HAR Microfluidic Device to Concentrate Microalgae

In this project the efforts were geared towards building and testing a high aspect ratio (HAR) microfluidic device to concentrate microalgae in a continuous flow microfluidic chip. This project was made possible through funding from USDA, SBIR phase-I grant to Phycal, Inc. Algae are a promising candidate for large-scale production of biofuels, an important source of renewable energy. However, a significant portion (20-40%) of the cost in the traditional processing comes from concentrating (dewatering) the algae from the dilute growing concentrations (~0.1 wt%). A continuous flow microfluidic dewatering chip has been designed using an innovative, patented lateral displacement array (LDA) design. The LDA consists of densely packed vertical posts that ‘bump’ particles of certain size towards the center of the chip thereby concentrating them at the center. Chips with such LDAs consisting of round or triangular posts, patterned by X-ray lithography into SUEX or molded by hot embossing into polycarbonate were used to fabricate microfluidic LDA devices. Initial microfluidic tests show that both taller posts and triangular shape result in lower flow resistance. Also using lower flow rate requires lower pump pressure to push the algae solution through the LDAs.