Unveiling biological activities of biosynthesized starch/silver-selenium nanocomposite using Cladosporium cladosporioides CBS 174.62.

BACKGROUND AND OBJECTIVES: Microbial cells capability to tolerate the effect of various antimicrobial classes represent a major worldwide health concern. The flexible and multi-components nanocomposites have enhanced physicochemical characters with several improved properties. Thus, different biological activities of biosynthesized starch/silver-selenium nanocomposite (St/Ag-Se NC) were assessed. METHODOLOGY: The St/Ag-Se NC was biosynthesized using Cladosporium cladosporioides CBS 174.62 (C. cladosporioides) strain. The shape and average particle size were investigated using scanning electron microscope (SEM) and high-resolution transmission electron microscope (HR-TEM), respectively. On the other hand, the St/Ag-Se NC effect on two cancer cell lines and red blood cells (RBCs) was evaluated and its hydrogen peroxide (H2O2) scavenging effect was assessed. Moreover, its effects on various microbial species in both planktonic and biofilm growth forms were examined. RESULTS: The St/Ag-Se NC was successfully biosynthesized with oval and spherical shape and a mean particle diameter of 67.87 nm as confirmed by the HR-TEM analysis. St/Ag-Se NC showed promising anticancer activity toward human colorectal carcinoma (HCT-116) and human breast cancer (MCF-7) cell lines where IC50 were 21.37 and 19.98 µg/ml, respectively. Similarly, little effect on RBCs was observed with low nanocomposite concentration. As well, the highest nanocomposite H2O2 scavenging activity (42.84%) was recorded at a concentration of 2 mg/ml. Additionally, Staphylococcus epidermidis (S. epidermidis) ATCC 12,228 and Candida albicans (C. albicans) ATCC 10,231 were the highly affected bacterial and fungal strains with minimum inhibitory concentrations (MICs) of 18.75 and 50 µg/ml, respectively. Moreover, the noticeable effect of St/Ag-Se NC on microbial biofilm was concentration dependent. A high biofilm suppression percentage, 87.5% and 68.05%, were recorded with S. epidermidis and Staphylococcus aureus (S. aureus) when exposed to 1 mg/ml and 0.5 mg/ml, respectively. CONCLUSION: The biosynthesized St/Ag-Se NC showed excellent antioxidant activity, haemocompatibility, and anti-proliferative effect at low concentrations. Also, it exhibited promising antimicrobial and antibiofilm activities.

Pomegranate Peel Extract Stabilized Selenium Nanoparticles Synthesis: Promising Antimicrobial Potential, Antioxidant Activity, Biocompatibility, and Hemocompatibility.

The green synthesis of selenium nanoparticles (Se NPs) had been synthesized by pomegranate peel extract (PPE). The antimicrobial, antioxidant, and anticancer activities of the synthesized Se NPs, as well as their hemocompatibility, were investigated. Se NPs were characterized by UV-Vis., SEM, XRD, HR-TEM, DLS, EDX, FTIR, and mapping techniques. HR-TEM image represented the spheroidal forms with moderately monodispersed NPs with a mean diameter 14.5 nm. The SEM image of Se NPs, incorporated with PPE, exhibits uniform NP surfaces, and the appearance was clear. The antimicrobial results confirmed the potential of Se NPs to hinder the growth of some tested pathogenic microbes. Results revealed that Se NPs exhibited promising antibacterial activity against Escherichia coli, Pseudomonas aeruginosa, Bacillus subtilis, Staphylococcus aureus, and Streptococcus mutans where inhibition zones were 29, 16, 41, 22, and 54 mm, respectively. Likewise, it exhibited antifungal activity where the values of inhibition zones were 41, 40, 38, and 36 mm against Candida albicans, Cryptococcus neoformans, Aspergillus fumigatus, and A. niger, respectively. The antioxidant activities of Se NPs at concentrations 250-4000 µg/mL were greater than 90% in all cases. Se NP concentrations of 500 µg/mL or less are safe in usage according to hemocompatibility study. Se NPs had an IC50 of 113.73 µg/mL in a cytotoxicity experiment. Results revealed that Se NPs have promising anticancer activities against MCF7 and Mg63 cancerous cell line, where IC50 was 69.8 and 47.9 µg/mL, respectively. In conclusion, Se NPs were successfully biosynthesized using PPE for the first time; these Se NPs had promising antimicrobial, antioxidant, and anticancer activities.

Antifungal Activity of Biosynthesized Silver Nanoparticles (AgNPs) against Aspergilli Causing Aspergillosis: Ultrastructure Study.

