Biosynthesis, characterization, and antibacterial activity of gold nanoparticles

How nanomaterials act against bacterial structures? a narrative review focusing on nanoparticle molecular mechanisms

OBJECTIVE

In recent years, significant progress has been made in the field of nanotechnology for the treatment and prevention of biofilm formation and Multidrug-resistant bacteria (MDR). MDR bacteria challenges is hazardous when microorganisms induce the formation of biofilms, which amplify resistance to antibiotics and promote the development of multidrug-resistant conditions. The unique physicochemical properties of certain nanomaterials make nanotechnology a promising option for combating MDR infections. Several studies have introduced nanomaterials with different antibacterial mechanisms that can effectively destroy MDR bacteria and their biofilms. This study reviews the research results, focusing on the various nanoparticle mechanisms that target bacterial structures.

METHOD

To accomplish this study, we conducted investigations to gather articles and relevant studies from validated medical databases such as Scopus, PubMed, Google Scholar, and Web of Science. The selected publications from 2007 to 2023. In this review, we provide a brief overview of nanoparticles, their mechanisms, and how they function against the structure of bacteria. Furthermore, we discuss the recent advancements in using certain nanoparticles to combat infection-induced biofilms and complications caused by multidrug resistance.

FINDING

Our findings demonstrate that various nanoparticles have the potential to effectively overcome bacterial infectious diseases by targeting biofilms and antibiotic-resistant strains. Additionally, the development of a new drug delivery approach based on nanosystems shows promise in overcoming antibiotic resistance and biofilms.

Exploring In Vitro Antibiofilm Potential and In Vivo Toxicity Assessment of Gold Nanoparticles

In this study, biogenically synthesized AuNPs were first characterized via UV visible spectroscopy, SEM, XRD, and FTIR followed by toxicity evaluation using mice model. UV-visible spectroscopy of biogenic AuNPs showed peaks at 540-549 nm, while FTIR spectrum showed various functional groups involving O-H, Amide I, Amide II, O-H, C-H groups, and so on. SEM showed the size variation from 30 to 60 nm. Antibacterial potential against pathogenic isolates showed bigger ZOI (31.0 mm) against Pseudomonas aeruginosa AuNPs. Antibiofilm activity showing up to 100% inhibition at 90 µg mL-1 concentration of AuNPs. Toxicity evaluation showed LD50 as 70 mg kg-1. Exposure to AuNPs caused significant changes in the levels of serum AST (p < 0.05) at 100-150 mg kg-1 of AuNPs exposure. Histopathology of male albino mice kidney and liver revealed that mice exposed to maximum concentration of AuNPs showed necrosis, cell distortion, and hepatocytes detachment. Present study showed that biologically synthesized AuNPs possess effective antimicrobial and biofilm inhibitory potential. AuNPs strong bactericidal effect even at lower concentration suggest that NPs could have excellent potential for combating pathogens. In conclusion, nanotechnology may revolutionize human life and medical industry by developing innovative drugs with the potential to treat diseases in shorter and noninvasive time period. Hence, in vitro biosafety and experimental observations followed by in vivo outcomes are crucial in shifting the novel therapeutics into medical practice thus leading further into their future development.

Biodegradation of untreated plasticizers-free linear low-density polyethylene films by marine bacteria

Polyethylene significantly contributes to marine plastic pollution. This study focuses on isolating bacteria from sea water and microplastic samples collected from the Tyrrhenian Sea and evaluating their ability to degrade virgin plasticizers-free linear low-density polyethylene (LLDPE) films. The isolates grew on the plastic film under aerobic conditions in shaken flasks leading to LLDPE mass losses of up to 2.597 ± 0.971 % after 60 days incubation. Biofilm formation on the film surface was confirmed by adhered protein quantification while film surface erosion and appearance of functional groups were revealed using SEM and FTIR analyses confirming biodegradation capabilities especially for isolates Bacillus velezensis MT9, Vreelandella venusta MT1 and Vreelandellatitanicae MT11. This is the first report on the biodegradation of plasticizers-free non pretreated LLDPE films by marine Bacillus sp. and Vreelandella sp.; most of the LLDPE biodegradation studies have been so far performed on plasticizer containing, pre-treated, or naturally weathered films.

Myco-nanotechnological approach to synthesize gold nanoparticles using a fungal endophyte,Penicillium oxalicum, and unravelling its antibacterial activity and anti-breast cancer role via metabolic reprogramming

The present study has been designed to fabricate fungal endophyte-assisted gold nanoparticles (AuNPs) and elucidate their anti-breast cancer potential. The aqueous extract of fungal endophytePenicillium oxalicum(PO), associated with the medicinal plantAmoora rohituka, was used for the fabrication of AuNPs (POAuNPs). Physico-chemical characterization using Ultraviolet-visible spectroscopy, Fourier transform infrared, X-ray diffraction, Dynamic light scattering, Zeta potential, Transmission electron microscopy and Field emission scanning electron microscopy analysis revealed stable, uniform distribution, spherical shape and crystalline nature of POAuNPs with a size range of 3-46 nm. Furthermore, the POAuNPs potentially inhibited the growth of pathogenic bacterial strainsEscherichia coliandStaphylococcus aureus. The synthesized POAuNPs have shown potential antioxidant effects against 2,2-diphenyl-1-picrylhydrazyl (DPPH), superoxide and nitric oxide (NO) radical scavenging assays with an EC50value of 8.875 ± 0.082, 52.593 ± 2.506 and 43.717 ± 1.449 µg mL-1, respectively. Moreover, the value of EC50for the total antioxidant capacity of POAuNPs was found to be 23.667 ± 1.361 µg mL-1. The cell viability of human breast cancer cells, MDA-MB-231 and MCF-7, was found to be reduced after treatment with POAuNPs, and IC50values were found to be 19.753 ± 0.640 and 35.035 ± 0.439 µg mL-1, respectively. Further,in vitrobiochemical assays revealed that POAuNPs induces metabolic reprogramming in terms of reduced glucose uptake, increased lactate dehydrogenase (LDH) release and, disruption of oxidative balance through depletion of glutathione levels, increased nitric oxide (NO) and lipid peroxidation levels as a possible pathway to suppress human breast cancer cell proliferation. Apoptosis-specific nuclear modulations induced by POAuNPs in human breast cancer cells were validated through 4',6-diamidino-2-phenylindole (DAPI) nuclear staining. The present investigation thus attempts to show the first ever fabrication of AuNPs using an aqueous extract ofP. oxalicumassociated withA. rohituka. The results revealed unique physico-chemical characteristics of mycogenic AuNPs, and screening their effect against breast cancer via metabolic reprogramming and induction of apoptosis thus adds great significance for cancer therapeutics, suggesting further exploration to develop nanotherapeutic drugs.

Biologically synthesized nanoparticles: barley-mediated silver and gold nanoparticles and caged gold nanoplatform for advanced drug delivery system engineering in medicine

The integration of green synthesis methods and advanced nanostructure designs holds significant promise for the development of innovative nanomaterials with diverse biomedical applications. This commentary delves into the use of barley grains for the eco-friendly synthesis of silver and gold nanoparticles, highlighting their potential as biocompatible agents with potent antibacterial properties. The barley-mediated synthesis approach not only offers a sustainable and cost-effective method for producing these nanoparticles but also underscores their remarkable efficacy against pathogenic bacteria. The barley-mediated approach not only offers a sustainable and cost-effective method for producing biocompatible nanoparticles but also demonstrates remarkable antibacterial efficacy against pathogenic bacteria. By critically evaluating the strengths and potential gaps in this synthesis approach, this commentary emphasizes the importance of integrating green synthesis techniques with advanced nanoparticle applications. Future research directions should aim at optimizing synthesis processes, ensuring enhanced stability and biocompatibility, and exploring the full potential of biologically synthesized nanoparticles in medical treatments and environmental sustainability. This focus on sustainable synthesis and application could pave the way for the next generation of nanomaterials, offering significant advancements in both healthcare and ecological preservation. By examining the strengths, gaps, and potential synergies between these two approaches, this commentary underscores the importance of sustainable synthesis techniques and the development of multifunctional nanoparticles. This integrated approach could lead to the creation of next-generation nanomaterials, offering significant advancements in medical treatments and environmental sustainability.

