Poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) supports adhesion and migration of mesenchymal stem cells and tenocytes

AIM: To establish the potential of poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) (PHBHHx) as a material for tendon repair. METHODS: The biocompatibility of PHBHHx with both rat tenocytes (rT) and human mesenchymal stem cells (hMSC) was explored by monitoring adhesive characteristics on films of varying weight/volume ratios coupled to a culture atmosphere of either 21% O2 (air) or 2% O2 (physiological normoxia). The diameter and stiffness of PHBHHx films was established using optical coherence tomography and mechanical testing, respectively. RESULTS: Film thickness correlated directly with weight/volume PHBHHx (r2 = 0.9473) ranging from 0.1 mm (0.8% weight/volume) to 0.19 mm (2.4% weight/volume). Film stiffness on the other hand displayed a biphasic response which increased rapidly at values > 1.6% weight/volume. Optimal cell attachment of rT required films of ≥ 1.6% and ≥ 2.0% weight/volume PHBHHx in 2% O2 and 21% O2 respectively. A qualitative adhesion increase was noted for hMSC in films ≥ 1.2% weight/volume, becoming significant at 2% weight/volume in 2% O2. An increase in cell adhesion was also noted with ≥ 2% weight/volume PHBHHx in 21% O2. Cell migration into films was not observed. CONCLUSION: This evaluation demonstrates that PHBHHx is a suitable polymer for future cell/polymer replacement strategies in tendon repair.

Silk fibroins modify the atmospheric low temperature plasma-treated poly (3-hydroxybutyrate-co-3-hydroxyhexanoate) film for the application of cardiovascular tissue engineering

Tissue engineered scaffold is one of the hopeful therapies for the patients with organ or tissue damages. The key element for a tissue engineered scaffold material is high biocompatibility. Herein the poly (3-hydroxybutyrate-co-3-hydroxyhexanoate) (PHBHHx) film was irradiated by the low temperature atmospheric plasma and then coated by the silk fibroins (SF). After plasma treatment, the surface of PHBHHx film became rougher and more hydrophilic than that of original film. The experiment of PHBHHx flushed by phosphate buffer solution (PBS) proves that the coated SF shows stronger immobilization on the plasma-treated film than that on the untreated film. The cell viability assay demonstrates that SF-coated PHBHHx films treated by the plasma significantly supports the proliferation and growth of the human smooth muscle cells (HSMCs). Furthermore, the scanning electron microscopy and hemotoylin and eosin (HE) staining show that HSMCs formed a cell sub-monolayer and secreted a large amount of extracellular matrix (ECM) on the films after one week's culture. The silk fibroins modify the plasma-treated PHBHHx film, providing a material potentially applicable in the cardiovascular tissue engi-neering.

Effects of Quenching Temperature and Time on Pore Diameter of Poly (3-hydroxybutyrate-co-3-hydroxyhexanoate) Porous Scaffolds and MC3T3-E1 Osteoblast Response to the Scaffolds

Poly（3-hydroxybutyrate-co-3-hydroxyhexanoate） （PHBHHx） scaffolds were prepared by thermally inducing phase separation （TIPS） for bone reconstruction. Scanning electron microscopy and porosity measurements were used to analyze the structure and properties of the scaffolds. The pore diameter of the scaffolds could be easily controlled by changing the quenching temperature and time. The biocompatibility was assessed by examining the proliferation and morphology of MC 3T3-E1 osteoprogenitor cells seeded on the scaffolds. Cultures grown in the presence of a source of phosphate ions showed the formation of a mineralized extracellular matrix. The results indicate that PHBHHx scaffolds prepared using TIPS are a promising candidate for bone reconstruction.