Plasma polymerized non-fouling thin films for DNA immobilization

Development of DNA sensors has been an issue of great interest, owing to their potential applications in different fields, such as the diagnosis of infectious diseases, food quality control, or for environmental monitoring. Most DNA sensors involved the immobilization of single-stranded oligonucleotides, so-called DNA probes, onto the sensor surfaces. Here we report on a new approach for DNA probe immobilization using the streptavidin-biotin assembly coupled with a non-fouling thin film. Pulsed plasma polymerization of di(ethylene glycol) monovinyl ether (ppEO2) will result in non-fouling thin films, which are employed to immobilize streptavidin. By careful control of the thickness and the chemistry of ppEO2 films, the embedded streptavidin are able to bind the biotinylated oligonucleotides. The resulting DNA sensors show good resistance towards adsorption of both BSA and fibrinogen, and are employed to discriminate different DNA sequences from protein-containing sample solutions, as seen by surface plasmon enhanced fluorescence spectroscopy (SPFS). This result suggests that the present sensor is very promising for the detection of a DNA sequence from a complex solution.