Facile and eco-friendly fabrication of AgNPs coated silk for antibacterial and antioxidant textiles using honeysuckle extract

SERS analysis, DFT, and solution effects regarding the structural and optical characteristics of folic acid biomolecule adsorbed on a Cu3 metal cluster

The optical characteristics of folic acid (ABP) and metal clusters of copper (Cu3) at various locations were investigated by means of density functional theory (DFT) computations. Mulliken charge analysis and molecular electrostatic potential (MEP) surface show how charge moves from Cu3 to ABP through the various groups. The peak in the UV-Vis spectra of ABP-Cu3 is caused by bonding and anti-bonding orbitals. In both vacuum and aqueous conditions, the polarizability values of ABP-Cu3 cluster are significantly higher than those of pure ABP, indicating a possible enhancement of the nonlinear optical (NLO) effect. Our research investigates the possibility of using ABP adsorbed metal clusters for NLO materials. Surface enhanced Raman scattering (SERS) in the ABP adsorbed metal clusters enhances the vibrational modes of ABP. Adsorption energies are found to be in the range -17.08 to -58.52 kcal/mol in vacuum and -53.34 to -93.44 kcal/mol in aqueous medium for the different configurations for ABP-Cu3. It indicates that metal clusters adsorbed by ABP are stable in the aqueous media. Experimental IR and UV-Vis of ABP is in agreement with theoretically predicted ones.

Natural Extracts for Antibacterial Applications

Bacteria-induced epidemics and infectious diseases are seriously threatening the health of people around the world. In addition, antibiotic therapy has been inducing increasingly more serious bacterial resistance, which makes it urgent to develop new treatment strategies to combat bacteria, including multidrug-resistant bacteria. Natural extracts displaying antibacterial activity and good biocompatibility have attracted much attention due to greater concerns about the safety of synthetic chemicals and emerging drug resistance. These antibacterial components can be isolated and utilized as antimicrobials, as well as transformed, combined, or wrapped with other substances by using modern assistive technologies to fight bacteria synergistically. This review summarizes recent advances in natural extracts from three kinds of sources-plants, animals, and microorganisms-for antibacterial applications. This work discusses the corresponding antibacterial mechanisms and the future development of natural extracts in antibacterial fields.

The Effects of the Mixed Fermentation of Honeysuckle Cereal Mixed Flour on the Dough Characteristics and Bread Quality

This study investigated the effects of the mixed solid fermentation of honeysuckle cereal mixed flour with lactic acid bacteria and yeast on dough characteristics and bread quality. Honeysuckle powder and whole wheat flour were mixed to make reconstituted cereal flour, and yeast and Lactobacillus plantarum were implanted and mixed to make dough for fermentation. The dynamic rheological properties of the dough were determined, and the properties of the reconstituted cereal flour bread were determined, including the texture characteristics and color; then, the sensory evaluation and antioxidant capacity of the bread were determined. The storage modulus (G′) and loss modulus (G″) of the dough increased gradually with the increase in the honeysuckle powder content, and the loss tangent value, tanδ (G″/G′), was less than 1.0. The loss tangent value of the dough had no significant change (p > 0.05) with the increase in honeysuckle powder content; the L* value of the bread decreased from 88.50 to 76.00, the a* value increased from −1.87 to 0.79, and the b* value decreased from 21.04 to 13.68 with the increase in the amount of honeysuckle powder. When the honeysuckle powder addition was 4%, the reconstituted cereal bread was bright yellow and gave off a hint of bean and wheat flavor and had the best taste and quality. The hardness, chewiness, and the recovery of the bread decreased when the content of the honeysuckle powder was in the range of 0~4%, but the elasticity and the antioxidant and antiaging activity of the bread increased significantly (p > 0.05). It was determined that the best content of honeysuckle powder was 4%. The mixed microbial fermentation of honeysuckle cereal mixed flour can improve the quality and enhance the nutritional value of bread.

Fabricating Antibacterial Polyethylene Terephthalate Substrates Through an Industrial Approach by Applying Emulsions of Copper-Based Nanoparticles

In this research, various emulsions of copper-based nanoparticles were synthesized through the chemical reduction method followed by utilizing the pad–dry–cure technique as an industrial approach to manufacturing bactericidal polyethylene terephthalate (PET) substrates. Copper sulfate/copper acetate, sodium hypophosphite (SHP)/ascorbic acid, and cetyltrimethylammonium bromide were employed as salts, reducing agents, and stabilizers, respectively. Also, a spin finish oil was used for forming an emulsion. The effects of type and amount of copper salt and reductant as well as the use of resin and stabilizer were investigated concerning antibacterial activities, weight, and color changes of coated samples to find optimum formulation. Field-emission scanning electron microscope (FESEM) images, mapping/energy-dispersive spectroscopy (EDX), X-ray diffraction (XRD) pattern, Raman spectroscopy, and UV–visible spectrophotometer was proved successful in synthesis and loading of copper-based emulsions on the PET substrates. The results revealed that change of copper salt, substituting SHP with ascorbic acid, the addition of resin, and the use of surfactant yielded negligible effect, enhancing impact, reducing the influence, and improving efficacy on bactericidal characteristics of the treated samples, respectively. Based on findings, the samples coated by emulsion containing only copper sulfate/SHP and emulsion including only copper acetate were considered optimum samples indicating 100% bactericidal properties against both S. aureus and E. coli pathogenic bacteria. Despite showing bactericidal activities, it was further found that the treated samples exhibited cell toxicity toward human skin cells implying their applications in indirect contact usages. Coated samples further indicated a good washing fastness even after 20 washing cycles. This route can be considered as a facile industrially applicable method for imparting bactericidal properties to polymeric substrates. Furthermore, such emulsions can potentially be consumed as an antibacterial spin finish oil in melt-spinning to develop antibacterial textiles.

