Polyhydroxyalkanoate (PHA) scaffolds with good mechanical properties and biocompatibility

Area of Science:

• Biomaterials Science
• Polymer Chemistry
• Tissue Engineering

Background:

• Microbial polyesters like polyhydroxyalkanoates (PHAs) offer tunable properties for biomedical applications.
• Polyhydroxybutyrate (PHB) and poly(hydroxybutyrate-co-hydroxyhexanoate) (PHBHHx) are PHAs with distinct characteristics.
• Developing advanced biomaterials for tissue regeneration is a key challenge in regenerative medicine.

Purpose of the Study:

• To fabricate and characterize films and scaffolds from blends of PHB and PHBHHx.
• To evaluate the mechanical properties of PHBHHx/PHB films.
• To assess the biocompatibility and potential for cartilage generation of PHBHHx/PHB scaffolds using chondrocytes.

Main Methods:

• Blending of PHB and PHBHHx polyesters to create films and scaffolds.
• Mechanical testing, specifically elongation to break, to determine film properties.
• Chondrocyte cell culture on PHBHHx/PHB scaffolds.
• Scanning electron microscopy (SEM) for cell morphology and proliferation assessment.
• Energy dispersive X-ray (EDX) analysis to determine elemental composition of the extracellular matrix.

Main Results:

• Increasing PHBHHx content in PHBHHx/PHB films from 40% to 60% significantly improved elongation to break from 15% to 106%.
• Scaffolds composed of 60 wt% PHBHHx demonstrated robust chondrocyte growth and proliferation.
• EDX analysis revealed a Ca/P molar ratio of 1.66 in the extracellular matrix, closely matching natural hydroxyapatite (1.67).

Conclusions:

• PHBHHx/PHB blends can be processed into films with enhanced mechanical flexibility.
• PHBHHx/PHB scaffolds support chondrocyte viability and proliferation, crucial for cartilage tissue engineering.
• The observed elemental composition suggests effective physiological function for cartilage matrix generation by chondrocytes on these scaffolds.