Tuned biodegradation using poly(hydroxybutyrate-co-valerate) nanobiohybrids: Emerging biomaterials for tissue engineering and drug delivery

Our studies focus on controlled and tuned biodegradation, mechanism of biodegradation, biocompatibility, genotoxicity and controlled and sustained drug release performance of poly(hydroxybutyrate-co-valerate) nanohybrids. Nanohybrids were prepared using layered silicates with two different surface modifiers through a solution route. Biodegradation has been investigated in compost, microorganisms (pseudomonas stutzeri) and pure enzymes, showing both enhanced and suppressed rates as compared to that of the pure polymer. Two nanoclays that increased the strong filler dependency phenomena were used to control the biodegradation rate. Complete biodegradation mechanism has been revealed, which indicates that the pH of the medium dictates the rate of biodegradation by activating the enzyme responsible for degradation. Biodegradation has also been controlled by optimizing the processing conditions of the specimens. Biocompatibility of the nanohybrids has been tested at the intra-cellular level by sub-cellular localization of HIPK2 protein, in addition to the typical cell adherence on the nanohybrid films demonstrating that there is no induced genotoxic stress either from the polymer or from the nanoparticles. Biocompatible nanohybrids have been used for drug delivery, showing sustained and controlled release of drugs in presence of nanoparticles. Hence, the developed nanohybrids illustrate potential biomaterials for tissue engineering and drug delivery.