Novel chitosan-poly(vinyl acetate) biomaterial suitable for additive manufacturing and bone tissue engineering applications

Chitosan, a biocompatible and biodegradable natural polymer, offers great promise as a biomaterial for tissue engineering applications. Chitosan scaffolds have previously been fabricated using additive manufacturing techniques, however, the use of crosslinkers, weak mechanical stability and structural resolution remain problematic. In this study Chitosan-PVAc biopolymer blends were prepared using a non-organic solvent that can prepare a three-dimensional printable biopolymer in less time than conventional methods. Prepared films were characterised using SEM, FTIR and thermogravimetric analysis. Additionally, the swelling properties, biodegradability and printability of the scaffolds were also studied. The fabricated films were biodegradable within a 3-week period and showed controllable swelling properties. Results indicated no toxicity and cells attached onto films. Additionally, hydrogels showed antibacterial activity against S. aureus, S. epidermidis and E.coli, which could potentially prevent implant related infections. Additive manufacturing simulation of PVAc composite 3% chitosan and PVAc composite 4% chitosan were able to produce a layered scaffold without using crosslinkers and therefore confirming printability. Cytocompabability were assessed using a resazurin assay and cell attachment. From these results, we concluded that the printable PVAc composite 3% chitosan and PVAc composite 4% chitosan biopolymer blends meet the requirements of a biomaterial and can potentially be used for biomedical implants.

A Concise Review on the Physicochemical Properties of Biopolymer Blends Prepared in Ionic Liquids

An enhancement of environmental concern lately has improved the awareness of researchers in employing eco-friendly solvents for processing biopolymers. Recently, ionic liquids have been utilized to prepare biopolymer blends as they are non-volatile and recyclable. Biopolymers such as cellulose, chitin, chitosan, keratin, lignin, silk, starch, and zein are widely used for the preparation of biopolymer blends via dissolution in ionic liquids, followed by coagulation procedure. In this concise review, three types of ionic liquids based on imidazolium cations combined with different counter anions that are frequently utilized to prepare biopolymer blends are described. Moreover, three types of biopolymer blends that are prepared in ionic liquids were classified, specifically polysaccharide/polysaccharide blends, polysaccharide/polypeptide blends, and polysaccharide/bioplastic blends. The physicochemical properties of biopolymer blends prepared in different imidazolium-based ionic liquids are also concisely reviewed. This paper may assist the researchers in the polymer blend area and generate fresh ideas for future research.

Molecular Modeling Analyses for Modified Biopolymers

Biopolymer blends and structural modifications with phenol and hydroxymethylcarbonyl (HMC) are studied to show the ability to interact with amino acids as promising to act as HIV protease inhibitors. Chitosan (Cs), cellulose (Cel), starch (Str) and gelatin (Gel) as well as their blends as Cs/Cel; Cs/Str; Cs/Gel with ratios 3:1; 2:2; 1:3 were subjected to molecular modeling. These biopolymers, as well as their blends, are calculated with quantum mechanical calculations at PM6 level of theory. QSAR, surface area, and volume properties of the interaction of phenol and HMC upon Cs/Cel; Cs/Str; Cs/Gel in the different positions of the four units are calculated at the same level of theory. QSAR descriptors for studied polymers show a change in their physical properties as result of blending. Depending on QSAR calculations, the interaction of phenol and HMC with Cs/Cel and Cs/Str blends for ratio 1:3 through the first unit increases the reactivity of these modified structures. The solubility of modified blends is increased by increasing chitosan units in the proposed modified blends. The surface area of modified Cs/Cel ratios increases comparing with modified Cs/Str and Cs/Gel ratios. This recommends the modified blends of Cs/Cel ratio can be used as promising HIV protease inhibitors drugs.