Continuous cell culture monitoring using a compact microplate reader with a silicone optical technology-based spatial filter.

Continuous cell monitoring is very important for the maintenance and control of cell multiplication and differentiation. This paper presents a compact microplate reader that is able to continuously measure a 24-well microplate (6 × 4 wells) using the optical absorption measurement method. The 24-channel plate reader consisted of a spatial filter, light emitting diode light source, and color sensors and was similarly sized with the cell culture microwell plates. A spatial filter was previously fabricated by our group using silicone optical technology (SOT). This SOT-based spatial filter has an excellent noise reduction effect. Light reflection at the optical path interface can be absorbed and only forward light can be transmitted; accordingly, a larger S/N ratio than that of conventional optical systems is expected. The fabricated 24-channel plate reader permits real-time cell monitoring during cultivation on the clean bench and in cell culture conditions by incorporating the SOT spatial filter. Using the device, it was possible to continuously evaluate the concentration and pH of reagents in the 24 wells in real time. Moreover, cell activity and protein production were detectable using the device. These results suggest that the newly fabricated device is a promising tool for the evaluation of cell behaviors for cell management.