Yu-Hwa Lo - Academia.edu (original) (raw)

Papers by Yu-Hwa Lo

Research paper thumbnail of Computational cell analysis for label-free detection of cell properties in a microfluidic laminar flow

Research paper thumbnail of Measuring Electric Charge and Molecular Coverage on Electrode Surface from Transient Induced Molecular Electronic Signal (TIMES)

Scientific Reports, Nov 7, 2019

Research paper thumbnail of Nucleic Acid Aptamers: An Emerging Tool for Biotechnology and Biomedical Sensing

Research paper thumbnail of Micro-fabricated fluorescence-activated cell sorter

Research paper thumbnail of Session III. Biomedical imaging and AO.-Medical Imaging Systems Using Bio-Inspired Fluidic Lenses

Research paper thumbnail of Non-Invasive Blood Flow Speed Measurement Using Optics

Research paper thumbnail of Label-free image-encoded microfluidic cell sorter with a scanning Bessel beam

APL photonics, Jul 1, 2021

Research paper thumbnail of Image-guided cell sorting using fast scanning lasers

APL photonics, Apr 1, 2020

Research paper thumbnail of Array atomic force microscopy for real-time multiparametric analysis

Proceedings of the National Academy of Sciences of the United States of America, Mar 8, 2019

Research paper thumbnail of High Sensitivity, Rapid Detection of Virus in High Traffic Environments

Frontiers in Bioengineering and Biotechnology

The global pandemic caused by the SARS-CoV-2 virus has underscored the need for rapid, simple, sc... more The global pandemic caused by the SARS-CoV-2 virus has underscored the need for rapid, simple, scalable, and high-throughput multiplex diagnostics in non-laboratory settings. Here we demonstrate a multiplex reverse-transcription loop-mediated isothermal amplification (RT-LAMP) coupled with a gold nanoparticle-based lateral flow immunoassay (LFIA) capable of detecting up to three unique viral gene targets in 15 min. RT-LAMP primers associated with three separate gene targets from the SARS-CoV-2 virus (Orf1ab, Envelope, and Nucleocapsid) were added to a one-pot mix. A colorimetric change from red to yellow occurs in the presence of a positive sample. Positive samples are run through a LFIA to achieve specificity on a multiplex three-test line paper assay. Positive results are indicated by a characteristic crimson line. The device is almost fully automated and is deployable in any community setting with a power source.

Research paper thumbnail of Cameraless High-throughput 3D Imaging Flow Cytometry

The limitation of today's imaging flow cytometer (IFC) systems is resulted from the projectio... more The limitation of today's imaging flow cytometer (IFC) systems is resulted from the projection problem: collapsing 3D information onto a 2D image causes lack of tomographic three-dimensional (3D) resolution and reduced information contents, limiting the reliability of spot counting or co-localization crucial to cell phenotyping. We present a solution to the problem by demonstrating three-dimensional imaging flow cytometry (3D-IFC), a high-throughput 3D cell imager based on optical sectioning microscopy. We combine orthogonal light-sheet scanning illumination with our previous spatiotemporal transformation detection to produce 3D cell image reconstruction from a cameraless single-pixel photodetector readout. We demonstrate this capability by co-capturing 3D fluorescence and label-free side-scattering images of single cells in flow with a throughput of approximately 500 cells per second.

Research paper thumbnail of Perovskite superlattices with efficient carrier dynamics

Compared with their three-dimensional counterparts, low-dimensional metal halide perovskites with... more Compared with their three-dimensional counterparts, low-dimensional metal halide perovskites with periodic inorganic/organic structures have shown promising stability and hysteresis-free electrical performance, which paves the way for next-generation optoelectronic devices. However, when integrated in devices, they have relatively limited efficiencies because devices usually require carrier transport through the film thickness direction. In conventionally grown single crystals, the carrier transport in the thickness direction is hindered by the insulating organic spacers. In addition, the strong quantum confinement from the organic spacers limits the generation and transport of free carriers. The carrier dynamics is further compromised by the presence of grain boundaries in polycrystals. Here, we report a low-dimensional metal halide perovskite superlattice with efficient carrier transport in three dimensions by epitaxial growth. Epitaxy on a slightly lattice-mismatched substrate co...