Biogenic synthesis of AgNPs via polyherbal formulation: Mechanistic neutralization and toxicological impact on acetylcholinesterase from Bungarus sindanus venom

This study aims to examine the biogenic production, characterization, and anti-acetylcholinesterase (AAChE) properties of polyherbal formulation PHF-extract-synthesized silver nanoparticles (PHF-AgNPs). The Elapidae snake Bungarus sindanus has extremely dangerous venom for humans and contains a high amount of AChE (acetylcholinesterase). Inhibiting AChE leads to acetylcholine buildup, affecting neurotransmission. The study tested silver nanoparticles as AChE inhibitors using kinetics. Their production was confirmed through ultraviolet (UV) spectrometry at 425 nm (SPR peak of 1.94), and stabilizing functional groups were identified via Fourier transform infrared spectroscopy (FT-IR). The average length of 20 nm was confirmed by analyzing the scanning electron microscopy (SEM) data. Energy-dispersive X-ray spectroscopy (EDX) identified silver as the primary component of PHF-AgNPs (26%). Statistical analysis showed that the activity of AChE in krait venom decreased by up to 45% and 37% at a given dose of ACh (0.5 mM) by PHF and AgNPs, respectively. Utilizing the Lineweaver-Burk plot for kinetic analysis, a competitive type of inhibition is found. RESEARCH HIGHLIGHTS: Successfully synthesized PHF-extract-induced silver nanoparticles (PHF-AgNPs) demonstrated through UV spectrometry and characterized as crystalline with an average size of 45 nm by X-ray diffraction. PHF-AgNPs effectively inhibited acetylcholinesterase (AChE), an enzyme critical in neurotransmission, reducing its activity in krait venom by up to 45% at certain concentrations. Kinetic analysis revealed that the inhibition mechanism of AChE by PHF-AgNPs is competitive, offering potential for therapeutic applications in neurologically related conditions.

Investigate the biological activities of Lawsonia inermis extract synthesized from TiO2 doped graphene oxide nanoparticles

Nanoparticles of titanium dioxide (TiO2) were made by reacting graphene oxide (GO) with Lawsonia inermis leaf extract. X-ray diffraction (XRD) analysis revealed crystalline TiO2 doped GO nanoparticles composed of a variety of anatase phases. Initially, UV-vis spectroscopy was performed to confirm the biogenesis of TiO2 doped GO nanoparticles (NP's). Using SEM, the research showed that the biosynthesized TiO2 nanoparticles were mostly spherical, polydispersed, and of a nanoscale size. Because of the energy dispersive X-ray spectroscopy (EDS) pattern, distinct and robust peaks of titanium (Ti) and oxygen (O) were observed, which were supportive of the formation of TiO2 nanoparticles. By using fourier transform infrared (FTIR) spectroscopy, it was demonstrated that terpenoids, flavonoids, and proteins are involved in the biosynthesis and production of TiO2 doped GO nanoparticles. 2,2-diphenylpicrylhydrazyl (DPPH) assays were conducted to evaluate the free radical scavenging activity of TiO2 doped GO nanoparticles. Additionally, the TiO2 doped GO NPs had enhanced antioxidant activity when compared with the TiO2 matrix. A series of pure TiO2 and TiO2 doped GO nanoparticles (5, 10, 50, and 100 mg/mL) solutions were investigated for their antibacterial activities. In the current study, zebrafish embryos exposed to pure TiO2 and TiO2 doped GO nanoparticles were toxic and suffered a low survival rate based on concentration. During photocatalysis, O2˙ and ˙OH radicals are rapidly produced because of the reactive species trapping experiment. It was estimated that pure TiO2 nanoparticles and those doped with GO were 80% effective in degrading methyl orange(MO) after 120 min, respectively. RESEARCH HIGHLIGHTS: The UV-vis absorption spectra showed a maximum absorbance peak at 290 nm. SEM, the pure TiO2 doped GO NPs exhibit agglomeration and spherical shape. When tested in zebrafish embryos, TiO2 NPs are toxic at high concentrations. GO nanoparticles showed better antioxidant activity. NPs exhibited concentration dependent antioxidative activity.

Modified frankincense resin stabilized gold nanoparticles for enhanced antioxidant and synergetic activity in in-vitro anticancer studies

For the first time, Frankincense resin (FR) has been carboxymethylated to produce CMFR - AuNPs and the conjugate was utilized for the Doxorubicin drug loading. The carboxymethylation of the carboxylic, phenolic, and hydroxyl functional groups of FR has been developed into carboxymethylated Frankincense resin (CMFR). A novel CMFR-AuNPs was synthesized using the developed CMFR as a stabilizing and reducing agent. The antibacterial, antioxidant, and in-vitro anticancer activities were investigated by using CMFR-AuNPs and CMFR - AuNPs@DOX. CMFR-AuNPs demonstrated antioxidative properties by quenching DPPH radicals effectively. CMFR-AuNPs and DOX@CMFR-AuNPs demonstrated strong antibacterial activity against K. pneumoniae, S. aureus, B. subtilis, and E. coli. The cell viability was tested for CMFR -AuNPs at various concentrations of Dox-loaded CMFR -AuNPs (CMFR-AuNPs + Dox1, CMFR-AuNPs + Dox 2, & CMFR-AuNPs + Dox 3). The highest inhibition was observed on MCF-7 and HeLa cell lines using CMFR-AuNPs + Dox 3, respectively. Various techniques such as UV, FTIR, TGA, XRD, SEM, EDAX and TEM were used to characterize the designed CMFR and CMFR-AuNPs. After carboxy methylation, the amorphous nature of FR changed to crystallinity, as reflected in the XRD spectra. The XRD spectrum of the CMFR- AuNPs showed FCC structure due to the involvement of hydroxyl and carboxylic functional groups of CMFR strongly bound with the AuNPs. TGA results revealed that the CMFR is thermally more stable than FR. TEM revealed that CMFR - AuNPs were well dispersed, spherical, and hexagonal with an average diameter of 7 to 10 nm, while the size of doxorubicin loaded (DOX@CMFR-AuNPs) AuNPs was 11 to 13 nm. Green CMFR-AuNPs have the potential to enhance the drug loading and anticancer efficacy of drugs.

Biomimetic synthesis of nanoparticles: A comprehensive review on green synthesis of nanoparticles with a focus on Prosopis farcta plant extracts and biomedical applications

The synthesis of nanoparticles (NPs) using environmentally friendly methods has garnered significant attention in response to concerns about the environmental impact of various nanomaterial manufacturing techniques. To address this issue, natural resources like extracts from plants, fungi, and bacteria are employed as a green alternative for nanoparticle synthesis. Plant extracts, which contain active components such as terpenoids, alkaloids, phenols, tannins, and vitamins, operate as coating and reducing agents. Bacteria and fungi, on the other hand, rely on internal enzymes, sugar molecules, membrane proteins, nicotinamide adenine dinucleotide (NADH), and nicotinamide adenine dinucleotide phosphate (NADPH) dependent enzymes to play critical roles as reducing agents. This review collects recent advancements in biomimetic methods for nanoparticle synthesis, critically discussing the preparation approaches, the type of particles obtained, and their envisaged applications. A specific focus is given on using Prosopis fractal plant extracts to synthesize nanoparticles tailored for biomedical applications. The applications of this plant and its role in the biomimetic manufacturing of nanoparticles have not been reported yet, making this review a pioneering and valuable contribution to the field.

Antimicrobial Coatings Based on a Photoreactive (Meth)acrylate Syrup and Ferulic Acid-The Effectiveness against Staphylococcus epidermidis

A novel photopolymerizable (meth)acrylate oligomer syrup modified with ferulic acid (FA) was verified as an antimicrobial coating binder against a biofilm of Staphylococcus epidermidis. A solution-free UV-LED-initiated photopolymerization process of aliphatic (meth)acrylates and styrene was performed to prepare the oligomer syrup. The influence of ferulic acid on the UV crosslinking process of the varnish coatings (kinetic studies using photo-DSC) as well as their chemical structure (FTIR) and mechanical (adhesion, hardness), optical (gloss, DOI parameter), and antibacterial properties against S. epidermidis were investigated. The photo-DSC results revealed that FA has a positive effect on reducing the early occurrence of slowing processes and has a favorable effect on the monomer conversion increment. It turned out, unexpectedly, that the more FA in the coating, the greater its adhesion to a glass substrate and hardness. The coating containing 0.9 wt. part of FA exhibited excellent antimicrobial properties against S. epidermidis, i.e., the bacterial number after 24 h was only 1.98 log CFU/mL. All the coatings showed relatively high hardness, gloss (>80 G.U.), and DOI parameter values (30-50 a.u.).

Highly Specific Polyphenolic Colloids as Alternatives to Antimicrobials in Livestock Production

The dispersion of antibiotics in livestock farming represents a health concern worldwide, contributing to the spread of antimicrobial-resistant bacteria through animals, the environment, and humans. Phenolic compounds could be alternatives to antibiotics, once drawbacks such as their low water solubility, bioavailability, and reduced stability are overcome. Although nano- or micro-sized formulations could counter these shortcomings, they do not represent cost-effective options. In this study, three phenolic compounds, obtained from wood-processing manufacturers, were characterized, revealing suitable features such as their antioxidant activity, size, and chemical and colloidal stability for in-field applications. The minimum inhibitory concentration (MIC) of these colloidal suspensions was measured against six bacterial strains isolated from livestock. These particles showed different inhibition behaviors: Colloidal chestnut was effective against one of the most threatening antibiotic-resistant pathogens, i.e., S. aureus, but ineffective toward E. coli. Instead, colloidal pine showed a weak effect on S. aureus but specificity toward E. coli. The present proof-of-concept points at colloidal polyphenols as valuable alternatives for antimicrobial substitutes in the livestock context.

