Synthesis, characterization and antifungal activity of chemically and fungal-produced silver nanoparticles against Trichophyton rubrum

A review of microbes mediated biosynthesis of silver nanoparticles and their enhanced antimicrobial activities

In recent decades, biosynthesis of metal and (or) metal oxide nanoparticles using microbes is accepted as one of the most sustainable, cost-effective, robust, and green processes as it does not encompass the usage of largely hazardous chemicals. Accordingly, numerous simple, inexpensive, and environmentally friendly approaches for the biosynthesis of silver nanoparticles (AgNPs) were reported using microbes avoiding conventional (chemical) methods. This comprehensive review detailed an advance made in recent years in the microbes-mediated biosynthesis of AgNPs and evaluation of their antimicrobial activities covering the literature from 2015-till date. It also aimed at elaborating the possible effect of the different phytochemicals, their concentrations, extraction temperature, extraction solvent, pH, reaction time, reaction temperature, and concentration of precursor on the shape, size, and stability of the synthesized AgNPs. In addition, while trying to understand the antimicrobial activities against targeted pathogenic microbes the probable mechanism of the interaction of produced AgNPs with the cell wall of targeted microbes that led to the cell's reputed and death have also been detailed. Lastly, this review detailed the shape and size-dependent antimicrobial activities of the microbes-mediated AgNPs and their enhanced antimicrobial activities by synergetic interaction with known commercially available antibiotic drugs.

Penicillium chrysogenum: Beyond the penicillin

Almost one century after the Sir Alexander Fleming's fortuitous discovery of penicillin and the identification of the fungal producer as Penicillium notatum, later Penicillium chrysogenum (currently reidentified as Penicillium rubens), the molecular mechanisms behind the massive production of penicillin titers by industrial strains could be considered almost fully characterized. However, this filamentous fungus is not only circumscribed to penicillin, and instead, it seems to be full of surprises, thereby producing important metabolites and providing expanded biotechnological applications. This review, in addition to summarizing the classical role of P. chrysogenum as penicillin producer, highlights its ability to generate an array of additional bioactive secondary metabolites and enzymes, together with the use of this microorganism in relevant biotechnological processes, such as bioremediation, biocontrol, production of bioactive nanoparticles and compounds with pharmaceutical interest, revalorization of agricultural and food-derived wastes or the enhancement of food industrial processes and the agricultural production.

Synergistic Effect of Silver Nanoparticles with Antibiotics for Eradication of Pathogenic Biofilms

BACKGROUND

The increase in nosocomial multidrug resistance and biofilm-forming bacterial infections led to the search for new alternative antimicrobial strategies other than traditional antibiotics. Silver nanoparticles (AgNP) could be a viable treatment due to their wide range of functions, rapid lethality, and minimal resistance potential. The primary aim of this study is to prepare silver nanoparticles and explore their antibacterial activity against biofilms.

METHODS

AgNPs with specific physicochemical properties such as size, shape, and surface chemistry were prepared using a chemical reduction technique, and then characterized by DLS, SEM, and FTIR. The activity of AgNPs was tested alone and in combination with some antibiotics against MDR Gram-negative and Gram-positive planktonic bacterial cells and their biofilms. Finally, mammalian cell cytotoxicity and hemolytic activity were tested using VERO and human erythrocytes.

RESULTS

The findings of this study illustrate the success of the chemical reduction method in preparing AgNPs. Results showed that AgNPs have MIC values against planktonic organisms ranging from 0.0625 to 0.125 mg/mL, with the greatest potency against gram-negative bacteria. It also effectively destroyed biofilm-forming cells, with minimal biofilm eradication concentrations (MBEC) ranging from 0.125 to 0.25 mg/ml. AgNPs also had lower toxicity profiles for the MTT test when compared to hemolysis to erythrocytes. Synergistic effect was found between AgNPs and certain antibiotics, where the MIC was dramatically reduced, down to less than 0.00195 mg/ml in some cases.

CONCLUSION

The present findings encourage the development of alternative therapies with high efficacy and low toxicity.

Nanotechnology-Based Approaches for Cosmeceutical and Skin Care: A Systematic Review

Cosmeceuticals have gained great importance and are among the top-selling products used for skin care. Because of changing lifestyles, climate, and increasing pollution, cosmeceuticals are utilized by every individual, thereby making cosmeceuticals a fruitful field for research and the economy. Cosmeceuticals provide incredibly pleasing aesthetic results by fusing the qualities of both cosmetics and medicinal substances. Cosmeceuticals are primarily utilized to improve the appearance of skin by making it smoother, moisturized, and wrinkle-free, in addition to treating dermatological conditions, including photoaging, burns, dandruff, acne, eczema, and erythema. Nanocosmeceuticals are cosmetic products that combine therapeutic effects utilizing nanotechnology, allowing for more precise and effective target-specific delivery of active ingredients, and improving bioavailability.

Nanoformulations Insights: A Novel Paradigm for Antifungal Therapies and Future Perspectives

Currently, fungal infections are becoming more prevalent worldwide. Subsequently, many antifungal agents are available to cure diseases like pemphigus, athlete's foot, acne, psoriasis, hyperpigmentation, albinism, and skin cancer. Still, they fall short due to pitfalls in physiochemical properties. Conventional medications like lotion, creams, ointments, poultices, and gels are available for antifungal therapy but present many shortcomings. They are associated with drug retention and poor penetration problems, resulting in drug resistance, hypersensitivity, and diminished efficacy. On the contrary, nanoformulations have gained tremendous potential in overcoming the drawbacks of conventional delivery. Furthermore, the potential breakthroughs of nanoformulations are site-specific targeting. It has improved bioavailability, patient-tailored approach, reduced drug retention and hypersensitivity, and improved skin penetration. Nowadays, nanoformulations are gaining popularity for antifungal therapy against superficial skin infections. Nanoformulations-based liposomes, niosomes, nanosponges, solid lipid nanoparticles, and potential applications have been explored for antifungal therapy due to enhanced activity and reduced toxicity. Researchers are now more focused on developing patient-oriented target-based nano delivery to cover the lacunas of conventional treatment with higher immune stimulatory effects. Future direction involves the construction of novel nanotherapeutic devices, nanorobotics, and robust methods. In addition, for the preparations of nanoformulations for clinical studies, animal modeling solves the problems of antifungal therapy. This review describes insights into various superficial fungal skin infections and their potential applications, nanocarrier-based drug delivery, and mechanism of action. In addition, it focuses on regulatory considerations, pharmacokinetic and pharmacodynamic studies, clinical trials, patents, challenges, and future inputs for researchers to improve antifungal therapy.

