A digital microfluidic system for serological immunoassays in remote settings

Science Translational Medicine
25 April 2018  Vol 10, Issue 438
http://stm.sciencemag.org/

Research Articles
A digital microfluidic system for serological immunoassays in remote settings
By Alphonsus H. C. Ng, Ryan Fobel, Christian Fobel, Julian Lamanna, Darius G. Rackus, Aimee Summers, Christopher Dixon, Michael D. M. Dryden, Charis Lam, Man Ho, Nooman S. Mufti, Victor Lee, Mohd Afiq Mohd Asri, Edward A. Sykes, M. Dean Chamberlain, Rachael Joseph, Maurice Ope, Heather M. Scobie, Alaine Knipes, Paul A. Rota, Nina Marano, Paul M. Chege, Mary Njuguna, Rosemary Nzunza, Ngina Kisangau, John Kiogora, Michael Karuingi, John Wagacha Burton, Peter Borus, Eugene Lam, Aaron R. Wheeler
Science Translational Medicine25 Apr 2018 Restricted Access
Abstract
Serosurveys are useful for assessing population susceptibility to vaccine-preventable disease outbreaks. Although at-risk populations in remote areas could benefit from this type of information, they face several logistical barriers to implementation, such as lack of access to centralized laboratories, cold storage, and transport of samples. We describe a potential solution: a compact and portable, field-deployable, point-of-care system relying on digital microfluidics that can rapidly test a small volume of capillary blood for disease-specific antibodies. This system uses inexpensive, inkjet-printed digital microfluidic cartridges together with an integrated instrument to perform enzyme-linked immunosorbent assays (ELISAs). We performed a field validation of the system’s analytical performance at Kakuma refugee camp, a remote setting in northwestern Kenya, where we tested children aged 9 to 59 months and caregivers for measles and rubella immunoglobulin G (IgG). The IgG assays were determined to have sensitivities of 86% [95% confidence interval (CI), 79 to 91% (measles)] and 81% [95% CI, 73 to 88% (rubella)] and specificities of 80% [95% CI, 49 to 94% (measles)] and 91% [95% CI, 76 to 97% (rubella)] (measles, n=140; rubella, n=135) compared with reference tests (measles IgG and rubella IgG ELISAs from Siemens Enzygnost) conducted in a centralized laboratory. These results demonstrate a potential role for this point-of-care system in global serological surveillance, particularly in remote areas with limited access to centralized laboratories.