Figure 3
Device design. (a) The complete photodiode array used for data collection. The array is height adjustable to ensure analysis at the surface of each individual sample. A 650 nm LED illuminates the sample and Mie scatter spectra are detected by photodiodes at increments of 10° from 10° to 80° relative to the tissue surface. The incident angle of the LED is adjustable through individual attachments, due to space constraints on this miniaturized device. (b) Each of the five attachments used to change the incident light angle. All five attachments have identical sizes and photodiode locations, with the only difference being the angle at which the LED is held. Using these attachments, the incident light angle can be changed between 90°, 100°, 110°, 120°, and 135°. (c) Mie scatter simulations used to determine the optimal wavelength to use for the light source within this device. Simulations were conducted based off of parameters for E. coli and specifications of the device designed. Based on these simulations, a 650 nm light source was selected as the optimal incident wavelength.
