Insights into Functional Tetracycline/Antioxidant Containing Chitosan Hydrogels as Potential Bio-Active Restorative Materials: Structure, Function and Antimicrobial Activity

Abstract

The human inflammatory periodontal diseases are amongst the most common of chronic diseases to affect adults. Periodontitis is regarded as “an inflammatory lesion, mediated by complex host-parasite interactions, that leads to the loss of connective tissue attachment to root surface cementum and adjacent alveolar bone”. Substantial data are available in the literature on the role of reactive oxygen species (ROS) and antioxidants in disorders such as the inflammatory diseases. However, remarkably little information is available on the periodontal diseases, which show many of the pathological features of other chronic inflammatory diseases. The periodontal tissues also provide an ideal medium within which to study mechanisms of ROS mediated tissue damage and of antioxidant defense in response to bacterial colonisation, through the non-invasive collection of GCF. The objectives of this study are to evaluate the novel chitosan based functional drug delivery systems which can be successfully incorporated into “dual action bioactive restorative materials” containing common antibiotics such as tetracycline, krill oil, aloe and aspirin as commonly used antioxidant species. Methods: The novel hydrogels will be investigated with respect to the antioxidant capacity and drug release capacity of the tetracycline from the designer drug delivery system, the use of SEM imaging for the characterization of the surfaces and reactive features of novel materials with antimicrobial potential. Results: A steady slow release of tetracycline, while maintaining antibiotic effects against the tested bacteria, for at least 10 days was shown from designer chitosan-antioxidant hydrogels. Within the limitations of the study design chitosan-antioxidant hydrogels are suitable materials for functional restorative and periodontal applications in vitro. The addition of antioxidants to the tetracycline containing prototype delivery system had a beneficial effect on the design of the hydrogel by slowing down the release of tetracycline and thereby enabling a sustainable antifungal activity over time.