Use of surfaces functionalized with phage tailspike proteins to capture and detect bacteria in biosensors and bioassays

Abstract

The food safety and human diagnostics markets are in need of faster working, reliable, sensitive, specific, low cost bioassays and biosensors for bacterial detection. This thesis reports the use of P22 bacteriophage tailspike proteins (TSP) immobilized on silanized silicon surfaces, roughened at a nano-scale, for specific capture and detection of Salmonella.

Towards developing TSP biosensors, TSP immobilization characteristics were studied, and methods to improve bacterial capture were explored. Atomic force microscopy was used to count TSP immobilized on gold thin-films. Surface density counts are dependent on the immobilization scheme used.

TSP immobilized on flat silicon (Si), silanized with 3-aminopropyltriethoxysilane and activated with glutaraldehyde, showed half the bacterial capture of gold thin-films. To improve bacterial capture, roughened mountain-shaped ridge-covered silicon (MSRCS) surfaces were coated with TSP and tested. Measurements of their bacterial surface density show that such MSRCS surfaces can produce bacterial capture close to or better than TSP-coated gold thin-films.