Fast and sensitive detection of an anthrax biomarker using SERS-based solenoid microfluidic sensor

We report the application of a fully automated surface-enhanced Raman scattering (SERS)-based solenoid-embedded microfluidic device to the quantitative and sensitive detection of anthrax biomarker poly-γ-d-glutamic acid (PGA) in solution. Analysis is based on the competitive reaction between PGA and PGA-conjugated gold nanoparticles with anti-PGA-immobilized magnetic beads within a microfluidic environment. Magnetic immunocomplexes are trapped by yoke-type solenoids embedded within the device, and their SERS signals were directly measured and analyzed. To improve the acccuracy of measurement process, external standard values for PGA-free serum were also measured through use of a control channel. This additional measurement greatly improves the reliability of the assay by minimizing the influence of extraneous experimental variables. The limit of detection (LOD) of PGA in serum, determined by our SERS-based microfluidic sensor, is estimated to be 100pg/mL. We believe that the defined method represents a valuable analytical tool for the detection of anthrax-related aqueous samples. •SERS-based microfluidic device was developed for sensitive anthrax biomarker detection.•Its LOD is three orders of magnitude more sensitive than corresponding ELISA method.•This technique shows potential for the rapid and sensitive detection of hazardous materials.