Abstract

Design, Validation and Evaluation of a Bioaffinity based Flow-biochemistry Device

Andras Guttman, Adjunct Professor, Northeastern University

Flow-biochemistry utilizes continuous flow biochemical devices for biocatalysis, biotransformation and biochemical interaction based flow-analytical systems. Bioaffinity based continuous flow processes show great potential in bioanalytical applications especially in miniaturized format enabling utilization of biochemical recognition. Immobilized bioaffinity agents such as antibodies, lectins, aptamers, etc., can be used to detect or capture biomolecules, cells or even microorganisms of interest. Proper immobilization of the affinity tags on a solid support (either on the microchannel wall or on nano-/microbeads) has great impact on the efficacy of the bioaffinity based microdevice. Design of flow-biochemistry based rare cell capture systems was supported by computational fluid dynamics modeling. Simulations enabled in-depth characterization of velocity field distribution inside different microfluidic operation units and fluidic connectors. Applying the computational simulation results, rare cell capture microfluidic chips were fabricated by soft lithography in PDMS and validated using yeast and melanoma cells for fluidic movement and affinity capture, respectively. The cell capture device comprised of a micropillar array design for cell manipulation in microfluidic applications. Special microfabrication methods, such as proton beam writing was also used to generate tilting pillars to increase their functional surface, enhance fluidic interactions and improve fluid dynamic behavior. The inner surface of the microchip was functionalized by oxygen plasma treatment followed by immobilization of various antibodies using Protein A/G mixture as linker. Surfactants were used to improve surface vetting, thus, achieving better antibody coverage on the surface. Trajectories of yeast cell movement were followed under a microscope and compared with the modeling results. Melanoma cells were used to evaluate the efficiency of the cell capture capability of the bioaffinity based f