Development of 4D Printed Photocurable Resin Modified with Functionalised Graphene Nanoplatelets for Biomedical Applications

The photopolymerisation-based 3D printing technique is widely used as a novel route for developing photo-sensitive resins for biomedical applications by incorporating nanoparticles. However, commercial resins are still limited with the high demand in the global market especially in medical devices, dentistry and tissue engineering. In this experimental research, functionalised graphene nanoplatelets (mGNP) are used as modifiers for a commercial photocurable resin to investigate chemical, thermal, mechanical, shape memory, antimicrobial and cytotoxicity characteristics. Flexural and hardness tests were used to study the mechanical properties. The fracture surface of the failed flexural sample was observed by scanning electron microscopy (SEM). The shape memory (SM) behaviour in terms of shape fixity and shape recovery was obtained using dynamic mechanical analysis (DMA). Contact angle goniometry is used to evaluate its hydrophilicity. The ISO 22196 standard method was conducted to evaluate the antibacterial activity of the 3D-printed nanocomposite surfaces. Results showed enhancement in the flexural, hardness, thermal conductivity, shape memory and antimicrobial behaviour for the nanocomposites modified with mGNP by 0.03, 0.06 and 0.1 wt%. In terms of antimicrobial efficacy, the nanocomposite with 0.1 wt% showed a significant reduction in bacterial count for both E. coli (Escherichia coli) and S. aureus (Staphylococcus aureus). The cell viability of all samples remained above 80% indicating the samples were non-toxic, which has the potential to be used for biomedical applications.