Microfluidic chip for automated screening of carbon dioxide conditions for microalgal cell growth

Abstract

This paper reports on a microfluidic device capable of screening carbon dioxide (CO) conditions for microalgal cell growth. The device mainly consists of a microfluidic cell culture (MCC) unit, a gas concentration gradient generator (CGG), and an in-line cell growth optical measurement unit. The MCC unit is structured with multiple aqueous-filled cell culture channels at the top layer, multiple CO flow channels at the bottom layer, and a commercial hydrophobic gas semipermeable membrane sandwiched between the two channel layers. The CGG unit provides different CO concentrations to support photosynthesis of microalgae in the culture channels. The integration of the commercial gas semipermeable membrane into the cell culture device allows rapid mass transport and uniform distribution of CO inside the culture medium without using conventional agitation-assisted convection methods, because the diffusion of CO from the gas flow channels to the culture channels is fast over a small length scale. In addition, automated in-line monitoring of microalgal cell growth is realized via the optical measurement unit that is able to detect changes in the light intensity transmitted through the cell culture in the culture channels. The microfluidic device also allows a simple grayscale analysis method to quantify the cell growth. The utility of the system is validated by growing cells under different low or very-low CO levels below the nominal ambient CO concentration.

A Novel System for Real-Time, In Situ Monitoring of CO2 Sequestration in Photoautotrophic Biofilms

“…This problem could potentially be addressed by mimicking the CSMS’s configuration, where concentrated CO 2 remains in a closed environment and is delivered to the culture across a permeable silicone membrane. While previous studies have discussed the use of membranes for this purpose [ 36 , 38 , 39 ], none to our knowledge have applied this specifically in the context of photoautotrophic biofilm CO 2 sequestration monitoring and optimization. From the data presented, it can be concluded that the system described here is capable of the reliable, real-time detection and quantification of CO 2 uptake by phototrophic biofilms.…”

Investigation and Optimization of CO2 Uptake

“…This problem could potentially be addressed by mimicking the CSMS's configuration, where concentrated CO2 remains in a closed environment and is delivered to the culture across a permeable silicone membrane. While previous studies have discussed the use of membranes for this purpose (Carvalho et al, 2001;Lee et al, 1989;Xu et al, 2017), none to our knowledge have applied this specifically in the context of photoautotrophic biofilm CO2 sequestration monitoring and optimization. From the data presented, it can be concluded that the system described here is capable of the reliable, real-time detection and quantification of CO2 uptake by phototrophic biofilms.…”

Microfluidic technology for plankton research

“…During the time period where microfluidic incubation mimics large flask conditions, the on-chip cell culturing is suitable to prospect the optimum of cell growth depending on the nutrient concentrations [13,14]. External factors such as the carbon dioxide concentration or light exposure can directly be tested in a microfluidic device [15,16 •• ]. For example, the effect of light intensity on the growth of phytoplankton is measured using a microfluidic device composed of two independent and superimposed microfluidic networks: one layer for cell incubation and a second top layer where dark dyes flow with different concentrations to impact light intensity (Figure 1d).…”