Polygonum bistorta Linn. as a green source for synthesis of biocompatible selenium nanoparticles with potent antimicrobial and antioxidant properties

Here, we report for the first time, green-synthesized selenium nanoparticles (SeNPs) using pharmacologically potent herb of Polygonum bistorta Linn. for multiple biomedical applications. In the study, a facile and an eco-friendly approach is utilized for synthesis of SeNPs using an aqueous roots extract of P. bistorta Linn. followed by extensive characterization via Fourier transform infrared spectroscopy, X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and Energy Dispersive X-Ray (EDX) analysis. The XRD and FTIR data determine the phase composition and successful capping of plant extract onto the surface of NPs while SEM and TEM micrographic examination reveals the elliptical and spherical morphology of the particles with a mean size of 69 ± 23 nm. After comprehensive characterization, the NPs are investigated for antifungal, antibacterial, antileishmanial, antioxidant, and biocompatibility properties. The study reveals that Polygonum bistorta Linn. synthesized SeNPs exhibit significant antibacterial and antifungal activities with Staphylococcus aureus and Fusarium oxysporum inducing the highest zone of inhibition of 14 ± 1.0 mm and 20 ± 1.2 mm, respectively at the concentration of 40 mg/mL. The NPs are also found to have antiparasitic potential against promastigote and amastigote forms of Leishmania tropica. Furthermore, the NPs are discovered to have excellent potential in neutralizing harmful free radicals thus exhibiting considerable antioxidant potential. Most importantly, Polygonum bistorta Linn. synthesized SeNPs showed substantial compatibility against blood cells in vitro studies, which signifies the nontoxic nature of the NPs. The study thus concludes that medicinally important Polygonum bistorta Linn. roots can be utilized as an eco-friendly, sustainable, and green source for the synthesis of pharmacologically potent selenium nanoparticles.

Ceramic conversion treated titanium implant abutments with gold for enhanced antimicrobial activity

INTRODUCTION

Peri-implantitis is an inflammatory process around dental implants that is characterised by bone loss that may jeopardize the long-term survival of osseo integrated dental implants. The aim of this study was to create a surface coating on titanium abutments that possesses cellular adhesion and anti-microbial properties as a post-implant placement strategy for patients at risk of peri-implantitis.

MATERIALS AND METHODSMETHODS

Titanium alloy Grade V stubs were coated with gold particles and then subjected to ceramic conversion treatment (CCT) at 620 °C for 3, 8 and 80 h. The surface characteristics and chemistry were assessed using scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), and X-ray diffraction (XRD) analysis. The leaching profile was investigated by inductively coupled plasma mass spectroscopy (ICP-MS) for all groups after 7, 14 and 28 days in contact with distilled water. A scratch test was conducted to assess the adhesion of the gold coating to the underlying titanium discs. Two bacterial species (Staphylococcus aureus (SA) & Fusobacterium nucleatum (FN)) were used to assess the antibacterial behaviour of the coated discs using a direct attachment assay test. The potential changes in surface chemistry by the bacterial species were investigated by grazing angle XRD.

RESULTS

The gold pre-coated titanium discs exhibited good stability of the coating especially after immersion in distilled water and after bacterial colonisation as evident by XRD analysis. Good surface adhesion of the coating was demonstrated for gold treated discs after scratch test analysis, especially titanium, following a 3-hour (3 H) ceramic conversion treatment. All coated discs exhibited significantly improved antimicrobial properties against both tested bacterial species compared to untreated titanium discs.

CONCLUSIONS

Ceramic conversion treated titanium with a pre-deposited gold layer showed improved antimicrobial properties against both SA and FN species than untreated Ti-C discs. Scratch test analysis showed good adherence properties of the coated discs the oxide layer formed is firmly adherent to the underlying titanium substrate, suggesting that this approach may have clinical efficacy for coating implant abutments.

A Comprehensive Review of Nanoparticles: From Classification to Application and Toxicity

Nanoparticles are structures that possess unique properties with high surface area-to-volume ratio. Their small size, up to 100 nm, and potential for surface modifications have enabled their use in a wide range of applications. Various factors influence the properties and applications of NPs, including the synthesis method and physical attributes such as size and shape. Additionally, the materials used in the synthesis of NPs are primary determinants of their application. Based on the chosen material, NPs are generally classified into three categories: organic, inorganic, and carbon-based. These categories include a variety of materials, such as proteins, polymers, metal ions, lipids and derivatives, magnetic minerals, and so on. Each material possesses unique attributes that influence the activity and application of the NPs. Consequently, certain NPs are typically used in particular areas because they possess higher efficiency along with tenable toxicity. Therefore, the classification and the base material in the NP synthesis hold significant importance in both NP research and application. In this paper, we discuss these classifications, exemplify most of the major materials, and categorize them according to their preferred area of application. This review provides an overall review of the materials, including their application, and toxicity.

Interactions shape aquatic microbiome responses to Cu and Au nanoparticle treatments in wetland manipulation experiments

In natural systems, organisms are embedded in complex networks where their physiology and community composition is shaped by both biotic and abiotic factors. Therefore, to assess the ecosystem-level effects of contaminants, we must pair complex, multi-trophic field studies with more targeted hypothesis-driven approaches to explore specific actors and mechanisms. Here, we examine aquatic microbiome responses to long-term additions of commercially-available metallic nanoparticles [copper-based (CuNPs) or gold (AuNPs)] and/or nutrients in complex, wetland mesocosms over 9 months, allowing for a full growth cycle of the aquatic plants. We found that both CuNPs and AuNPs (but not nutrient) treatments showed shifts in microbial communities and populations largely at the end of the experiment, as the aquatic plant community senesced. we examine aquatic microbiomes under chronic dosing of NPs and nutrients Simplified microbe-only or microbe + plant incubations revealed that direct effects of AuNPs on aquatic microbiomes can be buffered by plants (regardless of seasonal As mesocosms were dosed weekly, the absence of water column accumulation indicates the partitioning of both metals into other environmental compartments, mainly the floc and aquatic plants photosynthetically-derived organic matter. Overall, this study identifies the potential for NP environmental impacts to be either suppressed by or propagated across trophic levels via the presence of primary producers, highlighting the importance of organismal interactions in mediating emerging contaminants' ecosystem-wide impacts.

Biogenic fabrication of a gold nanoparticle sensor for detection of Fe3+ ions using a smartphone and machine learning

In recent years, smartphones have been integrated into rapid colorimetric sensors for heavy metal ions, but challenges persist in accuracy and efficiency. Our study introduces a novel approach to utilize biogenic gold nanoparticle (AuNP) sensors in conjunction with designing a lightbox with a color reference and machine learning for detection of Fe3+ ions in water. AuNPs were synthesized using the aqueous extract of Eleutherine bulbosa leaf as reductants and stabilizing agents. Physicochemical analyses revealed diverse AuNP shapes and sizes with an average size of 19.8 nm, with a crystalline structure confirmed via SAED and XRD techniques. AuNPs exhibited high sensitivity and selectivity in detection of Fe3+ ions through UV-vis spectroscopy and smartphones, relying on nanoparticle aggregation. To enhance image quality, we developed a lightbox and implemented a reference color value for standardization, significantly improving performance of machine learning algorithms. Our method achieved approximately 6.7% higher evaluation metrics (R 2 = 0.8780) compared to non-normalized approaches (R 2 = 0.8207). This work presented a promising tool for quantitative Fe3+ ion analysis in water.

Silk Sericin and Its Composite Materials with Antibacterial Properties to Enhance Wound Healing: A Review

Wound infections may disrupt the normal wound-healing process. Large amounts of antibiotics are frequently used to prevent pathogenic infections; however, this can lead to resistance development. Biomaterials possessing antimicrobial properties have promising applications for reducing antibiotic usage and promoting wound healing. Silk sericin (SS) has been increasingly explored for skin wound healing applications owing to its excellent biocompatibility and antioxidant, antimicrobial, and ultraviolet-resistant properties. In recent years, SS-based composite biomaterials with a broader antimicrobial spectrum have been extensively investigated and demonstrated favorable efficacy in promoting wound healing. This review summarizes various antimicrobial agents, including metal nanoparticles, natural extracts, and antibiotics, that have been incorporated into SS composites for wound healing and elucidates their mechanisms of action. It has been revealed that SS-based biomaterials can achieve sustained antimicrobial activity by slow-release-loaded antimicrobial agents. The antimicrobial-loaded SS composites may promote wound healing through anti-infection, anti-inflammation, hemostasis, angiogenesis, and collagen deposition. The manufacturing methods, benefits, and limitations of antimicrobial-loaded SS materials are briefly discussed. This review aims to enhance the understanding of new advances and directions in SS-based antimicrobial composites and guide future biomedical research.

