An off-on-type electrochemiluminescent immunosensor based on resonance energy transfer and a liposome-assisted strategy for signal amplification

An off-on-type electrochemiluminescence (ECL) system for a myoglobin (Myo) assay was proposed by coupling a resonance energy transfer (RET) strategy with functional liposomes as probes. Specifically, black-phosphorus nanosheets (BP NSs), as energy-donors, were introduced into an ECL system, and MnO2 NSs (energy-acceptors) were reduced on the surface of BP NSs in situ to form the BP/MnO2 nanocomposites. Thanks to a perfect spectral match between BP NSs and MnO2 NSs, efficient ECL-RET occurred in BP/MnO2 nanocomposites. Glutathione (GSH)-loaded liposomes (as probes for the regulation and amplification of signals) were immobilized in a 96-well plate through a sandwich immunoreaction. The abundant GSH lysed from liposomes could reduce MnO2 to Mn2+ effectively and destroy the RET, thus regulating the degree of recovery of the ECL signal from BP NSs. The absence and presence of GSH generated the signal-off and signal-on states of the BP/MnO2 nanocomposites-based ECL system. The amount of Myo could be estimated by the degree of recovery of the signal. Benefiting from these phenomena, a good linear relationship ranging from 1.0 x 10(-13) to 1.0 x 10(-7) g mL(-1) was found and the limit of detection was down to 2.5 x 10(-14) g mL(-1) for Myo. Furthermore, the ECL system revealed a favorable performance for the determination of Myo in samples of human serum.

Automated summary

An off-on-type electrochemiluminescence (ECL) system for Myoglobin (Myo) assay was developed using black-phosphorus nanosheets (BP NSs) and MnO2 nanosheets (MnO2 NSs) as nanocomposites. The system utilized resonance energy transfer (RET) and functional liposomes as probes. The ECL signal was regulated by glutathione (GSH) released from liposomes, allowing for the estimation of Myo concentration. The ECL system demonstrated a good linear relationship for Myo detection in human serum samples.