Functionalized Silver Nanoparticles Research Articles

Extracellular Matrix Mimicking Wound Microenvironment Responsive Amyloid-Heparin@TAAgNP Co-Assembled Hydrogel: An Effective Conductive Antibacterial Wound Healing Material.

Bioengineered composite hydrogel platforms made of a supramolecular coassembly have recently garnered significant attention as promising biomaterial-based healthcare therapeutics. The mechanical durability of amyloids, in conjunction with the structured charged framework rendered by biologically abundant key ECM component glycosaminoglycan, enables us to design minimalistic customized biomaterial suited for stimuli responsive therapy. In this study, by harnessing the heparin sulfate-binding aptitude of amyloid fibrils, we have constructed a pH-responsive extracellular matrix (ECM) mimicking hydrogel matrix. This effective biocompatible platform comprising heparin sulfate-amyloid coassembled hydrogel embedded with polyphenol functionalized silver nanoparticles not only provide a native skin ECM-like conductive environment but also provide wound-microenvironment responsive on-demand superior antibacterial efficacy for effective diabetic wound healing. Interestingly, both the cytocompatibility and antibacterial properties of this bioinspired matrix can be fine-tuned by controlling the mutual ratio of heparin sulfate-amyloid and incubated silver nanoparticle components, respectively. The designed biomaterial platform exhibits notable effectiveness in the treatment of chronic hyperglycemic wounds infected with multidrug-resistant bacteria, because of the integration of pH-responsive release characteristics of the incubated functionalized AgNP and the antibacterial amyloid fibrils. In addition to this, the aforementioned assemblage shows exceptional hemocompatibility with significant antibiofilm and antioxidant characteristics. Histological evidence of the incised skin tissue sections indicates that the fabricated composite hydrogel is also effective in controlling pro-inflammatory cytokines such as IL6 and TNFα expressions at the wound vicinity with significant upregulation of angiogenesis markers like CD31 and α-SMA.

Enhancement in the therapeutic efficacy of thymoquinone by its delivery through polypropylene glycol-functionalized silver nanoparticles

Metal nanoparticles with polymer capping have been used in a variety of analytical and biological applications. In this study, highly stable silver nanoparticles (AgNPs) functionalized with polypropylene glycol (PPG) were prepared using a chemical reduction approach. The drug delivery potential of the prepared PPG functionalized silver nanoparticles (PPG-AgNPs) was investigated using thymoquinone (TQ) as a model hydrophobic drug. The size, shape, drug encapsulation efficiency, and in-vitro release of PPG-AgNPs were investigated using different techniques such as Atomic force microscopy (AFM), Fourier transform infrared spectroscopy (FT-IR), UV–Visible (UV-Vis) spectroscopy, Thermogravimetric analysis (TGA), X-ray powder diffraction (PXRD), and zeta sizer. An in-vitro experiment and atomic force microscopy were used to evaluate the antibacterial activity of thymoquinone loaded in PPG-AgNPs. The antibacterial activity of TQ was significantly boosted by its delivery through PPG-AgNPs compared to the direct application of TQ. Moreover, the biofilm inhibiting potential of the PPG-AgNPs/TQ is remarkably enhanced as compared to TQ alone which is further endorsed by the microscopic analysis. Current work sheds light on the various parameters that can be tweaked to generate a variety of AgNP characteristics for enhancement in the therapeutic efficiency of drugs like thymoquinone.

Appraising the antibacterial/antioxidant activities of vancomycin as a novel nano-platfom: Characterization, in-vitro assessment and in-vivo radio-tracking in animal models