Currently, nanoparticles and nanomaterials are widely used for biomedical applications. In the present study, silver nanoparticles (AgNPs) were successfully biosynthesized using a cell-free extract (CFE) of Bacillus thuringiensis MAE 6 through a green and ecofriendly method. The size of the biosynthesized AgNPs was 32.7 nm, and their crystalline nature was confirmed by XRD, according to characterization results. A surface plasmon resonance spectrum of AgNPs was obtained at 420 nm. Nanoparticles were further characterized using DLS and FTIR analyses, which provided information on their size, stability, and functional groups. AgNPs revealed less cytotoxicity against normal Vero cell line [IC50 = 155 µg/mL]. Moreover, the biosynthesized AgNPs exhibited promising antifungal activity against four most common Aspergillus, including Aspergillus niger, A. terreus, A. flavus, and A. fumigatus at concentrations of 500 µg/mL where inhibition zones were 16, 20, 26, and 19 mm, respectively. In addition, MICs of AgNPs against A. niger, A. terreus, A. flavus, and A. fumigatus were 125, 62.5, 15.62, and 62.5 µg/mL, respectively. Furthermore, the ultrastructural study confirmed the antifungal effect of AgNPs, where the cell wall's integrity and homogeneity were lost; the cell membrane had separated from the cell wall and had intruded into the cytoplasm. In conclusion, the biosynthesized AgNPs using a CFE of B. thuringiensis can be used as a promising antifungal agent against Aspergillus species causing Aspergillosis.

Comparative Genotypic Analysis of RAPD and RFLP Markers for Molecular Variation Detection of Methicillin-Resistant Staphylococcus aureus Clinical Isolates.

Background and Objectives: Methicillin-resistant Staphylococcus aureus (MRSA) isolates are associated with various diseases ranged from mild superficial impairments to invasive infections. This study aimed to evaluate the ability of polymerase chain reaction (PCR) based methods namely, restriction fragment length polymorphism (RFLP) of the coa gene and random amplified polymorphic DNA (RAPD), to determine the genetic diversity of MRSA isolates. Materials and Methods: A total of 37 MRSA isolates were conventionally identified depending on their biochemical and microbiological culture characteristics. Genotypic confirmation was based on detection of the associated mecA gene. The genetic variation amongst MRSA isolates was evaluated following the coa gene-based RFLP and RAPD fingerprints. Results: Results illustrated that, the species specific coa gene was detected in all MRSA isolates. The irregular bands intensity, number, and molecular sizes of the PCR amplicons demonstrated the coa gene polymorphism. The incompatible AluI digestion patterns of these amplicons classified the tested MRSA isolates into 20 RFLP patterns which confirm the coa gene polymorphism. Additionally, the PCR-based RAPD analysis showed variable bands number with size range of approximately 130 bp to 4 kbp, which indicated the genetic variation of the tested MRSA isolates as it created 36 variable RAPD banding profiles. Conclusions: coa gene AluI enzymatic restriction sites, amongst the tested MRSA isolates, certify their genetic variation on the basis of the accurate but complicated and relatively expensive coa gene-based RFLP. Conversely, the results verified the excellent ability of the simple and cost-effective PCR-based RAPD analysis to discriminate between MRSA isolates without any preface data about the genome.

Mycosynthesis of Hematite (α-Fe2O3) Nanoparticles Using Aspergillus niger and Their Antimicrobial and Photocatalytic Activities.

Nanoparticles (NPs) and nanomaterials (NMs) are now widely used in a variety of applications, including medicine, solar energy, drug delivery, water treatment, and pollution detection. Hematite (α-Fe2O3) nanoparticles (Hem-NPs) were manufactured in this work by utilizing a cost-effective and ecofriendly approach that included a biomass filtrate of A. niger AH1 as a bio-reducer. The structural and optical properties of Hem-NPs were investigated using X-ray diffraction (XRD), transmission electron microscopy (TEM), dynamic light scattering (DLS), and UV-visible and Fourier-transform infrared (FTIR) spectroscopies. The results revealed that all of the studied parameters, as well as their interactions, had a significant impact on the crystallite size. The average diameter size of the biosynthesized Hem-NPs ranged between 60 and 80 nm. The antimicrobial and photocatalytic activities of Hem-NPs were investigated. The antimicrobial results of Hem-NPs revealed that Hem-NPs exhibited antibacterial activity against E. coli, B. subtilis, and S. mutans with MICs of 125, 31.25, and 15.62 µg/mL, respectively. Moreover, Hem-NPs exhibited antifungal activity against C. albicans and A. fumigatus, where the MICs were 2000 and 62.5 µg/mL, respectively. The efficiency of biosynthesized Hem-NPs was determined for the rapid biodegradation of crystal violet (CV) dye, reaching up to 97 percent after 150 min. Furthermore, Hem-NPs were successfully used more than once for biodegradation and that was regarded as its efficacy. In conclusion, Hem-NPs were successfully biosynthesized using A. niger AH1 and demonstrated both antimicrobial activity and photocatalytic activity against CV dye.