Synthesis and Characterization of Zinc Oxide Nanoparticles at Different pH Values from Clinopodium vulgare L. and Their Assessment as an Antimicrobial Agent and Biomedical Application

The current study attempts to evaluate the formation, morphology, and physico-chemical properties of zinc oxide nanoparticles (ZnO NPs) synthesized from Clinopodium vulgare extract at different pH values and to investigate their antimicrobial and biomedical application potential. The reduction of zinc ions to ZnO NPs was determined by UV spectra, which revealed absorption peaks at 390 nm at pH 5 and 348 nm at pH 9, respectively. The spherical morphology of the nanoparticles was observed using scanning electron microscopy (SEM), and the size was 47 nm for pH 5 and 45 nm for pH 9. Fourier-transformed infrared spectroscopy (FTIR) was used to reveal the presence of functional groups on the surface of nanoparticles. The antibacterial activity was examined against Staphylococcus aureus, Streptococcus pyogenes, and Klebsiella pneumonia via the agar-well diffusion method. Comparatively, the highest activities were recorded at pH 9 against all bacterial strains, and among these, biogenic ZnO NPs displayed the maximum inhibition zone (i.e., 20.88 ± 0.79 mm) against S. aureus. ZnO NPs prepared at pH 9 exhibited the highest antifungal activity of 80% at 25 mg/mL and antileishmanial activity of 82% at 400 mg/mL. Altogether, ZnO NPs synthesized at pH 9 show promising antimicrobial potential and could be used for biomedical applications.

Fabrication and Characterization of Ag-Graphene Nanocomposites and Investigation of Their Cytotoxic, Antifungal and Photocatalytic Potential

In the present study, we aimed to synthesize (Ag)_1-x(GNPs)_x nanocomposites in variable ratios (25% GNPs-Ag, 50% GNPs-Ag, and 75% GNPs-Ag) via an ex situ approach to investigate the incremental effects of GNPs (graphene nanoparticles) on AgNPs (silver nanoparticles). The prepared nanocomposites were successfully characterized using different microscopic and spectroscopic techniques, including X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, ultraviolet spectroscopy, and Raman spectroscopic analysis. For the evaluation of morphological aspects, shape, and percentage elemental composition, SEM and EDX analyses were employed. The bioactivities of the synthesized nanocomposites were briefly investigated. The antifungal activity of (Ag)_1-x(GNPs)_x nanocomposites was reported to be 25% for AgNPs and 66.25% using 50% GNPs-Ag against Alternaria alternata. The synthesized nanocomposites were further evaluated for cytotoxic potential against U87 cancer cell lines with improved results (for pure AgNPs IC₅₀: ~150 µg/mL, for 50% GNPs-Ag IC₅₀: ~12.5 µg/mL). The photocatalytic properties of the nanocomposites were determined against the toxic dye Congo red, and the percentage degradation was recorded as 38.35% for AgNPs and 98.7% for 50% GNPs-Ag. Hence, from the results, it is concluded that silver nanoparticles with carbon derivatives (graphene) have strong anticancer and antifungal properties. Dye degradation strongly confirmed the photocatalytic potential of Ag-graphene nanocomposites in the removal of toxicity present in organic water pollutants.

Using inorganic nanoparticles to fight fungal infections in the antimicrobial resistant era

Fungal infections pose a serious threat to human health and livelihoods. The number and variety of clinically approved antifungal drugs is very limited, and the emergence and rapid spread of resistance to these drugs means the impact of fungal infections will increase in the future unless alternatives are found. Despite the significance and major challenges associated with fungal infections, this topic receives significantly less attention than bacterial infections. A major challenge in the development of fungi-specific drugs is that both fungi and mammalian cells are eukaryotic and have significant overlap in their cellular machinery. This lack of fungi-specific drug targets makes human cells vulnerable to toxic side effects from many antifungal agents. Furthermore, antifungal drug resistance necessitates higher doses of the drugs, leading to significant human toxicity. There is an urgent need for new antifungal agents, specifically those that can limit the emergence of new resistant species. Non-drug nanomaterials have primarily been explored as antibacterial agents in recent years; however, they are also a promising source of new antifungal candidates. Thus, this article reviews current research on the use of inorganic nanoparticles as antifungal agents. We also highlight challenges facing antifungal nanoparticles and discuss possible future research opportunities in this field. STATEMENT OF SIGNIFICANCE: Fungal infections pose a growing threat to human health and livelihood. The rapid spread of resistance to current antifungal drugs has led to an urgent need to develop alternative antifungals. Nanoparticles have many properties that could make them useful antimycotic agents. To the authors' knowledge, there is no published review so far that has comprehensively summarized the current development status of antifungal inorganic nanomaterials, so we decided to fill this gap. In this review, we discussed the state-of-the-art research on antifungal inorganic nanoparticles including metal, metal oxide, transition-metal dichalcogenides, and inorganic non-metallic particle systems. Future directions for the design of inorganic nanoparticles with higher antifungal efficacy and lower toxicity are described as a guide for further development in this important area.

Emerging Trends in Advanced Translational Applications of Silver Nanoparticles: A Progressing Dawn of Nanotechnology

Nanoscience has emerged as a fascinating field of science, with its implementation in multiple applications in the form of nanotechnology. Nanotechnology has recently been more impactful in diverse sectors such as the pharmaceutical industry, agriculture sector, and food market. The peculiar properties which make nanoparticles as an asset are their large surface area and their size, which ranges between 1 and 100 nanometers (nm). Various technologies, such as chemical and biological processes, are being used to synthesize nanoparticles. The green chemistry route has become extremely popular due to its use in the synthesis of nanoparticles. Nanomaterials are versatile and impactful in different day to day applications, resulting in their increased utilization and distribution in human cells, tissues, and organs. Owing to the deployment of nanoparticles at a high demand, the need to produce nanoparticles has raised concerns regarding environmentally friendly processes. These processes are meant to produce nanomaterials with improved physiochemical properties that can have significant uses in the fields of medicine, physics, and biochemistry. Among a plethora of nanomaterials, silver nanoparticles have emerged as the most investigated and used nanoparticle. Silver nanoparticles (AgNPs) have become vital entities of study due to their distinctive properties which the scientific society aims to investigate the uses of. The current review addresses the modern expansion of AgNP synthesis, characterization, and mechanism, as well as global applications of AgNPs and their limitations.

Mycosynthesis of Metal-Containing Nanoparticles-Synthesis by Ascomycetes and Basidiomycetes and Their Application

Fungi contain species with a plethora of ways of adapting to life in nature. Consequently, they produce large amounts of diverse biomolecules that can be generated on a large scale and in an affordable manner. This makes fungi an attractive alternative for many biotechnological processes. Ascomycetes and basidiomycetes are the most commonly used fungi for synthesis of metal-containing nanoparticles (NPs). The advantages of NPs created by fungi include the use of non-toxic fungus-produced biochemicals, energy efficiency, ambient temperature, pressure conditions, and the ability to control and tune the crystallinity, shape, and size of the NPs. Furthermore, the presence of biomolecules might serve a dual function as agents in NP formation and also capping that can tailor the (bio)activity of subsequent NPs. This review summarizes and reviews the synthesis of different metal, metal oxide, metal sulfide, and other metal-based NPs mediated by reactive media derived from various species. The phyla ascomycetes and basidiomycetes are presented separately. Moreover, the practical application of NP mycosynthesis, particularly in the fields of biomedicine, catalysis, biosensing, mosquito control, and precision agriculture as nanofertilizers and nanopesticides, has been studied so far. Finally, an outlook is provided, and future recommendations are proposed with an emphasis on the areas where mycosynthesized NPs have greater potential than NPs synthesized using physicochemical approaches. A deeper investigation of the mechanisms of NP formation in fungi-based media is needed, as is a focus on the transfer of NP mycosynthesis from the laboratory to large-scale production and application.