The antibacterial nano-platforms have recently been developed as a result of an increasing prevalence of the bacterial resistance to various standard antibiotics. The aim of this study is to improve the vancomycin antibacterial efficacy against various resistant-bacteria using a unique nano-platform. Vancomycin functionalized silver nanoparticles (Ag-VanNPs) were properly synthesized showing a significant UV–Vis absorbance at 426 nm, average particle size of 20 ± 4.3 nm, mean hydrodynamic size of 185 ± 8.5 nm and zeta potential of +19 mV. Ag-VanNPs were investigated for its in-vitro antibacterial activity against various (G + ve and G-ve) bacterial strains declaring a synergistic antibacterial action that outperformed pure vancomycin. Compared to free vancomycin, Ag-VanNPs had showed significant reduction in MIC/MBC concentrations with FIC/FBC indices ≤0.5, suggesting a synergistic action with fewer adverse effects. The in-vitro viability and hemolysis studies revealed that Ag-VanNPs were non-toxic and biocompatible. The in-vivo studies of [131I] I–Ag-VanNPs in normal mice model showed their in-vivo stability and elimination mainly via hepatobiliary and renal pathways. Moreover, significant accumulations of [131I] I–Ag-VanNPs in the inflammatory muscle were seen in the in-vivo distribution of the inflamed mice model, which was represented by the potential T/NT ratios ≥1 at all research time points. Therefore, [131I] I–Ag-VanNPs may have better antibacterial activities against both kinds of Gram bacteria in addition to being a promising anti-inflammatory nano-radiopharmaceutical.

Membrane Penetrating-Cationic Peptide BP100 Functionalized Silver Nanoparticles as Efficient Antibacterial Agents

Membrane Penetrating-Cationic Peptide BP100 Functionalized Silver Nanoparticles as Efficient Antibacterial Agents

Synthesis and Characterization of Silver Nanoparticles Conjugated with Triazole‐N‐acetamide Thiazole Derivatives for Selective Detection of Cymoxanil in Complex Samples

AbstractCymoxanil (CYM) is one of the most important fungicides for various vegetables and fruits. However, its routine detection is still expensive due to high‐cost equipment. In this context, the silver nanoparticle‐based colorimetric probe was synthesized using triazole‐N‐acetamide thiazole (TAT) derivative as a stabilizer. The triazole‐N‐ acetamide thiazole (TAT) derivative functionalized silver nanoparticles (TAT‐AgNPs) were used as a probe for selective, efficient, rapid and quantitative determination of CYM in tap and river water. The characterization of TAT‐AgNPs was accomplished through UV‐visible, Fourier transform infrared spectroscopy (FTIR), atomic force microscopy (AFM), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and Zetasizer analysis. Highly sensitive surface plasmonic resonance band at 400 nm indicated complete reduction of Ag+ by using 1 : 15 (v/v) (TAT: AgNO3). The limit of detection (LOD), which corresponds to signal‐to‐noise ratio 3, is 0.013 μmol L−1, showed a linear response as a function of CYM concentration from 1 to 100 μM. Furthermore, the probe shows good selectivity when exposed to a series of interfering pesticides. TAT‐AgNPs were also spiked with blood plasma and the effects of relevant interfering studies were evaluated. The nanosensor detects the CYM tap water and river water samples. It confirmed that nanosensor can detect CYM in biological and environmental samples.

Secnidazole functionalized silver nanoparticles as trace level colorimetric sensor for the detection of cadmium ions

Cadmium (Cd2+) has been declared as possible cancer causing heavy metal ion in humans and animals. Here in this research work we used an economical, facile, simpler, and one pot method for the formation of secnidazole derived silver nanoparticles (SEC-AgNPs). SEC-AgNPs were characterized through advanced techniques like, ultraviolet-visible (UV-Vis) spectroscopy, Fourier Transform infrared (FTIR) spectroscopy, dynamic light scattering (DLS) technique, zeta potential (ZP) analysis, field emission scanning electron microscopy (FESEM) and atomic force microscopy (AFM). These prepared SEC-AgNPs were investigated and verified as extremely sensitive, highly stable, rapidly responding and cost-effective colorimetric sensor for the low level detection of Cd2+. As-developed colorimetric Cd2+ sensor proved to be extremely selective in the presence of eighteen monovalent, divalent, trivalent and tetravalent metal ions and associated anions showing negligible interference with even ten-fold greater concentration of these ions as compared to Cd2+. The SEC-AgNPs based colorimetric Cd2+ sensor was linearly responsive to Cd2+ in the range of 5–27 µM with limit of detection (LOD) equal to 0.021 µM and LOQ value of 0.07 µM with R2 of 0.9965. The newly developed SEC-AgNPs based colorimetric sensor was successfully applied for cadmium detection in real tap water sample and human blood plasma samples within acceptable recovery levels.