Metal nanoparticles produced by plants with antibacterial properties against Staphylococcus aureus

Staphylococcus aureus (S. aureus) is a pathogenic bacteria that causes a variety of potentially fatal infections. The emergence of antibiotic-resistant strains of S. aureus has made treatment even more difficult. In recent years, nanoparticles have been used as an alternative therapeutic agent for S. aureus infections. Among various methods for the synthesis of nanoparticles, the method utilizing plant extracts from different parts of a plant, such as root, stem, leaf, flower, seeds, etc. is gaining widespread usage. Phytochemicals present in plant extract are an inexpensive, eco-friendly, natural material that act as reducing and stabilization agent for the nanoparticle synthesis. The utilization of plant-fabricated nanoparticles against S. aureus is currently in trend. The current review discusses recent findings in the therapeutic application of phytofabricated metal-based nanoparticles against Staphylococcus aureus.

The Ameliorative Role of Eugenol against Silver Nanoparticles-Induced Hepatotoxicity in Male Wistar Rats

Background

Silver nanoparticles (AgNPs) utilization is becoming increasingly popular. The existing investigation evaluates the ameliorative impact of eugenol (Eug) against the toxic influences of AgNPs on rats' liver.

Methods

Sixty adult male rats were enrolled equally into control, Eug (100 mg kg⁻¹ orally), AgNPs-low dose (1 mg kg⁻¹ i.p), AgNPs-high dose (2 mg kg⁻¹ i.p), Eug + AgNPs-low dose (100 mg kg⁻¹ orally + 1 mg kg⁻¹ i.p), and Eug + AgNPs high dose (100 mg kg⁻¹ orally + 2 mg kg⁻¹ i.p). All the groups were treated daily for 30 days, subsequently serum aspartate transaminase (AST), alanine transaminase (ALT), alkaline phosphatase (ALP), total protein, total albumin, lactate dehydrogenase (LDH), total oxidative capacity (TOC), malondialdehyde (MDA), tumor necrosis factor-alpha (TNF-α), total antioxidant capacity (TAC), and interleukin 6 (IL-6) levels were measured; hepatic tissues superoxide dismutase (SOD), catalase (CAT), reduced glutathione (GSH), and glutathione peroxidase (GPx) levels were evaluated; histopathology and histomorphometry were documented in the liver of all groups; and Bcl-2, P53, Caspase-3, and TNF-α reactive proteins were also immunohistochemically detected.

Results

AgNPs significantly triggered oxidative stress in hepatic tissues, characterized by elevated levels of AST, ALT, ALP, LDH, TOC, MDA, TNF-α, and IL-6 correlating with considerable decline in total protein, total albumin, TAC, SOD, CAT, GSH, and GPx. These changes were paralleled with histopathological alterations remarkable by devastation of the ordinary hepatic structure, with decrease in the numbers of normal hepatocytes, elevation in the numbers of necrotic hepatocytes, periportal and centrilobular inflammatory cells, deteriorated Kupffer cells, and dilated/congested central and portal veins. Alongside, a marked diminution in Bcl-2 immunoreactivity and a significant elevation in P53, Caspase-3, and TNF-α immunoreactivities were recorded. Supplementation of AgNPs-treated animals with Eug reversed most of the biochemical, histopathological, and immunohistochemical changes.

Conclusion

This study proposed that Eug has an ameliorative effect against AgNPs-induced hepatotoxicity.

Lonicera caerulea (Haskap berries): a review of development traceability, functional value, product development status, future opportunities, and challenges

Lonicera caerulea is a honeysuckle plant with a long development history. It is defined as a "homology of medicine and food" fruit because it is rich in bioactive substances. By-products (such as pomace, leaves, stems, and flowers), which also have beneficial values, will be produced during processing. Nevertheless, the reuse of derivatives and the further development of new products of Lonicera caerulea are still a challenge. Firstly, this paper traced the development history of Lonicera caerulea and summarized its primary nutrients and bioactive substances, subsequently discussed the research progress and underlying molecular mechanisms of its functional properties, and introduced the application and potential of Lonicera caerulea in the fields of food, health products, cosmetics, medicine, and materials. Finally, this paper put forward the future research direction to promote the development of the Lonicera caerulea industry. To sum up, Lonicera caerulea, as a potential raw material, can be used to produce more functional products. Besides, more in-depth clinical trials are needed to clarify the specific molecular mechanism of the practical components of Lonicera caerulea and improve the rate of development and utilization.HighlightsThe original species of Lonicera caerulea subgroup had appeared on the earth as early as the end of the third century.Lonicera caerulea has been introduced into North America since the 18th century, but the introduction process has not ended until now.Lonicera caerulea widely exists in Eurasia and North America and it has excellent cold tolerance, early maturity and ornamental.The fruits, stems, leaves and flowers of Lonicera caerulea all have bioactive value, but the specific molecular mechanism and utilization need to be improved.Lonicera caerulea has been widely used in food, medicine, health products, cosmetics and materials, but there are still great challenges.

