PLoS By Category | Recent PLoS Articles

Hematology - Microbiology - Physics

Nanometer-Scale Sizing Accuracy of Particle Suspensions on an Unmodified Cell Phone Using Elastic Light Scattering
Published: Tuesday, October 02, 2012
Author: Zachary J. Smith et al.

by Zachary J. Smith, Kaiqin Chu, Sebastian Wachsmann-Hogiu

We report on the construction of a Fourier plane imaging system attached to a cell phone. By illuminating particle suspensions with a collimated beam from an inexpensive diode laser, angularly resolved scattering patterns are imaged by the phone's camera. Analyzing these patterns with Mie theory results in predictions of size distributions of the particles in suspension. Despite using consumer grade electronics, we extracted size distributions of sphere suspensions with better than 20 nm accuracy in determining the mean size. We also show results from milk, yeast, and blood cells. Performing these measurements on a portable device presents opportunities for field-testing of food quality, process monitoring, and medical diagnosis.