Formation of lipid corona on Ag nanoparticles and its impact on Ag+ ion dissolution and aggregation of Ag nanoparticles against external stimuli

The application of lipid coated nanoparticles has been expanding in nanoscience over the past few years. Lipid corona formation is one of the novel ways for the lipid conjugation around the nanoparticles. Although several properties of nanoparticles and lipids are well reported in literature in last few years, the dependency of lipid corona formation on metallic core and surface ligands is poorly understood. The aggregation, surface oxidation and metal ions dissolution of nanoparticles limit their usefulness in various applications. Besides all the reported methods to overcome all of these limitations, lipid corona could be an alternative, feasible, and more efficient method. In the current manuscript, we investigate the interaction of aromatic amino acids (tyrosine and tryptophan) functionalized silver nanoparticles (Ag-Tyr and Ag-Trp NPs) with different surface charged and phase states lipid vesicles and compare them with the reported amino acid functionalized gold nanoparticles (Au-AA NPs). The effectiveness of different zwitterionic and positively charged lipid coated Ag-Tyr and Ag-Trp NPs to prevent the aggregation and Ag+ ion dissolution of Ag NPs against different external stimuli (acidic pH, high NaCl concentration, and freeze-thaw cycles) are investigated. Our results reveal that surface ligands around the NPs play crucial role for lipid corona formation irrespective of the metallic core of NPs. Although all the lipid coated Ag NPs exhibit greater stability against external stimuli than native Ag NPs, zwitterionic lipid coated Ag NPs is better choice than positively charged lipid coated Ag NPs. This study on lipid corona and its stability will help the nanoresearcher to choose the suitable lipid for lipid corona formation.

A green-micro-synthesis of curcumin functionalized silver nanoparticles for bacteria inhibition and glucose sensor electrode modifier

A novel strategy for silver nanoparticles synthesis has been developed in a simple way. The method promotes green synthesis by using demineralized water as the primary solvent, sunlight as the energy source, and the small volume of the reaction. The silver nanoparticles were obtained by utilizing the autooxidation pathways of curcumin that was dissolved in ethanol. Interestingly, the volume of curcumin at the microliter level could produce AgNPs with good properties. The materials were characterized using UV–Visible spectrophotometer, Fourier Transform Infra-Red Spectroscopy (FTIR), Scanning Electron Microscope (SEM), Transmission Electron Microscopy (TEM), Energy Dispersive X-ray Spectroscopy (EDX), and Nano Particle Analyzer. The bacterial inhibition activity of silver nanoparticles (cAgNPs) was tested against Eschericia coli ATRCC6633 and Staphylococcus aureus ATRCC6633. This material showed good activity in inhibiting Gram-negative and Gram-positive bacteria compared to the control Ag + ion and curcumin. MIC (Minimum Inhibitory Concentration) and MBC (Minimum Bactericidal Concentration) test results exhibited a good performance of cAgNPs against E. coli ATRCC6633 and S. aureus ATRCC6633. Carbon paste electrode (CPE) modified with cAgNPs was used to detect glucose using Differential Pulse Voltammetry (DPV) technique. The cAgNPs were electrodeposited on CPE using cyclic voltammetry (CV) technique. The modified electrode showed promising results to be applied for glucose detection due to its good linearity and sensitivity. In addition, this work will give new insight into a sustainable method for producing silver nanomaterials that provide good bacteria inhibition and enhance the CPE performance to detect glucose.

Detection of Fe(III) ion based on bifunctionalized silver nanoparticles: Sensitivity, selectivity and environmental safety

Functionalized silver nanoparticles (AgNPs) are widely used as optical sensors for heavy metal ions in water, due to their versatile, easy and cheap preparations and due to their peculiar physico-chemical properties. Surface functionalization plays a key role in AgNPs chemical-physical behavior as capping agents can affect sensitivity, selectivity but alsoenvironmental safety. In this framework, AgNPs are synthetised and properly functionalized using two capping agents to induce hydrophilic behavior and selectivity, respectively citrate (cit) and glutathione (GSH). The opportune choice of these capping agents induces size control and stability for AgNPs-cit-GSH in water (Ø = 4 ± 0.2 nm; ζ-potential = - 60 ± 1 mV) and make available selectively detection of Fe (III) in the range 0.5–10.0 ppm. Environmental safety was also evaluated using standardized ecotoxicity assays (ecosafety) with freshwater and marine microalgae which show a low-to-negligible effects, with exception only at the highest tested concentration (10 mg/L) but only for the freshwater one.

