RNase H-recycling-assisted dual-channel graphene oxide-aptamer biosensor for rapid detection of CRP and LDL in patients with coronary artery disease.

Designing nanostructured interfaces that integrate molecular recognition with signal amplification is critical for advancing high-performance biosensors. Graphene oxide (GO) has emerged as a versatile nanomaterial in biosensing due to its high surface area, biocompatibility, and superior fluorescence quenching efficiency. Here, we report an engineered graphene oxide-aptamer interface coupled with RNase H-driven signal recycling for multiplexed detection of C-reactive protein (CRP) and low-density lipoprotein (LDL). In this system, GO functions as both a nanoscale fluorescence quencher and aptamer carrier. Target binding initiates RNase H-catalyzed cleavage of aptamer-probe duplexes, releasing fluorophores and regenerating recognition sites for continuous signal amplification. The hybrid interface exhibits high probe stability, rapid response kinetics, and suppressed background fluorescence, achieving detection limits of 1.0 ng/mL (CRP) and 2.0 nM (LDL). The modular design enables extension to other biomarkers by aptamer substitution. Compared to ELISA, the graphene oxide-aptamer mediated RNase H amplification (GO-ARH) assay achieves enhanced sensitivity, reduced assay time, and compatibility with microarray and POC workflows.