Category: Micro- and Nanotechnologies
Liquid biopsy is the future alternative to the needle biopsy. The invasive needle biopsy requires expertise and labor, while all it takes for the liquid biopsy is blood collection. Circulating tumor cells (CTCs) in cancer patients' blood are well known for causing metastasis in the cancer patients because the escaped CTCs from the primary tumor site move to the distant organs through the blood vessels. Even though the clinical society has found its importance since 1990s, technical limitations barred the scientists from studying them exclusively. There have been improvements in enriching and enumerating CTCs, but the clinicians could not relate CTC count to the cancer status. Thus, the genomic or transcriptomic landscape of CTCs was studied to extract out the valuable genetic aberrations, but the genetic heterogeneity of cancer barred the wide-use of CTCs as a clinical tool. Also, because each and every CTCs from one cancer patient has unique genetic character, the throughput and sensitivity of the platform that can isolate CTCs in single cell level is very important.
Because of such values of CTCs, there have been efforts to detect the CTCs from the patient blood. But only few platforms are available to analyze the whole genome of the CTCs with high resolution after the separation of the CTCs. Here, we applied Laser-induced Isolation of Microstructure On transferrable-chip and sequencing (LIMO-seq) to retrieve the CTCs and sequence the whole genome using next generation sequencing (NGS). With the simple photo-lithography process, we designed the biochip consisting of the separable microstructures and applied LIMO-seq to solve the current limitations of the single CTC genome analysis. Using the chip, we showed that the CTCs captured by the immune-affinity reaction were readily isolated at a single cell level from the chip using LIMO-seq. We also built automated pulsed-laser device that can readily isolate the single CTCs after the automated image-analysis of the whole chip. We analyzed the whole genome and transcriptome sequences of the isolated single cells for the molecular profiling using NGS technology. The isolation of the captured CTCs with LIMO-seq will enable CTC-based diagnostics for treating and monitoring the cancer patients. Also, since this platform can be applied to any devices with microstructures, we believe that LIMO-seq would be an automating tool, bridging the gap between the bioMEMS field and the industry.
Amos Lee– Ph.D. Candidate, Seoul National University, Seoul, Seoul-t'ukpyolsi, Republic of Korea