Hydrodynamic investigation of polymeric scaffold degradation for bone regeneration applications

Porous, polymeric scaffolds are being designed for controlled delivery of nutrients that support osseous tissue growth and vascular formation for the treatment of maxillofacial trauma. Premature degradation of these hydrophilic, polyvinyl alcohol (PVA)-based scaffolds can occur due to pulsatile nature of blood flow and mechanical loading. Our hypothesis is that vascular network growth (or neovascularization) emanating from the maxillary artery initiates swelling and erosion of PVA-based scaffolds, and dispersion of released polymers. Scaffold structural properties were determined by tensile testing of PVA structures at different hydration times. Diffusivity of PVA suspensions and their size distribution were measured in a dynamic light scattering instrument. Viscoelastic rheology measurements established the viscosity-averaged molecular weight of the PVA suspensions in deionized water. Scaffold fragmentation was monitored in a flow loop under varying flow pulsatility using MEMS-based pressure catheters and an ultrasonic flow rate sensor. Knowledge gained will facilitate the design of scaffold matrices using biocompatible polymers with tunable degradation characteristics and predictable material release.