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Programmable Droplet-based Lab on a Chip Systems

Final Report Summary - PDB-LOCS (Programmable Droplet-based Lab on a Chip Systems)

Scientific and Technological Achievements:
The goal of the programmable droplet-based lab-on-a-chip systems (PDB-LOCs) project is to develop a PCB-based integrated microdroplet-based system for low-cost fabrication and complete integration of microdroplet based microfluidic systems. Droplet-based microfluidic systems, i.e. two-phase flow systems are demanding microfluidic systems which require the use of two immiscible fluids instead of having a single fluid stream. Although these systems offer significant benefits compared to the conventional systems, they require several off-chip components to function. The main objective of this project was to use the well-established printed circuit board (PCB) technology to devise a fully functional droplet based platform for electrical control and detection of microdroplets.

Through this 4-year project, the researcher developed an on-PCB droplet microfluidic system. First, the development of capacitive droplet sensors and the dielectrophoretic droplet sorting modules were completed using conventional microfabricated devices using clean room facilities at Bilkent University, UNAM. After geometry optimization and development of the read-out and actuation electronics, the system was transformed to a PCB platform. During this transfer process, one of the main technological innovations was regarding the integration of the microfluidic channels on the PCBs. For this process, two techniques have been developed: i) through the use of thin glass slides, PDMS microfluidic channels have been prepared and simply placed on the PCB electrodes, ii) a PDMS membrane sealing method is developed and fully PDMS channels have been fabricated. It has been shown that the novel PDMS sealing method was very effective in achieving a narrow separation between the electrodes and the droplets, which results in better sensing and sorting capability.

In summary, at the end of the project a battery-powered, USB-interfaced PCB platform has been developed for detection of sorting of microdroplets. The sensing and actuation electrodes were implemented on PCB traces together with all the required circuitry on the same PCB. This allowed very high sensitivities for detection of microdroplets. In addition, since the channels are independently designed and placed reversibly onto the PCBs, the channels can be replaced which allows reuse of the PCBs. The demonstrated system is reprogrammable and can be further extended for microfluidic assays that rely on microdroplets.

Researcher’s career development and integration to the host institution:
Another purpose of the project is to enable the complete integration of the researcher to the host institution and provide him a way to establish his independent research group while transferring his know-how to his host institution. Through this Marie Curie career integration project, Dr. Caglar Elbuken was able to establish his research group which consists of 1 M.S. student, 4 Ph.D. students, 1 post-doctoral fellow and 1 project engineer as of October 2016. Dr. Elbuken supervised 2 master’s thesis through this project. In the meantime, he has also completed 2 other projects as principal investigator. As of October 2016, he is involved in 6 more projects at different roles varying from principal investigator, researcher and consultant. In addition, Dr. Elbuken developed strong relationships with industry. He has licensed a portable microfluidic bilirubin detection system to one of the local companies. This patent-pending technology is currently being transferred to the company for product development. Dr. Elbuken also developed a handheld portable detection system which is used for rapid monitoring of coagulation time (PT and APTT) for patients on anticoagulant therapy. These prototypes originated from Dr. Elbuken’s CIG project which relied on continuous flow system, but extensively uses the PCB detection circuitries developed through the CIG project.

As part of the above activities, Dr. Elbuken produced 12 journal articles (8 published, 2 accepted, 2 under review) and 20 conference proceedings. He gave 17 invited talks at several organizations. He offered a new graduate level course at his institution through which he received extremely positive feedback through the course evaluations. During his first 4 years at the host institution, Dr. Elbuken also contributed significantly to the development of his institution. He prepared UNAM’s first annual report which is a 100-page document publication that summarizes the achievements of the institution. He organized the nano-colloquium series for 2 years and hosted world-renowned experts at Bilkent University. He co-organized an international and a national conference on biosensors. He also served at several committees including infrastructure development, safety and student admission committees. As an important indication of the researcher’s dedication to serving his institution, he was promoted as the Assistant Director of UNAM being responsible from the infrastructure and internal/external users.

Thanks to the MC CIG project, Dr. Elbuken was able to establish his laboratory very rapidly and became productive. The resources provided to Dr. Elbuken enabled him to output a steady and increasing publication record. He has not only contributed to his institution scientifically, but he also transferred his organizational experience to his host university.