Green-Based Approach to Synthesize Silver Nanoparticles Using the Fungal Endophyte Penicillium oxalicum and Their Antimicrobial, Antioxidant, and In Vitro Anticancer Potential

A green-based approach for the synthesis of silver nanoparticles has gained tremendous attention in biomedical applications. Fungal endophytes have been recognized as a remarkable biological source for the synthesis of potential nanodrugs. The present study focuses on the fabrication of silver nanoparticles using the fungal endophyte Penicillium oxalicum (POAgNPs) associated with the leaf of the Amoora rohituka plant. Sharp UV-visible spectra at 420 nm appeared due to the surface plasmon resonance of POAgNPs and the reduction of silver salt. FT-IR analysis revealed the presence of functional groups of bioactive compounds of P. oxalicum responsible for the reduction of silver salt and validated the synthesis of POAgNPs. A high degree of crystallinity was revealed through XRD analysis, and microscopy-based characterizations such as AFM, TEM, and FESEM showed uniformly distributed, and spherically shaped nanoparticles. Furthermore, POAgNPs showed a potential inhibitory effect against bacterial and fungal strains of pathogenic nature. POAgNPs also exhibited potential antioxidant activity against the synthetically generated free radicals such as DPPH, superoxide, hydroxyl, and nitric oxide with EC50 values of 9.034 ± 0.449, 56.378 ± 1.137, 34.094 ± 1.944, and 61.219 ± 0.69 μg/mL, respectively. Moreover, POAgNPs exhibited cytotoxic potential against the breast cancer cell lines, MDA-MB-231 and MCF-7 with IC50 values of 20.080 ± 0.761 and 40.038 ± 1.022 μg/mL, respectively. POAgNPs showed anticancer potential through inhibition of wound closure and by altering the nuclear morphology of MDA-MB-231 and MCF-7 cells. Further anticancer activity revealed that POAgNPs induced apoptosis in MDA-MB-231 and MCF-7 cells by differential expression of genes related to apoptosis, tumor suppression, and cell cycle arrest and increased the level of Caspase-3. The novel study showed that P. oxalicum-mediated silver nanoparticles exhibit potential biological activity, which can be exploited as nanodrugs in clinical applications.

Mechanisms of Antifungal Properties of Metal Nanoparticles

The appearance of resistant species of fungi to the existent antimycotics is challenging for the scientific community. One emergent technology is the application of nanotechnology to develop novel antifungal agents. Metal nanoparticles (NPs) have shown promising results as an alternative to classical antimycotics. This review summarizes and discusses the antifungal mechanisms of metal NPs, including combinations with other antimycotics, covering the period from 2005 to 2022. These mechanisms include but are not limited to the generation of toxic oxygen species and their cellular target, the effect of the cell wall damage and the hyphae and spores, and the mechanisms of defense implied by the fungal cell. Lastly, a description of the impact of NPs on the transcriptomic and proteomic profiles is discussed.

Antifungal Effect of Nanoparticles against COVID-19 Linked Black Fungus: A Perspective on Biomedical Applications

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is a highly transmissible and pathogenic coronavirus that has caused a 'coronavirus disease 2019' (COVID-19) pandemic in multiple waves, which threatens human health and public safety. During this pandemic, some patients with COVID-19 acquired secondary infections, such as mucormycosis, also known as black fungus disease. Mucormycosis is a serious, acute, and deadly fungal infection caused by Mucorales-related fungal species, and it spreads rapidly. Hence, prompt diagnosis and treatment are necessary to avoid high mortality and morbidity rates. Major risk factors for this disease include uncontrolled diabetes mellitus and immunosuppression that can also facilitate increases in mucormycosis infections. The extensive use of steroids to prevent the worsening of COVID-19 can lead to black fungus infection. Generally, antifungal agents dedicated to medical applications must be biocompatible, non-toxic, easily soluble, efficient, and hypoallergenic. They should also provide long-term protection against fungal growth. COVID-19-related black fungus infection causes a severe increase in fatalities. Therefore, there is a strong need for the development of novel and efficient antimicrobial agents. Recently, nanoparticle-containing products available in the market have been used as antimicrobial agents to prevent bacterial growth, but little is known about their efficacy with respect to preventing fungal growth, especially black fungus. The present review focuses on the effect of various types of metal nanoparticles, specifically those containing silver, zinc oxide, gold, copper, titanium, magnetic, iron, and carbon, on the growth of various types of fungi. We particularly focused on how these nanoparticles can impact the growth of black fungus. We also discussed black fungus co-infection in the context of the global COVID-19 outbreak, and management and guidelines to help control COVID-19-associated black fungus infection. Finally, this review aimed to elucidate the relationship between COVID-19 and mucormycosis.

Biogenic silver nanoparticles as antifungal agents

In recent years, an increase in multidrug-resistant fungal strains has been observed, which, together with the limited number of clinically available antifungal agents, highlights the need for the development of new antifungal agents. Due to the proven antifungal activity of silver nanoparticles (AgNPs), there is a growing interest in their use in the treatment of fungal infections. Nanoparticles are usually synthesised through a variety of physical and chemical processes that are costly and pollute the environment. For this reason, biogenic synthesis is emerging as an environmentally friendly technology and new strategies are increasingly based on the use of biogenic AgNPs as antifungal agents for clinical use. The aim of this review is to compare the antifungal activity of different biogenic AgNPs and to summarise the current knowledge on the mechanisms of action and resistance of fungi to AgNPs. Finally, a general analysis of the toxicity of biogenic AgNPs in human and veterinary medicine is performed.

Antifungal nanosuspensions with surfactants and silver for the treatment of onychomycosis

Fungal nail infection (Onychomycosis) often requires prolonged treatment and is associated with a high risk of resistance to treatment. Here in this contribution, we introduce a novel approach to enhance penetration and antifungal activity of the antifungal drug griseofulvin (GF). Solid dispersions were prepared with hydroxypropyl methylcellulose acetate succinate (HPMCAS) and combined with surfactant (either sodium dodecyl sulphate (SDS), dodecyl trimethylammonium bromide (DTAB), or Pluronic F127) using mechanochemical activation. The prepared powders were then suspended with spray-dried silica-coated silver nanoparticles and applied onto infected bovine hooves to assess permeability and antifungal activity. The results showed that the prepared nanosuspensions significantly suppressed fungal activity causing disruption of fungal biofilms. Raman mapping showed enhanced permeation while dynamic vapor sorption (DVS), and particle size measurements showed varied effects depending on the type of surfactant and milling conditions. The prepared nanosuspensions displayed enhanced solubility of the poorly soluble drug reaching approximately 1.2 mg/mL. The results showed that the dispersions that contained DTAB displayed maximum efficacy while the inclusion of colloidal silver did not seem to significantly improve the antifungal activity compared to other formulations.

