Optofluidic microsystem with quasi-3 dimensional gold plasmonic nanostructure arrays for online sensitive and reproducible SERS detection.
Practical applications of chemical and biological detections through surface-enhanced Raman scattering (SERS) require high reproducibility, sensitivity, and efficiency, along with low-cost, straightforward fabrication. In this work, we integrated a poly-(dimethylsiloxane) (PDMS) chip with quasi-3D gold plasmonic nanostructure arrays (Q3D-PNAs), which serve as SERS-active substrates, into an optofluidic microsystem for online sensitive and reproducible SERS detections. The Q3D-PNA PDMS chip was fabricated through soft lithography to ensure both precision and low-cost fabrication. The optimal dimension of the Q3D-PNA in PDMS was designed using finite-difference time-domain (FDTD) electromagnetic simulations with a simulated enhancement factor (EF) of 1.6×10(6). The real-time monitoring capability of the SERS-based optofluidic microsystem was investigated by kinetic on/off experiments through alternatively flowing Rhodamine 6G (R6G) and ethanol in the microfluidic channel. A switch-off time of ∼2 min at a flow rate of 0.3 mL min(-1) was demonstrated. When applied to the detection of low concentration malathion, the SERS-based optofluidic microsystem with Q3D-PNAs showed high reproducibility, significantly improved efficiency and higher detection sensitivity via increasing the flow rate. The optofluidic microsystem presented in this paper offers a simple and low-cost approach for online, label-free chemical and biological analysis and sensing with high sensitivity, reproducibility, efficiency, and molecular specificity.
Department of Chemical Engineering, University of Washington, Seattle, WA 98195, USA; State Key Laboratory of Precision Measurement Technology and Instruments, Department of Precision Instruments, Tsinghua University, Beijing 100084, PR China. Electronic address: dengy2000@tsinghua.edu.cn.
Yan
Y
Deng
Department of Chemical Engineering, University of Washington, Seattle, WA 98195, USA.
Matthew N
MN
Idso
Department of Chemical Engineering, University of Washington, Seattle, WA 98195, USA.
Daniel D
DD
Galvan
Department of Chemical Engineering, University of Washington, Seattle, WA 98195, USA. Electronic address: qyu@u.washington.edu.
Qiuming
Q
Yu
D004129:Dimethylpolysiloxanes / Q000737:chemistry; D006046:Gold / Q000737:chemistry*; D020407:Internet / Q000191:economics; D008294:Malathion / Q000032:analysis*; D053768:Metal Nanoparticles / Q000737:chemistry*; D046210:Microfluidic Analytical Techniques / Q000191:economics / Q000295:instrumentation; D013059:Spectrum Analysis, Raman / Q000295:instrumentation; D013499:Surface Properties
D004129:Dimethylpolysiloxanes; C013830:baysilon; D006046:Gold; D008294:Malathion
Online detection; Optofluidic microsystem; Plasmonic nanostructure; Surface-enhanced Raman scattering (SERS)