New water-soluble chitin derivative with high antibacterial properties for potential application in active food coatings.

The synthesis of new chitin derivatives through ultrasound-assisted treatment of the chitin with 1-azido-3-chloropropan-2-ol under Green Chemistry conditions is described. This is the first example of ultrasound-assisted polymer analogues transformation of chitin unaccompanied by noticeable backbone degradation or deacetylation. The obtained water-soluble azido chitin derivatives are characterized by high antibacterial activity, which is comparable with that of commercial antibiotics ampicillin and gentamicin. At the same time, they were demonstrated almost identical in vitro toxicity as unmodified chitin and chitosan. The antibacterial activity of the obtained polymers is mainly provided by azido moiety in their macromolecules. The conjugation of azido moiety to chitin backbone strongly diminishes the toxicity of the azido pharmacophore, but preserves its antibacterial properties. The most potent chitin derivative was used for the film coating of Ricotta cheese samples. This food coating proved to be efficient for the prolongation of shelf life of Ricotta cheese.

Chitosan derivatives and their based nanoparticles: ultrasonic approach to the synthesis, antimicrobial and transfection properties.

In the present work, we demonstrate that alkylation of chitosan by alkyl halides, aza-Michael reaction with chitosan, and AdN-E reaction of chitosan with aldehydes can be efficiently mediated by ultrasound. An optimization of ultrasonic irradiation parameters allowed us to (i) accelerate the rate of the reactions dramatically, (ii) achieve high selectivity, and (iii) preserve integrity of the polysaccharide backbone avoiding its depolymerization. We evaluated antibacterial/antifungal and transfection activity of 8 different derivatives of chitosan and their based nanoparticles in vitro. Moreover, we studied antibacterial activity of the most efficient polymer and their based nanoparticles in vivo. The tested polymer proved to be superior to reference commercial antibiotics ampicillin and gentamicin.