Ultrahigh sensitivity made simple: nanoplasmonic label-free biosensing with an extremely low limit-of-detection for bacterial and cancer diagnostics.
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.
Department of Applied Physics, Chalmers University of Technology, Göteborg, Sweden.
S
S
Chen
M
M
Svedendahl
M
M
Käll
L
L
Gunnarsson
A
A
Dmitriev
D001426:Bacterial Proteins / Q000032:analysis*; D004867:Equipment Design; D006801:Humans; D057230:Limit of Detection; D008297:Male; D017430:Prostate-Specific Antigen / Q000032:analysis*; D016601:RNA-Binding Proteins / Q000032:analysis*; D013211:Staphylococcus aureus / Q000737:chemistry*; D020349:Surface Plasmon Resonance / Q000191:economics / Q000295:instrumentation / Q000379:methods*
D001426:Bacterial Proteins; C444739:Eap-N protein, Staphylococcus aureus; D016601:RNA-Binding Proteins; D017430:Prostate-Specific Antigen