Biological Applications of Ball-Milled Synthesized Biochar-Zinc Oxide Nanocomposite Using Zea mays L

Nanotechnology is one of the vital and quickly developing areas and has several uses in various commercial zones. Among the various types of metal oxide-based nanoparticles, zinc oxide nanoparticles (ZnO NPs) are frequently used because of their effective properties. The ZnO nanocomposites are risk-free and biodegradable biopolymers, and they are widely being applied in the biomedical and therapeutics fields. In the current study, the biochar-zinc oxide (MB-ZnO) nanocomposites were prepared using a solvent-free ball-milling technique. The prepared MB-ZnO nanocomposites were characterized through scanning electron microscopy (SEM), energy-dispersive X-ray (EDX) spectroscopy, X-ray powder diffraction (XRD), and thermogravimetric analysis (TGA), Fourier-transform infrared spectroscopy (FTIR), and ultraviolet–visible (UV) spectroscopy. The MB-ZnO particles were measured as 43 nm via the X-ray line broadening technique by applying the Scherrer equation at the highest peak of 36.36°. The FTIR spectroscope results confirmed MB-ZnO’s formation. The band gap energy gap values of the MB-ZnO nanocomposites were calculated as 2.77 eV by using UV–Vis spectra. The MB-ZnO nanocomposites were tested in various in vitro biological assays, including biocompatibility assays against the macrophages and RBCs and the enzymes’ inhibition potential assay against the protein kinase, alpha-amylase, cytotoxicity assays of the leishmanial parasites, anti-inflammatory activity, antifungal activity, and antioxidant activities. The maximum TAC (30.09%), TRP (36.29%), and DPPH radicals’ scavenging potential (49.19%) were determined at the maximum dose of 200 µg/mL. Similarly, the maximum activity at the highest dose for the anti-inflammatory (76%), at 1000 μg/mL, alpha-amylase inhibition potential (45%), at 1000 μg/mL, antileishmanial activity (68%), at 100 μg/mL, and antifungal activity (73 ± 2.1%), at 19 mg/mL, was perceived, respectively. It did not cause any potential harm during the biocompatibility and cytotoxic assay and performed better during the anti-inflammatory and antioxidant assay. MB-ZnO caused moderate enzyme inhibition and was more effective against pathogenic fungus. The results of the current study indicated that MB-ZnO nanocomposites could be applied as effective catalysts in various processes. Moreover, this research provides valuable and the latest information to the readers and researchers working on biopolymers and nanocomposites.

Biological Synthesis of Silver Nanoparticles and Prospects in Plant Disease Management

Exploration of nanoparticles (NPs) for various biological and environmental applications has become one of the most important attributes of nanotechnology. Due to remarkable physicochemical properties, silver nanoparticles (AgNPs) are the most explored and used NPs in wide-ranging applications. Also, they have proven to be of high commercial use since they possess great chemical stability, conductivity, catalytic activity, and antimicrobial potential. Though several methods including chemical and physical methods have been devised, biological approaches using organisms such as bacteria, fungi, and plants have emerged as economical, safe, and effective alternatives for the biosynthesis of AgNPs. Recent studies highlight the potential of AgNPs in modern agricultural practices to control the growth and spread of infectious pathogenic microorganisms since the introduction of AgNPs effectively reduces plant diseases caused by a spectrum of bacteria and fungi. In this review, we highlight the biosynthesis of AgNPs and discuss their applications in plant disease management with recent examples. It is proposed that AgNPs are prospective NPs for the successful inhibition of pathogen growth and plant disease management. This review gives a better understanding of new biological approaches for AgNP synthesis and modes of their optimized applications that could contribute to sustainable agriculture.

Microbial silver resistance mechanisms: recent developments

In this mini-review, after a brief introduction into the widespread antimicrobial use of silver ions and nanoparticles against bacteria, fungi and viruses, the toxicity of silver compounds and the molecular mechanisms of microbial silver resistance are discussed, including recent studies on bacteria and fungi. The similarities and differences between silver ions and silver nanoparticles as antimicrobial agents are also mentioned. Regarding bacterial ionic silver resistance, the roles of the sil operon, silver cation efflux proteins, and copper-silver efflux systems are explained. The importance of bacterially produced exopolysaccharides as a physiological (biofilm) defense mechanism against silver nanoparticles is also emphasized. Regarding fungal silver resistance, the roles of metallothioneins, copper-transporting P-type ATPases and cell wall are discussed. Recent evolutionary engineering (adaptive laboratory evolution) studies are also discussed which revealed that silver resistance can evolve rapidly in bacteria and fungi. The cross-resistance observed between silver resistance and resistance to other heavy metals and antibiotics in bacteria and fungi is also explained as a clinically and environmentally important issue. The use of silver against bacterial and fungal biofilm formation is also discussed. Finally, the antiviral effects of silver and the use of silver nanoparticles against SARS-CoV-2 and other viruses are mentioned. To conclude, silver compounds are becoming increasingly important as antimicrobial agents, and their widespread use necessitates detailed understanding of microbial silver response and resistance mechanisms, as well as the ecological effects of silver compounds. Figure created with BioRender.com.

Emerging trends of nanotechnology in advanced cosmetics

The cosmetic industry is dynamic and ever-evolving. Especially with the introduction and incorporation of nanotechnology-based approaches into cosmetics for evincing novel formulations that confers aesthetic as well as therapeutic benefits. Nanocosmetics acts via numerous delivery mechanisms which involves lipid nanocarrier systems, polymeric or metallic nanoparticles, nanocapsules, dendrimers, nanosponges,etc. Each of these, have particular characteristic properties, which facilitates increased drug loading, enhanced absorption, better cosmetic efficacy, and many more. This article discusses the different classes of nanotechnology-based cosmetics and the nanomaterials used for their formulation, followed by outlining the categories of nanocosmetics and the scope of their utility pertaining to skin, hair, nail, lip, and/or dental care and protection thereof. This review also highlights and discusses about the key drivers of the cosmetic industry and the impending need of corroborating a healthy regulatory framework, refocusing attention towards consumer needs and trends, inculcating sustainable techniques and tenets of green ecological principles, and lastly making strides in nano-technological advancements which will further propel the growth of the cosmetic industry.