Multifunctional Silver Nanoparticles Based on Chitosan: Antibacterial, Antibiofilm, Antifungal, Antioxidant, and Wound-Healing Activities.

The purpose of this study is to create chitosan-stabilized silver nanoparticles (Chi/Ag-NPs) and determine whether they were cytotoxic and also to determine their characteristic antibacterial, antibiofilm, and wound healing activities. Recently, the development of an efficient and environmentally friendly method for synthesizing metal nanoparticles based on polysaccharides has attracted a lot of interest in the field of nanotechnology. Colloidal Chi/Ag-NPs are prepared by chemical reduction of silver ions in the presence of Chi, giving Chi/Ag-NPs. Physiochemical properties are determined by Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), transmission electron microscopy (TEM), dynamic light scattering (DLS), and scanning electron microscopy with energy-dispersive X-ray spectroscopy (SEM-EDX) analyses. TEM pictures indicate that the generated Chi/Ag-NPs are nearly spherical in shape with a thin chitosan covering around the Ag core and had sizes in the range of 9-65 nm. In vitro antibacterial activity was evaluated against Staphylococcus aureus and Pseudomonas aeruginosa by a resazurin-mediated microtiter plate assay. The highest activity was observed with the lowest concentration of Chi/Ag-NPs, which was 12.5 µg/mL for both bacterial strains. Additionally, Chi/Ag-NPs showed promising antifungal features against Candida albicans, Aspergillus fumigatus, Aspergillus terreus, and Aspergillus niger, where inhibition zones were 22, 29, 20, and 17 mm, respectively. Likewise, Chi/Ag-NPs revealed potential antioxidant activity is 92, 90, and 75% at concentrations of 4000, 2000, and 1000 µg/mL, where the IC50 of Chi/Ag-NPs was 261 µg/mL. Wound healing results illustrated that fibroblasts advanced toward the opening to close the scratch wound by roughly 50.5% after a 24-h exposure to Chi/Ag-NPs, greatly accelerating the wound healing process. In conclusion, a nanocomposite based on AgNPs and chitosan was successfully prepared and exhibited antibacterial, antibiofilm, antifungal, antioxidant, and wound healing activities that can be used in the medical field.

Green Biosynthesis of Selenium Nanoparticles Using Orange Peel Waste: Characterization, Antibacterial and Antibiofilm Activities against Multidrug-Resistant Bacteria.

There is an increase of pathogenic multidrug-resistant bacteria globally due to the misuse of antibiotics. Recently, more scientists used metal nanoparticles to counteract antibacterial resistance. In this study, orange peel waste (OPW) was used for selenium nanoparticles' (Se-NPs) biosynthesis through the green and ecofriendly method, and their applications as antibacterial and antibiofilm agents. Green biosynthesized Se-NPs were characterized using FTIR, XRD, SEM, EDAX, and TEM. Characterization results revealed that biosynthesized Se-NPs were highly crystalline, spherical, and polydisperse, and had sizes in the range of 16-95 nm. The biosynthesized Se-NPs were evaluated as antibacterial and antibiofilm activities against multidrug-resistant bacteria. Results illustrated that Se-NPs exhibited potential antibacterial activity against Gram-positive bacteria (S. aureus ATCC 29213 and biofilm-producing clinical isolates of S. aureus) and Gram-negative bacteria (Pseudomonas aeruginosa PAO1, MDR, biofilm, and quorum-sensing and producing clinical isolates of MDR P. aeruginosa, MDR E. coli, and K. pneumonia). Moreover, results illustrated that S. aureus ATCC 29213 was the most sensitive bacteria to Se-NPs at 1000 µg/mL, where the inhibition zone was 35 mm and MIC was 25 µg/mL. Furthermore, Se-NPs at 0.25 and 0.5 MIC decreased the biofilm significantly. The largest inhibition of biofilm was noticed in MDR K. pneumonia, which was 62% and 92% at 0.25 and 0.5 MIC, respectively. In conclusion, Se-NPs were successfully biosynthesized using OPW through the green method and had promising antibacterial and antibiofilm activity against multidrug-resistant bacteria, which can be used later in fighting resistant bacteria.