Tribo-Mechanical and Antibacterial Performance of 3D Printed hBN/PEGDA Nanocomposites for Load-Bearing Tissue Engineering Applications.

Abstract

Photo-cross-linkable polyethylene glycol diacrylate (PEGDA (Mn ≈ 700)) is gaining importance as a potential biomaterial for tissue engineering due to its excellent biocompatibility and its ability to imitate the structural and functional characteristics of native human tissues. However, the limited mechanical and tribological properties of PEGDA constrain its application in load-bearing tissue engineering. To address the challenges associated with the limited mechanical and tribological properties of PEGDA, an attempt has been made to enhance its performance by incorporating an inorganic nanofiller hexagonal boron nitride (hBN). Here, stereolithography (SLA), an additive manufacturing technique, was used to synthesize the hBN-reinforced PEGDA nanocomposite, rendering superior mechanical, thermal, and tribological properties. PEGDA and phenylbis (2,4,6-trimethylbenzoyl) phosphine oxide (BAPOs) photoinitiator were mixed with hBN nanoplatelets (with varying concentrations of 0.25%, 0.50%, 0.75%, and 1.0% w/w) to prepare a composite resin. The SLA-printed PEGDA and hBN/PEGDA nanocomposites were characterized meticulously by using mechanical, physical, thermal, and tribological characterization techniques. As a result, hBN-incorporated PEGDA nanocomposite samples demonstrated significant improvement in the tensile, compressive, and flexural strength at 71.62%, 76.22%, and 31.89%, respectively, compared to that of pristine PEGDA. The fractography of the fractured surfaces revealed a pure brittle fracture in both pristine PEGDA and hBN/PEGDA nanocomposite samples. In addition to evaluating mechanical strength, the tribological performance of PEGDA and its hBN-reinforced nanocomposites was also assessed, revealing a substantial reduction in wear and frictional force upon nanofiller incorporation. The 3D printed samples were also characterized by differential scanning calorimetry (DSC), Fourier transform infrared spectroscopy (FTIR), and wettability test. DSC thermograms and wettability measurements indicated that both the glass transition temperature and the hydrophilicity of the nanocomposites increased with higher hBN weight concentrations. Furthermore, the antibacterial property tests were conducted with two Gram-positive and Gram-negative bacteria, and it was found that the hBN-incorporated PEGDA composite resin inhibits antimicrobial properties.