Functionalized gold and persistent luminescence nanoparticle-based ratiometric absorption and TR-FRET nanoplatform for high-throughput sequential detection of L-cysteine and insulin

In vitro diagnostic is a crucial component of healthcare systems for early diagnosis of diseases and follow-up therapy, which generally makes clinical diagnosis faster, easier, and painless for patients. Herein, we report a dual-signaling nanoplatform for ratiometric absorption and time-resolved fluorescence resonance energy transfer based on L-cysteine-mediated aggregated gold nanoparticles and long afterglow nature of persistent luminescence nanoparticles. With this nanoplatform, we have achieved high-throughput sequential detection of L-cysteine and insulin in human serum without matrix interference. The proposed nanoplatform shows excellent linearity and precision for the determination of L-cysteine in the range of 10 nM to 5.5 μM with the limit of detection (LOD) of 2.2 nM and for the detection of insulin in the range of 12 pM to 3.44 nM with LOD of 2.06 pM. The developed dual-signaling nanoplatform has been successfully applied for the sequential determination of L-cysteine and insulin in human serum.