Systematic Study on a Quantitative Analysis of Multicomponents by Single Marker (QAMS) Method for Simultaneous Determination of Eight Constituents in Pneumonia Mixture by UPLC-MS/MS

Pneumonia mixture was formulated and is available to treat children acute pneumonia and acute bronchitis in our hospital for nearly forty years, but there are few studies of its quality evaluation or control. In this paper, a new strategy for quality evaluation of pneumonia mixture was explored and verified through qualitative and quantitative analyses of multicomponents by single marker (QAMS) by UPLC-MS/MS. Baicalein was selected as an internal reference, and the relative correction factors (RCFs) and the relative retention time (RRT) of (R, S)-goitrin, amygdalin, chlorogenic acid, pseudoephedrine hydrochloride, ephedrine hydrochloride, ammonium glycyrrhizinate, and baicalin were established. The robustness and durability of the QAMS method were investigated. RCF values calculated by the average (AVG) method and linear regression (LRG) method had good repeatability and were acceptable for quantitative analysis, and the RTT combined with the exact masses of precursor and fragment ions and their abundance could be adopted for accurately positioning the chromatographic peak of the eight constituents. The consistency and feasibility of the QAMS method were verified by comparing the contents of the seven components calculated by a classic and validated external standard method (ESM) with those of the QAMS method, which reduces analytical cost and time of detection and avoids the problem of the diversity and large quantity of reference standards. The results demonstrated that the QAMS method developed in this paper could provide a new, alternative, and promising method to comprehensively and effectively determine multicomponents and control the quality of pneumonia mixture or even a group of similar medicines.

Characterization and Antimicrobial Activity of Silver Nanoparticles Synthesized with the Peel Extract of Mango

The green synthesis of silver nanoparticles (AgNPs) from biological waste, as well as their excellent antibacterial properties, is currently attracting significant research attention. This study synthesized AgNPs from different mango peel extract concentrations while investigating their characteristics and antibacterial properties. The results showed that the AgNPs were irregular with rod-like, spherical shapes and were detected in a range of 25 nm to 75 nm. The AgNPs displayed antibacterial activity against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus), showing a more significant impact when synthesized with 0.20 g/mL of mango peel extract. Therefore, the antibacterial effect of different diluted AgNP concentrations on the growth kinetic curves of E. coli and S. aureus after synthesis with 0.20 g/mL mango peel extract was analyzed. The results indicated that the AgNP antibacterial activity was higher against S. aureus than against E. coli, while the AgNP IC50 in these two strains was approximately 1.557 mg/mL and 2.335 mg/L, respectively. This research provides new insights regarding the use of postharvest mango byproducts and the potential for developing additional AgNP composite antibacterial materials for fruit and vegetable preservation.

Preparation, characterization, and antibacterial properties of hybrid nanofibrous scaffolds for cutaneous tissue engineering

Since polymeric nanofibrous scaffolds have been widely used in tissue regeneration, the risk of bacterial infections should not be neglected. In the present work, poly-caprolactone-silk fibroin-soluble eggshell membrane-silver nanoparticles (PCL-SF-SESM-AgNPs) and caprolactone-silk fibroin-soluble eggshell membrane-chitosan (PCL-SF-SESM-CS) scaffolds were fabricated via the electrospinning method for cutaneous regeneration. The composition, morphology, hydrophilicity, and mechanical features of prepared scaffolds were evaluated using Fourier transform infrared (FT-IR), scanning electron microscope (SEM), tensile, and water contact angle tests. The existence of AgNPs in PCL/SF/SESM/AgNPs nanofibers was confirmed by UV-visible, Transmission electron microscopes (TEM), and X-Ray Diffraction (XRD) patterns. Besides, cell adhesion, proliferation, and differentiation process of cutaneous progenitor cells, namely basal cell carcinoma (BCCs), toward keratinocyte-like cells were evaluated using MTT analysis, DAPI, Immunofluorescence imaging (IF), and Real-Time Quantitative Reverse Transcription PCR (QRT-PCR) assay. The results indicated that prepared nanofibrous mats are appropriate candidates for cutaneous regeneration and in advanced in vivo applications could be used. Lastly, the antimicrobial potential of prepared nanofibers against microorganisms such as E. coli, S. aureus, and C. Albicans was analyzed using the disc diffusion method. Results revealed that chitosan-containing nanofibrous scaffolds indicate inhibition against S. aureus, but PCL-SF-SESM as control group not. In addition, against C. albicans any antifungal activity was not observed.

The antimicrobial effect of 400 nm femtosecond laser and silver nanoparticles on gram-positive and gram-negative bacteria

Silver nanoparticles are well-known for their antimicrobial effect. However, they are potentially toxic in high doses. We explored the possibility of enhancing the bactericidal effect of low concentrations of silver nanoparticles with blue light femtosecond laser irradiation, since such concentrations are less toxic. The growth dynamics of Pseudomonas aeruginosa, Listeria monocytogenes and methicillin-resistant Staphylococcus aureus grown in pre-synthesized silver nanoparticles were measured with or without pre-irradiation with 50 mW and 400 nm femtosecond laser irradiation. With each bacterium, combined treatment with laser and silver nanoparticles significantly reduced bacterial growth, indicating that this form of treatment could be beneficial in the ongoing efforts to reduce the deleterious effects of antibiotic resistant Gram-positive and Gram-negative bacteria. The combined treatment was more antimicrobial than treatment with silver nanoparticles alone or photo-irradiation alone. P. aeruginosa and L. monocytogenes were more susceptible to the bactericidal effects of silver nanoparticles, and the combination of laser treatment and silver nanoparticles than MRSA.

