Figure 3.
An illustration of the principle for glucose detection with different types of monitoring methods. Working principles of (A) photoacoustic spectroscopy for glucose monitoring. Adapted with permission from 53. Copyright 2017, MDPI. (B) optical transducer. Adapted with permission from 103. Copyright 2018, American Chemical Society. (C) Different devices used for image acquisition of the colorimetric reaction: (left-top) sCMOS, CCD-based digital camera (right-top), smartphone (left-bottom), image scanner (right-bottom), and the naked eye. (D) The working principle of the image sensor from the colorimetric reaction.