Microwave-accelerated metal-enhanced detection method
The present invention relates to systems and methods using microwave accelerated surface plasmonics for the detection of target species. The system has a metallic surface and the system is exposed to microwave energy for increasing detection time and/or the reaction kinetics of the target species and other interacting participants in the system so that plasmonic emissions from the metallic surface alone or coupled with emissions from a luminescing entity are detected.
1. A microwave-accelerated metal-enhanced method for detection of biological target species in a testing sample comprising:
a) providing a detection system comprising: a glass or polymeric surface substrate comprising a multiplicity of metallic nanostructures positioned thereon, wherein the metallic nanostructures are spherical-like particles having a diameter from about 10 nm to 60 nm, wherein the metallic nanostructures are modified with coupling agents for binding with target species suspected of being in the testing sample, and a fluorescing entity having binding affinity for a specific epitope, functional group or nucleotide sequence on the target species, wherein the target species comprises a protein, peptide, small molecule, or DNA;
b) introducing the testing sample to the glass or polymeric surface substrate comprising a multiplicity of metallic nanostructures positioned thereon, wherein the testing sample is suspected of containing at least one target species for binding with the coupling agents; and then applying microwave energy to the testing sample at low power to cause an increase in heat in the detection system and increase the binding kinetics of a chemical reaction between the target species in the testing sample and coupling agents, wherein the microwave energy has an intensity in a range of about 0.0001 μW/cm 2 to about 1000 μW/cm 2 and increases binding of any target species in the testing sample to the coupling agent;
c) introducing the fluorescing entity having binding affinity for the target species, wherein such fluorescing entity binds with any target species in the test sample and wherein the specific epitope, functional group or nucleotide sequence is located on the target species at a distance from the metallic nanostructures for positioning the fluorescing entity a distance from about 4 nm to about 30 nm from the metallic nanostructures upon binding of the fluorescing entity with the target species;
d) applying an excitation energy to at least the fluorescing entity; and
e) measuring a surface plasmonic emission spectrum from said metallic nanostructures and a fluorescence emission spectrum from said fluorescing entity; and
f) detecting, using a computer processor, the presence and amount of said biological target species based on said fluorescence emission spectra.
2. The detection method of claim 1 , wherein the microwaves have a frequency in a range of from about 10 8 to about 10 12 Hz.
3. The detection method of claim 1 , wherein the metallic nanostructures comprise metal selected from among gold, copper, silver, aluminum, and alloys including one or more of said metals.
4. The detection method of claim 1 , wherein said microwaves do not degrade the target and testing sample.
5. The detection method of claim 1 , wherein the spherical-like particles are positioned from at least about 50 nm from each other.