Abstract

Novel Multiplexing and Precision Sensing Approaches for Liquid Biopsy

Sehyun Shin, Professor & Director, Korea University

Every year, there are about 899,000 new cases and 260,000 mortalities, comprising 6 percent of all cancer deaths globally. Cancer detection is a critical approach for preventing cancer deaths because cases caught early are often more treatable. The development of non-invasive methods to detect and monitor tumors remains a major challenge in oncology. Liquid biopsy such as circulating tumor cells (CTCs), exosomes and circulating tumor DNA (ctDNA) has the potential to provide information about cancers without invasive biopsy. It has been rapidly developing since it yields minimum invasiveness, easy repetitive sampling, and whole mutation representation. These circulating biomarkers can be easily obtained from biofluids such as saliva and blood. Although PCR and NGS (Next Generation Sequencing) based ctDNA detection methods have been introduced, there are still unmet needs to detect ctDNA for clinical applications. We presented a clampSPR (closed-loop amplification PCR-based Surface Plasmon Resonance) sensometry for detecting ctDNAs with multiplexing assay; detect biomolecules with label-free analysis via changes in the refractive index on the sensing film of the SPR sensor in real time. The proposed clampSPR system is similar to real time PCR. After a sample is loaded to the system, it is circulated through a closed-loop channel with passing three different temperature zones by an innovative microfluidic pumping system. Target genes in a sample are amplified as two folds per circulation. Furthermore, encoded hydrogel microparticles were added for multiplexing. This system is fast as 30 minutes for 40 cycles. In addition, it is portable, minimize the sample volume with low cost. Conclusively, our novel approaches can apply to clinical diagnosis of cancer with several advantages such as high sensitivity and multiplexing.