Valorizing pomegranate wastes by producing functional silver nanoparticles with antioxidant, anticancer, antiviral, and antimicrobial activities and its potential in food preservation

The food sector generates massive amounts of waste, which are rich in active compounds, especially polyphenols; therefore, valorizing these wastes is a global trend. In this study, we produce silver nanoparticles from pomegranate wastes, characterized by enhanced antioxidant, anticancer, antiviral, and antimicrobial properties and investigated their potential to maintain the fruit quality for sixty days in market. The pomegranate waste-mediated silver nanoparticles (PPAgNPs) were spherical shape (measured by TEM), 20 nm (Zeta sizer), negatively charged −25.98 mV (Zeta potential), and surrounded by active groups (FTIR). The PPAgNPs scavenged 94 % of DPPH radicals and inhibited the growth of pathogens, i.e., Staphylococcus aureus, Listeria monocytogenes, Campylobacter jejuni, Salmonella typhi and Candida with inhibition zones diameters (16–45 mm). They impeded the development of breast and colon cancer cell lines by 80 and 78 %, increased the activity of apoptosis marker caspase 3, and inhibited 82 % of COVID-19. The PPAgNPs were added to the rat diet at 80, 160, and 320 µg/kg levels. PPAgNPs administered at a concentration of 160 µg/kg in the rat diet resulted in the best growth performance, normal liver and kidney parameters (p = 0.029–0.038), lowered lipid profile, malondialdhyde (MDA), and raised glutathion reduced (GSH), total protein (TP). Also, the reduced gene expression of Interleukin 6 (IL-6) and Tumor necrosis factor alpha (TNF-α) in albino rats' serum indicates the anti-inflammatory effect of PPAgNPs. PPAgNPs developed a functional coating to preserve mandarin fruit for 60 days by dipping technique. The active coat containing PPAgNPs can effectively preserve the fruit for 60 days.

2]Biphenyl‐extended pillar[6]arene functionalized silver nanoparticles for catalysis and label‐free detection

AbstractSynthetic macrocycles have served as principal tools for supramolecular chemistry since their establishment, and the investigation of macrocycles‐aided organic‐inorganic hybrid nanomaterials has also attracted broad interest in chemistry and material communities during the past decade owing to their widespread applications in optical sensing, catalytic degradation, biomedicine, and other related fields. Herein, a new class of silver nanoparticles (AgNPs) modified by anionic water‐soluble [2]biphenyl‐extended pillar[6]arene (WBpP6), namely WBpP6‐AgNPs, is designed and synthesized through a facile one‐pot method. WBpP6‐AgNPs with good dispersion and stability exhibit efficient catalytic properties toward the hydrogenation of a series of aromatic nitro compounds and also show good performance in label‐free detection toward diquat.

Rhodamine B functionalized silver nanoparticles paper discs as turn-on fluorescence sensor, coupled with a smartphone for the detection of microbial contamination in drinking water.

The precise detection of pathogenic microorganisms is crucial for the reduction of water-borne diseases. Herein, a filter-paper-based florescent chemosensor was fabricated for the detection of Escherichia coli and Staphylococcus aureus contamination exploiting protein-DNA interaction between the target and a specific probe. The sensing mechanism involved the self-assembly of Rhodamine B (RhB) on silver nanoparticles (AgNPs) surface that was labeled with a single-stranded DNA probe. This causes the fluorescence quenching of RhB by a distant-dependant process. The hybridization between pathogen-specific probe and bacterial surface protein causes the release of fluorescence of RhB, which was observed under UV light. For paper-based bio-surface preparation, the mixture comprising RhB-AgNP-ssDNA was drop-casted on filter paper discs. The conditions were optimized using isolated genomic DNA of the microbes. The method was applied for E.coli detection using an eae gene-based probe targeting intimin protein and S. aureus detection using tuf gene-based probe targeting EF-tuf protein on the microbe's surface. The chemosensor had a notable specificity and selectivity for E.coli, and S. aureus, with detection limits of 0.6 × 108 and 0.37 × 103CFU/mL respectively. Moreover, the sensor was tested on real water samples, whichpresented excellent reproducibility of results (RSD ≤ 0.24%). Furthermore, the gradient change of fluorescence was captured by a smartphone, which allows direct detection of pathogens in a sensitive semi-quantitative way without the need for expensive instruments. The designed chemosensor can serve as a simple, inexpensive, and rapid method for the on-site detection of microbial contamination in drinking water.

