THE EFFECT OF SURFACE HETEROGENEITY ON WETTABILITY OF POROUS THREE DIMENSIONAL (3-D) SCAFFOLDS OF POLY(3-HYDROXYBUTYRIC ACID) (PHB) AND POLY(3-HYDROXYBUTYRIC-CO-3-HYDROXYVALERIC ACID) (PHBV)

Abstract

Biopolymers such as poly(3-hydroxybutyric acid) (PHB) and poly(3-hydroxybutyric-co-3-hydroxyvaleric acid) (PHBV) are preferred ingredients for the manufacture of materials especially in tissue engineering and regenerative medicine application because they are biocompatible, biodegradable and do not possess any environmental problems associated with their production, fabrication, use and disposal. For that reason, studies have been initiated to produce a 3-D biomimetic scaffolds with an improved thickness greater than 1 mm as an alternative material to synthetic polymers in tissue engineering application. The purpose of this study is to evaluate the physico-chemical surface properties of these polymeric 3-D structures and its corresponding thin films prior to be used as biomimetic materials. To measure the surface free energy (wettability), a Cassie-Baxter contact angle correction for heterogeneous wetting of two liquids (water and methylene iodide) were utilized. To verify its wettability, surface free energies were used to estimate the interfacial energy, work of adhesion and spreading coefficient. The results indicate that the calculated Cassie-Baxter contact angle correction method have proven to exhibit one dominant factor that cause a huge deviation from the true contact angles of its corresponding thin films which is surface heterogeneity. This material characteristic would possibly give a side effect (e.g., low cell attachment and proliferation) against cell-biomaterial affinity as highly hydrophobic material are most likely to be unfavorable for the absorption of essential extracellular matrix proteins (compounds that give a signal to cell to attach on the solid surface).