Silver Nanoparticles Stabilized with Phosphorus-Containing Heterocyclic Surfactants: Synthesis, Physico-Chemical Properties, and Biological Activity Determination

Phosphorus-containing heterocyclic cationic surfactants alkyldimethylphenylphospholium bromides with the alkyl chain length 14 to 18 carbon atoms were used for the stabilization of silver nanodispersions. Zeta potential of silver nanodispersions ranges from +35 to +70 mV, which indicates the formation of stable silver nanoparticles (AgNPs). Long-chain heptadecyl and octadecyl homologs of the surfactants series provided the most intensive stabilizing effect to AgNPs, resulting in high positive zeta potential values and smaller diameter of AgNPs in the range 50–60 nm. A comparison with non-heterocyclic alkyltrimethylphosphonium surfactants of the same alkyl chain length showed better stability and more positive zeta potential values for silver nanodispersions stabilized with heterocyclic phospholium surfactants. Investigations of biological activity of phospholium-capped AgNPs are represented by the studies of antimicrobial activity and cytotoxicity. While cytotoxicity results revealed an increased level of HepG2 cell growth inhibition as compared with the cytotoxicity level of silver-free surfactant solutions, no enhanced antimicrobial action of phospholium-capped AgNPs against microbial pathogens was observed. The comparison of cytotoxicity of AgNPs stabilized with various non-heterocyclic ammonium and phosphonium surfactants shows that AgNPs capped with heterocyclic alkyldimethylphenylphospholium and non-heterocyclic triphenyl-substituted phosphonium surfactants have the highest cytotoxicity among silver nanodispersions stabilized by the series of ammonium and phosphonium surfactants.

Rapid Antibacterial Effects of Silk Fabric Constructed through Enzymatic Grafting of Modified PEI and AgNP Deposition

Enzymatic antibacterial finishing is an eco-friendly alternative to develop functional silk-based materials. However, the low accessibility of tyrosine residues distributed in fibroin chains restricts the laccase-mediated functionalization of silk fibers (SF). To address this issue, a highly reactive p-hydroxyphenylacetic acid-modified polyethyleneimine (mPEI) was enzymatically grafted onto fibroin using laccase, aiming at constructing an antibacterial matrix of mPEI on the fiber surface. Subsequently, in situ deposition of silver nanoparticles (i.e., AgNPs) into the newly built mPEI network was performed to form a rapid antibacterial layer. The results indicated that laccase efficiently catalyzes the mPEI coupling, the zeta potential of SF-g-mPEI increases from -32 to 21.70 mV, and the silver content reaches 1.81% after AgNP embedment. Based on the combined two-step treatments, the obtained silk fabric exhibited excellent antibacterial abilities against two bacteria, including Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli). The antibacterial rates of both bacteria reached 99.9% within 30 min of contact, remaining over 99.9% within 18 h of contact even after washing 10 times. The present work provides an enzyme-mediated method for construction of silk fabric with durable and rapid antibacterial activity.

Green Synthesized Silver Nanoparticles Immobilized on Activated Carbon Nanoparticles: Antibacterial Activity Enhancement Study and Its Application on Textiles Fabrics

This research aimed to enhance the antibacterial activity of silver nanoparticles (AgNPs) synthesized from silver nitrate (AgNO3) using aloe vera extract. It was performed by means of incorporating AgNPs on an activated carbon nanoparticle (ACNPs) under ultrasonic agitation (40 kHz, 2 × 50 watt) for 30 min in an aqueous colloidal medium. The successful AgNPs synthesis was clarified with both Ultraviolet-Visible (UV-Vis) and Fourier Transform Infrared (FTIR) spectrophotometers. The successful AgNPs-ACNPs incorporation and its particle size analysis was performed using Transmission Electron Microscope (TEM). The brown color suspension generation and UV-Vis's spectra maximum wavelength at around 480 nm confirmed the existence of AgNPs. The particle sizes of the produced AgNPs were about 5 to 10 nm in the majority number, which collectively surrounded the aloe vera extract secondary metabolites formed core-shell like nanostructure of 8.20 ± 2.05 nm in average size, while ACNPs themselves were about 20.10 ± 1.52 nm in average size formed particles cluster, and 48.00 ± 8.37 nm in average size as stacking of other particles. The antibacterial activity of the synthesized AgNPs and AgNPs-immobilized ACNPs was 57.58% and 63.64%, respectively (for E. coli); 61.25%, and 93.49%, respectively (for S. aureus). In addition, when the AgNPs-immobilized ACNPs material was coated on the cotton and polyester fabrics, the antibacterial activity of the materials changed, becoming 19.23% (cotton; E. coli), 31.73% (polyester; E. coli), 13.36% (cotton; S. aureus), 21.15% (polyester; S. aureus).

