Microfluidic separation device

A microfluidic separation device comprising:

• a. a first sample channel region and a second sample channel region, wherein said first sample channel region comprises an array of channels that are smaller than said second channel region;
• b. a first detection region and a second detection region located at a planar interface of said first sample channel region;
• c. a detection channel;
• d. an illuminating electric field;
• e. Raman-scattering nanoparticles, wherein said Raman-scattering nanoparticles comprise surface plasmon resonances for detection when illuminated by said illuminating electric field, wherein said surface plasmon resonances create an enhanced local electric field along specific directions, wherein said enhanced local electric field results in an enhanced Raman response;
• and
• f. a Raman-scattering nanoparticle input channel disposed to input said Raman-scattering nanoparticles into said second sample channel region, wherein said Raman-scattering nanoparticles are larger than said cross-section of said first sample channel region and larger than said cross-section of said second detection region, wherein said Raman-scattering nanoparticles are disposed to collect in said first detection region to form region of densely packed said Raman-scattering nanoparticles.