Microfluidic fabrication of SERS-active microspheres for molecular detection.
In this paper, we demonstrated a microfluidic system for fabricating microspheres with hierarchical surface nanopatterns for molecular detection based on surface-enhanced Raman scattering (SERS). Briefly, a photocurable silica suspension was emulsified into monodisperse droplets using a microfluidic device composed of two coaxial glass capillaries. The silica particles in each droplet protruded through the interface and spontaneously formed a hexagonal array. After polymerization of the droplets, we selectively decorated the exposed areas of the silica particles with silver nanoparticles through electroless deposition. The resulting hierarchically-structured microspheres showed high sensitivity and fast binding kinetics in molecular detection based on SERS, owing to the dense array of hot spots on each microsphere and high mobility of the microspheres, respectively. Notably, the SERS signals from molecules adsorbed on the microspheres could be detected in both the dried and suspension states. In addition, we demonstrated that the SERS-active microspheres can be functionalized into structural colored or magnetoresponsive microspheres for advanced applications.
Hwang
Hyerim
H
National Creative Research Initiative Center for Integrated Optofluidic Systems, Department of Chemical and Biomolecular Engineering, KAIST, Daejeon 305-701, Korea.
Kim
Shin-Hyun
SH
Yang
Seung-Man
SM
D053768:Metal Nanoparticles / Q000737:chemistry / Q000648:ultrastructure; D046210:Microfluidic Analytical Techniques / Q000295:instrumentation / Q000379:methods*; D008863:Microspheres; D055616:Microtechnology / Q000295:instrumentation / Q000379:methods*; D049329:Nanostructures / Q000737:chemistry* / Q000648:ultrastructure; D012822:Silicon Dioxide / Q000737:chemistry*; D012834:Silver / Q000737:chemistry*; D013059:Spectrum Analysis, Raman / Q000379:methods*; D013499:Surface Properties
D012834:Silver; D012822:Silicon Dioxide