Revisiting ELISA with in situ amplification of biomarkers to boost its sensitivity

Abstract

The enzyme-linked immunosorbent assay (ELISA) stands as a pivotal instrument in diagnostics and biomedical research, widely used for the detection and quantification of specific proteins associated with diseases. Despite its critical role, ELISA's ability to identify low-concentration proteins remains a significant challenge, hindering its effectiveness in early diagnostics, an area of growing importance. This study introduces a novel approach termed nucleic acid-templated amplification (NATA) to enhance ELISA's sensitivity without significantly modifying the common practices of the present ELISA. Drawing inspiration from viral proliferation mechanisms, our approach integrates a cell-free protein synthesis step using DNA sequences that encode the target biomarkers. This approach enables an in situ 'amplification' of target proteins during ELISA, boosting their concentrations to detectable levels. Our results demonstrate a substantial enhancement in sensitivity, with ELISA now being able to detect protein biomarkers at femtomolar concentrations—approaching the sensitivity range typically reserved for PCR in nucleic acid analysis. This breakthrough not only broadens ELISA’s applicability in early disease diagnosis and monitoring therapeutic interventions but also marks a significant advancement in protein biomarker detection technology. With its modular design, our method also offers high versatility and sensitivity, offering an advanced approach for protein detection in clinical diagnostics and research.