Effect of Microsphere Concentration on Catechin Release from Microneedle Arrays.

In this work, microspheres were developed by cross-linking glutaraldehyde in an aqueous gelatin solution with a surfactant and solvent. A poly(vinyl alcohol) (PVA) solution was produced and combined with catechin-loaded microspheres. Different microsphere concentrations (0%, 5%, 10%, and 15%) were applied to the PVA microneedles. The moisture content, particle size, swelling, and drug release percentage of microneedles were studied using various microsphere concentrations. Fourier transform infrared and scanning electron microscopy (SEM) investigations validated the structure of gelatin microspheres as well as their decoration in microneedles. The SEM scans revealed that spherical microspheres with a wrinkled and folded morphology were created, with no physical holes visible on the surface. The gelatin microspheres generated had a mean particle size of 20-30 µm. Ex vivo release analysis indicated that microneedles containing 10% microspheres released the most catechin, with 42.9% at 12 h and 84.4% at 24 h.

Green Synthesis of Controlled Shape Silver Nanostructures and Their Peroxidase, Catalytic Degradation, and Antibacterial Activity.

Nanoparticles with unique shapes have garnered significant interest due to their enhanced surface area-to-volume ratio, leading to improved potential compared to their spherical counterparts. The present study focuses on a biological approach to producing different silver nanostructures employing Moringa oleifera leaf extract. Phytoextract provides metabolites, serving as reducing and stabilizing agents in the reaction. Two different silver nanostructures, dendritic (AgNDs) and spherical (AgNPs), were successfully formed by adjusting the phytoextract concentration with and without copper ions in the reaction system, resulting in particle sizes of ~300 ± 30 nm (AgNDs) and ~100 ± 30 nm (AgNPs). These nanostructures were characterized by several techniques to ascertain their physicochemical properties; the surface was distinguished by functional groups related to polyphenols due to plant extract that led to critical controlling of the shape of nanoparticles. Nanostructures performance was assessed in terms of peroxidase-like activity, catalytic behavior for dye degradation, and antibacterial activity. Spectroscopic analysis revealed that AgNDs demonstrated significantly higher peroxidase activity compared to AgNPs when evaluated using chromogenic reagent 3,3',5,5'-tetramethylbenzidine. Furthermore, AgNDs exhibited enhanced catalytic degradation activities, achieving degradation percentages of 92.2% and 91.0% for methyl orange and methylene blue dyes, respectively, compared to 66.6% and 58.0% for AgNPs. Additionally, AgNDs exhibited superior antibacterial properties against Gram-negative E. coli compared to Gram-positive S. aureus, as evidenced by the calculated zone of inhibition. These findings highlight the potential of the green synthesis method in generating novel nanoparticle morphologies, such as dendritic shape, compared with the traditionally synthesized spherical shape of silver nanostructures. The synthesis of such unique nanostructures holds promise for various applications and further investigations in diverse sectors, including chemical and biomedical fields.

Green in situ immobilization of gold and silver nanoparticles on bacterial nanocellulose film using Punica granatum peels extract and their application as reusable catalysts.

In this study, Punica granatum peels extract induced in situ deposition was applied to prepare Au and Ag nanoparticles on bacterial nanocellulose film. Bacterial nanocellulose provided as an eco-friendly and excellent support for the interaction of P. granatum peel biomolecules and further reduction of Au and Ag ions. Meanwhile, a possible in situ growth mechanism of Au and Ag on bacterial cellulose by P. granatum peel extract biomolecules was presented. Further, the metal nanoparticles incorporated bacterial cellulose films were used to catalyze the reduction of 4-nitrophenol. The results of the present study indicated excellent catalytic reduction properties of Au and Ag nanocellulose films for 4 consecutive cycles. In addition, Au and Ag incorporated cellulose nanofiber films exhibited superior antioxidant activity and improved mechanical properties compared to pristine cellulose nanofiber film. The findings of this study may provide new insights and broad application of bacterial cellulose and green synthesis method for the development of various metal-cellulose composites.

Biodegradable films based on chitosan and defatted Chlorella biomass: Functional and physical characterization.

Biodegradable films based on chitosan, glycerol, and defatted Chlorella biomass (DCB) were prepared and characterized in terms of thermal stability, mechanical, water barrier, and optical properties. Increasing DCB content from 5 to 25 wt% increased tensile strength of chitosan films by 235%. The incorporation of DCB decreased both moisture content and swelling degree of chitosan/defatted Chlorella biomass (Cs/DCB) films. Furthermore, increasing the content of defatted algal biomass decreased light transmission and reduced water vapor permeability of composite films by more than 60%. As confirmed by scanning electron microscopy and Fourier transform infrared analysis, such improvement in functional and physical properties is mainly due to the homogeneous and uniform distribution of DCB into the polymeric matrix along with the establishment of strong hydrogen bond interactions between chitosan and algal biomass constituents. Moreover, Cs/DCB composite films showed more than 50% of degradation in 60 days soil burial test.

Ultrasound Assisted Green Synthesis of Silver and Iron Oxide Nanoparticles Using Fenugreek Seed Extract and Their Enhanced Antibacterial and Antioxidant Activities.

This study reports a facile and ecofriendly approach for the ultrasound assisted synthesis of silver and iron oxide nanoparticles and their enhanced antibacterial and antioxidant activities. The fenugreek seed extract was used as reducing, capping, and stabilizing agent in the synthesis of nanoparticles. The transmission electron microscopy results showed that nanoparticles synthesized by ultrasonication have a smaller size (~20 nm) as compared to the nanoparticles fabricated by magnetic stirring (~40 nm). The color change of the solution from milky white to brown suggested the formation of silver nanoparticles which was confirmed by the presence of an absorbance peak at 396 nm. The results of powder X-ray diffraction and energy dispersive X-ray spectroscopy confirmed the crystallinity and elements present in nanoparticles synthesized using fenugreek seed extract. Fourier transform infrared analysis showed that the fenugreek seed phytochemicals were coated on the nanoparticle surface. Thermal gravimetric analysis showed the thermal degradation and stability of nanoparticles. Magnetization study of iron oxide nanoparticles confirmed the superparamagnetic nature. The silver nanoparticles showed antibacterial activities against both gram-negative (Escherichia coli) and gram-positive (Staphylococcus aureus) bacteria, while no antibacterial activities were observed for iron oxide nanoparticles. The ultrasound assisted nanoparticles showed higher stability and antibacterial and antioxidant activity compared with the nanoparticles fabricated by magnetic stirring.