Novel electrochemiluminescence resonance energy transfer platform involving PTCA@Fe(III)-MIL-88B-NH2@Au as a double-amplified emitter for the detection of cystatin C

A luminescent reagent, 3,4,9,10-perylenetetracarboxylic acid (PTCA), was linked to a metal–organic framework (MOF) Fe(III)-MIL-88B-NH2 through an amide reaction to form a PTCA@Fe(III)-MIL-88B-NH2 complex, and then gold nanoparticles (AuNPs) were grown in situ. Thus, the PTCA@Fe(III)-MIL-88B-NH2@Au electrochemiluminescence (ECL) probe was obtained. The MOF of 2-aminoterephthalic acid with large specific surface area, pore sizes, and structures, which served both as the carrier and a co-reaction promoter, promoted the conversion of more S2O82- into SO4•-, further enhancing the ECL signal of PTCA. An electrochemiluminescence resonance energy transfer (ECL-RET) platform was designed for the ultrasensitive and highly selective detection of cystatin C (CysC). The developed ECL-RET biosensor presented a linear range from 0.01 pg/mL to 100 ng/mL and a detection limit of 2.2 fg/mL (S/N = 3). Moreover, all the results showed that the developed ECL-RET biosensor broadened the application in the fields of biosensing and medical diagnosis.