Fluorescent detection of Mucin 1 protein based on aptamer functionalized biocompatible carbon dots and graphene oxide

Abstract

An ultrasensitive aptasensor for the detection of Mucin 1 (MUC1) protein based on fluorescence resonance energy transfer (FRET) between carbon dots (CDs) and graphene oxide (GO) is reported herein. Taking advantage of the strong fluorescence and good biocompatibility of CDs, the MUC1 aptamer was covalently conjugated to CDs (aptamer–CDs) to capture MUC1 protein through high affinity interaction between the aptamer and MUC1 protein. The FRET process between the aptamer–CDs and GO is easily achieved due to their efficient self-assembly through specific π–π interaction, in which the fluorescence of CDs was efficiently quenched. In the presence of the target MUC1 protein, the association constant between aptamer–CDs and MUC1 is bigger than that between aptamer–CDs and GO, leading to the release of the aptamer–CDs from GO, resulting in the recovery of the fluorescence of CDs. This aptamer was observed to detect MUC1 protein specifically and sensitively in a linear range from 20.0 to 804.0 nM with a detection limit of 17.1 nM. The developed aptasensor is highly biocompatible and nontoxic, which can be easily modified for the detection of other protein biomarker.