title: Convenient formation of nanoparticle aggregates on microfluidic chips for highly sensitive SERS detection of biomolecules.
abstract: Microfluidic chips combined with surface-enhanced Raman spectroscopy (SERS) offer an outstanding platform for rapid and high-sensitivity chemical analysis. However, it is nontrivial to conveniently form nanoparticle aggregrates (as SERS-active spots for SERS detection) in microchannels in a well-controlled manner. Here, we present a rapid, highly sensitive and label-free analytical technique for determining bovine serum albumin (BSA) on a poly(dimethylsiloxane) (PDMS) microfluidic chip using SERS. A modified PDMS pneumatic valve and nanopost arrays at the bottom of the fluidic microchannel are used for reversibly trapping gold nanoparticles to form gold aggregates, creating SERS-active spots for Raman detection. We fabricated a chip that consisted of a T-shaped fluidic channel and two modified pneumatic valves, which was suitable for fast loading of samples. Quantitative analysis of BSA is demonstrated with the measured peak intensity at 1,615 cm(-1) in the surface-enhanced Raman spectra. With our microfluidic chip, the detection limit of Raman can reach as low as the picomolar level, comparable to that of normal mass spectrometry.
authors: Department of Chemistry, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, China.
authors: Jianhua
authors: J
authors: Zhou
authors: Kangning
authors: K
authors: Ren
authors: Yihua
authors: Y
authors: Zhao
authors: Wen
authors: W
authors: Dai
authors: Hongkai
authors: H
authors: Wu
mesh_terms: D000818:Animals; D002417:Cattle; D004867:Equipment Design; D057230:Limit of Detection; D046210:Microfluidic Analytical Techniques / Q000295:instrumentation*; D053758:Nanoparticles / Q000032:analysis* / Q000648:ultrastructure; D012710:Serum Albumin, Bovine / Q000032:analysis*; D013059:Spectrum Analysis, Raman / Q000295:instrumentation*
chemical_list: D012710:Serum Albumin, Bovine