The Behavior of MXenes in Biological Media

The rapidly growing family of ultrathin layered two-dimensional (2D) transition metal carbides, nitrides, and carbonitrides, referred to as MXenes are steadily advancing as novel inorganic nanosystems for various electronic and optoelectronic applications. The metallic conductivity, hydrophilic nature, and other unique physiochemical properties qualifies 2D MXenes to meet the requirements of biomedicine such as in stem cell research. Stem cell therapies show great promise for the cure of neurological disorders, as stem cells can serve as cell replacement, while also secreting factors to enhance endogenous tissue regeneration. We investigate the impact of outstanding electrical and surface functional properties of MXenes in the application areas of stem cells. Our synthesis strategies allow us to synthesize highly conductive and stable colloidal aqueous dispersions of MXenes that are coated or drawn as films. These freestanding films of MXenes exhibit electrical conductivities ranging from 10 S.cm^-1 (V₄C₃T_x MXene) to 20,000 S.cm^-1(Ti₃C₂T_x MXene). By the virtue of such high electrical conductivities, MXene nanosheets are explored as interfaces for regulating stem cells. The stem cells grown using a technology that allows for the culture of stem cells in combination with 3D printing technology can be translated to novel therapies for bone regeneration and reconstruction. Stem cells cultured on MXene films enable higher synchronous electrical activities and higher proliferative ability. Our preliminary results suggest that owing to the 2D network, MXenes can be engineered as guided bone regeneration membranes that serve as a scaffold to induce stem cell attachment. This study is an important step toward understanding the potential of MXenes in stem cell research and biomedicine, in general.