Label-free electrogenerated chemiluminescence biosensor for quantization of CD44 on basis of its heterodimerization with matrix metalloproteinase-14

Abstract

CD44, which is expressed frequently and predominantly in invasive tumor cells, is substrate of a membrane-type matrix metalloproteinase (MT1-MMP, also named MMP-14) and its processing accompanies promotion of cell migration. The hemopexin-like domain of MMP-14 (PEX-14) is the region responsible for association with CD44. An electrogenerated chemiluminescence (ECL) biosensor was developed firstly for highly sensitive quantification of CD44 based on heterodimerization interaction between CD44 and PEX-14. In the work, PEX-14 was chosen to specially recognize target CD44. ECL emitter, ruthenium complex (Ru), was covalently coupled onto the surface of Co, Mo2C-carbon nanofiber@polydopamine (Co, Mo2C-CNF@PDA) modified glassy carbon electrode. PEX-14 was further attached to the modified surface, the ECL fabricated successfully. In theory, the ECL signal decreases after binding to CD44. Under the optimal experimental conditions, the designed biosensor exhibited excellent sensitivity with a wide linear range of 0.002–250 ng mL−1 and a detection limit of 0.001 ng mL−1. The biosensor is demonstrated by detecting of living cells expressing CD44 (MDA-MB-231 cancer cells as model). The development of the label-free ECL biosensor integrated with functionalized nanofiber will provide a prospect for studying invasion and metastasis of cancer cells based on the interaction between CD44 and PEX of MMPs.