| AVS 55th International Symposium & Exhibition | |
| Nanometer-scale Science and Technology | Wednesday Sessions |
| Session NS+NC-WeA |
| Session: | Nanoscale Devices and Sensors |
| Presenter: | A. Singh, University of Alberta, Canada |
| Authors: | A. Singh, University of Alberta, Canada N. Glass, National Institute for Nanotechnology NRC, Canada L. Gervais, National Institute for Nanotechnology NRC, Canada M. Gel, National Institute for Nanotechnology NRC, Canada M. Tolba, University of Guelph, Canada L. Brovko, University of Guelph, Canada M. Griffiths, University of Guelph, Canada S. Evoy, National Institute for Nanotechnology NRC, Canada |
| Correspondent: | Click to Email |
Bacteriophages are class of viruses that infect bacteria and use them as a host for replication. These phages are highly bacterial-strain specific and thus have the potential to be used as naturally sensitive and selective probes for the detection of pathogens. We have already reported the use of the biotin-streptavidin affinity to immobilize biotinylated phages onto gold surfaces. However, the need of genetic modification limits the versatility of this approach. Thus, there is a need to develop a simple universal process to immobilize phages onto sensor surfaces. We studied different surface modification protocols for gold substrates and their efficiency to capture phages and subsequently the bacteria was analyzed by using SEM and Fluorescence Microscopy. Wild type T4 phage was chosen as the model system for the study with E. coli EC12 strain as the host bacteria. Control experiments were performed with 3 non-host bacterial strains (E. coli 6M1N1, NP 30 and NP 10) to ensure specificity and selectivity of the system. The thiol binding chemistry on gold surfaces was utilized to modify the surface by using cysteine and cysteamine. The results revealed that the gold surfaces modified with cysteine or cysteamine and further activated by treatment with gluteraldegyde enables best phages density and bacteria capture as compared to other modifications. The SEM study for phage immobilization shows that a surface density of 15 ± 3 phages/µm2 was obtained. In our previous work, the biotin-streptavidin interaction was used to immobilize biotin expressing genetically-engineered phages which gave us a surface density of 10 ± 5 phages/µm2. Thus, the surface modification of the substrate enables a better phage density. The protocol was then duplicated on to a gold-coated cantilever surface, which again showed successful phage immobilization and subsequent bacterial capture. Microcantilever-based detection has been shown to have a mass sensitivity equivalent to that of a single bacterium. The shift in the resonance peaks of the cantilever, before and after the treatment of phage immobilized surface to bacteria, has been used as a measure to confirm bacterial capture. Thus, we illustrate a universal approach towards specific capture and detection of pathogenic bacteria, which could be potentially be employed in numerous sensing platforms such as microresonators, surface plasmon resonance, and quartz-crystal microbalance.