In this study, we developed an optical biosensor for simultaneous
detection of glucose and lactate as biomarkers for monitoring
cell growth conditions. Using the simple camera function of a
smartphone, we were able to simultaneously quantify the concentrations
of glucose and lactate in cell culture media with
high accuracy and reproducibility. In addition, the entire biosensing
system, including the embedded CCD camera, was designed
using the functional features of a smartphone. Since the PAD
allows low-cost analyses, we propose that the biosensor would
be used commercially. Taken together, our results indicate that
the smartphone-based optical sensing system can be applied to
PAD-based colorimetric assays; given the fact that enzymatic
colorimetric assay is a frequently used method. The high portability,
applicability, and cost-effectiveness of the smartphone-based
sensing system might minimize limitations of time and space in
real-time cell culture monitoring.