Proceedings 2020, 4, x; doi: FOR PEER REVIEW www.mdpi.com/journal/proceedings Proceedings Design and FEM Simulation of an Asymmetric Pinched Flow Fractionation Microfluidic System for high-Throughput Screening Applications † Carlos E. Torres 1,‡ , Saúl C. Gomez 1,‡ , Andres Aranguren 2 , Johann F. Osma 2 , Luis H. Reyes 3 and Juan C. Cruz 1,4, * 1 Department of Biomedical Engineering, Universidad de los Andes, Cra. 1E No. 19a-40, Bogotá, DC 111711, Colombia; ce.torres10@uniandes.edu.co (C.E.T.); sc.gomez11@uniandes.edu.co (S.C.G.) 2 Department of Electrical and Electronic Engineering, Universidad de los Andes, Cra. 1E No. 19a-40, Bogotá, DC 111711, Colombia; a.aranguren@uniandes.edu.co (A.A.); jf.osma43@uniandes.edu.co (J.F.O.) 3 Department of Food and Chemical Engineering, Universidad de los Andes, Cra. 1E No. 19a-40, Bogotá, DC 111711, Colombia; lh.reyes@uniandes.edu.co 4 School of Chemical Engineering and Advanced Materials, The University of Adelaide, Adelaide 5005, South Australia, Australia * Correspondence: jc.cruz@uniandes.edu.co † Presented at the 2nd International Online-Conference on Nanomaterials, 15–30 November 2020; Available online: https://iocn2020.sciforum.net/. ‡ These authors contributed equally. Published: 15 November 2020 Abstract: The separation of microscopic encapsulates is an area of increasing importance due to applications in a wide variety of fields ranging from the production of cosmetics and pharmaceuticals to the search for new molecules and genetically modified microorganisms. Major challenges are related to the proximity in physicochemical properties of the encapsulating material and the suspension media. We have recently started a research program to search for translocating peptides using a surface display system that locates the possible candidate molecules on yeasts' surface. At this point, the encapsulated yeasts need to be separated and collected for further analyses. An attractive route for separation is microfluidics, as they permit control over the flow rates and interaction times. Here, we explored in silico an asymmetric pinched Flow fractionation (AsPFF) microfluidic system for separating particles in the range of 50 and 500 µm. The simulations involved the particle tracing module of COMSOL Multiphysics intending to mainly separate yeasts of 40 µm and liposomes of 200 µm with the encapsulated yeasts. We investigated flow rate ratios in the range of 1:25 to 1:50 over the system’s 11 different outlets. The results show separation efficiencies above 90%, which are very encouraging and open the opportunity to further explore this microfluidic system experimentally via low-cost manufacturing via the laser cut PMMA devices developed by us over the past few years. Moreover, this opens the opportunity for improving separation efficiencies in other biological and biomedical applications of interest. Keywords: particle; separation; microfluidic; Comsol 1. Introduction High throughput screening (HTS) is a technique commonly employed in pharmaceutical and biotechnology industries that allows identifying compounds with pharmacological or biological activity in a large-scale process. This ultimately facilitates the analysis of thousands to millions of samples in considerably short periods ranging from minutes to a few hours [1]. To achieve this, certain technologies have been developed recently that involve robotics, high-density microplates,