Site-encoded DNA strategies for Optical Multiplexed Platforms

Abstract

Diagnostics point to a future based on molecular signatures rather than on the detection of single biomarkers. In this respect, microarray is a powerful technology showing great potential for providing huge amounts of information in a single chip. However, for peptides, proteins or metabolites, the technology is not as straightforward as for the DNA. Contrarily to the relatively high homogeneity of nucleic acids, these targets show great molecular variability and physicochemical features (different hydrophobicity, acidic or basic characters, etc.) and biofunctionality. Preventing protein denaturation and maintaining structural conformations are key issues. An alternative to circumvent these limitations is the use of DNA for manufacturing the chips. Directed Immobilization (DDI) strategies have been used to spatially assemble mixtures of distinct biomolecules and nanomaterials. DDI manufactured chips provide reversible immobilization efficiencies on reusable microarrays and biosensor chips. In combination with the exceptional features of antibodies and their almost infinite specificities, DDI strategies can allow expanding the number of substances that can be analyzed in a single chip providing high multiplexed and multimodal possibilities. In this communication, distinct optical platforms such as fluorescence site-encoded DNA addressable hapten-microarray, SPR and LSPR platforms manufactured using DDI we will be discussed. Hence, a hapten microarray for androgenic anabolic steroids (AAS) analysis was developed using DDI. For this purpose, haptenoligonucleotide probes were synthesized and hybridized with complementary oligonucleotides immobilized on top of a glass surface. The microchip was able to detect several illegal substances with a detectability according the regulations of the World Anti-Doping Agency and the European Commission regarding food safety issues. The same strategy was implemented on a SPR-imaging device demonstrating the possibility to use this approach for re-usable devices. The same maximum signal was recovered after regenerating the chip by dehybridization of the oligonucleotide chains. Finally, a LSPR chip was manufactured using DDI by specifically addressing gold nanoparticles (AuNP) with different optical properties on distinct sites of a glass surface. Preliminary results showed that this approach could allow developing LSPR chips with excellent analytical features using an alternative fabrication method to the more sophisticated lithographic techniques.