Tannic Acid-Functionalized Silver Nanoparticles as Colorimetric Probe for the Simultaneous and Sensitive Detection of Aluminum(III) and Fluoride Ions.

In this study, we employed tannic acid (TA)-functionalized silver nanoparticles (TA@AgNPs) as colorimetric probe for the simultaneous and sensitive detection of Al(III) and F- ions. The proposed sensor was based on the aggregation and anti-aggregation effects of target Al(III) and F- ions on TA@AgNPs, respectively. Because of the strong coordination bond between Al(III) ions and TA, the addition of Al(III) ions to TA@AgNPs could cause aggregation and, hence, result in a significant change in the absorption and color of the test solution. Interestingly, in the presence of F- ions, the aggregation effect of Al(III) ions on TA@AgNPs can be effectively prevented. The extent of aggregation and anti-aggregation effects was concentration-dependent and can be used for the quantitative detection of Al(III) and F- ions. The as-proposed sensor presented the sensitive detection of Al(III) and F ions with limits of detection (LOD) of 0.2 and 0.19 μM, respectively. In addition, the proposed sensor showed excellent applicability for the detection of Al(III) and F- ions in real water samples. Moreover, the sensing strategy offered a simple, rapid, and sensitive detection procedure and could be used as a potential alternative to conventional methods, which usually involve sophisticated instruments, complicated processes, and a long detection time.

A Minor Groove Binder with Significant Cytotoxicity on Human Lung Cancer Cells: The Potential of Hesperetin Functionalised Silver Nanoparticles.

Natural drug functionalised silver (Ag) nanoparticles (NPs) have gained significant interest in pharmacology related applications due to their therapeutic efficiency. We have synthesised silver nanoparticle using hesperetin as a reducing and capping agent. This work aims to discuss the relevance of the hesperetin functionalised silver nanoparticles (H-AgNPs) in the field of nano-medicine. The article primarily investigates the anticancer activity of H-AgNPs and then their interactions with calf thymus DNA (ctDNA) through spectroscopic and thermodynamic techniques. The green synthesised H-AgNPs are stable, spherical in shape and size of 10 ± 3nm average diameter. The complex formation of H-AgNPs with ctDNA was established by UV-Visible absorption, fluorescent dye displacement assay, isothermal calorimetry and viscosity measurements. The binding constants obtained from these experiments were consistently in the order of 104 Mol-1. The melting temperature analysis and FTIR measurements confirmed that the structural alterations of ctDNA by the presence of H-AgNPs are minimal. All the thermodynamic variables and the endothermic binding nature were acquired from ITC experiments. All these experimental outcomes reveal the formation of H-AgNPs-ctDNA complex, and the results consistently verify the minor groove binding mode of H-AgNPs. The binding constant and limit of detection of 1.8μM found from the interaction studies imply the DNA detection efficiency of H-AgNPs. The cytotoxicity of H-AgNPs against A549 and L929 cell lines were determined by in vitro MTT cell viability assay and lactate dehydrogenase (LDH) assay. The cell viability and LDH enzyme release are confirmed that the H-AgNPs has high anticancer activity. Moreover, the calculated LD50 value for H-AgNPs against lung cancer cells is 118.49µl/ml, which is a low value comparing with the value for fibroblast cells (269.35µl/ml). In short, the results of in vitro cytotoxicity assays revealed that the synthesised nanoparticles can be considered in applications related to cancer treatments. Also, we have found that, H-AgNPs is a minor groove binder, and having high DNA detection efficiency.

