Development of a hybridization chain reaction-powered lab-on-fiber device for ultrafast point-of-care testing of circulating tuor DNA in whole blood

Circulating tumor DNA (ctDNA) demonstrates great promise in the guidance of prognostication, diagnosis, and surveillance of cancers, which highlights the need for rapid and sensitive point-of-care testing (POCT) tech-nologies. Hybridization chain reaction (HCR)-based optical biosensors provide excellent solutions due to their prominent features. However, the requirement of a sophisticated and expensive optical readout device, relatively long detection time, and heating hold back their scalability and clinical applications. Here, an innovative HCR-powered lab-on-fiber device (HCR-LOFD) was developed for rapid on-site detection of ctDNA with high sensi-tivity, specificity, and reproducibility. A LOFD with a compact all-fiber optical structure was constructed for the fluorescence detection of the HCR system. Combining HCR, fluorescence energy resonant transfer, and the evanescent wave fluorescence principle, HCR-LOFD achieved the quantitative detection of KRAS G12D, the 12th amino acid from glycine (Gly) mutated aspartate (Asp) and the most common mutation of KARS, in 5 min at room temperature based on end-point detection mode or real-time fluorescence detection mode. This new assay platform was also successfully applied for the direct detection of KRAS G12D in whole blood with simple dilution. The application of HCR-LOFD not only greatly simplifies the complexity of optical readout devices and improves their scalability but also potentially serves as a sample-to-answer solution for the detection of bio-markers in limited medical resource regions.

Automated summary

Circulating tumor DNA (ctDNA) has shown promising potential in the prognosis, diagnosis, and surveillance of cancers, necessitating the need for rapid and sensitive point-of-care testing (POCT) technologies. Hybridization chain reaction (HCR)-based optical biosensors offer excellent solutions, but their scalability and clinical applications are hindered by the requirement of expensive optical readout devices, long detection time, and heating. This study presents an innovative HCR-powered lab-on-fiber device (HCR-LOFD) for rapid on-site detection of ctDNA with high sensitivity, specificity, and reproducibility. The HCR-LOFD combines HCR, fluorescence energy resonant transfer, and the evanescent wave fluorescence principle to achieve quantitative detection of KRAS G12D in 5 minutes at room temperature, simplifying optical readout devices and potentially serving as a solution for biomarker detection in limited medical resource regions.