Medical Applications of Silver and Gold Nanoparticles and Core-Shell Nanostructures Based on Silver or Gold Core: Recent Progress and Innovations

Nanoparticles (NPs) of noble metals such as silver (Ag NPs) or gold (Au NPs) draw the attention of scientists looking for new compounds to use in medical applications. Scientists have used metal NPs because of their easy preparation, biocompatibility, ability to influence the shape and size or modification, and surface functionalization. However, to fully use their capabilities, both the benefits and their potential threats should be considered. One possibility to reduce the potential threat and thus prevent the extinction of their properties resulting from the agglomeration, they are covered with a neutral material, thus obtaining core-shell nanostructures that can be further modified and functionalized depending on the subsequent application. In this review, we focus on discussing the properties and applications of Ag NPs and Au NPs in the medical field such as the treatment of various diseases, drug carriers, diagnostics, and many others. In addition, the following review also discusses the use and potential applications of Ag@SiO2 and Au@SiO2 core-shell nanostructures, which can be used in cancer therapy and diagnosis, treatment of infections, or tissue engineering.

A new colorimetric aptasensor for paraquat detection based on the designed aptamer with multiple paraquat binding sites in combination with gold nanoparticles

The presence of paraquat in the environment poses a danger to human health, leading to a growing demand for an uncomplicated and highly responsive method to detect paraquat. This work reports a new, simple, and sensitive colorimetric aptasensor based on the designed aptamers containing 1-5 paraquat binding sites (R1-R5) in combination with gold nanoparticles (AuNPs). Although the aptamers with more binding sites exhibited greater paraquat interaction capability, the aptasensor based on the R3 aptamer showed the highest detection sensitivity for paraquat in a linear range of 5-50 nM with a limit of detection of 1.29 nM, meaning that it is 2.14 fold more sensitive than the R1-aptasensor. This R3-aptasensor selectively detected paraquat but not the other tested herbicides, including difenzoquat, 2,4-D, ametryn, atrazine, and glufosinate. Also, it efficiently detected paraquat spiked in water samples within the precision acceptance criterion of recovery rates (96.8-105.0%) and the relative standard deviations (1.50-3.81%). These results demonstrated the development of a new aptasensor for paraquat detection, in which the multiple paraquat binding sites of the aptamers could enhance detection sensitivity.

Antibacterial and hemocompatibility potentials of nano-gold-cored alginate preparation against anaerobic bacteria from acne vulgaris

Acne is a prevalent dermatological disease, with high global incidence, and is a health menace. The current study aimed to isolate and characterize the anaerobic bacteria responsible for the condition. Causes of a total of 70 acne-based bacterium isolates obtained from patients of mild, moderate, and severe acne, 24 were Clostridium innocuum, 21 were Lactobacillus plantarum, 13 were Anaerococcus prevotii, and 12 were Peptoniphilus asaccharolyticus. Nearly 69% of males were suffering, while the rest were females at 31%. The 15-30 years old age group was the most affected. The gold/alginate nanoparticles' nanopreparation (GANPs) produced from chloroauric acid and sodium alginate was an effective treatment against the acne conditions under the experimental conditions. The nanopreparation exhibited significant inhibitory activity against anaerobic bacterial isolates, with a minimum inhibitory concentration of 200 µg/ml for A. prevotii and P. asaccharolyticus, and 400 µg/ml for C. innocuum and L. plantarum. The in vitro efficacy of the GANPs on human blood parameters was also assessed. The concurrent results suggested potential antibacterial activity and hemocompatibility of the product, which has promise to be used as a successful antibacterial agent for acne.

Monstera deliciosa mediated single step biosynthesis of gold nanoparticles by bottom-up approach and its non-antimicrobial properties

In this study, we have stated the green biosynthesis of gold nanoparticles (AuNPs) by utilizing the extract of Monstera deliciosa leaves (MDL) as a reducing agent. Biosynthesized flat, thin, and single-crystalline gold nanotriangles obtained through centrifugation are then analyzed by different characterization techniques. The UV - visible absorption spectra of AuNPs exhibited maxima bands in the range of 500-590 nm, indicating a characteristic of AuNPs. XRD analysis revealed the formation of the (111)-oriented face-centered cubic (FCC) phase of AuNPs. ATR-IR spectra showed signatures of stretching vibrations of O-H, C-H, C=C, C=O, C-O, and C-N, accompanied by CH3 rocking vibrations present in functional groups of biomolecules. FESEM images confirmed spherical nanoparticles with an average diameter in the range of 53-66 nm and predominantly triangular morphology of synthesized AuNPs within the size range of 420-800 nm. NMR, GC-MS, and HR-MS studies showed the presence of different biomolecules, including phenols, flavonoids, and antioxidants in MDL extracts, which play a crucial role of both, reducing as well as stabilizing and capping agents to form stable AuNPs by a bottom-up approach. They were then investigated for their antibacterial assay against Gram-positive (S. aureus, B. subtilis) and Gram-negative (E. coli, P. aeruginosa) microorganisms, along with testing of antifungal potential against various fungi (Penicillium sp., Aspergillus flavus, Fusarium oxysporum, Rhizoctonia solani) using the well diffusion method. Here, biosynthesized AuNPs showed non-antimicrobial properties against all four used bacteria and fungi, showing their suitability as a contender for biomedical applications in drug delivery ascribed to their inert and biocompatible nature.

Supplementary Information

The online version contains supplementary material available at 10.1007/s13205-023-03898-0.

Chitosan/aloe vera gel coatings infused with orange peel essential oils for fruits preservation

Continuous fruit waste poses significant environmental and economic challenges, necessitating innovative fruit coating technologies. This research focuses on harnessing discarded orange peels to extract essential oil (OPEO), which is then integrated into a chitosan/aloe vera (CTS/AVG) matrix. The study comprehensively characterised the coating in terms of its physicochemical properties, antioxidant capacity, and antimicrobial efficacy. The investigation involved an analysis of particle size and distribution in the coating solutions, highlighting changes induced by the incorporation of orange peel essential oil (1 %, 2 % and 3 % v/w) into the chitosan/aloe vera (4:1 v/v) matrix, including particle size reduction and enhanced Brownian motion. The study quantifies a 33.21 % decrease in water vapour transmission rate and a reduction in diffusion coefficient from 9.26 × 10-11 m2/s to 6.20 × 10-11 m2/s following the addition of OPEO to CTS/AVG. Assessment of antioxidant potential employing DPPH radical scavenging assays, revealed that CTS/AVG/3 %OPEO exhibited notably superior radical scavenging activity compared to CTS/AVG, CTS/AVG/1 %OPEO, and CTS/AVG/2 %OPEO, demonstrated by its IC50 value of 17.01 ± 0.45 mg/mL. The study employs the well diffusion method, demonstrating a higher susceptibility of gram-negative bacteria to the coating solutions than gram-positive counterparts. Remarkably, CTS/AVG/3 %OPEO displayed the most pronounced inhibition against Escherichia coli, generating an inhibitory zone diameter of 14 ± 0.8 mm. The results collectively emphasised the potential of CTS/AVG/3 %OPEO as a viable natural alternative to synthetic preservatives within the fruit industry, attributed to its exceptional antioxidant and antimicrobial properties.

Antimicrobial Hydrogels: Potential Materials for Medical Application

Microbial infections based on drug-resistant pathogenic organisms following surgery or trauma and uncontrolled bleeding are the main causes of increased mortality from trauma worldwide. The prevalence of drug-resistant pathogens has led to a significant increase in medical costs and poses a great threat to the normal life of people. This is an important issue in the field of biomedicine, and the emergence of new antimicrobial materials hydrogels holds great promise for solving this problem. Hydrogel is an important material with good biocompatibility, water absorption, oxygen permeability, adhesion, degradation, self-healing, corrosion resistance, and controlled release of drugs as well as structural diversity. Bacteria-disturbing hydrogels have important applications in the direction of surgical treatment, wound dressing, medical device coating, and tissue engineering. This paper reviews the classification of antimicrobial hydrogels, the current status of research, and the potential of antimicrobial hydrogels for one application in biomedicine, and analyzes the current research of hydrogels in biomedical applications from five aspects: metal-loaded hydrogels, drug-loaded hydrogels, carbon-material-loaded hydrogels, hydrogels with fixed antimicrobial activity and biological antimicrobial hydrogels, and provides an outlook on the high antimicrobial activity, biodegradability, biocompatibility, injectability, clinical applicability and future development prospects of hydrogels in this field.

Streptomyces monashensis MSK03-mediated synthesis of gold nanoparticles: characterization and antibacterial activity

Nanotechnology is a cutting-edge field with diverse applications, particularly in the utilization of gold nanoparticles (AuNPs) due to their stability and biocompatibility. AuNPs serve as pivotal components in medical applications, with a specific emphasis on their significant antibacterial efficacy. This study focuses on synthesizing AuNPs using the cell-free supernatant of Streptomyces monashensis MSK03, isolated from terrestrial soil in Thailand. The biosynthesis process involved utilizing the cell-free supernatant of S. monashensis MSK03 and hydrogen tetrachloroauric acid (HAuCl4) under controlled conditions of 37 °C and 200 rpm agitation. Characterization studies revealed spherical AuNPs with sizes ranging from 7.1 to 40.0 nm (average size: 23.2 ± 10.7 nm), as confirmed by TEM. UV-Vis spectroscopy indicated a localized surface plasmon resonance (LSPR) band at 545 nm, while XRD analysis confirmed a crystalline structure with characteristics of cubic lattice surfaces. The capping molecules on the surface of AuNPs carry a negative charge, indicated by a Zeta potential of -26.35 mV, and FTIR analysis identified functional groups involved in reduction and stabilization. XANES spectra further confirmed the successful reduction of Au3+ to Au0. Moreover, the synthesized AuNPs demonstrated antibacterial activity against drug-resistant strains of Pseudomonas aeruginosa and Acinetobacter baumannii. Interestingly, the AuNPs showed non-toxicity to Vero cell lines. These significant antibacterial properties of the produced nanoparticles mean they hold great promise as new antimicrobial treatments for tackling the increasing issue of antibiotic resistance.

