Accelerated life testing of a point-of-care vertical-flow immunoassay system for biothreat detection
Accelerated Life Testing (ALT) is a method for product testing by subjection to higher-than-normal stress conditions (e.g., temperature, humidity, vibration, or pressure) to uncover failures in a short amount of time. This study aims to apply ALT to a Vertical-Flow Immunoassay (VFI) device to determine failure criteria of capture antibody stability on a multiplexed mini-VFI membrane. This was accomplished through the exposure of a mini-VFI device to multiple temperature and humidity conditions using a Controlled Environment Chamber. These devices were tested with a 1 ng/mL concentration of three targets (LcrV, F1, Ft LPS), after exposure to several environmental conditions in several package conditions. Due to antibody denaturation, the LcrV assay showed an overall increase in target-specific signal as environmental conditions worsened with a large increase in background signals at the highest stress condition, while the F1 and Ft LPS assays demonstrated an overall decrease in target-specific signal with relatively low background signal, even with increasing stress conditions. Results also indicated a high number of failures in high stress environmental conditions and exposed to environment package conditions using the limit of detection calculation for each assay. These results identified the failure criteria for further ALT experiments on the mini-VFI system.