Poly(hydroxyalkanoates): Emerging Biopolymers in Biomedical Fields and Packaging Industries for a Circular Economy

Abstract

Poly(hydroxyalkanoates) (PHAs) are a class of sustainable, bio-based thermoplastic polymers with attractive physiochemical properties, including non-toxicity, biocompatibility, elastomeric behavior by design, and piezoelectric characteristics. In the ongoing effort to reduce plastics waste, PHAs can play a substantial role due to their inherent biodegradability free of microplastics, customizable properties, and versatile applications. This includes their tremendous potential in a broad range of biomedical applications. Biomass-based materials have recently gained great interest in the health sector, given the vast amount of interdisciplinary research in bioengineering and medicine. Implantable biomaterials should not elicit any negative response at the implantation site, which differentiates them from general-purpose polymers. PHAs do not induce any thrombosis or antigenic response even after being in contact with blood in the human body during long-term use. The biocompatibility of PHAs is also a key factor in the rapid growth and proliferation of tissues onto and within these materials when served as tissue engineering scaffolds. By application, the biomedical field was estimated to be the second-largest market share for PHAs, in terms of volume, in 2022. While PHA-based materials bring forth a broad range of opportunities, they also present challenges that have limited their widespread use and a greater market share. A better understanding of their physiochemical properties and biodegradation rates, production challenges, and the need for cost-effective strategies are some of the hurdles that need to be addressed. This review paper provides an overview of the commonly used PHA homopolymers and copolymers in biomedical fields and packaging industries. The introduction of the manuscript presents the concept of bioplastics and their environmental significance, highlighting the urgent need for alternatives to conventional fossil-based plastics. The next sections briefly cover the synthesis, properties, as well as homopolymer and copolymer formulations, followed by the application of PHA-based materials in the biomedical field. Current opportunities and challenges, together with some insight into the future gathered from the published studies, have been brought in the concluding section of this paper.