Effect of storage conditions on the performance of nitrocellulose test strips used in lateral flow assays

The effect of long-term storage of membrane materials on the performance of lateral flow assays (LFAs) has never been studied. We experimentally examined the impact of common lab storage conditions on the performance of different types of membrane materials typically used to fabricate LFAs, e.g. cellulose source pads, glass fiber conjugate pads, and nitrocellulose test membranes. Changes in flow properties, protein affinity, fluid imbibition/hydrophobicity, and LFA signal development were measured after storage under varied temperatures, humidity levels, and light and particulate matter exposure, for 1, 2 and 7 months. At the end of 7 months, the lateral imbibition rates decreased by 6±0.41x for nitrocellulose membranes exposed to light and dust, and 4.5±1.15x for nitrocellulose membranes stored at 37°C, in comparison to control membranes. These results shed light upon the significant shift in performance parameters of diagnostic membranes with long term storage.