Assessment of the MT1-MMP expression level of different cell lines by the naked eye

Membrane type 1 matrix metalloproteinase (MT1-MMP) is expressed in most tumors and is believed to play a key role in the development, invasion and metastasis of tumors. There is an urgent need to develop a simple method to detect the MT1-MMP expression level on cells. In this current study, we demonstrated a red emission Au cluster probes with the specific targeting of MT1-MMP on human dopaminergic neuroblastoma (SH-SY5Y) cells. More importantly, utilizing the intrinsic enzyme-like activity of the Au cluster probes, the expression level of MT1-MMP on the SH-SY5Y cells could be assessed by the naked eye without cell lysis and protein extraction process. Furthermore, SH-SY5Y, human breast cancer (MCF-7), and human bronchial epithelial (16-HBE) cell lines with different MT1-MMP expression level could be distinguished using the Au cluster probes by the naked eye. Meanwhile, fluorescence intensity and Au count determined by inductively coupled plasma mass spectrometry (ICP-MS) were used to verify the feasibility of this simple analytical method. Our proposed method is rapid, convenient, and accurate and could be assessed by the naked eye. This visual assessment method of tumor-associated proteins has immense implications in sorting tumor cells.