Trichoderma: An Eco-Friendly Source of Nanomaterials for Sustainable Agroecosystems

Traditional nanoparticle (NP) synthesis methods are expensive and generate hazardous products. It is essential to limit the risk of toxicity in the environment from the chemicals as high temperature and pressure is employed in chemical and physical procedures. One of the green strategies used for sustainable manufacturing is microbial nanoparticle synthesis, which connects microbiology with nanotechnology. Employing biocontrol agents Trichoderma and Hypocrea (Teleomorphs), an ecofriendly and rapid technique of nanoparticle biosynthesis has been reported in several studies which may potentially overcome the constraints of the chemical and physical methods of nanoparticle biosynthesis. The emphasis of this review is on the mycosynthesis of several metal nanoparticles from Trichoderma species for use in agri-food applications. The fungal-cell or cell-extract-derived NPs (mycogenic NPs) can be applied as nanofertilizers, nanofungicides, plant growth stimulators, nano-coatings, and so on. Further, Trichoderma-mediated NPs have also been utilized in environmental remediation approaches such as pollutant removal and the detection of pollutants, including heavy metals contaminants. The plausible benefits and pitfalls associated with the development of useful products and approaches to trichogenic NPs are also discussed.

Green synthesis of selenium nanoparticles and evaluate their effect on the expression of ERG3, ERG11, and FKS1 antifungal resistance genes in Candida albicans and Candida glabrata

Drug resistance in Candida species has been considerably increased in the last decades. Given the opposition to antifungal agents, toxicity, and interactions of the antimicrobial drugs, identifying new antifungal agents seems essential. This study assessed the antifungal effects of nanoparticles (NPs) on the standard strains of Candida albicans and Candida glabrata and determined the expression genes, including ERG3, ERG11, and FKS1. Selenium nanoparticles (Se-NPs) were biosynthesized with a standard strain of C. albicans and approved by several methods including, UV-Vis spectrophotometer, XRD technique, FTIR analysis, FESEM microscopy, and EDX diagram. The antifungal susceptibility testing performed the minimum inhibitory concentrations (MICs) using the CLSI M27-A3 and M27-S4 broth microdilution method. The expression of the desired genes was examined by the real-time PCR assay between untreated and treated by antifungal drugs and Se-NPs. The MICs of itraconazole, amphotericin B, and anidulafungin against C. albicans and C. glabrata were 64, 16, and 4 µg/ml. In comparison, reduced the MIC values ​​for samples treated with Se-NPs to 1 and 0.5 µg/ml. The results obtained from real-time PCR and analysis of the ∆∆C_q values showed that the expression of ERG3, ERG11, and FKS1 genes was significantly down-regulated in Se-NPs concentrations (P<0.05). This study's evidence implies biosafety Se-NPs have favorable effects on the reducing expression of ERG3, ERG11, and FKS1 antifungal resistance genes in C. albicans and C. glabrata.

Silver Nanoparticles as Chlorhexidine and Metronidazole Drug Delivery Platforms: Their Potential Use in Treating Periodontitis

Purpose

Materials and Methods

Results

Conclusion

Biological Synthesis of Nanocatalysts and Their Applications

Over the past few decades, the synthesis and potential applications of nanocatalysts have received great attention from the scientific community. Many well-established methods are extensively utilized for the synthesis of nanocatalysts. However, most conventional physical and chemical methods have some drawbacks, such as the toxicity of precursor materials, the requirement of high-temperature environments, and the high cost of synthesis, which ultimately hinder their fruitful applications in various fields. Bioinspired synthesis is eco-friendly, cost-effective, and requires a low energy/temperature ambient. Various microorganisms such as bacteria, fungi, and algae are used as nano-factories and can provide a novel method for the synthesis of different types of nanocatalysts. The synthesized nanocatalysts can be further utilized in various applications such as the removal of heavy metals, treatment of industrial effluents, fabrication of materials with unique properties, biomedical, and biosensors. This review focuses on the biogenic synthesis of nanocatalysts from various green sources that have been adopted in the past two decades, and their potential applications in different areas. This review is expected to provide a valuable guideline for the biogenic synthesis of nanocatalysts and their concomitant applications in various fields.

Metal Nanoparticles as Novel Antifungal Agents for Sustainable Agriculture: Current Advances and Future Directions

The use of metal nanoparticles is considered a good alternative to control phytopathogenic fungi in agriculture. To date, numerous metal nanoparticles (e.g., Ag, Cu, Se, Ni, Mg, and Fe) have been synthesized and used as potential antifungal agents. Therefore, this proposal presents a critical and detailed review of the use of these nanoparticles to control phytopathogenic fungi. Ag nanoparticles have been the most investigated nanoparticles due to their good antifungal activities, followed by Cu nanoparticles. It was also found that other metal nanoparticles have been investigated as antifungal agents, such as Se, Ni, Mg, Pd, and Fe, showing prominent results. Different synthesis methods have been used to produce these nanoparticles with different shapes and sizes, which have shown outstanding antifungal activities. This review shows the success of the use of metal nanoparticles to control phytopathogenic fungi in agriculture.

Biogenic Silver Nanoparticles: What We Know and What Do We Need to Know?

Nanobiotechnology is considered to be one of the fastest emerging fields. It is still a relatively new and exciting area of research with considerable potential for development. Among the inorganic nanomaterials, biogenically synthesized silver nanoparticles (bio-AgNPs) have been frequently used due to their unique physicochemical properties that result not only from their shape and size but also from surface coatings of natural origin. These properties determine antibacterial, antifungal, antiprotozoal, anticancer, anti-inflammatory, and many more activities of bio-AgNPs. This review provides the current state of knowledge on the methods and mechanisms of biogenic synthesis of silver nanoparticles as well as their potential applications in different fields such as medicine, food, agriculture, and industries.

Fabrication of Silver Nanoparticles Against Fungal Pathogens

The use of silver nanoparticles (AgNPs) against various pathogens is now being well recognized in the agriculture and health sector. Nanoparticles have been shown to exhibit various novel properties and these properties, on other hand, rely upon the size, shape, and morphology of these particles. Moreover, these physical characteristics enable them to interact with microbes, plants, and animals. Smaller-sized particles have shown more toxicity than larger-sized nanoparticles. AgNPs have shown growth inhibition of many fungi like Aspergillus fumigates, A. niger, A. flavus, Trichophyton rubrum, Candida albicans, and Penicillium species. According to the current hypothesis, AgNPs act by producing reactive oxygen species and free radicals, which cause protein denaturation, nucleic acid and proton pump damage, lipid peroxidation, and cell wall damage. Therefore, they alter the cell membrane permeability, causing cell death. This mini-review summarizes the use of silver nanoparticles against fungal pathogens and fungal biofilm in the agricultural sector.

The revolution of cosmeceuticals delivery by using nanotechnology: A narrative review of advantages and side effects

BACKGROUND

The qualified and paradigm jump in the formulation and production of cosmeceuticals refer in some way to the great revolution in nanotechnology. Nowadays, the industry of nano-formulated cosmeceuticals plays a significant and essential role in the evolution and growth of the pharmaceutical industries. This review manuscript focuses on the use of nanocarriers in delivering the cosmetic agents into the target area such as skin, hair, and nails.