Spinach protein-capped silver nanoparticles with low hemolytic activity inhibit methicillin-resistant Staphylococcus aureus biofilm formation as a new therapeutic approach

BackgroundThe methicillin-resistant Staphylococcus aureus (MRSA) was designated as a high-priority pathogen by the World Health Organization. Cardiovascular and thoracic surgery complications frequently involve MRSA infection. Treatment of newly emerging resistant S. aureus strains is clinically challenging due to the natural tendency of MRSA survival through biofilm formation. The failure of traditional antibiotic therapy necessitates development of next-generation therapeutic molecules. ObjectivesSilver nanoparticles were investigated to treat MRSA in order to overcome the challenges of antibiotic therapy. MethodsSpinach protein functionalized silver nanoparticles (SPAgNPs) were synthesized by reducing with sodium borohydride. The resazurin microtiter assay was used to determine the minimum inhibitory concentration (MIC) of SPAgNPs against MRSA. The antibiofilm activity was investigated using a crystal violet assay at sub-MIC levels and validated using scanning electron microscopy. To demonstrate the mechanism of action of SPAgNPs, the virulence factors involved in MRSA biofilm formation were examined. SEM was used to evaluate the hemocompatibility of human red blood cells. Results and conclusionThe synthesized SPAgNPs showed characteristic yellow colour with surface Plasmon resonance maximum at 418 nm. Powder X-ray diffraction and transmission electron microscopy analysis confirmed that the particles are crystalline with a size range from 14 to 40 nm. SPAgNPs have antibacterial activity at a minimum inhibitory concentration (MIC) of 1.25 mM, killing MRSA via disrupting membrane integrity and producing excess reactive oxygen species. Strikingly, SPAgNPs inhibit MRSA biofilm formation at sub-MIC (0.625 mM). Scanning electron microscopy study reveals that SPAgNPs trigger biofilm inhibition without causing cell damage. Hence the NPs are very effective in preventing pathogens from triggering stress responses. SPAgNPs suppress exopolysaccharide production, cell surface hydrophobicity, and staphyloxanthin biosynthesis. Testing SPAgNPs against human red blood cells reveals that NPs do not harm human cells, suggesting that the SPAgNPs are biocompatible. The findings show that SPAgNPs could be explored as next-generation materials for treating MDR pathogenic infection linked with biofilms.

Crown ether functionalized silver nanoparticles for colorimetric detection of alkali earth metals in real boiler feed water samples

Crown ether functionalized silver nanoparticles for colorimetric detection of alkali earth metals in real boiler feed water samples

A colorimetric and fluorometric dual-mode probe for Cu2+detection based on functionalized silver nanoparticles.

A novel colorimetric/fluorescent probe (AgNPs-GSH-Rh6G2) was prepared by linking silver nanoparticles (AgNPs) with rhodamine 6G derivative (Rh6G2) using glutathione (GSH) as a linker molecule. The prepared probe showed obvious fluorescence change and colorimetric response after adding copper ions. Based on this phenomenon, a colorimetric/fluorescence dual-mode detection method was constructed to recognize copper ions. The linear ranges of fluorescence detection and colorimetric detection were 0.10 to 0.45mM and 0.15 to 0.65mM, respectively, and the limit of detection were 0.18μM and 24.90 μΜ. In addition, the dual-mode probe has achieved satisfactory results in the detection of copper ions in sediment samples. The successful construction of AgNPs-GSH-Rh6G2 not only provide a reliable tool for the detection of copper ions, but also shed light on a new idea for the multi-mode development of the detection platform.

Deposition of Daldinia starbaeckii (ELF) functionalized silver nanoparticles on urinary catheter tube using chitosan polymer to prevent microbial biofilms formation during UTI infection.

