Glucose and lactate analyses employing enzymatic
colorimetric assay
We prepared glucose and lactate samples in PBS (concentrations
ranging from 0–16 mM and 0–1 mM, respectively), and applied
15 L of each onto the sample-loading zone of the PAD. The resultant
blue color in the detection zone ofthe PAD was registered every
5 s using the smartphone gadget developed. Similarly, samples of
RPMI-1640, in which L-929 cells were cultured for 1, 24, 48, and
96 h, were loaded and the images recorded every 10 s. The color
intensities were then quantified using the image analysis software,
ImageJ.