(64d) Microscopic and in Vitro Testing of a Chitosan-Based Bone Adhesive

For patients with an average age of 65 years, fractures have a worldwide incidence of 53.4 per thousand people / year in women and 24.9 per 1000 people / year in men. In contrast, for patients under 18 years of age, the incidence is 20.2 per thousand people per year. In general, fractures are due to falls and extremely serious traumatisms. Currently, the goal of treatment for fractures is to achieve the greatest possible functional recovery of the affected segment. This is generally achieved by providing the biological conditions to facilitate consolidation of the fractured fragments in an adequate position. Due to their extension and location some fractures are, however, challenging to treat and may seriously compromise the future functionality of the affected limb. One of the most challenging fractures are the so-called comminuted type where bone fragmentation is severe. Currently, a number of products are available on the market for prosthetic fixation and bone reconstruction. One of the most widely used products are bone cements; however, they fail to provide sufficient adhesion when precise environmental conditions are unmet.

Previous work from the investigation group presented as a possible solution a novel chitosan-based bone adhesive as a biological and biocompatible solution with attractive adhesive performance in both dry and aqueous conditions. This bio-product was thought to provide a facile route for the reduction of the complex comminute fractures with significantly enhanced precision. This translates into a reduction in the costs associated with the treatment of fractures while shorten the surgery time.

The aim of this work is to benchmark the performance of the developed bio-adhesive against a commercially available polymethyl methacrylate-based bone cement. Performance was evaluated via mechanical tests through the butt joint test (BJT) to estimate the maximum strength at rupture (MSR) at the bone-adhesive joint in an effort to simulate conditions of an actual orthopedic surgery. In this regard, under dry conditions at 24 hours, MSR values of 167.31 ± 14.41 kPa and 844.2 ± 35.51 kPa were estimated for the bio-adhesive and the bone cement, respectively. MTT assays suggest a significant cytotoxicity for bone cement compared with the bio-adhesive. To confirm this notion, we are currently conducting cytotoxicity tests via LDH on Vero cells. Additionally, to observe migration and adhesion of osteoblasts to the bio-adhesive, we are imaging cells via scanning electron microscopy and stained nuclei with the aid of confocal microscopy. Tests conducted here are intended to gain insights into the requirements and attributes for further testing of the bioadhesive in vivo.