Viral Nanoparticles as Lateral Flow Assay Reporters: Analysis of Capture Kinetics, Stabilization, and Detection In Blood

Key advances in healthcare have arisen from the implementation of point-of-care (POC) testing in lightly-equipped laboratories, in the field, or at home. POC tests are used in the detection of various analytes, biomarkers, and pathogens, and are widely used due to their convenience, low cost, and reliability. One of the best-known POC tests is the lateral flow immuno-chromatographic assay (LFA). When used as an LFA reporter particle, M13 bacteriophages have demonstrated low limits of detection in the laboratory, and their integration into a complete practical assay was investigated in this work. We developed a rapid and very sensitive LFA, and demonstrated its storage stability and use with whole blood. A second line of investigation concerned measurement of the kinetics of LFA reporter interaction and capture in porous matrices. Such measurements have been difficult, especially on time scales below one second. A rapid-filtration system for short-time-scale measurement of the kinetics of binding in membranes is described. The system is composed of a mechanical syringe pump driving fluid through a membrane resting on a stainless-steel mesh membrane, which is connected to a vacuum pump to remove excess fluid, and computer-controlled solenoids to bring the membrane abruptly into and out of fluidic contact with the syringe at precisely-controlled times. We used this technology to characterize the binding of M13 bacteriophage onto LFA membranes at flow rates from 0.5 to 8 mL/sec over times ranging from 50 - 1000 msec. Under optimized conditions, this approach showed an increase in binding in a flow-rate and time-dependent manner. Potential applications of rapid-filtration analysis include the study of chromatographic and membrane adsorption, membrane-based assays, and medical diagnostics. The integration of M13 bacteriophage into complete LFAs and understanding their capture mechanism will lead to insights on how to improve the sensitivity and utility of LFAs.