Multiplexed Sensing Probe for Bioreactors for Cellular Agriculture

A portable scalable multiplexed thread-based sensing microprobe for continuous monitoring of pH and ammonium ions during the biofermentation process is demonstrated. Continuous real-time monitoring can facilitate active intervention to improve cell growth in a bioreactor to help maintain phenotype. Each sensing microprobe consists of a 3-D-printed shell (length 14.2 mm, outer diameter 9 mm) to hold separate working and reference electrode threads about 1.0 mm in length. Inlets and outlets facilitate continuous flow during monitoring. The functionality of the constructed microprobe was evaluated in a simulated microreactor with different pH, temp, and ion concentrations that resembles a fermentation environment. The sensitivity and selectivity of sensors were evaluated, and results indicate promising dynamic range for pH (2.86 to 7.81) and ammonium (10
$\mu$
M to 100 mM) for bioreactor monitoring.