Virus diagnostics using Fabry–Perot interference films of macroporous silicon

In this paper, the possibility of detecting viruses, specifically influenza A virus, based on changes in the spectra of total reflection from macroporous silicon (macro-pSi) films, is demonstrated for the first time. Macro-pSi films with a pore diameter of about 100 nm were produced by electrochemical etching of crystalline silicon substrates. The porosity of the macro-pSi, calculated using the Bruggeman effective medium model, was 75%. Electron microscopy showed that such highly porous films adsorb of 50–100 nm in size viruses on their surface and inside the pores, but the efficiency of adsorption significantly increases when the surface of the nanostructures is functionalized with monoclonal antibodies, providing specific binding of viruses. The reflection spectra of macro-pSi films demonstrate a series of interference fringes, the intensity of which dramatically changes upon virus adsorption. The results obtained demonstrate the possibility of a simple and effective optical method for virus diagnostics using Fabry-Perot interference in macro-pSi films.