A comprehensive study on the surface property changes of antibodies on interacting with Ti₃C₂T_x, V₂CT_x, or Mo₂TiC₂T_x MXenes

MXenes are nanomaterials composed of layered transition metal carbides and nitrides and are considered to have considerable potential in the biomedical translation field. However, the biological and toxicological behaviours of nanomaterials (NMs) are regulated by protein-corona formation, which leads to conformational changes in proteins and impacts their biological functions. Thus, in this work, we synthesized four different MXenes (multi-layered titanium carbide (Ti₃C₂T_x-ML); single-layered titanium carbide (Ti₃C₂T_x-SL); single-layered molybdenum titanium carbide (Mo₂TiC₂T_x-SL); and multi-layered vanadium carbide (V₂CT_x-ML)) and studied their physicochemical interactions with a model protein immunoglobin G (IgG) from human serum. The conformational, thermal, and colloidal stabilities of IgG were investigated after exposing IgG to MXenes for 15 min at IgG/MXene ratios of 40:1 and 20:1. Circular dichroism (CD) spectroscopy revealed that the secondary structure of IgG underwent a concentration-dependent conformational change after exposure to all four MXenes. ζ-potential studies showed that Ti₃C₂T_x-ML MXene had the highest negative surface charge due to the presence of abundant fluorine (F) surface groups. However, this increased the hydrophilicity of IgG/MXene solution and eventually caused IgG aggregation and destabilization. Furthermore, Ti₃C₂T_x-ML MXene had a greater tendency to produce protein coronas than the other MXenes. This study describes a versatile means of examining the properties of MXenes responsible for protein coronas and lays a foundation for establishing the connection between protein corona formation and the biological functions of MXenes.