Ultrahigh sensitivity made simple: nanoplasmonic label-free biosensing with an extremely low limit-of-detection for bacterial and cancer diagnostics
Artikel i vetenskaplig tidskrift, 2009
We present a simple and robust scheme for biosensing with an ultralow limit-of-detection down
to several pg cm−2 (or several tens of attomoles cm−2) based on optical label-free biodetection
with localized surface plasmon resonances. The scheme utilizes cost-effective optical
components and comprises a white light source, a properly functionalized sensor surface
enclosed in a simple fluidics chip, and a spectral analyzer. The sensor surface is produced by a
bottom-up nanofabrication technique with hole mask colloidal lithography. Despite its
simplicity, the method is able to reliably detect protein–protein binding events at low picomolar
and femtomolar concentrations, which is exemplified by the label-free detection of the
extracellular adherence protein (EAP) found on the outer surface of the bacterium
Staphylococcus aureus and of prostate-specific antigen (PSA), which is believed to be a prostate
cancer marker. These experiments pave the way towards an ultra-sensitive yet compact
biodetection platform for point-of-care diagnostics applications.