Angular Photodiode Array-Based Device to Detect Bacterial Pathogens in a Wound Model

Abstract

We have developed a device that is able to rapidly and specifically diagnose bacterial pathogens in a wound model based on Mie scatter spectra from a tissue surface. The Mie scatter spectra collected is defined as the intensity of Mie scatter over the angle of detection from a tissue surface. A 650 nm LED perpendicular to the surface illuminates a tissue sample (90°) and photodiodes positioned in 10° increments from 10° to 80° of backscatter act as the detectors to collect these Mie scatter spectra. Through principal component analysis of the Mie scatter spectra collected, we have shown significant differences between Mie scatter spectra of tissues with bacterial pathogens versus those without, as well as significant differences between each species of bacteria tested. The device developed has been tested with a porcine dermis wound model, with samples inoculated with one of three bacterial species (Staphylococcus aureus, Escherichia coli, or Salmonella Typhimurium). Such a device could be critical in the monitoring of a wound for infection and rapid, specific diagnosis of a bacterial wound infection, which would significantly reduce the time and cost associated with specific diagnosis of a bacterial wound infection currently.

Label-Free Mie Scattering Identification of Tumor Tissue Using an Angular Photodiode Array

“…Our laboratory has employed this method toward more biological matrices including identifying bacterial presence and species on a human and animal skin as well as on a wound, i.e. skin and wound infection, without using any labels [1,2]. Labels can be added to amplify such Mie scattering intensities, for example the submicronor micron-sized beads with high refractive indices such as polystyrene and TiO2.…”