Antibacterial Activity and Mechanisms of Action of Inorganic Nanoparticles against Foodborne Bacterial Pathogens: A Systematic Review

Foodborne disease outbreaks due to bacterial pathogens and their toxins have become a serious concern for global public health and security. Finding novel antibacterial agents with unique mechanisms of action against the current spoilage and foodborne bacterial pathogens is a central strategy to overcome antibiotic resistance. This study examined the antibacterial activities and mechanisms of action of inorganic nanoparticles (NPs) against foodborne bacterial pathogens. The articles written in English were recovered from registers and databases (PubMed, ScienceDirect, Web of Science, Google Scholar, and Directory of Open Access Journals) and other sources (websites, organizations, and citation searching). "Nanoparticles," "Inorganic Nanoparticles," "Metal Nanoparticles," "Metal-Oxide Nanoparticles," "Antimicrobial Activity," "Antibacterial Activity," "Foodborne Bacterial Pathogens," "Mechanisms of Action," and "Foodborne Diseases" were the search terms used to retrieve the articles. The PRISMA-2020 checklist was applied for the article search strategy, article selection, data extraction, and result reporting for the review process. A total of 27 original research articles were included from a total of 3,575 articles obtained from the different search strategies. All studies demonstrated the antibacterial effectiveness of inorganic NPs and highlighted their different mechanisms of action against foodborne bacterial pathogens. In the present study, small-sized, spherical-shaped, engineered, capped, low-dissolution with water, high-concentration NPs, and in Gram-negative bacterial types had high antibacterial activity as compared to their counterparts. Cell wall interaction and membrane penetration, reactive oxygen species production, DNA damage, and protein synthesis inhibition were some of the generalized mechanisms recognized in the current study. Therefore, this study recommends the proper use of nontoxic inorganic nanoparticle products for food processing industries to ensure the quality and safety of food while minimizing antibiotic resistance among foodborne bacterial pathogens.

Spotlight on therapeutic efficiency of green synthesis metals and their oxide nanoparticles in periodontitis

Periodontitis, one of the most prevalent dental diseases, causes the loss of bone and gum tissue that hold teeth in place. Several bacteria, commonly present in clinically healthy oral cavities, may induce and perpetuate periodontitis when their concentration rises in the gingival sulcus. Antibacterial effect against various Gram-negative and Gram-positive bacteria, including pathogenic and drug-resistant ones, has been shown for several distinct transient metal and metal oxide NPs. Therefore, NPs may be used in biomedicine to treat periodontal problems and in nanotechnology to inhibit the development of microorganisms. Instead of using harmful chemicals or energy-intensive machinery, biosynthesis of metal and metal oxide nanoparticles (NPs) has been suggested. To produce metal and metal oxide NPs, the ideal technique is "Green" synthesis because of its low toxicity and safety for human health and the environment. Gold NPs (AuNPs) appear to be less toxic to mammalian cells than other nanometals because their antibacterial activity is not dependent on reactive oxygen species (ROS). AgNPs also possess chemical stability, catalytic activity, and superior electrical and thermal conductivity, to name a few of their other advantageous characteristics. It was observed that zinc oxide (ZnO) NPs and copper (Cu) NPs exhibited discernible inhibitory effects against gram-positive and gram-negative bacterial strains, respectively. ZnO NPs demonstrated bactericidal activity against the microorganisms responsible for periodontitis. Medications containing magnetic NPs are highly effective against multidrug-resistant bacterial and fungal infections. The titanium dioxide (TiO2) NPs are implicated in elevating salivary peroxidase activity in individuals diagnosed with chronic periodontitis. Furthermore, specific metallic NPs have the potential to enhance the antimicrobial efficacy of periodontitis treatments when combined. Therefore, these NPs, as well as their oxide NPs, are only some of the metals and metal oxides that have been synthesized in environmentally friendly ways and shown to have therapeutic benefits against periodontitis.

Facile fabrication and antibacterial properties of chitosan/acrylamide/gold nanocomposite hydrogel incorporated with Chaetomium globosium extracts from Gingko biloba leaves

Microorganisms are a unique part of our ecosystem because they affect the survival of living organisms. Although pathogenic microorganisms could be detrimental to the plants, animals, and humans, beneficial microbes have provided significant improvement in the growth and development of living organisms. In this study, the fungus Chaetomium globosium was isolated from the medicinal tree Gingko biloba, and then incorporated into a polymerization system to fabricate chitosan/acrylamide/gold (CS/Am/Au) nanocomposite hydrogels. The as-prepared hydrogel displayed increased mechanical strength due to the reinforcement of Au (gold) nanocomposites within the hydrogel matrix. Also, the equilibrium pH responsive swelling rates of the hydrogels gradually increased as the pH increases due to partial acid and basic hydrolysis occurring in the hydrogel as well as formation of hydrogen bond. In addition, the hydrogel demonstrated promising antibacterial activities against selected gram-positive (Staphylococcus epidermidis and Staphylococcus aureus) and gram-negative (Pseudomonas aeruginosa) bacterial strains with an average MIC90 of 0.125 mg/mL at a dosage of 1.0 mg/L. The obtained results are quite promising towards resolving several health challenges and advancing the pharmaceutical industries.

Recent advance on nanoparticles or nanomaterials with anti-multidrug resistant bacteria and anti-bacterial biofilm properties: A systematic review

Objective

With the wide spread of Multidrug-resistant bacteria (MDR) due to the transfer and acquisition of antibiotic resistance genes and the formation of microbial biofilm, various researchers around the world are looking for a solution to overcome these resistances. One potential strategy and the best candidate to overcome these infections is using an effective nanomaterial with antibacterial properties against them.

Methods

and analysis: In this study, we overview nanomaterials with anti-MDR bacteria and anti-biofilm properties. Hence, we systematically explored biomedical databases (Web of Sciences, Google Scholar, PubMed, and Scopus) to categorize related studies about nanomaterial with anti-MDR bacteria and anti-biofilm activities from 2007 to December 2022.

Results

In total, forty-one studies were investigated to find antibacterial and anti-biofilm information about the nanomaterial during 2007-2022. According to the collected documents, nineteen types of nanomaterial showed putative antibacterial effects such as Cu, Ag, Au, Au/Pt, TiO2, Al2O3, ZnO, Se, CuO, Cu/Ni, Cu/Zn, Fe3O4, Au/Fe3O4, Au/Ag, Au/Pt, Graphene O, and CuS. In addition, seven types of them considered as anti-biofilm agents such as Ag, ZnO, Au/Ag, Graphene O, Cu, Fe3O4, and Au/Ag.

Conclusion

According to the studies, each of nanomaterial has been designed with different methods and their effects against standard strains, clinical strains, MDR strains, and bacterial biofilms have been investigated in-vitro and in-vivo conditions. In addition, nanomaterials have different destructive mechanism on bacterial structures. Various nanoparticles (NP) introduced as the best candidate to designing new drug and medical equipment preventing infectious disease outbreaks by overcome antibiotic resistance and bacterial biofilm.

Facile one-step synthesis of gold nanoparticles using Viscum album and evaluation of their antibacterial potential

Nanostructure gold nanoparticles (Au NPs) are well-known biological active materials, synthesised under different environment-friendly approaches that has gained significant interest in the field of biomedicine. This study investigated a novel, fast, easy, cost-effective and the eco-friendly method to synthesise Au NPs from mediated Viscum album Linn plant extract, where the plant metabolites act as stabilising and reducing agents. The synthesised Au NPs were analysed by UV/Vis spectroscopy that gave strong signals and a sharp absorption peak at 545nm due to the presence of surface plasmon resonance (SPR) bands. In addition, energy dispersive X-ray spectroscopy (EDX) showed that strong signals of Au NPs appeared at 9.7 and 2.3keV, as the rays of light passed. X-ray diffraction recognised the crystalline material and provided information on the cell unit that the synthesised Au NPs are face-centreed cubic in structure. The diffraction of X-ray spectra showed intense peaks at 38.44°, 44.7°, 44.9° and 77.8°. The mediated V. album plant extracts and synthesised Au NPs were screened against gram-positive and gram-negative (Enterobacter , Salmonella typhi , Escheria coli and Bacillus subtilis ) bacterial strains, confirming their antibacterial potential. Au NPs showed strong antibacterial activity due to its unique steric configuration. Au NPs damaged bacterial cell membrane leading to the leakage of the cytoplasm and death of the cell.

