Topological and morphological analysis of gamma rays irradiated chitosan-poly (vinyl alcohol) blends using atomic force microscopy

Development of Nano-Antifungal Therapy for Systemic and Endemic Mycoses

Fungal mycoses have become an important health and environmental concern due to the numerous deleterious side effects on the well-being of plants and humans. Antifungal therapy is limited, expensive, and unspecific (causes toxic effects), thus, more efficient alternatives need to be developed. In this work, Copper (I) Iodide (CuI) nanomaterials (NMs) were synthesized and fully characterized, aiming to develop efficient antifungal agents. The bioactivity of CuI NMs was evaluated using Sporothrix schenckii and Candida albicans as model organisms. CuI NMs were prepared as powders and as colloidal suspensions by a two-step reaction: first, the CuI2 controlled precipitation, followed by hydrazine reduction. Biopolymers (Arabic gum and chitosan) were used as surfactants to control the size of the CuI materials and to enhance its antifungal activity. The materials (powders and colloids) were characterized by SEM-EDX and AFM. The materials exhibit a hierarchical 3D shell morphology composed of ordered nanostructures. Excellent antifungal activity is shown by the NMs against pathogenic fungal strains, due to the simultaneous and multiple mechanisms of the composites to combat fungi. The minimum inhibitory concentration (MIC) and minimum fungicidal concentration (MFC) of CuI-AG and CuI-Chitosan are below 50 μg/mL (with 5 h of exposition). Optical and Atomic Force Microscopy (AFM) analyses demonstrate the capability of the materials to disrupt biofilm formation. AFM also demonstrates the ability of the materials to adhere and penetrate fungal cells, followed by their lysis and death. Following the concept of safe by design, the biocompatibility of the materials was tested. The hemolytic activity of the materials was evaluated using red blood cells. Our results indicate that the materials show an excellent antifungal activity at lower doses of hemolytic disruption.

Isolation and characterization of cellulose nanocrystals from Cucumis sativus peels

Cucumber (Cucumis sativus) peels waste being a potential cellulosic sources, were used for extracting cellulose nanocrystals (CNCs), and characterized in the present study. Firstly, the cucumber peels were purified chemically through acid, alkali, and bleaching treatments for cellulose isolation. Later obtained cellulose was acid (60 wt% H₂SO₄) hydrolyzed at 45 ℃ for 45 min to obtain CNC45 suspension, and again 10 min sonicated for CNC45-S10 suspension. The effect of sonication on the particle size of CNC45, and CNC45-S10 were investigated with Dynamic light Scattering and Atomic force microscopy. The microstructural changes, thermal, and crystalline properties of resulting fibers and CNC45 were analysed after each treatments through scanning electron microscopy, thermo-gravimetric analyser, and X-ray diffraction respectively. The acid-hydrolysed CNC45 from cucumber peels showed rod-like shape with high crystallinity (74.1 %), excellent thermal stability (>200 °C), and negative zeta potential values (<-30 mV), and CNC45 can be used as potential nanofillers.