Wenyue Li - Academia.edu (original) (raw)
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Papers by Wenyue Li
ACS sensors, Jan 23, 2018
The development of high performing and accessible sensors is crucial to future point-of-care diag... more The development of high performing and accessible sensors is crucial to future point-of-care diagnostic sensing systems. Here, we report on a gold-titanium dioxide-gold metal-insulator-metal plasmonic nanocup array device for spectrometer-free refractometric sensing with a performance exceeding conventional surface plasmon resonance sensors. This device shows distinct spectral properties such that a superstrate refractive index increase causes a transmission intensity increase at the peak resonance wavelength. There is no spectral shift at this peak and there are spectral regions with no transmission intensity change, which can be used as internal device references. The sensing mechanism, plasmon-cavity coupling optimization, and material properties are studied using electromagnetic simulations. The optimal device structure is determined using simulation and experimental parameter sweeps to tune the cavity confinement and the resonance coupling. An experimental sensitivity of 800 ΔT...
The Journal of Physical Chemistry C, 2018
The advancement of SERS as an analytical tool requires substrates that provide both sensitive and... more The advancement of SERS as an analytical tool requires substrates that provide both sensitive and reproducible measurements. In this work, a gold-titanium dioxide-gold metalinsulator-metal capped polymer nanopillar array SERS substrate is presented and optimized for SERS-based biosensing applications. The optical properties of the multilayered nanoantenna array are investigated using a combination of simulation and experimental studies. It is found that hot spot engineering, the plasmon resonance of the array, and cavity structure optimization all contribute to fundamental SERS sensor properties such as enhancement factor and enhancement factor uniformity, which are critically studied using this highly tunable device. A spatially averaged enhancement factor of (2.4 ± 0.8) x 10 7 with sufficient error for quantitative studies is demonstrated at an excitation wavelength of 633 nm. The label-free detection of protein-protein interactions on the metal-insulator-metal nanopillar array surface is then demonstrated including for the cancer biomarker cancer antigen 125 at a concentration of 100 ng/mL.
Lab on a Chip, 2013
Smartphone-based optical detection is a potentially easy-to-use, handheld, true point-of-care dia... more Smartphone-based optical detection is a potentially easy-to-use, handheld, true point-of-care diagnostic tool for the early and rapid detection of pathogens. Paper microfluidics is a low-cost, field-deployable, and easy-to-use alternative to conventional microfluidic devices. Most paper-based microfluidic assays typically utilize dyes or enzyme-substrate binding, while bacterial detection on paper microfluidics is rare. We demonstrate a novel application of smartphone-based detection of Salmonella on paper microfluidics. Each paper microfluidic channel was pre-loaded with anti-Salmonella Typhimurium and anti-Escherichia coli conjugated submicroparticles. Dipping the paper microfluidic device into the Salmonella solutions led to the antibody-conjugated particles that were still confined within the paper fibers to immunoagglutinate. The extent of immunoagglutination was quantified by evaluating Mie scattering from the digital images taken at an optimized angle and distance with a smartphone. A smartphone application was designed and programmed to allow the user to position the smartphone at an optimized angle and distance from the paper microfluidic device, and a simple image processing algorithm was implemented to calculate and display the bacterial concentration on the smartphone. The detection limit was single-cell-level and the total assay time was less than one minute.
ACS sensors, Jan 23, 2018
The development of high performing and accessible sensors is crucial to future point-of-care diag... more The development of high performing and accessible sensors is crucial to future point-of-care diagnostic sensing systems. Here, we report on a gold-titanium dioxide-gold metal-insulator-metal plasmonic nanocup array device for spectrometer-free refractometric sensing with a performance exceeding conventional surface plasmon resonance sensors. This device shows distinct spectral properties such that a superstrate refractive index increase causes a transmission intensity increase at the peak resonance wavelength. There is no spectral shift at this peak and there are spectral regions with no transmission intensity change, which can be used as internal device references. The sensing mechanism, plasmon-cavity coupling optimization, and material properties are studied using electromagnetic simulations. The optimal device structure is determined using simulation and experimental parameter sweeps to tune the cavity confinement and the resonance coupling. An experimental sensitivity of 800 ΔT...
The Journal of Physical Chemistry C, 2018
The advancement of SERS as an analytical tool requires substrates that provide both sensitive and... more The advancement of SERS as an analytical tool requires substrates that provide both sensitive and reproducible measurements. In this work, a gold-titanium dioxide-gold metalinsulator-metal capped polymer nanopillar array SERS substrate is presented and optimized for SERS-based biosensing applications. The optical properties of the multilayered nanoantenna array are investigated using a combination of simulation and experimental studies. It is found that hot spot engineering, the plasmon resonance of the array, and cavity structure optimization all contribute to fundamental SERS sensor properties such as enhancement factor and enhancement factor uniformity, which are critically studied using this highly tunable device. A spatially averaged enhancement factor of (2.4 ± 0.8) x 10 7 with sufficient error for quantitative studies is demonstrated at an excitation wavelength of 633 nm. The label-free detection of protein-protein interactions on the metal-insulator-metal nanopillar array surface is then demonstrated including for the cancer biomarker cancer antigen 125 at a concentration of 100 ng/mL.
Lab on a Chip, 2013
Smartphone-based optical detection is a potentially easy-to-use, handheld, true point-of-care dia... more Smartphone-based optical detection is a potentially easy-to-use, handheld, true point-of-care diagnostic tool for the early and rapid detection of pathogens. Paper microfluidics is a low-cost, field-deployable, and easy-to-use alternative to conventional microfluidic devices. Most paper-based microfluidic assays typically utilize dyes or enzyme-substrate binding, while bacterial detection on paper microfluidics is rare. We demonstrate a novel application of smartphone-based detection of Salmonella on paper microfluidics. Each paper microfluidic channel was pre-loaded with anti-Salmonella Typhimurium and anti-Escherichia coli conjugated submicroparticles. Dipping the paper microfluidic device into the Salmonella solutions led to the antibody-conjugated particles that were still confined within the paper fibers to immunoagglutinate. The extent of immunoagglutination was quantified by evaluating Mie scattering from the digital images taken at an optimized angle and distance with a smartphone. A smartphone application was designed and programmed to allow the user to position the smartphone at an optimized angle and distance from the paper microfluidic device, and a simple image processing algorithm was implemented to calculate and display the bacterial concentration on the smartphone. The detection limit was single-cell-level and the total assay time was less than one minute.