Porous Silicon-Based DNA Biosensor for Human Papillomavirus Detection: Towards the Design of Fast and Portable Test

We have developed porous silicon (PSi) biosensors for detecting high-risk human papilloma virus 16 and 18, (HPV16 and HPV18), frequently associated with the generation of pre-cancerous and cancerous lesions. For this purpose, we used PSi, a biocompatible material characterized by its remarkable optical properties and porous structure that provides an easily modifiable surface. Here, ssDNA oligonucleotides of HPV 16 and 18 were attached inside PSi pores using standard amino-silane and glutaraldehyde chemistry (PSiMc/HPV-ssDNA). The PSiMc/HPV-ssDNA device was characterized during all the modification steps by infrared spectroscopy (FTIR) and scanning electron microscopy (SEM) to have reliable information about the biosensor's chemistry and stability. Molecular binding on the PSi surface was optically detected based on a shift of the reflectance spectra and corroborated by fluorescence microscopy. The magnitude of the resonance shift was directly related to the concentration of biomolecules attached to the pore walls. It was found that the PSi biosensor can selectively discriminate between complementary and non-complementary DNA. These studies suggest that the proposed screening strategy based on PSiMc/HPV-ssDNA-ccDNA using reflectance spectra shift may be suitable for the design of novel and practical portable devices for HPV detection. To perform this work, we have selected a PSi microcavity, mainly due to its optical features (resonance modes) in the reflectance spectra that allow the detection of material infiltrated into the porous structure.