Synthesis and application of electrospun polyvinylidene fluoride/ polyvinylidene glycol nanofibrous membrane for enhanced biomarker detection in immunochromatography assay

Immunochromatography assay (ICA) stands as a pioneering point-of-care testing (POCT) method, leveraging the simplicity, portability, and versatility of dry-strip testing method, chromatographic and antigen-antibody immunological reaction. Despite its numerous advantages, the shortcomings like low sensitivity, limited matrix, restricted matrix compatibility, and uncontrollable chromatographic rates, have hindered the ICA application. To overcome the aforementioned challenges, we proposed constructing a novel ICA strip based on homemade hydrophilic, flexible membranes to replace the commercially available nitrocellulose (NC). The key to the innovation lies in the spinning solution of a blend of poly (vinylidene fluoride) (PVDF) and polyethylene glycol (PEG), which is made into a nanofibrous membrane named EPVDF/PEG membrane by electrostatic spinning technique. This membrane, due to its high specific surface area and high porosity, can be loaded with more detection reagents than normal substrates, increasing the reaction time and achieving improved detection sensitivity. This membrane also has adjustable chromatographic rate, high protein loading capacity, good biocompatibility and excellent colouring ability. As a result, the established EPVDF/PEG-based ICA strips demonstrate an ultralow detection limit, as low as 0.5 mIU center dot mL- 1 when human chorionic gonadotropin (HCG) serves as the biomarker model, which is a 50-fold increase in detection sensitivity compared to commercial strips. Furthermore, EPVDF/PEG-based ICA strips can be produced on a large scale for the availability of efficient and mature electrospinning technologies. In summary, this work offers a transformative advancement in ICA development, potentially opening new horizons for sensitive biomarker detection.