(27bt) Regulating Cell Function to Accelerate Bone Cell Growth Using Micro- to-Nano Crumpled Mxene Multilayers.

Although orthopedic implants are considered suitable replacements for missing, damaged or degenerated, parts of a body (such as joint, bone and cartilage, in case of injury, degenerative disease and trauma), slow and insufficient tissue regeneration is still a critical issue that could lead to mechanical loosening and implant failure. To tackle this problem, one possible solution is to use surface topographies with periodic features that can interact with mammalian cells to regulate cell function. In this study, we demonstrate the crumpled MXene/hydroxyapatite (HAP) multilayers through layer-by-layer approach on a polystyrene substrate to investigate the interactions between the crumpled MXene-based films and mammalian cells. MXene is a 2D sheet-like nanomaterial with osteoconductivity, biocompatibility and antimicrobial properties, and HAP is the primary inorganic component of hard tissue in the body and is biocompatible and highly osteoconductive. By shrinking the substrate, and due to the difference in the elastic modulus of the substrate and the coating, the multilayer MXene/HAP films form a periodic structure that offers tunable properties in both wavelength and amplitude. This can be achieved through the selection of the number of bilayers, which effectively changes the thickness of the film. By leveraging this capability, it becomes possible to fabricate structures ranging from nano- to micro-scale, thereby enabling the study of micro- to nano-bio interactions at the implant interface. Specifically, we aim to evaluate the effects of different surface feature sizes on the proliferation, morphology, adhesion, and differentiation of preosteoblast cells. Our design incorporates the use of both osteoconductive materials, using MXene and HAP, and topography to regulate cell function. Our preliminary testing has demonstrated that the micro-topography induces early cell adhesion, cell elongation and cell proliferation compared to the nano- and submicron-topography. It is an ongoing study, and will be advantageous over other sophisticated patterning methods such as e-beam lithography and nanoimprinting, as it is simple, inexpensive, and allows for scalable nanoscale control. This study offers the potential to significantly enhance the success rate of implants in tissue engineering, by employing a scalable and simple method that combines topographical strategies with the use of osteoconductive materials.