Nanofibrillated chitosan/polycaprolactone bionanocomposite scaffold with improved tensile strength and cellular behavior

Fabrication of scaffolds with improved mechanical properties and favorable cellular compatibility is crucial for many tissue engineering applications. This study was aimed to improve mechanical and biological properties of polycaprolactone (PCL), which is a common biocompatible and biodegradable synthetic polymer in tissue engineering. Nanofibrillated chitosan (NC) was used as a natural nanofiller to produced PCL nanobiocomposite scaffold with both enhanced mechanical properties and appropriate biological properties.
Surface morphology and orientation of chitosan nanofibrils was investigated via atomic force microscopy (AFM). PCL/NC suspension solutions with various content of NC were prepared using dimethylformamide as a dipolar solvent to obtain homogenous solutions. The scaffolds were produced through a solvent casting procedure at room temperature. The prepared scaffolds was characterized using scanning electron microscopy (SEM), attenuated total reflection- fourier transform infrared (ATR-IR) spectroscopy, X-Ray diffraction (XRD), uniaxial mechanical testing, contact angle (CA) measurements and swelling and weight loss analysis. In vitro studies were also exceeded to evaluate the cellular compatibility of the prepared scaffolds.
The average diameter of chitosan nanofibrils was measured 88±10 nm. The existence of NC in nanocomposite was proven by ATR-FTIR and XRD results. Interestingly, incorporation of 10% of NC into PCL, improved the tensile strength of scaffolds from 2.7 to 6.5 MPa while reduced the elasticity. What is more, water contact angel of the membranes was decreased from 133° to 88˚ which imply more surface wettability of nanocomposite scaffolds in comparison to PCL. Furthermore, the swelling ratio and weight loss rate of bionanocomposites were increased 30% and 2.5%, respectively. MTT biocompatibility assay and cell adhesion test demonstrated superior cellular behavior of the fibroblasts on nanocomposite scaffolds in comparison to pure PCL scaffold.
The acquired results expressed that the PCL/NC bionanocomposite can be a reliable candidate for tissue engineering applications.