METHODS

Many steps were performed in the preparation of this review including identification of different classes of nanocarriers for delivery of nanocosmeceuticals, literature survey of relevantstudies regarding the applications of nanotechnology in cosmeceuticals and their toxicological effects.

RESULTS

When nanoparticles introduced in the cosmetic industry, the quality and the elegance of the final products were raised significantly. Sadly, this revolution is accompanied by many health hazards as these tiny molecules can penetrate intact skin barriers and cause undesired effects. Cosmeceuticals with nanotechnology include sunscreens, hair cleansing products, nail products, and agents fighting fine lines.

CONCLUSIONS

The expansion and growth of the cosmetic industry and the introduction of nanotechnology in cosmeceuticals industry necessitates the urgent need for scientific research investigating their efficacy, safety profile and use.

The effect of biosynthesized selenium nanoparticles on the expression of CYP51A and HSP90 antifungal resistance genes in Aspergillus fumigatus and Aspergillus flavus

The application of biological nanoparticles (NPs) can be considered as a way to overcome the problem of antifungal resistance in pathogenic fungi. This study takes a new approach to biosynthesized NPs influence on the expression of CYP51A and HSP90 antifungal resistance genes in Aspergillus fumigatus and A. flavus, and comparison with antifungal agents. Selenium NPs (Se-NPs) were biosynthesized using Aspergillus strains and their production was proved by several methods including, UV-Vis, XRD, FTIR, FESEM, and EDX techniques. The minimum inhibitory concentrations (MICs) of Aspergillus strains were determined using the CLSI M38-A2 broth microdilution method. The differences in expression levels of CYP51A and HSP90 genes were examined between untreated and treated of A. fumigatus and A. flavus using itraconazole and amphotericin B and biosynthesized Se-NPs through real-time PCR. After confirming the results of NPs synthesis, the MIC of itraconazole and amphotericin B against A. fumigatus and A. flavus was 4 μg/ml. Based on the real-time PCR results, the obtained ∆∆CTs for these strains were -0.18, -1.46, and -1.14. Whereas the MIC values for treated samples with Se-NPs have decreased to 0.5 μg/ml, and the ∆∆CTs for these were -0.25, -1.76, and -1.68. The expression of CYP51A and HSP90 genes was significantly down-regulated through the use of Se-NPs against A. fumigatus and A. flavus.

Nanoarchitectures in Management of Fungal Diseases: An Overview

Fungal infections, from mild itching to fatal infections, lead to chronic diseases and death. Antifungal agents have incorporated chemical compounds and natural products/phytoconstituents in the management of fungal diseases. In contrast to antibacterial research, novel antifungal drugs have progressed more swiftly because of their mild existence and negligible resistance of infections to antifungal bioactivities. Nanotechnology-based carriers have gained much attention due to their magnificent abilities. Nanoarchitectures have served as excellent carriers/drug delivery systems (DDS) for delivering antifungal drugs with improved antifungal activities, bioavailability, targeted action, and reduced cytotoxicity. This review outlines the different fungal diseases and their treatment strategies involving various nanocarrier-based techniques such as liposomes, transfersomes, ethosomes, transethosomes, niosomes, spanlastics, dendrimers, polymeric nanoparticles, polymer nanocomposites, metallic nanoparticles, carbon nanomaterials, and nanoemulsions, among other nanotechnological approaches.

In Vitro Antifungal Activity of Green Synthesized Silver Nanoparticles in Comparison to Conventional Antifungal Drugs Against Trichophyton Interdigitale, Trichophyton Rubrum and Epidermophyton Floccosum

BACKGROUND

Dermatophytosis is a globally distributed fungal infection. Treatment failure and relapse is common in this disease. Silver nanoparticles are known for their promising antimicrobial activity. The aim of this study was to determine the antifungal activity of these nanoparticles against common dermatophyte species.

METHODS

A set of 30 molecularly identified dermatophytes including Trichophyton interdigitale (n=10), Trichophyton rubrum (n=10), and Epidermophyton floccosum (n=10) were used in this study. Green synthesized silver nanoparticles using chicory (Cichorium intybus) were tested for their antifungal activity in comparison to fluconazole, itraconazole and terbinafine. Interspecies differences in minimum inhibitory concentrations of antifungal drugs and silver nanoparticles were tested using Kruskal-Wallis test in SPSS software version 21.

RESULTS

The highest minimum inhibitory concentrations (MICs) among antifungal drugs were observed for fluconazole [range: 4-64 μg/mL, geometric mean (GM) =17.959 μg/mL], followed by itraconazole (range: 0.008-0.5, GM= 0.066) and terbinafine (range: 0.004-0.25 μg/mL, GM=0.027 μg/mL). Silver nanoparticles showed potent antifungal activity against all dermatophyte isolates with MICs (range: 0.25-32 μg/mL, GM=4.812 μg/mL) higher than those of itraconazole and terbinafine, but lower than fluconazole. MIC values of silver nanoparticles demonstrated significant differences between species (P=0.044), with E. floccosum having the highest MICs (GM=9.849 μg/mL) compared to T. interdigitale (GM=3.732 μg/mL) and T. rubrum (GM=3.031 μg/mL).

CONCLUSION

Silver nanoparticles demonstrated promising anti-dermatophyte activity against the studied dermatophytes. Due to their wide-spectrum activity against other fungal and bacterial pathogens, they could be a potential choice, at least in the case of cutaneous and superficial infections.

Scanning electron microscopy of bio-fabricated Fe2 O3 nanoparticles and their application to control brown rot of citrus

Citrus is the leading fruit crop of Pakistan and exported to different parts of the world. Due to suitable weather condition, this crop is affected by different biotic factors which seriously deteriorate its quality and quantity. During the months of November 2018 to January 2019, citrus brown rot symptoms were recurrently observed on sweet oranges in National Agricultural Research Centre (NARC), Islamabad. Causal agent of citrus brown rot was isolated, characterized, and identified as Fusarium oxysporum. For environment-friendly control of this disease, leaf extract of Azadirachta indica was used for the green synthesis of iron oxide (Fe₂ O₃ ) nanoparticles. These nanoparticles were characterized before their application for disease control. Fourier transform infrared spectroscopy (FTIR) of these synthesized nanoparticles described the presence of stabilizing and reducing compounds like alcohol, phenol, carboxylic acid, and alkaline and aromatic compounds. X-Ray diffraction (XRD) analysis revealed the crystalline nature and size (24 nm) of these nanoparticles. Energy dispersive X-Ray (EDX) analysis elaborated the presence of major elements in the samples. Scanning electron microscopy (SEM) confirmed the spinal shaped morphology of prepared nanoparticles. Successfully synthesized nanoparticles were evaluated for their antifungal potential. Different concentrations of Fe₂ O₃ nanoparticles were used and maximum mycelial inhibition was observed at 1.0 mg/ml concentration. On the basis of these findings, it could be concluded that Fe₂ O₃ nanoparticles, synthesized in the leaf extract of A. indica, can be successfully used for the control of brown rot of sweet oranges.