Revolutionizing Nanotechnology with Filago desertorum Extracts: Biogenic Synthesis of Silver Nanoparticles Exhibiting Potent Antioxidant and Antibacterial Activities

In this study, we described the environmentally friendly biosynthesis of silver nanoparticles (AgNPs) utilizing ethanolic extract of Filago desertorum (F. desertorum) as a capping and reducing agent. We also looked at the antioxidant and antibacterial capacities of AgNPs. In order to determine the size, shape, and crystallinity of the created AgNPs, the current project was designed to produce AgNPs utilizing the crude extract of the F. desertorum. The effectiveness of the project was evaluated by UV-visible spectrophotometry, Fourier transform infrared spectroscopy, scanning electron microscopy, and X-ray diffraction. AgNPs are monodispersed and spherical and have 50 nm average particle diameters, as determined using Image J software calculations and SEM observation. Four significant peaks from an XRD study, located at 38.46, 44.63, 64.81, and 77.74 nm, were used to calculate the average crystalline size of AgNPs which was reported to be 15 nm. In the crude extract of F. desertorum, it is possible to see the functional group peaks of a number of substances that are essential for bioreduction and the stability of the AgNPs. Antibacterial and antioxidant properties of AgNPs in vitro (DPPH, ABTS, H2O2, phosphomolybdenum, and ferric reducing power) were examined using conventional methods. The AgNPs showed maximum DPPH (72.51% with IC50 = 144.61 μg/mL), ABTS (75.24% with IC50 = 131.21 μg/mL), hydrogen peroxide (73.33% with IC50 = 115.05 μg/mL), phosphomolybdenum activity (73.43% with IC50 = 75.25 μg/mL), and observing reducing power (0.25) at a concentration of 250 g/mL. Inhibition by the AgNPs against the bacterial strain Staphylococcus aureus was greatest (12 mm). According to the current findings, AgNPs produced by F. desertorum have the highest potential for free radical scavenging and antibacterial activity, which can result in antioxidant and antibiotic agents.

Tuning Au/SiO2 nanostructures from 1D to 3D interconnected nanotube networks using polycarbonate porous templates

We report a simple process, based on the combination of sol-gel deposition and nano-templating with polycarbonate membranes, for the synthesis of 1D to 3D free-standing silica (SiO2) interconnected nanotube (NT) networks. The thickness and porosity of the SiO2 nanotube walls can be, respectively, controlled by adjusting the ethanol amount in the sol-gel reaction mixture and by the addition or not of a porogen agent during the synthesis. Internal functionalization of 1D and 3D porous and non-porous SiO2 NTs by Au nanoparticles (NPs) was then performed using electroless deposition leading to particle sizes ranging from 15 to 20 nm. Characterization of all these systems by SEM-EDX, TEM, ICP and XPS clearly demonstrated the impact of the porosity of SiO2 on the amount and localization of Au NPs. Selective functionalization of the inner or the inner + outer surfaces of SiO2 NTs was achieved by keeping or freeing the SiO2 NTs from the template prior to electroless deposition, respectively. Moreover, UV-visible analysis confirmed plasmon resonance associated with Au NPs in all functionalized systems, paving the way to applications in many fields such as nano-medicine or (photo-)catalysis. In particular, the free-standing interconnected silica-based nanotube systems provide unique features of great interest for use in nanoscale fluidic bioseparation, sensing, and flow (photo)-catalytic chemistry, as demonstrated herein for the photodegradation of methylene blue.

Evaluating Antimicrobial Effectiveness of Gold Nanoparticles against Streptococcus oralis

Biofilm includes many microorganisms that causes the periodontal diseases. The increased drugs resistance against the infectious diseases is a major issue owing to excessive using of a broad spectrum of antibiotics. Recently, metallic nanoparticles (NPs) are being administered to control the growth of different types of microorganisms. For instance, gold nanoparticles (Au NPs) are found to be successful to control and limit the bacterial pathogenicity in the oral cavity without any cytotoxic effects on the human body. Aim. In this paper, it was aimed to detect the antibacterial effect of Au NPs and compare with chlorhexidine (CHX) against Streptococcus oralis (S. oralis) in dental plaque of patients with chronic periodontitis. Materials and Methods. First, supragingival and subgingival plaque samples were collected from the patients suffering from periodontal disease and incubated under aerobic or/and anaerobic conditions. Second, the morphological examination, and biochemical test by Vitec 2 machine are used to confirm the S. oralis species. Third, the synthesis of Au NPs was carried out by seed growth method and their properties were characterized. Finally, the antimicrobial effect of the Au NPs against S. oralis was evaluated by Agar well diffusion method for different Au NPs concentrations (100, 50, 25, 12.5, 6.25, 3.125, 1.562, 0.781, 0.391, 0.195, and 0.097 ppm). CHX was used as the positive control and distilled water as the negative control. The antibacterial activity data were statistically analyzed by least significant difference (LSD) using the Statistical Program for Social Science (SPSS) version 22. Results. The Au NPs with an average particles size of 43 nm, polycrystalline face-centered cubic structure were characterized. The Au NPs at 100 ppm concentration had similar antibacterial effect of CHX for inhibiting the growth of S. oralis, with no significant difference. Conclusions. The Au NPs as an antibacterial agent could be equally effective against S. oralis similar to the CHX when used at higher concentration.

Silk Sericin Protein: Turning Discarded Biopolymer into Ecofriendly and Valuable Reducing, Capping, and Stabilizing Agent for Nanoparticles Synthesis Using Sonication

This current study is designed to incorporate sericin protein as a reducing, capping, and stabilizing agent to synthesize sonication‐mediated silver nanoparticles. Fabrication of sericin‐reduced silver nanoparticles (Sr‐AgNPs) is confirmed using UV–visible spectrophotometry, zeta sizer, scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), X‐Ray diffraction (XRD), and thermogravimetric analysis (TGA). UV–Vis spectral peak of Sr‐AgNPs is observed at 420–440nm while the average size is found between 3 to 30 nm. SEM also confirms the reduction of large‐sized (1–40 µm) sericin macromolecules into nanometric hexagonal and triangular silver nanoparticles with a normal distribution (polydispersity index > 0.5). FTIR peaks from 500 to 4000cm−1 are analyzed for sericin while Sr‐AgNPs peaks with minor shifts (700–1000 cm−1 (COOCO stretching) in Sr‐AgNPs) are also observed. XRD peaks of 2θ at 27° with multiple low peaks at 38.2°, 47°, 49°, and 63.8° authenticate the amorphous nature of sericin and sharp peaks at 36°, 48°, 54.3°, and 61.9° with miller indices (hkl) of 98, 111, 200, and 211, assess the crystalline structure of Sr‐AgNPs. TGA reveals that sericin enhances the stability of silver NPs at high temperature (200–600 °C) by lowering the percentage weight loss from 70–80% to 60–65%.

Study of biological properties of gold nanoparticles: Low toxicity, no proliferative activity, no ability to induce cell gene expression and no antiviral activity

Gold nanoparticles (AuNPs) are a fundamental building block of many applications across nanotechnology as they have excellent biosafety which make them promising for a broad range of biomedical applications. Here we explore their in vivo toxicity, cytotoxicity and proliferative capacity in human keratinocyte HaCaT cells, their ability to induce gene expression and their antiviral properties against a surrogate of SARS-CoV-2. These nanoparticles were characterized by transmission electron microscopy, dynamic light scattering and zeta potential. The results showed that these AuNPs with sizes ranging from 10 to 60 nm are non-toxic in vivo at any concentration up to 800 μg/mL. However, AuNP cytotoxicity in human HaCaT cells is time-dependent, so that concentrations of up to 300 μg/mL did not show any in vitro toxic effect at 3, 12 and 24 h, although higher concentrations were found to have some significant toxic activity, especially at 24 h. No significant proliferative activity was observed when using low AuNP concentrations (10, 20 and 40 μg/mL), while the AuNP antiviral tests indicated low or insignificant antiviral activity. Surprisingly, none of the 13 analyzed genes had their expressions modified after 24 h's exposure to AuNPs. Therefore, the results show that AuNPs are highly stable inactive materials and thus very promising for biomedical and clinical applications demanding this type of materials.

