Starch based biodegradable graft copolymer for the preparation of silver nanoparticles

Evaluation of Antimicrobial and Anti-Biofilm Formation Activities of Novel Poly(vinyl alcohol) Hydrogels Reinforced with Crosslinked Chitosan and Silver Nano-Particles

Novel hydrogels were prepared by blending chitosan and poly(vinyl alcohol), PVA, then crosslinking the resulting blends using trimellitic anhydride isothiocyanate at a concentration based on chitosan content in the blends. The weight ratios of chitosan: PVA in the blends were 1:3, 1:1, and 3:1 to produce three hydrogels symbolized as H13, H11, and H31, respectively. For a comparison, H10 was also prepared by crosslinking pure chitosan with trimellitic anhydride isothiocyanate. For further modification, three H31/silver nanocomposites (AgNPs) were synthesized using three different concentrations of silver nitrate to obtain H31/AgNPs1%, H31/AgNPs3% and H31/AgNPs5%. The structures of the prepared samples were emphasized using various analytical techniques. PVA has no inhibition activity against the tested microbes and biofilms. The antimicrobial and anti-biofilm formation activities of the investigated samples was arranged as: H31/AgNPs5% ≥ H31/AgNPs3% > H31/AgNPs1% > H10 > H31 > H11 > H13 > chitosan. H31/AgNPs5% and H31/AgNPs3% were more potent than Vancomycin and Amphotericin B against most of the tested microbes. Interestingly, H31 and H31/AgNPs3% were safe on the normal human cells. Consequently, hydrogels resulting from crosslinked blends of chitosan and PVA loaded with AgNPs in the same structure have significantly reinforced the antimicrobial and inhibition activity against the biofilms of PVA.

Water-Soluble Starch-Based Copolymers Synthesized by Electron Beam Irradiation: Physicochemical and Functional Characterization

Modification of natural polymers for applications in the treatment of waste and surface waters is a continuous concern of researchers and technologists in close relation to the advantages they provide as related to classical polymeric flocculants. In this work, copolymers of starch-graft-polyacrylamide (St-g-PAM) were synthesized by electron beam irradiation used as the free radical initiator by applying different irradiation doses and dose rates. St-g-PAM loaded with ex situ prepared silver nanoparticles was also synthesized by using an accelerated electron beam. The graft copolymers were characterized by chemical analysis, rheology, and differential scanning calorimetry (DSC). The results showed that the level of grafting (monomer conversion coefficient and residual monomer concentration), intrinsic viscosity and thermal behavior (thermodynamic parameters) were influenced by the irradiation dose, dose rate and presence of silver nanoparticles. The flocculation performances of the synthesized copolymers were also tested on water from the meat industry in experiments at the laboratory level. In the coagulation–flocculation process, the copolymer aqueous solutions showed good efficiency to improve different water quality indicators.

Studies of simultaneous electrochemical sensing of Hg2+ and Cd2+ ions and catalytic reduction properties of 4-nitrophenol by CuO, Au, and CuO@Au composite nanoparticles synthesised using a graft copolymer as a bio-template

Simultaneous electrochemical detection of Hg2+ and Cd2+ ions and catalytic reduction of 4NP to 4AP using a novel synthesized graft copolymer/CuO@Au NPs composite.

Green synthesis of quaternized chitosan/silver nanocomposites for targeting mycobacterium tuberculosis and lung carcinoma cells (A-549)

Lung cancer (LC) is the most-deadly type of cancer representing a major public health problem worldwide. Tuberculosis TB is another infectious disease influencing lungs that causes death especially in developing countries. The present study is the first to report antimycobacterial activity of TMC/Ag nanocomposite. It aims to solve the case of lung cancer and its most associative pathogen. The current study reports one pot green biosynthesis of silver nanocomposite in presence of biodegradable biopolymer (N,N,N-trimethyl chitosan chloride, TMC) as both reducing and stabilizing agent. The structure of TMC/Ag nanocomposite was characterized with different analysis tools including TEM, XRD and UV-vis spectrophotometer techniques. TEM images showed that Ag nanoparticles were well distributed spheres and their diameter ranged from 11 to17.5 nm. While, XRD pattern of TMC/Ag nanocomposite showed diffraction peaks related to the crystalline nature of Ag nanoparticles. In addition, UV-vis spectrum revealed a broad absorption peak at 400 nm attributing to the surface Plasmon resonance (SPR) of Ag. TMC/Ag nanocomposite exhibited a promising in vitro antimycobacterial activity with MIC of 1.95 μg/mL. On the other hand, The antitumor activity results of nanocomposites against both lung carcinoma cells (A-549) and normal lung cells (WI 38) revealed that nanocomposite cytotoxicity against A-549 cells with IC₅₀ of 12.3 μg/mL, whereas the IC₅₀ value against normal WI 38 cells was 357.2 μg/mL.

Green synthesis of antimicrobial and antitumor N,N,N-trimethyl chitosan chloride/poly (acrylic acid)/silver nanocomposites

The present study is imported to solve two critical problems we face in our daily life which are microbial pollution and colon cancer. One pot green synthesis of a water soluble polyelectrolyte complex (PEC) between cationic polysaccharide as N,N,N-trimethyl chitosan chloride (TMC) and anionic polymer as poly (acrylic acid) (PAA) in presence of silver nanoparticles to yield (TMC/PAA/Ag) nanocomposites with different Ag weight ratios. Structure of TMC, PAA and TMC/PAA (PEC) were proved via different analysis tools. TMC/PAA and its Ag nanocomposites are used as antimicrobial agents against different pathogenic bacteria and fungi to solve microbial pollution. TMC/PAA-Silver nanocomposites had the highest antimicrobial activity which increases with increasing Ag %. Cytotoxicity data confirmed also that TMC/PAA/Ag (3%) had the most cytotoxic effect (the less cell viability %) towards colon cancer. TMC/PAA (PEC) was formed through electrostatic interactions between N-quaternized (-N⁺R₃) groups in TMC and carboxylate (-COO^-) groups in PAA.

In situ preparation of Tricholoma mushroom polysaccharide-g-poly(N,N-dimethyl acrylamide-co-acrylic acid)–CuO composite nanoparticles for highly sensitive and selective sensing of Th4+ in aqueous medium

A highly selective and sensitive sensor for Th⁴⁺ was developed for the first time using Tricholoma mushroom polysaccharide-based graft copolymer–CuO composite nanoparticles by colorimetric and electrochemical method.