Multifunctional hybrid nanoplatform based on Fe3O4@Ag NPs for nitric oxide delivery: development, characterization, therapeutic efficacy, and hemocompatibility

The combination of Fe₃O₄@Ag superparamagnetic hybrid nanoparticles and nitric oxide (NO) represents an innovative strategy for a localized NO delivery with a simultaneous antibacterial and antitumoral actions. Here, we report the design of Fe₃O₄@Ag hybrid nanoparticles, coated with a modified and nitrosated chitosan polymer, able to release NO in a biological medium. After their synthesis, physicochemical characterization confirmed the obtention of small NO-functionalized superparamagnetic Fe₃O₄@Ag NPs. Antibacterial assays demonstrated enhanced effects compared to control. Bacteriostatic effect against Gram-positive strains and bactericidal effect against E. coli were demonstrated. Moreover, NO-functionalized Fe₃O₄@Ag NPs demonstrated improved ability to reduce cancer cells viability and less cytotoxicity against non-tumoral cells compared to Fe₃O₄@Ag NPs. These effects were associated to the ability of these NPs act simultaneous as cytotoxic (necrosis inductors) and cytostatic compounds inducing S-phase cell cycle arrest. NPs also demonstrated low hemolysis ratio (<10%) at ideal work range, evidencing their potential for biomedical applications. Targeted and hemocompatible nitric oxide-releasing multi-functional hybrid nanoparticles for antitumor and antimicrobial applications.

Eco-Friendly and Facile Synthesis of Antioxidant, Antibacterial and Anticancer Dihydromyricetin-Mediated Silver Nanoparticles

Background

Dihydromyricetin (DMY), a natural flavonoid, has reportedly antibacterial, antioxidant, anticancer and other properties. In the present study, DMY was used as a reducing agent and stabilizer to synthesize silver nanoparticles (AgNPs), and the optimal conditions for its synthesis were studied. The DMY-AgNPs were investigated for their DPPH scavenging properties and their potential against human pathogenic and food-borne bacteria viz. Escherichia coli (E. coli), and Salmonella. In addition, DMY-AgNPs also showed excellent inhibitory effects on cancer Hela, HepG2 and MDA-MB-231 cell lines.

Methods

The dihydromyricetin-mediated AgNPs (DMY-AgNPs) were characterized by ultraviolet-visible spectrophotometer (UV-Vis spectra), scanning electron microscopy (SEM), transmission electron microscopy (TEM), dynamic light scattering (DLS), Fourier-transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), and X-ray powder diffraction (XRD). Antioxidant activity of DMY-AgNPs was determined by 1.1-diphenyl-2-picrylhydrazyl (DPPH) scavenging. The antibacterial activity was determined by 96-well plate (AGAR) gradient dilution, while anticancer potential was determined by MTT assay.

Results

The results showed that the dispersion of AgNPs had the maximum UV-visible absorption at about 410 nm. The synthesized nanoparticles were almost spherical. FTIR was used to identify functional groups that may lead to the transformation of metal ions into nanoparticles. The results showed that the prepared AgNPs were coated with biological molecules in the extraction solution. The biosynthesized DMY-AgNPs exhibited good antioxidant properties, at various concentrations (0.01-0.1mg/mL), the free radical scavenging rate was about 56-92%. Furthermore, DMY-AgNPs possessed good antibacterial properties against Escherichia coli (E. coli), and Salmonella at room temperature. The minimum inhibitory concentrations (MIC) were 10^-6 g/L, and 10^-4 g/L, respectively. The bioactivity of DMY-mediated AgNPs was studied using MTT assay against Hela, HepG2 and MDA-MB-231 cancer cell lines, and all showed good inhibitory effects.

Conclusion

The present study provides a green approach for the synthesis of DMY-AgNPs which exhibited stronger antioxidant, antibacterial and anticancer properties compared to the dihydromyricetin. DMY-AgNPs can serve as an economical, efficient, and effective antimicrobial material for its applications in food and pharmaceutical fields.

Green and Facile Synthesis and Antioxidant and Antibacterial Evaluation of Dietary Myricetin-Mediated Silver Nanoparticles

Myricetin (MY) is a dietary flavonoid which exhibits a wide spectrum of biological properties, viz., antibacterial, antioxidant, anticancer, and so forth. The lower solubility in aqueous medium and hence lesser bioavailability of MY limits the use of such dietary flavonoids in further in vivo research. To overcome bioavailability limitations, a number of drug-delivery systems are being investigated. Herein, MY-mediated silver nanoparticles (MY-AgNPs) were synthesized by a green approach to improve the therapeutic efficacy of MY. MY-AgNPs were characterized by ultraviolet-visible spectroscopy (UV-Vis), scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier transform infrared (FTIR) spectroscopy, and X-ray powder diffraction (XRD). The results showed that the dispersion of AgNPs had the maximum UV-vis absorption at about 410 nm. The synthesized nanoparticles were almost spherical. MY-AgNPs were further investigated against human pathogenic bacteria, and their antioxidant potential was also determined. The free radical scavenging rate was about 60-87%. MY-AgNPs had good antibacterial activity against Escherichia coli and Salmonella at room temperature with minimum inhibitory concentrations of 10-4 and 10-5 g/L, respectively.

