A Submicron Coulter Counter for Enumeration of Viruses and Nanoparticles

The ability to detect, identify, and enumerate particles on the scale of tens or hundreds of nanometers with a point-of-care device would enable great strides forward in treating and preventing infectious diseases, especially in resource-limited settings. Here we demonstrate the ability of a submicron Coulter counter to enumerate nanoparticles in buffer including synthetic beads and several species of virus. Furthermore, we investigate modifications to basic Coulter counting that may enable the determination of structural characteristics of certain viruses or even specific virus identity. This technology complements previous work on a microfluidic cytometer for the enumeration of CD4+ T cells [1] and can lead to the development of a novel, point-of-care diagnostic device to facilitate the treatment of HIV/AIDS in resource-limited settings. The direct counting of particles of around 100 nm can also be extended to the detection of human exosomes with several potential applications in disease diagnosis [2]. In the future, additional techniques will be developed for the interrogation of viruses and exosomes in whole blood samples.1. Watkins, NN, et al. Lab Chip. 2011, 11, 1437-47.2. Record, M, et al. Biochem Pharmacol. 2011, 81, 1171-82.