Continuous oxygen supply in pump-less micro-bioreactor based on microfluidics

Abstract

This research aims a continuous and uniform oxygen tensions and oxygen gradients supply in microfluidic cell culture chip based micro-bioreactor without any external pumps by modifying the existing siphon based perfusion strategy using conventional tools to control constant hydrostatic pressure for constant fluid flow rate. In this study, the microfluidic based micro-bioreactor is fabricated using a polydimethylsiloxane (PDMS) replication process. The micro-bioreactor chip is composed of simple oxygen perfusion setup connecting to capillary-like branched microchannels and a cell culture and support loading area. The function of the new pump-less fluid perfusion in microfluidic cell culture chip and maintains constant oxygen supply in the cell culture area has been experimentally evaluated. And the results demonstrate that this proposed microfluidic flow system in a micro-bioreactor is proved to provide a linear distribution of oxygen throughout the cell culture area without any external and internal interference. Also, oxygen diffusion into the culture area through a microscale channel has been successfully established by the constant hydraulic pressure controlled by siphoning effect. Such flow system was used in a PDMS based microfluidic micro-bioreactor design to provide the high-throughput oxygen diffusion and perfusion, and the uniform oxygen/nutrient distribution continuously supplied for dermal fibroblast cell culture. This could be a potential and effective model to be incorporated into tissue regeneration studies, drug screening model, and in cancer tissue model studies for understanding angiogenesis, where oxygen tension and perfusion cultures play important roles.