Silk Polymers and Nanoparticles: A Powerful Combination for the Design of Versatile Biomaterials

Silk fibroin (SF) is a natural protein largely used in the textile industry but also in biomedicine, catalysis, and other materials applications. SF is biocompatible, biodegradable, and possesses high tensile strength. Moreover, it is a versatile compound that can be formed into different materials at the macro, micro- and nano-scales, such as nanofibers, nanoparticles, hydrogels, microspheres, and other formats. Silk can be further integrated into emerging and promising additive manufacturing techniques like bioprinting, stereolithography or digital light processing 3D printing. As such, the development of methodologies for the functionalization of silk materials provide added value. Inorganic nanoparticles (INPs) have interesting and unexpected properties differing from bulk materials. These properties include better catalysis efficiency (better surface/volume ratio and consequently decreased quantify of catalyst), antibacterial activity, fluorescence properties, and UV-radiation protection or superparamagnetic behavior depending on the metal used. Given the promising results and performance of INPs, their use in many different procedures has been growing. Therefore, combining the useful properties of silk fibroin materials with those from INPs is increasingly relevant in many applications. Two main methodologies have been used in the literature to form silk-based bionanocomposites: in situ synthesis of INPs in silk materials, or the addition of preformed INPs to silk materials. This work presents an overview of current silk nanocomposites developed by these two main methodologies. An evaluation of overall INP characteristics and their distribution within the material is presented for each approach. Finally, an outlook is provided about the potential applications of these resultant nanocomposite materials.

An Updated Review on Silver Nanoparticles in Biomedicine

Silver nanoparticles (AgNPs) represent one of the most explored categories of nanomaterials for new and improved biomaterials and biotechnologies, with impressive use in the pharmaceutical and cosmetic industry, anti-infective therapy and wound care, food and the textile industry. Their extensive and versatile applicability relies on the genuine and easy-tunable properties of nanosilver, including remarkable physicochemical behavior, exceptional antimicrobial efficiency, anti-inflammatory action and antitumor activity. Besides commercially available and clinically safe AgNPs-based products, a substantial number of recent studies assessed the applicability of nanosilver as therapeutic agents in augmented and alternative strategies for cancer therapy, sensing and diagnosis platforms, restorative and regenerative biomaterials. Given the beneficial interactions of AgNPs with living structures and their nontoxic effects on healthy human cells, they represent an accurate candidate for various biomedical products. In the present review, the most important and recent applications of AgNPs in biomedical products and biomedicine are considered.

Silver nanoparticles (AgNPs) and AgNO3 perturb the specification of human hepatocyte-like cells and cardiomyocytes

Silver nanoparticles (AgNPs) are commonly utilized industrial compounds mostly because of their antimicrobial properties. Nevertheless, our understanding of their potential developmental toxicity in humans is still limited. Embryonic stem cells (ESCs) are powerful in vitro tools for developmental toxicity assessments of chemicals. Here, we evaluated the potential developmental toxicity during early embryogenesis of AgNPs and AgNO₃ with human ESC (hESC)-based differentiation systems in vitro. We found that human relevant concentrations of AgNPs and Ag ions affected the specification of two of the three primary germ layers, endoderm and mesoderm, without drastically affecting ectoderm. Furthermore, the two forms of Ag impaired the generation and functions of hepatocytes-like cells derived from endoderm, by decreasing the expression of important liver markers such as AFP, ALB, and HNF4A, and altering glycogen storage. When considering cardiac development, AgNPs and AgNO₃ manifested opposite adverse effects, in that AgNPs increased while AgNO₃ decreased the expression of typical cardiac markers (NKX2.5, MYH6, and ISL) in hESC-derived cardiomyocytes. In conclusion, our findings argue for a potential developmental toxicity of AgNP doses we are exposed to, or levels detected in the human body, especially at very early stages during embryogenesis, and which may not be just due to Ag leakage. Moreover, mesendoderm-derived cell types, tissues and organs may be more prone to AgNP toxicity than ectoderm lineages.

Non-cytotoxic silver nanoparticle levels perturb human embryonic stem cell-dependent specification of the cranial placode in part via FGF signaling

Silver nanoparticles (AgNPs) are compounds used in numerous consumer products because of their desirable optical, conductive and antibacterial properties. However, several in vivo and in vitro studies have raised concerns about their potential developmental toxicity. Here, we employed a human embryonic stem cell model to evaluate the potential ectodermal toxicity of AgNPs, at human relevant concentrations. Among the four major ectodermal lineages tested, only cranial placode specification was significantly affected by AgNPs and AgNO3, morphology-wise and in the expression of specific markers, such as SIX3 and PAX6. Mechanistically, we found that the effects of AgNPs on the cranial placode differentiation were probably due to Ag ion leakage and mediated by the FGF signaling. Thus, AgNPs may have the ability to alter the early stages of embryonic development.

