Fabrication and properties of polyhydroxybutyrate/kaolin nanocomposites and evaluation of their biocompatibility for biomedical applications

The polyhydroxybutyrate biopolymer nanocomposites (C1–C10) were fabricated by solvent casting method with different loading of kaolin and polyethylene glycol. Scanning electron microscopy showed that the microstructure of the composites varied with different kaolin loading. X‐ray diffraction and Fourier transform infrared spectroscopy analysis confirm the presence of kaolin in the polymer matrix due to the intercalation and formation of hydrogen bond. The contact angle of the nanocomposites decreased with increasing kaolin loading indicating an improvement in wettability of the nanocomposites. Thermogravimetric and differential scanning calorimetry analysis showed that the Tmax and Tm of the nanocomposites increased with increasing kaolin loading. The mechanical property of the nanocomposite fabricated with 10 wt% kaolin (C10) was found to have identical mechanical property with natural bone that was selected as an optimum nanocomposite. The nanocomposite showed prolonged blood clotting time exhibiting anticoagulant nature of the nanocomposite. Moreover, low protein adsorption (168 ± 8 μg/cm2), suppressed platelet adhesion (75 ± 2 × 109 platelets/cm2) and less complement activation (118 ± 5 mg/dl for C3 and 658 ± 5 mg/dl for C4) showed the improvement in surface properties of the nanocomposite. In vitro bioactivity studies revealed the formation of hydroxyapatite layer on the surface of the nanocomposites. Eventually, the nanocomposites (C10) showed no cytotoxic effect on MG‐63 cells as tested through MTT assay and it is biologically safe. This work addresses the fabrication of biopolymer‐based nanocomposites using low‐cost clay as a nanofiller for biomedical applications. Along with good physicochemical characteristics, the fabricated nanocomposite showed better biocompatibility and bioactivity suggesting that the nanocomposite is suitable for biomedical applications. The composite is non cytotoxic which can be utilized for bone tissue engineering.