Application of silver nanoparticles and CdSe quantum dots sensitized with of C-like lectin for detection of St. aureus. Comparison of various approaches.

C-type lectin from hen egg shell as a recognition ligand for detection of St. aureus was applied. Three approaches for detection of bacteria were used and the sensitivities of the assays were compared. Two of them included spherical and anisotropic silver nanoparticles sensitized by lectin. In these cases the optical changes as a result of interaction of sensitized nanoparticles with bacteria were measured. In the third approach hybrid system of CdSe quantum dots-anisotropic silver nanoparticles sensitized by lectin was applied. Here fluorescent changes as a result of resonance energy transfer between nanoparticles as consequence of their interaction with bacteria were measured. The data demonstrate that assays with spherical silver nanoparticles permit to detect St. aureus in the range of 6 × 104 /mL-2 × 107 /mL, anisotropic silver nanoparticles in the range of 2 × 105 /mL-1 × 108 /mL, CdSe-Ag hybrid system in the range of 6 × 103 /mL-2 × 107 /mL. The data demonstrate that hybrid system CdSe-Ag with resonance energy transfer provides the best sensitivity.