Bioactive chitosan/ellagic acid films with UV-light protection for active food packaging

Fabrication & Characterization of Chitosan Coated Biologically Synthesized TiO2 Nanoparticles against PDR E. coli of Veterinary Origin

“…Fundamental steps for the generation of ROS are described as follow Wang et al and Zhu et al reported ROS generating antibacterial TiO 2 NPs. ey explored that these TiO 2 NPs have potential to increase the permeability of microbial cell membrane and induce detrimental e ects inside the microbial cells, such as oxidation of intracellular Coenzyme A and lipid peroxidation, which successively cause cell death [41][42][43]. Gramnegative bacteria, apart from the cell membrane, possess an additional outer layer membrane, consisting of phospholipids, proteins and lipopolysaccharides, which are impermeable to most molecules [44].…”

“…e TiO 2 displayed antimicrobial activity when bacterial cells exposed to it [40]. Chitosan has been reported intrinsic antimicrobial action against Gramnegative bacteria [41]. When bacterial cell treated with CS-NPs coated TiO 2 NPs as demonstrated in the Figure 14, TiO 2 undergoes the chemical reaction and generates the ROS .…”

“…is play an essential role in the growth inhibition of PDR strain of E. coli by oxidizing polyunsaturated phospholipids of microbial cell membranes causing alterations in cellular morphology and cytoplasmic leakage [41,42]. In Figure 14, proposed mechanism of action has been shown to describe the destruction of E. coli a Gram-negative bacteria.…”

Modification of Chitosan by Zincke Reaction: Synthesis of a Novel Polycationic Chitosan-Pyridinium Derivative

“…The percent weight gain of this material was 35.5%, indicating an important chemical modification degree. Other conditions were evaluated to increase the percent weight gain of the chitosan material, including the use of microwave ( Table 1, entry 5), ultrasound ( Table 1, entry 6), a binary solvent system (entries [6][7][8][9][10][11] and homogeneous reaction conditions (entries 11-13). In the case of microwave assisted reaction, it was observed the rapid formation of red dianil salts, but the suspension color indicated that the ring closure step was too slow to be observed.…”

“…2 Moreover, this polymer displays interesting properties such as biodegradability, biocompatibility, low toxicity and great potential for chemical modification, providing an exciting platform for the development of different materials with various physicochemical properties. 3 A great number of modulated chemical reactions may be performed on chitosan C-2 free amino and C-3 and C-6 hydroxyl groups, 4 yielding novel polymers with applications in different fields such as biomedicine, 5 environmental chemistry, 6 agriculture, 7 biotechnology industry, 8 food products, 9 molecular biology, 10 etc. The most common chitosan chemical modifications include N-phthaloylation, N-carboxyalkylation, N and/or O-acylation/alkylation, O-carboxymethylation, quaternization, Schiff base formation, phosphorylation, graft copolymerization, O-sulfonation, among others.…”