Blends of poly-3-hydroxybutyrate and poly-ε-caprolactone: Morphology, properties and biocompatibility

Abstract

A series of films was obtained from blends of poly-3-hydroxybutyrate (PHB) and poly-s-caprolactone (PCL). The structure, physical, mechanical and biological properties of the films were studied, depending on the ratio of the components. The microscopic structure of mixed films was determined by the main component of the blend: the films were porous with a predominance of PHB and relatively smooth with a predominance of PCL. The highest values of elongation at break (229-269%), as well as the local maximum values of tensile strength (14-15 MPa) were noted for blends with 5-25% PHB content. At PHB content of 25% and 75%, local maxima of Young's modulus were observed (507 and 655 MPa, respectively). When the ratio of the components in the blend was equal (50:50 by weight), the films were heterogeneous and had the lowest values of mechanical strength (ultimate strength and elongation at break were 3 MPa and 15.5%, respectively). A study of the biocompatibility of mixed films in a culture of NIH 3T3 mouse fibroblasts based on determination of the number of adhered cells in the MTT test showed the absence of cytotoxic action, as well as high adhesion and cell proliferation, in some cases exceeding the data for films from pure PHB and PCL. This demonstrates the suitability of PHB-PCL blends for the production of cell carriers for tissue engineering and other reconstructive technologies.