Development of an Optically-Induced Dielectrophoretic (Odep) Force-Based Polymerase Chain Reaction (Pcr) Module and Its Application in an Odep-Based Microfluidic System for the Drug-Resistance Evaluation of Blood Circulating Tumor Cells (Ctcs)

Microfluidic systems for polymerase chain reaction (PCR) have been widely proposed in recent years. However, these systems normally require precise thermal and fluidic controls that could increase the complexity in terms of design, fabrication, and operation. In addition, the DNA molecules amplified in these systems are technically-demanding to handle (e.g. concentration or collection) that might, for example, affect the performance of subsequent DNA detection. To address these issues, an optically-induced dielectrophoresis (ODEP)-based microfluidic PCR module will be developed in the first year project. The PCR module mainly features in (1) the use of two thermal sources to generate a thermal gradient that provides the temperatures required for PCR, and (2) the utilization of ODEP force to manipulate the movements of the magnetic microbeads, acting as the carrier of DNA molecules, in the thermal gradient field for PCR operation, and finally for the DNA collection and concentration. Overall, the proposed PCR module is simple in terms of design, fabrication, and operation, and is found particularly useful to perform DNA amplication and detection for the cases with limited DNA sample. For the application side, the circulating tumor cells (CTCs) in blood circulation system are mainly responsible for cancer metastasis, and thus are the important chemotherapeutic target. The CTCs isolated from a blood sample can be used for the detection of their DNA mutation points. Such information can be used for predicting CTCs’ responses to chemotherapeutic drugs. The ultimate goal is to achieve so-called personalized chemotherapy. However, such attempt is hampered by the technical limit of current CTC isolation methods to harvest the CTCs with high cell purity. To tackle the issue, an integrated ODEP-based microfluidic system with the PCR module (finished in the first year project) incorporated will be developed in the second year project. In the system, ODEP force will be used to manipulate the cells, and magnetic mcrobeads for CTC isolation/purification, CTC lysis, target DNA sequence isolation/purification, DNA amplification, and the subsequent DNA detection. In this work, we will explore the optimal operating conditions and evaluate its working performances. For demonstrating its practical application, moreover, we will use the proposed system to isolate the CTCs from the blood samples of metastastic lung cancer patients, and then to further detect their DNA mutation points (e.g., T790M、KRAS、BRAF V600E). Investigations will be performed to see if the detection results are linkable to the responses of the individual patient treated with a specific chemotherapeutic drug. Through the clinical studies, we will evaluate the feasibility of using the outcomes of DNA mutation point detection to assist the medical doctors to select a suitable chemotherapeutic drug for an individual cancer patient. As a whole, we hope the proposed research project can benefit future cancer care particularly on personalized chemotherapy.

Project ID:PB10701-0270
External Project ID:MOST105-2221-E182-028-MY3