Chemiluminescence Detection of a Protein through the Aptamer-Controlled Catalysis of a Porphyrin Probe

Sensitive and selective protein detection based on the aptamer-controlled noncovalent porphyrin probe self-assembly is reported for the first time. Vascular endothelial growth factor (VEGF) is a predominant biomarker in cancer angiogenesis. In this work, a positively charged porphyrin probe, manganese(III) meso-tetrakis(N-methylpyridinum-4-yl)porphyrin (Mn-PyP), was prepared. Using it as a catalyst, a label-free chemiluminescence (CL) turn-on approach for sensitive VEGF detection is developed. Mn-PyP could catalyze the luminol CL reaction. The VEGF aptamer could induce aggregation of Mn-PyP. As a result, the Mn-PyP-catalyzed CL reaction is efficiently suppressed. Upon the addition of VEGF, the specific binding of VEGF to the aptamer weakens the interactions between the aptamer and Mn-PyP. The Mn-PyP monomers are released, and a turn-on CL signal is thus detected. Our method is quite sensitive; 50 pM of VEGF could be easily detected. It is also very selective against other proteins. Our assay provides an aptamer-based efficient way for protein quantification.