Artificial neural network approach for prediction of AuNPs biosynthesis by Streptomyces flavolimosus, characterization, antitumor potency in-vitro and in-vivo against Ehrlich ascites carcinoma

Gold nanoparticles (AuNPs) have emerged as promising and versatile nanoparticles for cancer therapy and are widely used in drug and gene delivery, biomedical imaging, diagnosis, and biosensors. The current study describes a biological-based strategy for AuNPs biosynthesis using the cell-free supernatant of Streptomyces flavolimosus. The biosynthesized AuNPs have an absorption peak at 530-535 nm. The TEM images indicate that AuNPs were spherical and ranged in size from 4 to 20 nm. The surface capping molecules of AuNPs are negatively charged, having a Zeta potential of - 10.9 mV. FTIR analysis revealed that the AuNPs surface composition contains a variety of functional groups as -OH, C-H, N-, C=O, NH3+, amine hydrochloride, amide group of proteins, C-C and C-N. The bioprocess variables affecting AuNPs biosynthesis were optimized by using the central composite design (CCD) in order to maximize the AuNPs biosynthesis. The maximum yield of AuNPs (866.29 µg AuNPs/mL) was obtained using temperature (35 °C), incubation period (4 days), HAuCl4 concentration (1000 µg/mL) and initial pH level 6. Comparison was made between the fitness of CCD versus Artificial neural network (ANN) approach based on their prediction and the corresponding experimental results. AuNPs biosynthesis values predicted by ANN exhibit a more reasonable agreement with the experimental result. The anticancer activities of AuNPs were assessed under both in vitro and in vivo conditions. The results revealed a significant inhibitory effect on the proliferation of the MCF-7 and Hela carcinoma cell lines treated with AuNPs with IC50 value of 13.4 ± 0.44 μg/mL and 13.8 ± 0.45 μg/mL for MCF-7 and Hela cells; respectively. Further, AuNPs showed potential inhibitory effect against tumor growth in tumor-bearing mice models. AuNPs significantly reduced the tumor volume, tumor weight, and decreased number of viable tumor cells in EAC bearing mice.

Highly sensitive colorimetric aptasensor for 17β-estradiol detection in milk based on the repetitive-loop aptamer

Trace of 17β-estradiol (E2) contamination in food has been a concern for its negative impacts on human health, leading to the need for an E2-monitoring system. This work reported a new simple, sensitive, and colorimetric E2 detection based on the designed repetitive-loop aptamer and gold nanoparticles (AuNPs). The designed aptamers (L2-L5) exhibited a higher binding capability to E2 than the original truncated aptamer (L1). Although L3-L5 aptamers exhibited the highest binding capability, only L3-aptasensor demonstrated the sensitive detection of E2 in a range of 0.05-0.8 nM, with the limit of detection at 13.1 pM. The developed L3-aptasensor was 7.7-folds more sensitive for E2 detection than the L1-aptasensor. It selectively detected E2, but not the other tested chemicals with similar structures: progesterone, genistein, diethylstilbestrol, bisphenol A, and chloramphenicol. The L3-aptasensor efficiently detected E2 spiked in milk samples within the precision acceptance criterion of recovery rates (100.1%-113.0%) and the relative standard deviations (5.24%-11.06%). These results demonstrated the development of a new aptasensor based on the designed repetitive-loop aptamer that could enhance E2-detection sensitivity and be potentially used for detecting E2 in milk samples with high accuracy and reliability.

Acceleration in healing of infected full-thickness wound with novel antibacterial γ-AlOOH-based nanocomposites

This study was conducted to synthesize γ-AlOOH (bohemite)-based nanocomposites (NCs) of Au/γ-AlOOH-NC and its functionalized derivative using chitosan (Au/γ-AlOOH/Ctn-NC) and with the help of one-step Mentha piperita. The physicochemical characteristics of the NCs were investigated. In addition, biomedical properties, such as antibacterial activity under in vitro and in vivo conditions, and cell viability were assessed. Wound healing activity on infected wounds and histological parameters were assessed. The gene expressions of TNF-α, Capase 3, Bcl-2, Cyclin-D1 and FGF-2 were investigated. The TEM and FESEM images showed the sheet-like structure for bohemite in Au/γ-AlOOH-NC with Au nanoparticles in a range of 14-15 nm. The elemental analysis revealed the presence of carbon, oxygen, aluminum, and Au elements in the as-synthesized Au/γ-AlOOH. The results for toxicity showed that the produced nanocomposites did not show any cytotoxicity. Biomedical studies confirmed that Au/γ-AlOOH-NC and Au/γ-AlOOH/Ctn-NC have anti-bacterial properties and could expedite the wound healing process in infected wounds by an increase in collagen biosynthesis. The administration of ointment containing Au/γ-AlOOH-NC and Au/γ-AlOOH/Ctn-NC decreased the expressions of TNF-α, and increased the expressions of Capase 3, Bcl-2, Cyclin-D1 and FGF-2. The novelty of this study was that bohemite and Au nanoparticles can be used as a dressing to accelerate the wound healing process. In green synthesis of Au/γ-AlOOH-NC, phytochemical compounds of the plant extract are appropriate reagents for stabilization and the production of Au/γ-AlOOH-NC. Therefore, the new bohemite-based NCs can be considered as candidate for treatment of infected wounds after future clinical studies.

Evaluation of Antibacterial Mechanism of Action, Tyrosinase Inhibition, and Photocatalytic Degradation Potential of Sericin-Based Gold Nanoparticles

In recent times, numerous natural materials have been used for the fabrication of gold nanoparticles (AuNPs). Natural resources used for the synthesis of AuNPs are more environment friendly than chemical resources. Sericin is a silk protein that is discarded during the degumming process for obtaining silk. The current research used sericin silk protein waste materials as the reducing agent for the manufacture of gold nanoparticles (SGNPs) by a one-pot green synthesis method. Further, the antibacterial effect and antibacterial mechanism of action, tyrosinase inhibition, and photocatalytic degradation potential of these SGNPs were evaluated. The SGNPs displayed positive antibacterial activity (8.45-9.58 mm zone of inhibition at 50 μg/disc) against all six tested foodborne pathogenic bacteria, namely, Enterococcus feacium DB01, Staphylococcus aureus ATCC 13565, Listeria monocytogenes ATCC 33090, Escherichia coli O157:H7 ATCC 23514, Aeromonas hydrophila ATCC 7966, and Pseudomonas aeruginosa ATCC 27583. The SGNPs also exhibited promising tyrosinase inhibition potential, with 32.83% inhibition at 100 μg/mL concentration as compared to 52.4% by Kojic acid, taken as a reference standard compound. The SGNPs also displayed significant photocatalytic degradation effects, with 44.87% methylene blue dye degradation after 5 h of incubation. Moreover, the antibacterial mode of action of the SGNPs was also investigated against E. coli and E. feacium, and the results show that due to the small size of the nanomaterials, they could have adhered to the surface of the bacterial pathogens, and could have released more ions and dispersed in the bacterial cell wall surrounding environment, thereby disrupting the cell membrane and ROS production, and subsequently penetrating the bacterial cells, resulting in lysis or damage to the cell by the process of structural damage to the membrane, oxidative stress, and damage to the DNA and bacterial proteins. The overall outcome of the current investigation concludes the positive effects of the obtained SGNPs and their prospective applications as a natural antibacterial agent in cosmetics, environmental, and foodstuff industries, and for the management of environmental contagion.

Effect of size on physicochemical, antibacterial, and catalytic properties of Neolamarckia cadamba (burflower-tree) synthesized silver/silver chloride nanoparticles

Aqueous extract of Neolamarchia cadamba leaves were used in the synthesis of silver/silver chloride nanoparticles (Ag/AgCl NPs). Further they were separated based on their using step-wise centrifugation approach at 09,000, 12,000, and 15,000 rpm. Thus obtained NPs were characterized for their physicochemical features. NPs showed maximum absorbance at 455 nm, 415 nm, and 402 nm. All the NPs were found to be crystalline in nature with average crystallite size (nm) of 58.31, 23.43, and 09.56. Particle size distribution (nm) of NPs was observed to 435.43, 276.75, and 105.49, Surface charge (-mV) of NPs was observed to be 14.59, 23.90, and 32.17. Ag/AgCl NPs-rpm@15,000 showed antibacterial activity against Escherichia coli, coagulase-negative Staphylococci, and Staphylococcus aureus with zone of inhibition (mm) of 16.65, 13.69, and 14.02 at 50 µg per well, respectively. Ag/AgCl NPs-rpm@15,000 showed excellent catalytic activity in degradation of methyl red, methylene blue, rhodamine-B, and methyl orange dyes in the presence of sodium borohydride under 4, 6, 5, and 4 min with pseudo-first order rate constant (min^-1) of 0.981 (96.4%), 0.666 (97.1%), 0.905 (98.1%), and 1.032 (96.6%), respectively. Furthermore, Ag/AgCl NPs-rpm@15,000 showed good catalytic efficiency even under different dye combinations. Total combination was degraded under 18 min.

A Bifunctional Spray Coating Reduces Contamination on Surfaces by Repelling and Killing Pathogens

Surface-mediated transmission of pathogens is a major concern with regard to the spread of infectious diseases. Current pathogen prevention methods on surfaces rely on the use of biocides, which aggravate the emergence of antimicrobial resistance and pose harmful health effects. In response, a bifunctional and substrate-independent spray coating is presented herein. The bifunctional coating relies on wrinkled polydimethylsiloxane microparticles, decorated with biocidal gold nanoparticles to induce a "repel and kill" effect against pathogens. Pathogen repellency is provided by the structural hierarchy of the microparticles and their surface chemistry, whereas the kill mechanism is achieved using functionalized gold nanoparticles embedded on the microparticles. Bacterial tests with methicillin-resistant Staphylococcus aureus and Pseudomonas aeruginosa reveal a 99.9% reduction in bacterial load on spray-coated surfaces, while antiviral tests with Phi6─a bacterial virus often used as a surrogate to SARS-CoV-2─demonstrate a 98% reduction in virus load on coated surfaces. The newly developed spray coating is versatile, easily applicable to various surfaces, and effective against various pathogens, making it suitable for reducing surface contamination in frequently touched, heavy traffic, and high-risk surfaces.

