Frequency shifts in SERS for biosensing.
We report an observation of a peculiar effect in which the vibrational frequencies of antibody-conjugated SERS-active reporter molecules are shifted in quantitative correlation with the concentration of the targeted antigen. We attribute the frequency shifts to mechanical perturbations in the antibody-reporter complex, as a result of antibody-antigen interaction forces. Our observation thus demonstrates the potentiality of an antibody-conjugated SERS-active reporter complex as a SERS-active nanomechanical sensor for biodetection. Remarkably, our sensing scheme, despite employing only one antibody, was found to be able to achieve detection sensitivity comparable to that of a conventional sandwich immunoassay. Additionally, we have carried out a proof-of-concept study into using multiple "stress-sensitive" SERS reporters for multiplexed detection of antigen-antibody bindings at the subdiffraction limit. The current work could therefore pave the way to realizing a label-free high-density protein nanoarray.
The Blackett Laboratory, Imperial College London, Prince Consort Road, London, UK.
Kiang Wei
KW
Kho
U S
US
Dinish
Anil
A
Kumar
Malini
M
Olivo
D015374:Biosensing Techniques / Q000295:instrumentation*; D004867:Equipment Design; D019544:Equipment Failure Analysis; D007118:Immunoassay / Q000295:instrumentation*; D036103:Nanotechnology / Q000295:instrumentation*; D040081:Protein Array Analysis / Q000295:instrumentation*; D013059:Spectrum Analysis, Raman / Q000295:instrumentation*