Research paper thumbnail of Minimizing Iridium Oxide Electrodes for High Visual Acuity Subretinal Stimulation

eneuro, 2021

Vision loss from diseases of the outer retina, such as age-related macular degeneration, is among... more Vision loss from diseases of the outer retina, such as age-related macular degeneration, is among the leading causes of irreversible blindness in the world today. The goal of retinal prosthetics is to replace the photo-sensing function of photoreceptors lost in these diseases with optoelectronic hardware to electrically stimulate patterns of retinal activity corresponding to vision. To enable high-resolution retinal prosthetics, the scale of stimulating electrodes must be significantly decreased from current designs; however, this reduces the amount of stimulating current that can be delivered. The efficacy of subretinal stimulation at electrode sizes suitable for high visual acuity retinal prosthesis are not well understood, particularly within the safe charge injection limits of electrode materials. Here, we measure retinal ganglion cell (RGC) responses in a mouse model of blindness to evaluate the stimulation efficacy of 10, 20, and 30 μm diameter iridium oxide electrodes within ...

Research paper thumbnail of Differentiating and quantifying exosome secretion from a single cell using quasi-bound states in the continuum

Nanophotonics, 2020

One of the key challenges in biology is to understand how individual cells process information an... more One of the key challenges in biology is to understand how individual cells process information and respond to perturbations. However, most of the existing single-cell analysis methods can only provide a glimpse of cell properties at specific time points and are unable to provide cell secretion and protein analysis at single-cell resolution. To address the limits of existing methods and to accelerate discoveries from single-cell studies, we propose and experimentally demonstrate a new sensor based on bound states in the continuum to quantify exosome secretion from a single cell. Our optical sensors demonstrate high-sensitivity refractive index detection. Because of the strong overlap between the medium supporting the mode and the analytes, such an optical cavity has a figure of merit of 677 and sensitivity of 440 nm/RIU. Such results facilitate technological progress for highly conducive optical sensors for different biomedical applications.

Research paper thumbnail of Strain engineering and epitaxial stabilization of halide perovskites

Research paper thumbnail of Modeling Gain Mechanisms in Amorphous Silicon due to efficient carrier multiplication and trap induced junction modulation

Journal of Lightwave Technology, 2019

Research paper thumbnail of In Vivo Photovoltaic Performance of a Silicon Nanowire Photodiode–Based Retinal Prosthesis

Investigative Opthalmology & Visual Science, 2018

Research paper thumbnail of Reversing Coffee-Ring Effect by Laser-Induced Differential Evaporation

Scientific reports, Jan 16, 2018

The coffee-ring effect, ubiquitously present in the drying process of aqueous droplets, impedes t... more The coffee-ring effect, ubiquitously present in the drying process of aqueous droplets, impedes the performance of a myriad of applications involving precipitation of particle suspensions in evaporating liquids on solid surfaces, such as liquid biopsy combinational analysis, microarray fabrication, and ink-jet printing, to name a few. We invented the methodology of laser-induced differential evaporation to remove the coffee-ring effect. Without any additives to the liquid or any morphology modifications of the solid surface the liquid rests on, we have eliminated the coffee-ring effect by engineering the liquid evaporation profile with a CO laser irradiating the apex of the droplets. The method of laser-induced differential evaporation transitions particle deposition patterns from coffee-ring patterns to central-peak patterns, bringing all particles (e.g. fluorescent double strand DNAs) in the droplet to a designated area of 100 μm diameter without leaving any stains outside. The te...

