Clathrin-Mediated Endocytosis of Ti3C2 MXene Triggers M1 Polarization in RAW 264.7 Macrophages in Association with the Parallel Activation of MAPK, PI3K/Akt, and NF-κB Signaling Pathways

As the most widely used MXene, Ti 3 C 2 shows immense industrial and biomedical potential. However, its expansive application leads to inevitable environmental release, raising urgent biosafety and ecological concerns. The poorly understood mechanisms of its interaction with the innate immune system currently hinder comprehensive environmental health risk assessments. This study elucidates the mechanisms underlying Ti 3 C 2 MXene-induced immunotoxicity and pro-inflammatory activation in RAW 264.7 macrophages. Our findings suggest that the pro-inflammatory response is a sequential biological cascade closely associated with clathrin-mediated endocytosis. Upon internalization, Ti 3 C 2 MXene appears to engage a robust, parallel activation state characterized by simultaneous activation of the MAPK, PI3K/Akt, and NF-κB pathways. This signaling transition coincides with a profound transcriptional shift, including the upregulation of putative regulators such as Mmp9 , Ccl5 , and Ehfr . These genes are proposed to function as sensory amplifiers and feedback mediators that may contribute to the stabilization of a classical M1 polarized phenotype. Our findings provide a comprehensive molecular blueprint of MXene-induced activation in RAW 264.7 macrophages, offering critical insights into the biocompatibility of 2D nanomaterials and establishing a framework for risk intervention and environmental safety management.