Modified Nanoparticles as Potential Agents in Bone Diseases: Cancer and Implant-Related Complications

Materials sized 1-100 nm are the nanotechnology's field of interest. Because of the unique properties such as the ability to penetrate biological barriers and a high surface to volume ratio, nanoparticles (NPs) are a powerful tool to be used in medicine and industry. This review discusses the role of nanotechnology in bone-related issues: osteosarcoma (bone cancer), the biocompatibility of the implants and implant-related infections. In cancer therapy, NPs can be used as (I) cytotoxic agents, (II) drug delivery platforms and (III) in thermotherapy. In implant-related issues, NPs can be used as (I) antimicrobial agents and (II) adjuvants to increase the biocompatibility of implant surface. Properties of NPs depend on (I) the type of NPs, (II) their size, (III) shape, (IV) concentration, (V) incubation time, (VI) functionalization and (VII) capping agent type.

Biogenic synthesis and antimicrobial activity of silica-coated silver nanoparticles for esthetic dental applications

OBJECTIVES

this study aimed to synthesize AgNPs from green tea (GT) extract, forming GT-AgNPs, and to coat their surfaces with silica, resulting in light-colored Ag@SiO₂ nanoparticles.

MATERIALS AND METHODS

particles were characterized and tested for minimal inhibitory concentration (MIC), biofilm formation against Streptococcus mutans and cytotoxicity evaluation on dental pulp fibroblasts.

RESULTS

X-ray diffraction (XRD) confirmed the formation of pure AgNPs, whereas energy dispersive X-ray spectroscopy (EDS) mapped their elemental atoms. Dynamic light scattering (DLS) demonstrated formation of particles at nanoscale, with moderate polydispersity and negative zeta potential, in agreement with nanoparticle tracking analysis (NTA) size measurements. Fourier-transformed infrared (FTIR) spectroscopy confirmed the successful condensation of silica, which significantly increased surface area by 50%, as assayed by surface area analysis (BET). Thermogravimetric analysis showed a 18%-mass of silica on the surface of Ag@SiO₂NPs. Transmission electron microscopy (TEM) displayed the spherical shape of nanoparticles and average size of 11 nm for GT-AgNPs and Ag@SiO₂NPs. Ag@SiO₂NPs demonstrated potent antimicrobial action against S. mutans, with MIC determined as 600 μg/mL, and inhibition of approximately 44% (p < 0.05) of biofilm formation. At the MIC concentrations, both NPs did not exhibit cytotoxicity.

CONCLUSION

Ag@SiO₂NPs might have a useful application in dental materials.

CLINICAL SIGNIFICANCE

The possibility of incorporating antimicrobial properties in restorative materials without compromising esthetics makes the AgNPs@SiO₂ NPs promising agents against S. mutans biofilm formation, hence the prevention of dental caries. This represents a great step towards the development of more interactive biomaterials in dentistry to overcome clinical problems.

Nanomaterials for Skin Delivery of Cosmeceuticals and Pharmaceuticals

Skin aging is described as dermatologic changes either naturally occurring over the course of years or as the result of the exposure to environmental factors (e.g., chemical products, pollution, infrared and ultraviolet radiations). The production of collagen and elastin, the main structural proteins responsible for skin strength and elasticity, is reduced during aging, while their role in skin rejuvenation can trigger a wrinkle reversing effect. Elasticity loss, wrinkles, dry skin, and thinning are some of the signs that can be associated with skin aging. To overcome skin aging, many strategies using natural and synthetic ingredients are being developed aiming to reduce the signs of aging and/or to treat age-related skin problems (e.g., spots, hyper- or hypopigmentation). Among the different approaches in tissue regeneration, the use of nanomaterials loaded with cosmeceuticals (e.g., phytochemicals, vitamins, hyaluronic acid, and growth factors) has become an interesting alternative. Based on their bioactivities and using different nanoformulations as efficient delivery systems, several cosmeceutical and pharmaceutical products are now available on the market aiming to mitigate the signs of aged skin. This manuscript discusses the state of the art of nanomaterials commonly used for topical administration of active ingredients formulated in nanopharmaceuticals and nanocosmeceuticals for skin anti-aging.

Synthesis of Silver Nanoparticles Mediated by Fungi: A Review

The use of fungi as reducing and stabilizing agents in the biogenic synthesis of silver nanoparticles is attractive due to the production of large quantities of proteins, high yields, easy handling, and low toxicity of the residues. Furthermore, this synthesis process coats the nanoparticles with biomolecules derived from the fungus, which can improve stability and may confer biological activity. The aim of this review is to describe studies in which silver nanoparticles were synthesized using fungi as reducing agents, discussing the mechanisms and optimization of the synthesis, as well as the applications. The literature shows that various species of fungus have potential for use in biogenic synthesis, enabling the production of nanoparticles with different characteristics, considering aspects such as their size, surface charge, and morphology. The synthesis mechanisms have not yet been fully elucidated, although it is believed that fungal biomolecules are mainly responsible for the process. The synthesis can be optimized by adjusting parameters such as temperature, pH, silver precursor concentration, biomass amount, and fungus cultivation time. Silver nanoparticles synthesized using fungi enable the control of pathogens, with low toxicity and good biocompatibility. These findings open perspectives for future investigations concerning the use of these nanoparticles as antimicrobials in the areas of health and agriculture.

Antifungal activity of silver nanoparticles in combination with ketoconazole against Malassezia furfur

Malassezia furfur is lipophilic and lipid-dependent yeast, inhabitant of human skin microbiota associated with several dermal disorders. In recent years, along with the advances in nanotechnology and the incentive to find new antimicrobial drugs, there has been a growing interest in the utilization of nanoparticles for the treatment of skin microbial infections. This work aimed to study the in vitro inhibitory activity of silver nanoparticles (AgNP) against 41 M. furfur clinical isolates, visualize the interaction between AgNP-Malassezia, evaluate the synergism with ketoconazole (KTZ) and to produce an antimicrobial gel of AgNP–KTZ. The synthesized AgNP were randomly distributed around the yeast surface and showed a fungicidal action with low minimal inhibitory concentration values. AgNP showed no antagonistic effect with KTZ. The broad-spectrum antimicrobial property with fungicidal action of AgNP and its accumulation in affected areas with a sustained release profile, added to the great antifungal activity of KTZ against Malassezia infections and other superficial mycoses, allowed us to obtain a gel based on carbopol formulated with AgNP–KTZ with the potential to improve the topical therapy of superficial malasseziosis, reduce the number of applications and, also, prevent the recurrence.

Acinetobacter sp. mediated synthesis of AgNPs, its optimization, characterization and synergistic antifungal activity against C. albicans

AIMS

To synthesize silver nanoparticles (AgNPs) with cell free extract of Acinetobacter sp. and evaluate antifungal activity against planktonic and biofilm of Candida. Also, to study mechanism of antifungal action of AgNPs.