Research paper thumbnail of Quantitative Analysis of Exosome Secretion Rates of Single Cells

Research paper thumbnail of Medical Imaging Systems Using Bio-Inspired Fluidic Lenses

Optics in the Life Sciences, 2011

Research paper thumbnail of Computational cell analysis for label-free detection of cell properties in a microfluidic laminar flow

Research paper thumbnail of Measuring Electric Charge and Molecular Coverage on Electrode Surface from Transient Induced Molecular Electronic Signal (TIMES)

Scientific Reports, Nov 7, 2019

Research paper thumbnail of Nucleic Acid Aptamers: An Emerging Tool for Biotechnology and Biomedical Sensing

Research paper thumbnail of Micro-fabricated fluorescence-activated cell sorter

Research paper thumbnail of Session III. Biomedical imaging and AO.-Medical Imaging Systems Using Bio-Inspired Fluidic Lenses

Research paper thumbnail of Non-Invasive Blood Flow Speed Measurement Using Optics

Research paper thumbnail of Label-free image-encoded microfluidic cell sorter with a scanning Bessel beam

APL photonics, Jul 1, 2021

Research paper thumbnail of Image-guided cell sorting using fast scanning lasers

APL photonics, Apr 1, 2020

Research paper thumbnail of Array atomic force microscopy for real-time multiparametric analysis

Proceedings of the National Academy of Sciences of the United States of America, Mar 8, 2019

Research paper thumbnail of High Sensitivity, Rapid Detection of Virus in High Traffic Environments

Frontiers in Bioengineering and Biotechnology

The global pandemic caused by the SARS-CoV-2 virus has underscored the need for rapid, simple, sc... more The global pandemic caused by the SARS-CoV-2 virus has underscored the need for rapid, simple, scalable, and high-throughput multiplex diagnostics in non-laboratory settings. Here we demonstrate a multiplex reverse-transcription loop-mediated isothermal amplification (RT-LAMP) coupled with a gold nanoparticle-based lateral flow immunoassay (LFIA) capable of detecting up to three unique viral gene targets in 15 min. RT-LAMP primers associated with three separate gene targets from the SARS-CoV-2 virus (Orf1ab, Envelope, and Nucleocapsid) were added to a one-pot mix. A colorimetric change from red to yellow occurs in the presence of a positive sample. Positive samples are run through a LFIA to achieve specificity on a multiplex three-test line paper assay. Positive results are indicated by a characteristic crimson line. The device is almost fully automated and is deployable in any community setting with a power source.

Research paper thumbnail of Cameraless High-throughput 3D Imaging Flow Cytometry

The limitation of today's imaging flow cytometer (IFC) systems is resulted from the projectio... more The limitation of today's imaging flow cytometer (IFC) systems is resulted from the projection problem: collapsing 3D information onto a 2D image causes lack of tomographic three-dimensional (3D) resolution and reduced information contents, limiting the reliability of spot counting or co-localization crucial to cell phenotyping. We present a solution to the problem by demonstrating three-dimensional imaging flow cytometry (3D-IFC), a high-throughput 3D cell imager based on optical sectioning microscopy. We combine orthogonal light-sheet scanning illumination with our previous spatiotemporal transformation detection to produce 3D cell image reconstruction from a cameraless single-pixel photodetector readout. We demonstrate this capability by co-capturing 3D fluorescence and label-free side-scattering images of single cells in flow with a throughput of approximately 500 cells per second.

Research paper thumbnail of Perovskite superlattices with efficient carrier dynamics

Compared with their three-dimensional counterparts, low-dimensional metal halide perovskites with... more Compared with their three-dimensional counterparts, low-dimensional metal halide perovskites with periodic inorganic/organic structures have shown promising stability and hysteresis-free electrical performance, which paves the way for next-generation optoelectronic devices. However, when integrated in devices, they have relatively limited efficiencies because devices usually require carrier transport through the film thickness direction. In conventionally grown single crystals, the carrier transport in the thickness direction is hindered by the insulating organic spacers. In addition, the strong quantum confinement from the organic spacers limits the generation and transport of free carriers. The carrier dynamics is further compromised by the presence of grain boundaries in polycrystals. Here, we report a low-dimensional metal halide perovskite superlattice with efficient carrier transport in three dimensions by epitaxial growth. Epitaxy on a slightly lattice-mismatched substrate co...