Mechanochemical Synthesis of Nanoparticles for Potential Antimicrobial Applications

There is an increased interest in porous materials due to their unique properties such as high surface area, enhanced catalytic properties, and biological applications. Various solvent-based approaches have been already used to synthesize porous materials. However, the use of large volume of solvents, their toxicity, and time-consuming synthesis make this process less effective, at least in terms of principles of green chemistry. Mechanochemical synthesis is one of the effective eco-friendly alternatives to the conventional synthesis. It adopts the efficient mixing of reactants using ball milling without or with a very small volume of solvents, gives smaller size nanoparticles (NPs) and larger surface area, and facilitates their functionalization, which is highly beneficial for antimicrobial applications. A large variety of nanomaterials for different applications have already been synthesized by this method. This review emphasizes the comparison between the solvent-based and mechanochemical methods for the synthesis of mainly inorganic NPs for potential antimicrobial applications, although some metal-organic framework NPs are briefly presented too.

Nanomaterials and nanomaterials-based drug delivery to promote cutaneous wound healing

Various factors could damage the structure and integrity of skin to cause wounds. Nonhealing or chronic wounds seriously affect the well-being of patients and bring heavy burdens to the society. The past few decades have witnessed application of numerous nanomaterials to promote wound healing. Owing to the unique physicochemical characteristics at nanoscale, nanomaterials-based therapy has been regarded as a potential approach to promote wound healing. In this review, we first overview the wound categories, wound healing process and critical influencing factors. Then applications of nanomaterials with intrinsic therapeutic effect and nanomaterials-based drug delivery systems to promote wound healing are addressed in detail. Finally, current limitations and future perspectives of nanomaterials in wound healing are discussed.

Burdock-Derived Composites Based on Biogenic Gold, Silver Chloride and Zinc Oxide Particles as Green Multifunctional Platforms for Biomedical Applications and Environmental Protection

Green nanotechnology is a rapidly growing field linked to using the principles of green chemistry to design novel nanomaterials with great potential in environmental and health protection. In this work, metal and semiconducting particles (AuNPs, AgClNPs, ZnO, AuZnO, AgClZnO, and AuAgClZnO) were phytosynthesized through a "green" bottom-up approach, using burdock (Arctium lappa L.) aqueous extract. The morphological (SEM/TEM), structural (XRD, SAED), compositional (EDS), optical (UV-Vis absorption and FTIR spectroscopy), photocatalytic, and bio-properties of the prepared composites were analyzed. The particle size was determined by SEM/TEM and by DLS measurements. The phytoparticles presented high and moderate physical stability, evaluated by zeta potential measurements. The investigation of photocatalytic activity of these composites, using Rhodamine B solutions' degradation under solar light irradiation in the presence of prepared powders, showed different degradation efficiencies. Bioevaluation of the obtained composites revealed the antioxidant and antibacterial properties. The tricomponent system AuAgClZnO showed the best antioxidant activity for capturing ROS and ABTS•+ radicals, and the best biocidal action against Escherichia coli, Staphylococcus aureus and Pseudomonas aeruginosa. The "green" developed composites can be considered potential adjuvants in biomedical (antioxidant or biocidal agents) or environmental (as antimicrobial agents and catalysts for degradation of water pollutants) applications.

Nanocarriers for the delivery of antibiotics into cells against intracellular bacterial infection

The barrier function of host cells enables intracellular bacteria to evade the lethality of the host immune system and antibiotics, thereby causing chronic and recurrent infections that seriously threaten human health. Currently, the main clinical strategy for the treatment of intracellular bacterial infections involves the use of long-term and high-dose antibiotics. However, insufficient intracellular delivery of antibiotics along with various resistance mechanisms not only weakens the efficacy of current therapies but also causes serious adverse drug reactions, further increasing the disease and economic burden. Improving the delivery efficiency, intracellular accumulation, and action time of antibiotics remains the most economical and effective way to treat intracellular bacterial infections. The rapid development of nanotechnology provides a strategy to efficiently deliver antibiotics against intracellular bacterial infections into cells. In this review, we summarize the types of common intracellular pathogens, the difficulties faced by antibiotics in the treatment of intracellular bacterial infections, and the research progress of several types of representative nanocarriers for the delivery of antibiotics against intracellular bacterial infections that have emerged in recent years. This review is expected to provide a reference for further elucidating the intracellular transport mechanism of nanocarrier-drug complexes, designing safer and more effective nanocarriers and establishing new strategies against intracellular bacterial infection.

Synthesis of Biogenic Gold Nanoparticles by Using Sericin Protein from Bombyx mori Silk Cocoon and Investigation of Its Wound Healing, Antioxidant, and Antibacterial Potentials

Introduction

A number of biological wastes and factory waste materials have been tested recently for the eco-friendly biosynthesis of nanoparticles. Sericin protein (SSP) is usually removed from the silk cocoon during the degumming process in the process of making the silk, and this sericin protein is normally thrown away by the sericulture industries as waste materials. It is found that this sericin protein possesses a number of biological properties.

Methods

Considering this, in the present study, an effort has been made to biosynthesize gold nanoparticles (SSP-AuNPs) using the waste sericin solution as the reducing and capping agent and investigate its biopotential in terms of its wound healing, antioxidant and antibacterial activities.

Results

The synthesis of SSP-AuNPs was perceived by the visual color change and confirmed by UV-Vis spectroscopy with absorption maxima at 522 nm. Further characterization of SSP-AuNPs was done by TEM, EDS, XRD, FTIR, DLS, zeta potential, TGA, AFM, etc. The size of SSP-AuNPs was found out to be 54.82 nm as per the particle size analyzer and the zeta potential is -19.8 mV. The SSP-AuNPs displayed promising wound healing potential of 70.96 and 69.76% wound closure rate at 5 and 10 µg/mL respectively as compared to 74.91% by the Centella asiatica taken as a positive control. It also exhibited promising antioxidant potential in terms of the DPPH, ABTS free radical scavenging, reducing power potential, and total antioxidant capacity. Besides, the SSP-AuNPs also displayed significant antibacterial activities against the tested pathogenic bacterial with the diameter of inhibition zones ranging between 12.10 and 14.96 mm as compared to the positive control cephalexin that displayed inhibition zones ranging between 12.08 and 13.24 mm.

Discussion

Taken together, SSP-AuNPs could serve as an interesting candidate for food, cosmetics, and biomedical fields in the applications of wound healing, cosmetics, antibacterial bandages, and ointments, etc.

Chitosan-Coated Polymeric Silver and Gold Nanoparticles: Biosynthesis, Characterization and Potential Antibacterial Applications: A Review

Biosynthesized metal nanoparticles, especially silver and gold nanoparticles, and their conjugates with biopolymers have immense potential in various fields of science due to their enormous applications, including biomedical applications. Polymeric nanoparticles are particles of small sizes from 1 nm to 1000 nm. Among different polymeric nanoparticles, chitosan-coated silver and gold nanoparticles have gained significant interest from researchers due to their various biomedical applications, such as anti-cancer, antibacterial, antiviral, antifungal, anti-inflammatory technologies, as well as targeted drug delivery, etc. Multidrug-resistant pathogenic bacteria have become a serious threat to public health day by day. Novel, effective, and safe antibacterial agents are required to control these multidrug-resistant pathogenic microorganisms. Chitosan-coated silver and gold nanoparticles could be effective and safe agents for controlling these pathogens. It is proven that both chitosan and silver or gold nanoparticles have strong antibacterial activity. By the conjugation of biopolymer chitosan with silver or gold nanoparticles, the stability and antibacterial efficacy against multidrug-resistant pathogenic bacteria will be increased significantly, as well as their toxicity in humans being decreased. In recent years, chitosan-coated silver and gold nanoparticles have been increasingly investigated due to their potential applications in nanomedicine. This review discusses the biologically facile, rapid, and ecofriendly synthesis of chitosan-coated silver and gold nanoparticles; their characterization; and potential antibacterial applications against multidrug-resistant pathogenic bacteria.

Plasma-Initiated Grafting of Bioactive Peptide onto Nano-CuO/Tencel Membrane

A bioactive peptide has been successfully grafted onto nano-CuO impregnated Tencel membranes by a simple and rapid method involving a series of textile processes, and an atmospheric argon plasma treatment that requires no additional solvent or emulsifier. Surface morphology shows an apparent change from smooth, slightly roughened, and stripped with increasing plasma treatment time. The FT-IR characteristic peaks confirm the presence of the CuO nanoparticle and peptide on the extremely hydrophilic Tencel membranes that exhibit a zero-degree contact angle. Prepared nano-CuO/Tencel membranes with 90 s plasma treatment time exhibit excellent antimicrobial activity against E. coli and S. aureus, and promote fibroblast cell viability with the assistance of a grafted bioactive peptide layer on the membrane surface.