Functionalization of cellulose and synthetic materials for medical and industrial applications

Abstract

Modification of cellulose materials has a big potential both for the use as adsorbents for organic pollutants and for the use in the medical sector as material for wound dressings with an inherent antibiotic functionality. For the use in the medical field, the synthetic material's modification is of interest, especially for providing biodegradable surgical sutures less sensible to the formation of biofilm where dangerous bacteria grow. Being able to create side branches at the natural and synthetic polymer backbone, the adsorption of either pollutants or drugs can be tailored by modifiying those branches without losing the advantages of the used substrate. In this work, cellulose already grafted with GMA (Cell-g-GMA) was modified in order to either create better linking points for covalent linkage of antibiotics or change the polarity and therefore the adsorption capability. The results of the first part were translated to the modification of cellulose acetate with GMA by creating radicals on the substrate by a Fenton-type process and subsequent grafting. The so created branches of GMA then could again be modified in order to gain different adsorption capability. GMA branches were introduced also on biodegradable synthetic surgical sutures by using gamma-ray technology for the creation of radicals on the polymer backbone. The successful introduction of the side branches and their modification was certified by CP-MAS 13C NMR as well as by FT-IR spectroscopy. Their adsorption properties were tested by UV analysis, confirming the possibility to change adsorption properties when changing the polarity of the substrates. The Kirby-Bauer antimicrobial susceptibility testing methodology with Staph. aureus ATCC 29213 and E. coli ATCC 25922 was used for testing the suitability of GMA cellulose materials as drug delivery scaffolds. Materials adsorbed with a formulation of Amoxicillin with clavulanic acid had antimicrobial effect. Adsorption of Amoxicillin alone was tested by UV as its activity towards the used bacteria was too low to be tested in vitro. The same was true for covalently linked Amoxicillin, but formulations with clavulanic acid have not been tested yet.