Rapid and quantitative immunoassay for multiplexed and highly sensitive point-of-care diagnostics using rationally designed, self-assembled, SERS-active 3D superstructures

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Point-of-care diagnostics for personalized medicine requires rapid, quantitative, multiplexed and sensitive detection schemes. The current gold standard of immunoassays for protein detection is ELISA (enzyme-linked immuno-sorbent assay), which requires multiple time-consuming washing steps, signal amplification via the enzyme reaction and is restricted to one color with only limited sensitivity. The central aim of this proposal is to develop a novel platform for rapid and quantitative immunoassays for multiplexed and highly sensitive point-of-care diagnostics using surface-enhanced Raman scattering (SERS) nanotags/labels in combination with magnetic beads and microfluidics for capturing the target proteins and avoiding washing steps. 3D SERS-active glass-coated superstructures as novel SERS nanotags/labels will be synthesized via self-assembly of gold satellites on a gold nanorod core. The choice of optimal SERS-active 3D superstructures for use in assays will be guided by empirical structure-activity correlations in combination with computer simulations. Cytokines as a clinically relevant class of biomarkers will be used as a model system for establishing the SERS-based magnetic bead/microfluidic no-wash immunoassay in a portable configuration for point-of-care diagnostics. We aim at demonstrating the rapid and simultaneous detection of 5 different cytokines at femto- to attomolar concentrations. This analytical method is universally applicable to other target molecules by simply exchanging the corresponding ligands on the magnetic and SERS nanoparticles.