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

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

Biosensors & bioelectronics (2015-05-20)
Rongke Gao, Juhui Ko, Kiweon Cha, Jun Ho Jeon, Gi-eun Rhie, Jonghoon Choi, Andrew J deMello, Jaebum Choo
ABSTRACT

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 accuracy 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 100 pg/mL. We believe that the defined method represents a valuable analytical tool for the detection of anthrax-related aqueous samples.

MATERIALS
Product Number
Brand
Product Description

Sigma-Aldrich
Poly(dimethylsiloxane), viscosity 1.0 cSt (25 °C)
Sigma-Aldrich
Hexamethyldisiloxane, viscosity 0.65 cSt (25 °C)
Sigma-Aldrich
N-(3-Dimethylaminopropyl)-N′-ethylcarbodiimide, ≥97.0% (T)
Sigma-Aldrich
1,2-Dichloroethane, anhydrous, 99.8%
Sigma-Aldrich
N-Hydroxysuccinimide, 98%