Hybrid functional membranes through layer-by-layer assembly of Ti3C2Tx MXene and gelatin-stabilized calcium phosphate nanospheres

Abstract

MXene-based membranes exhibit promising properties for various applications; however, pure MXene membranes lack sufficient environmental stability and mechanical strength. This work demonstrates that incorporating gelatin-stabilized amorphous calcium phosphate (Gel-ACP) nanospheres into MXene membranes via layer-by-layer assembly significantly enhances flexibility and mechanical strength while retaining electrical conductivity. A pressure-assisted stacking technique was introduced to efficiently fabricate membranes with tunable thickness not achievable through single filtration steps. The Gel-ACP nanospheres, synthesized by co-precipitation of calcium phosphate within gelatin solution, provided a ductile and cytocompatible reinforcement that augmented the properties of the MXene matrix. Direct mixing of the components led to particle aggregation and non-uniform dispersion. In contrast, controlled layer-by-layer nanostructuring maintained membrane conductivity around 102 Scm−1 while dramatically improving mechanical integrity. The optimized hybrid membranes exhibited specific electromagnetic shielding effectiveness of ∼21,000 dBcm2g−1 and withstood over 90 kPa vacuum pressure without rupture, six times higher than pure MXene membranes. Cytocompatibility was confirmed by the proliferation of human mesenchymal stem cells on the membranes. Moreover, the layered membrane exhibited excellent adhesion to bone-mimicking structures, indicating potential utility for bone tissue engineering. Overall, this work provides new design principles for engineering hybrid membranes through controlled multicomponent assembly to overcome intrinsic limitations and impart multifunctionality.