Electrochemiluminescence resonance energy transfer system based on ox-MWCNTs-IGQDs and PdAg nanosheets for the detection of 5-fluorouracil in serum

Abstract

In this work, a novel electrochemiluminescence energy resonance transfer (ECL-RET) immunoassay based on ox-MWCNTs-IGQDs and PdAg nanosheets (PdAg NSs) was established for the ultrasensitive detection of 5-fluorouracil (5-FU) in serum. Exposure of graphene quantum dots by nitric acid etching of multi-walled carbon nanotubes to form ox-MWCNTs-IGQDs, which exhibited excellent electrochemiluminescence intensity. The prepared PdAg NSs have the characteristic of large specific surface area and low toxicity. Furthermore, ox-MWCNTs-IGQDs as ECL donor and PdAg NSs as ECL acceptor can directly carry 5-FU coating antigens and antibodies, respectively. Interference due to the introduction of other bridging molecules can be avoided. Based on the principle of competitive immunity, the 5-FU detection substance and 5-FU coating antigen will co-compete for the specific binding site on the scant antibody, realizing the efficient detection of 5-FU. Under optimal conditions, the proposed ECL immunosensor for 5-FU detection exhibited high sensitivity with a wide linear range from 0.0005 ng/mL to 500 ng/mL and a low detection limit at 0.17 pg/mL. This work took a simple approach to design the ECL immunosensor, the sensor had certain feasibility for the detection of 5-FU in the serum of cancer patients, and provided a new way for the detection of other small molecule anticancer drugs in the future.