Small-angle X-ray scattering and FTIR characterization of nanostructured poly (vinyl alcohol)/silicate hybrids for immunoassay applications

In the present work we aimed to develop and characterize hybrid organic–inorganic materials based on poly(vinyl alcohol) (PVA) polymer chemically modified by organosilanes and crosslinked network to be tested as solid support on immunoassay application. Hybrids were synthesized by reacting PVA with 5 different alkoxysilanes modifying chemical groups: tetraethoxysilane (TEOS), 3-mercaptopropyltriethoxysilane (MPTES), 3-glycidoxypropyltrimethoxysilane (GPTMS), 3-(triethoxysilyl)propylisocyanate (TESPI), and 3-aminopropyltriethoxysilane (APTES). PVA-derived hybrids were also modified by chemically crosslinking with glutaraldehyde (GA) during the synthesis reaction. In order to investigate the structure in the nanometer-scale, PVA-derived hybrids were characterized by using small-angle X-ray scattering synchrotron radiation (SAXS). Fourier transform infrared spectroscopy (FTIR) was used to investigate PVA hybrids chemical functionalities and their interaction with bovine herpesviruses. The morphology of silane modified PVA films were also analyzed by SEM coupled to EDX. The bioactivity assays were tested through Enzyme Linked Immunosorbent Assay (ELISA) with bovine herpesvirus (BoHV). SAXS results have indicated nano-ordered disperse domains for PVA hybrids with different X-ray scattering patterns for PVA polymer and PVA-derived hybrids. FTIR spectra have clearly showed that the proposed modifications of PVA by organosilanes were obtained. The chemical crosslinking of PVA polymer chain by GA was verified by FTIR. The immunoassay results have showed that PVA hybrids with chemically functionalized structures have played an important role on regulating to some extent the interaction of herpesvirus and solid substrate at the interface. These results have given strong evidence that PVA-derived hybrid nanocomposites were successfully formed with GA crosslinked network. Also, such PVA based material could be advantageously used in immunoassays with enhanced specificity for diagnosis.