METHODS AND RESULT

Acinetobacter spp were screened for synthesis of AgNPs. Physio-chemical parameters were optimized to obtained monodispersed nanoparticles. Optimized nanoparticles were characterized using spectroscopic, microscopic and diffraction techniques. Antifungal and biofilm disruption activity of AgNPs (10 ± 5 nm) were investigated against C. albicans. Mechanism of antifungal activity of nanosilver was deduced by growth curve, reactive oxygen species generation, thiol interaction and microscopic analysis. Acinetobacter sp. GWRFH 45 gave maximum synthesis of AgNPs. At optimized condition monodispersed, spherical nanoparticles were obtained which were crystalline with negative surface charge. AgNPs exhibited antifungal activity against planktonic cells and biofilm of Candida. AgNPs showed synergistic effect with amphotericin B as well as fluconazole against biofilm disruption. AgNPs were found to affect growth of Candida, generate reactive oxygen species and disrupt cellular morphology.

CONCLUSIONS

Cell free extract of A. calcoaceticus GWRFH 45 has ability to synthesize AgNPs. AgNPs alone and in combination with drugs have potential to inhibit C. albicans.

SIGNIFICANCE AND IMPACT OF THE STUDY

This is the first report of bacteriogenic AgNPs used in combination with antifungal drugs against Candida.

Development of a new synthetic xerogel nanoparticles of silver and zinc oxide against causative agents of dermatophytoses

BACKGROUND

Dermatophytes, which are the common causative agents of superficial infection on the human skin called dermatophytosis that can be treated by various antifungal drugs. Nanoparticles composed of such drugs have many benefits. A new form called xerogel of silver nanoparticles (Ag-NPs) and zinc oxide nanoparticles (ZnO-NPs) was prepared and tested against dermatophytes.

METHODS

Xerogel consists of Ag-NPs and ZnO-NPs was prepared. Characteristics of chemical composition, surface morphology, and nanoparticle size were determined. Antidermatophytic action of prepared xerogel was investigated against Trichophyton mentagrophytes and Trichophyton verrucosum.

RESULTS

The new preparation exhibited satisfactory character of xerogel nanoparticles. Trichophyton mentagrophytes showed more susceptibility to xerogel with lower minimum inhibitory concentration than T. verrucosum.

CONCLUSIONS

Xerogel nanoparticles composed of Ag and ZnO were successfully prepared. They had antidermatophytic action in specific concentrations.

Size and coating of engineered silver nanoparticles determine their ability to growth-independently inhibit aflatoxin biosynthesis in Aspergillus parasiticus

Recent studies from our laboratory indicate that engineered silver nanoparticles can inhibit aflatoxin biosynthesis even at concentrations at which they do not demonstrate antifungal activities on the aflatoxin-producing fungus. Whether such inhibition can be modified by altering the nanoparticles' physical properties remains unclear. In this study, we demonstrate that three differently sized citrated-coated silver nanoparticles denoted here as NP1, NP2, and NP3 (where, sizes of NP1 < NP2 < NP3) inhibit aflatoxin biosynthesis at different effective doses in Aspergillus parasiticus, the plant pathogenic filamentous fungus. Recapping NP2 with polyvinylpyrrolidone coating (denoted here as NP2p) also altered its ability to inhibit aflatoxin production. Dose-response experiments with NP concentrations ranging from 10 to 100 ng mL^-1 indicated a non-monotonic relationship between aflatoxin inhibition and NP concentration. The maximum inhibitory concentrations differed between the NP types. NP1 demonstrated maximum inhibition at 25 ng mL^-1. Both NP2 and NP3 showed maximum inhibition at 50 ng mL^-1, although NP2 resulted in a significantly higher inhibition than NP3. While both NP2 and NP2p demonstrated greater aflatoxin inhibition than NP1 and NP3, NP2p inhibited aflatoxin over a significantly wider concentration range as compared to NP2. Our results, therefore, suggest that nano-fungal interactions can be regulated by altering certain NP physical properties. This concept can be used to design NPs for mycotoxin prevention optimally.

Biological filters and their use in potable water filtration systems in spaceflight conditions

Providing drinking water to space missions such as the International Space Station (ISS) is a costly requirement for human habitation. To limit the costs of water transport, wastewater is collected and purified using a variety of physical and chemical means. To date, sand-based biofilters have been designed to function against gravity, and biofilms have been shown to form in microgravity conditions. Development of a universal silver-recycling biological filter system that is able to function in both microgravity and full gravity conditions would reduce the costs incurred in removing organic contaminants from wastewater by limiting the energy and chemical inputs required. This paper aims to propose the use of a sand-substrate biofilter to replace chemical means of water purification on manned spaceflights.

Role of Nanotechnology in Cosmeceuticals: A Review of Recent Advances

Nanotechnology manifests the progression in the arena of research and development, by increasing the efficacy of the product through delivery of innovative solutions. To overcome certain drawbacks associated with the traditional products, application of nanotechnology is escalating in the area of cosmeceuticals. Cosmeceuticals are regarded as the fastest growing segment of the personal care industry and the use has risen drastically over the years. Nanocosmeceuticals used for skin, hair, nail, and lip care, for conditions like wrinkles, photoaging, hyperpigmentation, dandruff, and hair damage, have come into widespread use. Novel nanocarriers like liposomes, niosomes, nanoemulsions, microemulsion, solid lipid nanoparticles, nanostructured lipid carrier, and nanospheres have replaced the usage of conventional delivery system. These novel nanocarriers have advantages of enhanced skin penetration, controlled and sustained drug release, higher stability, site specific targeting, and high entrapment efficiency. However, nanotoxicological researches have indicated concern regarding the impact of increased use of nanoparticles in cosmeceuticals as there are possibilities of nanoparticles to penetrate through skin and cause health hazards. This review on nanotechnology used in cosmeceuticals highlights the various novel carriers used for the delivery of cosmeceuticals, their positive and negative aspects, marketed formulations, toxicity, and regulations of nanocosmeceuticals.

Fungal silver nanoparticles: synthesis, application and challenges

PURPOSE

This paper aims to summarize recent developments regarding the synthesis, application and challenges of fungal AgNPs. Possible methods to overcome the challenge of synthesis and reduce the toxicity of AgNPs have been discussed.

MATERIALS AND METHODS

This review consults and summary a large number of papers.

RESULTS

Silver nanoparticles (AgNPs) have great potential in many areas, as they possess multiple novel characteristics. Conventional methods for AgNPs biosynthesis involve chemical agents, causing environmental toxicity and high energy consumption. Fungal bioconversion is a simple, low-cost and energy-efficient biological method, which could successfully be used for AgNPs synthesis. Fungi can produce enzymes that act as both reducing and capping agents, to form stable and shape-controlled AgNPs.

CONCLUSIONS

AgNPs have great potential in the medical and food industries, due to their antimicrobial, anticancer, anti-HIV, and catalytic activities. However, the observed in vitro and in vivo toxicity poses considerable challenges in the synthesis and application of AgNPs.