Reagent- and separation-free measurements of urine creatinine concentration using stamping surface enhanced Raman scattering (S-SERS)

Abstract

We report a novel reagent- and separation-free method for urine creatinine concentration measurement using stamping surface enhanced Raman scattering (S-SERS) technique with nanoporous gold disk (NPGD) plasmonic substrates, a label-free, multiplexed molecular sensing and imaging technique recently developed by us. The performance of this new technology is evaluated by the detection and quantification of creatinine spiked in three different liquids: creatinine in water, mixture of creatinine and urea in water, and creatinine in artificial urine within physiologically relevant concentration ranges. Moreover, the potential application of our method is demonstrated by creatinine concentration measurements in urine samples collected from a mouse model of nephritis. The limit of detection of creatinine was 13.2 nM (0.15 µg/dl) and 0.68 mg/dl in water and urine, respectively. Our method would provide an alternative tool for rapid, cost-effective, and reliable urine analysis for non-invasive diagnosis and monitoring of renal function.

Fabricating optical lenses by inkjet printing and heat-assistedin situcuring of polydimethylsiloxane for smartphone microscopy

“…4 PDMS has been employed to construct microfluidic devices since the 1990s, 5 and still maintains its wide applicability to date. [6][7][8][9][10] As a lens material, three types of fabrication techniques have been adopted: (1) lithographic methods, 11 (2) surface tension driven methods, 12 and (3) embossing methods. 13 These current approaches demonstrate the feasibility of creating PDMS lenses with good optical characteristics and reproducibility; however, they either require time-consuming fabrication procedures typically measured in hours, or have high costs due to lithographic and molding equipment required, and generally limit the size of the lens to the micrometer scale.…”

3D Plasmonic Nanoarchitecture As an Emerging Biosensing Platform

“…LSPR associated local field concentration has been shown to enhance a variety of electronic as well as vibrational spectroscopic techniques. Among those, prominent examples can be drawn from Raman scattering, infrared and near-infrared (NIR) absorption and fluorescence [8][9][10][11].…”

“…NPG arrays have been demonstrated in various plasmonic sensing mechanisms such as refractive index sensing via extinction spectroscopy, as well as spectroscopic fingerprinting by enhanced fluorescence, NIR absorption, and Raman spectroscopy [8][9][10][11]14]. A number of label-free biosensing applications have been developed in the past 4 years for nucleic acids, proteins, enzymes, metabolites, neurotransmitters, polycyclic aromatic hydrocarbons, carcinogenic environmental and food contaminants, and etc [11,[19][20][21][22][23].…”

“…LSPR associated local field concentration has been shown to enhance a variety of electronic as well as vibrational spectroscopic techniques. Among those, prominent examples can be drawn from Raman scattering, infrared and near-infrared (NIR) absorption and fluorescence [8][9][10][11].Traditional plasmonic nanomaterials are 1D (e.g., colloidal nanoparticles) or 2D (lithographically patterned nanostructure arrays) in nature, which typically result in sparse field concentration patterns. To improve efficiency and better utilization of hot-spots, the concept of 3D plasmonic nanoarchitecture, where abundant hot-spots are formed in a 3D volumetric fashion, have emerged [12].…”

Utilizing dynamic laser speckle to probe nanoscale morphology evolution in nanoporous gold thin films

“…Nanoporous gold (np-Au) is a porous metal produced through an alloy corrosion process, known as dealloying, that removes a less noble metal and leaves a three dimensional porous network of nanoscale Au ligaments and pores. Recently np-Au has received attention for its uses in biosensors, neural interfaces, catalysis, tunable molecular release, and the ease of morphology modification via photothermal treatment [11][12][13][14][15][16][17]. Through the thermal treatment of np-Au it is possible to selectively evolve the Au network thereby altering the characteristic morphology [18], an attractive feature for many emerging np-Au applications.…”