Delivered by Ingenta to: ? IP: 181.215.39.122 On: Thu, 18 Jan 2018 10:08:24 Copyright: American Scientific Publishers Copyright © 2017 American Scientific Publishers All rights reserved Printed in the United States of America Article Journal of Nanoscience and Nanotechnology Vol. 17, 4584–4591, 2017 www.aspbs.com/jnn Biocompatible and Biodegradable Hydrogels Based on Chitosan and Gelatin with Potential Applications as Wound Dressings Alexandra Rusanu 1 , Alexandra Isabela Tama¸ s 1 , Raluca Vulpe 2 , Alina Rusu 2 , Maria Butnaru 1 , and Liliana Vere¸ stiuc 1 ∗ 1 Faculty of Medical Bioengineering, ‘Grigore T. Popa’ University of Medicine and Pharmacy, 700454, Iasi, Romania 2 Faculty of Chemical Engineering and Environmental Protection, ‘Gheorghe Asachi’ Technical University, Bd. Mangeron, 71A, 700050, Iasi, Romania Hydrogels based on chitosan and gelatin, were prepared by freeze-drying and ionic crosslinking with sodium tripolyphosphate. The anionic crosslinker interact with the protonated amino groups of chitosan and gelatin via electrostatic attractions. The hydrogels with a three-dimensional structure are macroporous with elongated or spherical pores, randomly or uniformly distributed as a function of the crosslinking degree; the uniformity increases by increase the time of crosslinking. The hydro- gels absorb large quantities of phosphate buffered solution and simulated wound fluid. They are degraded by collagenase, the specific enzyme for collagens. Antimicrobial drug, Norfloxacin was loaded with good efficiency into hydrogel network and kinetics studies for drug release were car- ried out in phosphate buffered solutions. The drug release data analysis by mathematical models suggested a combination of swelling and matrix relaxation as major drug release mechanisms. Cyto- toxicity assays were performed in order to establish the possibility to use the hydrogels in contact with human body; the prepared hydrogels are biocompatible and stimulate the cells proliferation. Keywords: Hydrogels, Chitosan, Gelatin, Sodium Tripolyphosphate, Wound Dressing. 1. INTRODUCTION In recent years considerable efforts have been made to develop hydrogels based on natural macromolecules, as these materials are biocompatible, biodegradable and bioactive, necessary properties for materials used in contact with the human body. Furthermore, controlled porosity, pore size, degradation and mechanical properties comparable to those of the human tissues and appropri- ate biological response obtained from biocompatible and biodegradable materials are essential features for tissue engineering. 1 Chitosan and gelatin matrices can be used in many biomedical applications, but especially in skin tissue engineering due to their biological characteristics, high and intercommunicating porosity and variable mechanical properties. 2–4 ∗ Author to whom correspondence should be addressed. Chitosan is a polysaccharide obtained by deacetylation of chitin and is one of the most studied materials in appli- cations like bone tissue engineering and bioengineering of the damaged skin, due to its properties: biocompatibility, biodegradability, antimicrobial properties and the ability to be processed as scaffolds for cells adhesion and pro- liferation and stimulated tissues regeneration. 5–8 Scaffolds based on chitosan, which may include other small or large molecules have been considered for tissue engineering, tis- sue regeneration, targeting and controlled drug delivery, gene therapy, contact lenses, medical devices. 9 Chitosan plays an important role in the attachment, differentiation, and morphogenesis of cells, because of its structural sim- ilarities with glycosaminoglycans, polysaccharides present in natural tissues. 10 11 Gelatin, a partial hydrolysed collagen, is a natural polypeptide whose composition includes aminoacids with active groups (amino, carboxyl, hydroxyl and phenolic 4584 J. Nanosci. Nanotechnol. 2017, Vol. 17, No. 7 1533-4880/2017/17/4584/008 doi:10.1166/jnn.2017.14298