Bio-molecule functionalized rapid one-pot green synthesis of silver nanoparticles and their efficacy toward the multidrug resistant (MDR) gut bacteria of silkworms (Bombyx mori)

The present study aimed to synthesise bio-molecule functionalized silver nanoparticles (AgNPs) using leaf extract from mulberry variety S-1635 (Morus alba L.) and to explore its antibacterial efficacy against multidrug resistant (MDR) gut bacteria isolated from natural infection observed from silkworm larvae in rearing conditions. AgNPs formation was established by surface plasmon resonance at 480 nm. The crystallinity of the synthesised AgNPs was checked by HR-TEM and XRD analysis. SEM and TEM characterisation further exhibited the spherical, monodispersed, well scattered nature of the AgNPs with an average particle size of 11.8 nm ± 2.8. The presence of (111), (200), (220) and (311) planes in Bragg's reflections confirmed the face-cantered-cubic crystalline silver. EDX analysis confirmed the presence of elemental silver. FT-IR spectra revealed functional groups were responsible for the reduction of silver ions. The zeta potential value of -17.3 mV and -25.6 mV was recorded in MH and DMEM/F-12 media, respectively. The LC-QTOF/MS and HRMS spectra disclosed the presence of bioactive compounds like flavonoid, gallic acid, and stigmasterol, which are probably involved in the reduction and functionalization of AgNPs. The antibacterial efficacy of bio-molecule functionalized AgNPs and the naked AgNPs was tested on Gram-positive and Gram-negative bacteria isolated from silkworms and characterized by using 16S rDNA and gyrB genes. The cytotoxicity of AgNPs was tested on WRL-68, HEK-293, ACHN, and HUH-7 cell lines using MTT assay. This study provides an insight into the application of bio-molecule functionalized AgNPs for combating various silkworm pathogens which severely affect the agro-rural economy of developing countries.

Surface modified electrospun poly(lactic acid) fibrous scaffold with cellulose nanofibrils and Ag nanoparticles for ocular cell proliferation and antimicrobial application

Corneal and conjunctival infections are common ocular diseases, sometimes, causing severe and refractory drug-resistant bacteria infections. Fungal keratitis is a leading cause for blindness and traditional medical treatment is unsatisfactory. Thus, there is an urge to develop a new therapy to deal with these cases. In this study, we developed surface modified poly(lactic acid) (PLA) electrospun nanofibrous membranes (EFMs) with silver nanoparticles (AgNPs) and cellulose nanofibrils (CNF) as scaffolds for cell proliferation and antimicrobial application. The AgNPs with a very low content (below 0.1%) were easily anchored on the surface of PLA EFMs by CNF, which endowed the scaffold with hydrophilicity and antibacterial ability. The in-vitro cell co-culture experiments showed that the scaffold had great biocompatibility to ocular epithelial cells, especially the scaffolds coated by CNF, which significantly proliferated cells. Furthermore, the antibacterial activity could reach >95% inhibiting Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) due to the implantation of AgNPs, and the antifungal activity was also outstanding with most of the Fusarium spp. inhibited. Hence, the developed PLA EFMs with CNF and AgNPs are promising ocular bandages to promote cell proliferation and kill infectious pathogens, exhibiting potential applications in ocular wound healing in the future.

Impact of adding glucose-coated water-soluble silver nanoparticles to the silkworm larval diet on silk protein synthesis and related properties

Biological modifications of the silk fibroin (silk) material have broad applications in textiles, biomedical materials and other industrial materials. It is economical to incorporate nanoparticles to the biosynthesis of silk fibroin by adding them to silkworm larval diets. This strategy may result in the rapid stable production of modified silk. Glucose-coated silver nanoparticles (AgNPs) were used to improve the AgNPs' biocompatibility, and the AgNPs were efficiently incorporated into silk by feeding. Larvae fed with AgNPs produced silk with significantly improved antibacterial properties and altered silk secondary structures. Both positive and negative effects on the growth and synthesis of silk proteins were observed after different AgNPs doses. Larvae feeding with low concentration of 0.02% and medium 0.20% AgNPs have greater transfer efficiencies of AgNPs to silk compared with feeding high concentration of 2.00% AgNPs. In addition, the elongation and tensile strength of the produced silk fibers were also significantly increased, with greater mammalian cell compatibility. The appropriate AgNPs concentration in the diet of silkworms can promote the synthesis of silk proteins, enhance their mechanical properties, improve their antibacterial property and inhibit the presence of Gram-negative bacteria.

New avenues of controlling microbial infections through anti-microbial and anti-biofilm potentials of green mono-and multi-metallic nanoparticles: A review

Nanoparticles synthesized through the green route deserve special mention because this green technology is not only energy-efficient and cost-effective but also amenable to the environment. Various biological resources have been used for the generation of these 'green nanoparticles'. Biological wastes have also been focused in this direction thereby promoting the value of waste. Reports indicate that green nanoparticles exhibit remarkable antimicrobial activitiesboth singly as well as in combination with standard antibiotics. The current phenomenon of multi-drug resistance has resulted due to indiscriminate administration of high-doses of antibiotics followed by significant toxicity. In the face of this emergence of drug-resistant microbesthe efficacy of green nanoparticles might prove greatly beneficial. Microbial biofilm is another hurdle in the effective treatment of diseases as the microorganismsbeing embedded in the meshwork of the biofilmevade the antimicrobial agents. Nanoparticles may act as a ray of hope on the face of this challenge tooas they not only destroy the biofilms but also lessen the doses of antibiotics requiredwhen administered in combination with the nanoparticles. It should be further noted that the resistance mechanisms exhibited by the microorganisms seem not that relevant for nanoparticles. The current review, to the best of our knowledgefocuses on the structures of these green nanoparticles along with their biomedical potentials. It is interesting to note how a variety of structures are generated by using resources like microbes or plants or plant products and how the structure affects their activities. This study might pave the way for further development in this arena and future work may be taken up in identifying the detailed mechanism by which 'green' synthesis empowers nanoparticles to kill pathogenic microbes.