Catheter-associated urinary tract infections (CAUTI) are the most common healthcare problem in hospitals. In this study, we isolated the Daldinia starbaeckii (An endolichenic fungus from Roccella montagnie) and its biomass extract were used to simultaneously synthesize and deposit DSFAgNPs on the inner and outer surfaces of the catheter tube using chitosan biopolymer via In-situ deposition method. Perfectly designed D. starbaeckii extract functionalized DSFAgNPs were characterized by UV spectroscopy, FTIR, SEM, EDS, TEM, and XRD. The microbial efficacy of DSFAgNPs & DSFAgNPs coated catheter (CTH3) was evaluated against eight human pathogenic gram (+ / -) ive strains and Candida albicans. Results indicated DSFAgNPs showed significant biological activity against both gram (+ / -) ive bacteria with an average MIC90 of 4µl/ml. The most promising activity was observed against Helicobacter pylori. When bacteria strains allow to grow with CTH3 we reported significant reduction in colony formation unit (CFU/ml) in broth culture assay with an average 70% inhibition. Further, antibiofilm activity of CTH3 against P. aeruginosa showed strong inhibition of biofilm formation (85%). The study explored an alternate approach for significantly prevent CAUTI among hospital patients. We isolated an endolichenic fungus from lichen Roccella montagnei. The molecular characterization of fungus identified as Daldinia starbaeckii (DSF). The DSF was cultured and its fungal biomass exudes were used to simultaneously construct DSF-AgNPs and its deposition on the catheter surface using biopolymer chitosan via In-situ deposition method. Further, antimicrobial and antibiofilm efficacy of DSF-AgNPs was checked against urinary catheter contaminating and human pathogenic bacterial strains. Based on our research, we determined that DSF-AgNPs coating on a urinary catheter through this method is a cost-effective, eco-friendly approach to prevent catheter contamination.

A novel colorimetric/fluorescent dual-signal probe based on silver nanoparticles functionalized with L-cysteine and rhodamine 6G derivatives for copper ion detection and cell imaging

The dual-signal probe utilizing functionalized silver nanoparticles (AgNPs) is a promising sensing tool. Herein, a novel colorimetric/fluorescent dual-signal probe (AgNPs-L-Cys-Rh6G2) was fabricated for copper ion (Cu2+) detection and cell imaging by using L-cysteine as a “bridge” to connect AgNPs and rhodamine 6G derivatives. The AgNPs-L-Cys-Rh6G2 probe exhibits a dual-signal response to Cu2+ due to Rh6G2 hydrolysis, resulting in a high fluorescence response and a significant change in color from light yellow to pink under sunlight. The linear detection ranges of the AgNPs-L-Cys-Rh6G2 probe for Cu2+ were 100–450 μM and 150–650 μM using fluorescent and colorimetry methods, respectively. The detection limits were as low as 0.169 μM and 1.36 μM, respectively. Meanwhile, the proposed probe was applied to detect Cu2+ in the actual sediment with satisfactory recovery and low relative standard deviation. Furthermore, the probe was further employed for fluorescence imaging in HeLa cells. In brief, the developed AgNPs-L-Cys-Rh6G2 sensing platform can be used for simultaneous Cu2+ determination and cell imaging.

Facile ultrasonication-assisted synthesis of Purpald-functionalized silver nanoparticles for the rapid spectrophotometric detection of acetamiprid pesticide in food and environmental samples

In this work, we report a highly sensitive and selective colorimetric assay using purpald functionalized silver nanoparticles (P-AgNPs) as a probe for the detection of acetamiprid pesticide in food and environmental samples using Ultraviolet–visible (UV–Vis) spectrophotometric analysis. Several methods, including Fourier transforms infrared spectroscopy, X-ray diffraction spectroscopy, Transmission electron microscopy, X-ray photoelectron spectroscopy and Dynamic light scattering, were used to characterize the synthesized P-AgNPs. As prepared P-AgNPs were spherical in shape and the average particle size was determined to be 17.69 ± 0.3 nm based on TEM analysis. The surface plasmon resonance (SPR) band for P-AgNPs was observed at 445 nm (Visible spectral region). Interestingly, increased acetamiprid pesticide concentration in the sample solution, shows decreased SPR band absorbance due to aggregation of P-AgNPs by electrostatic repulsion. Results showed an excellent linearity range 2.49 to 82.06 µM and the lowest detection limit was 36 nM, the present method is applied to detect acetamiprid pesticide in a variety of environmental and food samples, including soil samples, tomato, carrot, bean, cabbage and cucumber samples, as well as tap and drinking water. Results indicate good accuracy and precision. Therefore, the presented method is proven to be a simple, fast, low-cost and efficient method for analysis of pesticides in food and environmental samples.