Development of novel functionally graded guided tissue regenerative membrane for periodontal lesions

Periodontal diseases are chronic inflammatory conditions affecting the supporting tissues of teeth caused by the prolonged accumulation of micro-organisms in the biofilm that forms on tooth surfaces. Conventional non-surgical and surgical treatments aim to halt disease progression and repair the lost periodontal tissues. Surgical therapies such as open flap debridement are aimed to replace the lost alveolar bone and guided tissue regeneration (GTR) is also used to treat this disease. Whilst the regeneration of lost support is an aim of
periodontal treatment, the outcomes of current approaches to periodontal regeneration (PR) are unpredictable. Consequently, significant laboratory and clinical research has been undertaken to explore the possibilities of improving the outcomes of treatment over the past
few decades. In this respect chitosan (CH), a well-known biopolymer holds promise to be fabricated in various forms. The aim of the project was to fabricate a trilayered functionally graded GTR membrane by fabricating surface and core layers of non-porous and porous morphologies with complete physiochemical and biological characterisation. Solvent Casting, Freeze gelation (FG) and Electrospinning was performed on CH alone and in combination with Hydroxyapatite (HA). Membranes were characterized with Scanning electron Microscopy, Fourier Transform Infrared Spectroscopy (FTIR), tensile testing, long term degradation and swelling studies were also performed. Cell culturing was performed using human osteosarcoma and progenitor cell line. Sirius red and Alizarin red assays were conducted to assess matrix deposition. Amongst the non-porous membranes fabricated by solvent casting, with Low molecular weight (LMw) CH:HA ratio of 30:70 showed better biocompatibility, and amongst the porous membranes made up of FG, ASa (ascorbic acid) :CH:HA (50:50) showed better stability and biocompatibility after in-vitro analysis. Histology of FG membranes conducted after in-vivo studies showed ASa:CH:HA to have higher cellular infiltration after 30 days of implantation. Electrospun fibres obtained in both aligned and random orientations were conducive to cellular attachment and mineralized matrix deposition with time. FTIR analysis showed strong co-ordination bond formation in between CH and HA. HA incorporated samples treated with simulated body fluid (SBF) showed an embryonic layer formation of hydroxyl carbonated apatite. Membranes can be combined together in different ways to achieve structural and functionally graded structures. A template was prepared using solvent casting and freeze gelation techniques to achieve functional gradients. Furthermore; CH and HA composite membranes could possibly be used for GTR applications in periodontal lesions and in addition these techniques could be further tuned to achieve desirable characteristics of a GTR membrane for PR and also holds promise to be used in other biomedical applications.