Comparison of three indirect immunoassay formats on a common paper-based microfluidic device architecture

Abstract

The ability to detect antibodies that are generated during an immune response is integral to the diagnosis and monitoring of infections. Assays that have been applied to the detection of antibodies are classically referred to as indirect immunoassays, which include three different formats: indirect, double-antigen sandwich, and total IgG capture. Each of these three approaches relies on a unique pair of reagents to capture the target antibody and transduce a detectable signal, which permits assays to be tuned for ideal performance based on the availability and quality of reagents, the resources available to the operator, and the complexity of the sample (e.g., serum vs. saliva). This flexibility, however, can complicate the development of diagnostic tests and increase the complexity of the devices required to perform them. A general platform that can enable the rapid development of inexpensive and simple diagnostic assays would be highly desirable, particularly for those assays intended for use in limited-resource settings. In this manuscript, we describe a paper-based microfluidic device architecture that is capable of supporting these three indirect immunoassay formats by simply changing reagents and without requiring significant alterations to the design or manufacture of the device. We compare the performances of these indirect immunoassays by developing assays for HIV antibodies in human serum. These results suggest that this device format has broad potential for the development of paper-based immunoassays.