor exhibited 9-fold amplification and another 6.4-fold metal enhancement in chemiluminescence intensity, which can be easily applied into trace detection of multiple protein markers using a disposable protein immunoarray. The FDD/hemin/AgNPs-based multiplex MEC imaging assay showed wide linear ranges over 5 orders of magnitude and detection limits down to 5× 10−5 ng L−1 and 1.8 × 10−4 U mL−1 for cardiac troponin T and carcinoma antigen 125, demonstrating a promising potential in application to protein analysis and clinical diagnosis. Moreover, the MEC nanosensor can be effectively delivered into cells with excellent biocompatibility and outstanding stability, offering a new tool for detection of intracellular targets and suggesting wide applications in bioassay.