Immunofunctionalisation of gold transducers for bacterial detection by physisorption.

摘要: Functionalisation of the sensing surface is a key factor in immunosensor fabrication as it allows target-selective capture and prevents nonspecific adsorption undesired components. Gold immunofunctionalisation using self-assembled monolayers (SAM) has been widely exploited to this end for detection small targets. However, we recently demonstrated that strategy fails when detecting whole bacteria cells (Baldrich et al., Anal Bioanal Chem 390:1557–1562, 2008). We now investigate different physisorption-based alternatives E. coli target organism. Our results demonstrate physisorption generates appropriate substrate specific on gold surfaces, providing limits down 105 mL−1 an ELISA-type colorimetric assay. Additionally, coverage highly reproducible assayed by impedance spectroscopy inter- intra-assay coefficients variation are below 10–15% all cases. These surfaces were stable, retained functionality did not suffer from significant biomolecule desorption after 10 days storage PBS at 37 °C, hence confirming cheap, simple efficient bacteria.