Correlating degradation of functionalized polycaprolactone fibers and fibronectin adsorption using atomic force microscopy

Abstract

In previous studies, a bioactive ligament prosthesis made of poly (ethylene terephthalate) and functionalized with sulfonate groups was proposed by our group for the reconstruction of injured ligaments. In vitro and in vivo experiments allowed elucidating the mechanism at the origin of the bioactivity of those prostheses, which involves fibronectin adsorption. As the subject evolves the next challenge was to elaborate a bioactive and biodegradable ligament able to maintain the bioactivity along with the degradation process. Polycaprolactone is the biodegradable polymer of choice for such application, due to its ability to degrade in the body environment without releasing cytotoxic by-products. To follow the evolution of the bioactivity of polycaprolactone, fibronectin adsorption, morphology, and mechanical properties on unmodified and functionalized surfaces were assessed using AFM techniques after real-time degradation under physiological conditions. The results showed that the hydrolytic degradation strongly occurred on functionalized fiber with 8.9 × 10−3w − 1 of degradation rate and half-life time 78 weeks. The degradation also affected to the conformation of fibronectin with the presence of protein aggregation on 72 weeks of degraded functionalized fiber.