title: Gold nanoparticle incorporated inverse opal photonic crystal capillaries for optofluidic surface enhanced Raman spectroscopy.
abstract: Novel transducers are needed for point of care testing (POCT) devices which aim at facile, sensitive and quick acquisition of health related information. Recent advances in optofluidics offer tremendous opportunities for biological/chemical analysis using extremely small sample volumes. This paper demonstrates nanostructured capillary tubes for surface enhanced Raman spectroscopy (SERS) analysis in a flow-through fashion. The capillary tube integrates the SERS sensor and the nanofluidic structure to synergistically offer sample delivery and analysis functions. Inside the capillary tube, inverse opal photonic crystal (IO PhC) was fabricated using the co-assembly approach to form nanoscale liquid pathways. In the nano-voids of the IO PhC, gold nanoparticles were in situ synthesized and functioned as the SERS hotspots. The advantages of the flow-through SERS sensor are multifold. The capillary effect facilities the sample delivery process, the nanofluidic channels boosts the interaction of analyte and gold nanoparticles, and the PhC structure strengthens the optical field near the SERS hotspots and results in enhanced SERS signals from analytes. As an exemplary demonstration, the sensor was used to measure creatinein spiked in artificial urine samples with detection limit of 0.9 mg/dL.
authors.affiliation: State Key Laboratory of Bioelectronics, School of Biological Science and Medical Engineering, Southeast University, Nanjing 210096, China; Laboratory of Environment and Biosafety Research Institute of Southeast University in Suzhou, Suzhou 215123, China. Electronic address: xwzhao@seu.edu.cn.
authors.forename: Xiangwei
authors.initials: X
authors.lastname: Zhao
authors.affiliation: State Key Laboratory of Bioelectronics, School of Biological Science and Medical Engineering, Southeast University, Nanjing 210096, China; Laboratory of Environment and Biosafety Research Institute of Southeast University in Suzhou, Suzhou 215123, China.
authors.forename: Jiangyang
authors.initials: J
authors.lastname: Xue
authors.affiliation: State Key Laboratory of Bioelectronics, School of Biological Science and Medical Engineering, Southeast University, Nanjing 210096, China; Laboratory of Environment and Biosafety Research Institute of Southeast University in Suzhou, Suzhou 215123, China.
authors.forename: Zhongde
authors.initials: Z
authors.lastname: Mu
authors.affiliation: Department of Electrical and Computer Engineering, Iowa State University, Ames, IA 50011, USA.
authors.forename: Yin
authors.initials: Y
authors.lastname: Huang
authors.affiliation: Department of Electrical and Computer Engineering, Iowa State University, Ames, IA 50011, USA. Electronic address: menglu@iastate.edu.
authors.forename: Meng
authors.initials: M
authors.lastname: Lu
authors.affiliation: State Key Laboratory of Bioelectronics, School of Biological Science and Medical Engineering, Southeast University, Nanjing 210096, China; Laboratory of Environment and Biosafety Research Institute of Southeast University in Suzhou, Suzhou 215123, China. Electronic address: gu@seu.edu.cn.
authors.forename: Zhongze
authors.initials: Z
authors.lastname: Gu
mesh_terms: D003404:Creatinine / Q000652:urine*; D004867:Equipment Design; D006046:Gold / Q000737:chemistry*; D006801:Humans; D056656:Lab-On-A-Chip Devices; D007834:Lasers; D053768:Metal Nanoparticles / Q000737:chemistry* / Q000648:ultrastructure; D055096:Optical Devices; D000067716:Point-of-Care Testing; D013059:Spectrum Analysis, Raman / Q000295:instrumentation*; D016482:Urinalysis / Q000295:instrumentation*
chemical_list: D006046:Gold; D003404:Creatinine
keywords: Inverse opal photonic crystal (IO PhC); Optofluidics; Point-of-care testing (POCT); Surface enhanced Raman spectroscopy (SERS)