Biomedical Applications of Silver Nanoparticles: An Up-to-Date Overview

During the past few years, silver nanoparticles (AgNPs) became one of the most investigated and explored nanotechnology-derived nanostructures, given the fact that nanosilver-based materials proved to have interesting, challenging, and promising characteristics suitable for various biomedical applications. Among modern biomedical potential of AgNPs, tremendous interest is oriented toward the therapeutically enhanced personalized healthcare practice. AgNPs proved to have genuine features and impressive potential for the development of novel antimicrobial agents, drug-delivery formulations, detection and diagnosis platforms, biomaterial and medical device coatings, tissue restoration and regeneration materials, complex healthcare condition strategies, and performance-enhanced therapeutic alternatives. Given the impressive biomedical-related potential applications of AgNPs, impressive efforts were undertaken on understanding the intricate mechanisms of their biological interactions and possible toxic effects. Within this review, we focused on the latest data regarding the biomedical use of AgNP-based nanostructures, including aspects related to their potential toxicity, unique physiochemical properties, and biofunctional behaviors, discussing herein the intrinsic anti-inflammatory, antibacterial, antiviral, and antifungal activities of silver-based nanostructures.

Secondary Metabolites in the Green Synthesis of Metallic Nanoparticles

The ability of organisms and organic compounds to reduce metal ions and stabilize them into nanoparticles (NPs) forms the basis of green synthesis. To date, synthesis of NPs from various metal ions using a diverse array of plant extracts has been reported. However, a clear understanding of the mechanism of green synthesis of NPs is lacking. Although most studies have neglected to analyze the green-synthesized NPs (GNPs) for the presence of compounds derived from the extract, several studies have demonstrated the conjugation of sugars, secondary metabolites, and proteins in these biogenic NPs. Despite several reports on the bioactivities (antimicrobial, antioxidant, cytotoxic, catalytic, etc.) of GNPs, only a handful of studies have compared these activities with their chemically synthesized counterparts. These comparisons have demonstrated that GNPs possess better bioactivities than NPs synthesized by other methods, which might be attributed to the presence of plant-derived compounds in these NPs. The ability of NPs to bind with organic compounds to form a stable complex has huge potential in the harvesting of precious molecules and for drug discovery, if harnessed meticulously. A thorough understanding of the mechanisms of green synthesis and high-throughput screening of stabilizing/capping agents on the physico-chemical properties of GNPs is warranted to realize the full potential of green nanotechnology.

A novel stellerite-based photocatalytic composite and its enhanced disinfection application

The aim of this work was to prepare, characterize and evaluate the potential of novel ZnO/stellerite composite photocatalysts against Staphylococcus aureus (S. aureus). SEM/EDS studies employed to study the surface morphological properties revealed stellerite as the catalysts carrier played a role of dispersant for ZnO nanoparticles. The XRD patterns of the ZnO/stellerite indicated hexagonal crystal structure with 20-30 nm size. It was found that the crystallite size of ZnO/stellerite was much smaller as compared to pure ZnO and increased with increasing ZnO loading amount. The results of optical properties of ZnO/stellerite showed smaller band gap in contrast to pure ZnO, investigated by UV-vis absorption. Due to the optimum ZnO loading, the as-prepared ZnO-20 composite had the highest BET surface area and the pore volume. Using the TG-DSC measurement, the high thermal stability of the product was studied for different temperature values. Antibacterial activity of ZnO/stellerite affected by the ZnO loading, concentration of samples and light conditions (under dark and UV irradiation conditions) was examined by disinfection of S. aureus. The as-prepared ZnO-20 composite with 100 mg/L was found to exhibit excellent inactivation efficiencies (87.65% in the dark and 97.67% under UV illumination) towards S. aureus. Compared with pure ZnO, the obtained composite photocatalysts showed significantly better antibacterial performance by studying the disinfection kinetics of S. aureus. Thus, the present study reveals that the novel ZnO/stellerite shows great potential for its use in the targeted disinfection applications.

Facile and Eco-Friendly Fabrication of Colored and Bioactive Silk Materials Using Silver Nanoparticles Synthesized by Two Flavonoids

Recently, there has been an increasing tendency towards the functionalization of silk using silver nanoparticles (AgNPs) to inhibit bacterial multiplication and disease spread. Considering environmental factors and sustainable development, the preparation of AgNPs using natural extracts is becoming a research hotspot. This study aims at fabricating colored and bioactive silk fabric using AgNPs synthesized by two representative flavonoids (quercetin and rutin). The effects of pH, temperature, and flavonoid concentration on the yield and particle size of AgNPs were studied. The color features and functionalities of the AgNPs-treated silk were also evaluated. The results showed that the AgNPs synthesized by quercetin were generated faster but displayed poorer size uniformity than those prepared by rutin. The as-prepared AgNPs showed good stability. The AgNPs prepared by rutin displayed a more uniform distribution on silk than those synthesized by quercetin. The antibacterial activity of AgNPs-treated silk remained over 90% against E. coli and S. aureus even after 30 washing cycles. The antioxidant activity of the treated silk gradually decreased during washing. The present research proposes a facile and eco-friendly method for the preparation of AgNPs-coated silk material using flavonoids, which can serve as hygiene-related and medical textile materials.