Functionalisation of polyhydroxybutyrate for diagnostic uses

Polyhydroxybutyrate (PHB) is a biodegradable and biocompatible biopolyester, naturally produced and self-assembled as spherical inclusions inside bacteria. These PHB particles contain a hydrophobic PHB core covalently coated with PHB synthase (PhaC), which serves as an anchoring linker for foreign proteins of interest. Protein engineering of PhaC enables the display of biologically active protein functions on the surface of PHB particles suitable for different applications. Many biomolecules, such as e.g. antigens, enzymes, fluorescent proteins were immobilized to PHB particles and exhibited superior functionalities when compared to their respective soluble counterparts. Recently, PHB particles have been successfully applied for various diagnostics applications. This mini review provides an overview of the unique design space of PHB particles towards the development of safe and cost-effective diagnostic tools, and highlights the important research progresses of manufacturing PHB particles-based diagnostics.