Covalent attachment of biotinylated molecular beacons via thiol-ene coupling. A study on conformational changes upon hybridization and streptavidin binding

The authors describe a method for the detection of DNA by using immobilized molecular beacons (MBs) on the surface of silicon, with a view on possible application in biosensing. MB hybridization and protein recognition were interrogated on silicon-on-insulator (SOI) surfaces by using fluorescently tagged probes. In order to better understand the conformational changes that occur to MBs upon hybridization, the process was studied by using dual polarization interferometry (DPI). A model system was developed that matches thickness, mass, and density parameters. The results experimentally demonstrate that hybridization promotes the displacement of a protein away from the surface. This finding may be further exploited in techniques such as photonic sensors, thereby paving the way to the design of more sensitive biosensors based on the use of MBs.