Pubudu Premarathne

As a researcher in bioengineering, my work focuses on the design, fabrication, and integration of advanced thermoplastic-based microfluidic systems for diagnostic and analytical applications. A key project involves developing a two-module integrated microfluidic system to streamline complex workflows, which is crucial for minimizing sample loss and enhancing reliability. This system is designed for acute lymphoblastic leukemia (ALL) diagnostics, with the first module isolating circulating tumor cells (CTCs) from blood and the second performing detailed downstream analyses like immunophenotyping and Fluorescence in situ hybridization (FISH). We utilize double-sided hot embossing for fabrication and are investigating noncontact, infrared-based laser heating to provide precise, rapid thermal control essential for efficient on-chip assay performance.
A second pillar of my research is the development and optimization of thermoplastic-based nano injection molding to fabricate high-precision micro- and nanofluidic devices. This work prioritizes materials like cyclic olefin polymer (COP) and cyclic olefin copolymer (COC) for their exceptional optical transparency, chemical resistance, and low autofluorescence, while also evaluating PMMA and polycarbonate. We fabricate master molds on silicon wafers using optical and beam pen lithography (BPL) in Class 100-10,000 cleanroom facilities. The overarching goal is to establish a scalable, cost-effective manufacturing platform for lab-on-a-chip and biosensing devices that integrates fluidic, optical, and thermal functionalities.
Finally, my research investigates the fundamental material properties of these thermoplastics (COC, COP, PMMA, PC) and their direct influence on device assembly, integration, and sensing performance. Using Differential Scanning Calorimetry (DSC), Thermogravimetric Analysis (TGA), and Gel Permeation Chromatography (GPC), we characterize thermal transitions and molecular properties to optimize bonding and molding conditions. This material-centric approach is critical for tackling integration challenges, such as patterning stable thin-film electrodes on thermoplastic substrates for resistive pulse sensing (RPS). This provides the foundation for developing robust, high-performance biosensing platforms with fully integrated electrical detection.