文摘
We report the synthesis and characterization of gold鈥揵acteriophage hybrids for biodetection purposes. The physical and optical properties of gold nanoparticles (AuNPs) and the biological features of the phages offer a multifunctional scaffold with great potential for nanotechnologically based biomedical applications. AuNPs, stabilized (PEGylated) using heterobifunctional polyethylene glycol (PEG), were coupled to methicillin-resistant S. aureus-specific phages. The PEG ligands contain a thiol group for stable anchoring to the gold surface and a terminal carboxylic acid group for further coupling to the outside of the PEG shell by carbodiimide chemistry. Transmission electron microscopic analysis showed that the NP鈥損hage bioconjugates are highly stable, with a median diameter of 90 nm. X-ray photoelectron spectroscopy was used to chemically characterize the surfaces of the PEG-functionalized AuNPs, the bacteriophages, and the gold鈥損hage hybrids. The role of the interface and the covalent coupling chemistry employed to attach the phages to the AuNPs have been delineated. Successful attachment of phages to AuNPs was confirmed by the presence of amide between the primary amines of the phages and the carboxylic acid terminal groups of the NPs and by the presence of carboxyl and amine species, which form hydrogen bonds.