Research paper thumbnail of Minimizing Iridium Oxide Electrodes for High Visual Acuity Subretinal Stimulation

eneuro, 2021

Vision loss from diseases of the outer retina, such as age-related macular degeneration, is among... more Vision loss from diseases of the outer retina, such as age-related macular degeneration, is among the leading causes of irreversible blindness in the world today. The goal of retinal prosthetics is to replace the photo-sensing function of photoreceptors lost in these diseases with optoelectronic hardware to electrically stimulate patterns of retinal activity corresponding to vision. To enable high-resolution retinal prosthetics, the scale of stimulating electrodes must be significantly decreased from current designs; however, this reduces the amount of stimulating current that can be delivered. The efficacy of subretinal stimulation at electrode sizes suitable for high visual acuity retinal prosthesis are not well understood, particularly within the safe charge injection limits of electrode materials. Here, we measure retinal ganglion cell (RGC) responses in a mouse model of blindness to evaluate the stimulation efficacy of 10, 20, and 30 μm diameter iridium oxide electrodes within ...

Research paper thumbnail of Differentiating and quantifying exosome secretion from a single cell using quasi-bound states in the continuum

Nanophotonics, 2020

One of the key challenges in biology is to understand how individual cells process information an... more One of the key challenges in biology is to understand how individual cells process information and respond to perturbations. However, most of the existing single-cell analysis methods can only provide a glimpse of cell properties at specific time points and are unable to provide cell secretion and protein analysis at single-cell resolution. To address the limits of existing methods and to accelerate discoveries from single-cell studies, we propose and experimentally demonstrate a new sensor based on bound states in the continuum to quantify exosome secretion from a single cell. Our optical sensors demonstrate high-sensitivity refractive index detection. Because of the strong overlap between the medium supporting the mode and the analytes, such an optical cavity has a figure of merit of 677 and sensitivity of 440 nm/RIU. Such results facilitate technological progress for highly conducive optical sensors for different biomedical applications.

Research paper thumbnail of Strain engineering and epitaxial stabilization of halide perovskites

Research paper thumbnail of Modeling Gain Mechanisms in Amorphous Silicon due to efficient carrier multiplication and trap induced junction modulation

Journal of Lightwave Technology, 2019

Research paper thumbnail of In Vivo Photovoltaic Performance of a Silicon Nanowire Photodiode–Based Retinal Prosthesis

Investigative Opthalmology & Visual Science, 2018

Research paper thumbnail of Reversing Coffee-Ring Effect by Laser-Induced Differential Evaporation

Scientific reports, Jan 16, 2018

The coffee-ring effect, ubiquitously present in the drying process of aqueous droplets, impedes t... more The coffee-ring effect, ubiquitously present in the drying process of aqueous droplets, impedes the performance of a myriad of applications involving precipitation of particle suspensions in evaporating liquids on solid surfaces, such as liquid biopsy combinational analysis, microarray fabrication, and ink-jet printing, to name a few. We invented the methodology of laser-induced differential evaporation to remove the coffee-ring effect. Without any additives to the liquid or any morphology modifications of the solid surface the liquid rests on, we have eliminated the coffee-ring effect by engineering the liquid evaporation profile with a CO laser irradiating the apex of the droplets. The method of laser-induced differential evaporation transitions particle deposition patterns from coffee-ring patterns to central-peak patterns, bringing all particles (e.g. fluorescent double strand DNAs) in the droplet to a designated area of 100 μm diameter without leaving any stains outside. The te...

Research paper thumbnail of Quantitative Analysis of Exosome Secretion Rates of Single Cells

Research paper thumbnail of Medical Imaging Systems Using Bio-Inspired Fluidic Lenses

Optics in the Life Sciences, 2011