The Experts below are selected from a list of 522 Experts worldwide ranked by ideXlab platform
Ki-hun Jeong - One of the best experts on this subject based on the ideXlab platform.
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Colorimetric Schirmer Strip for tear glucose detection
BioChip Journal, 2017Co-Authors: Byoung-hoon Kang, Moonseong Park, Ki-hun JeongAbstract:Human tears have attracted attention with easy-accessible indicators of healthcare monitoring. Recently self-monitoring of tear glucose in place of blood glucose has been developed with microfluidic paper-based analysis for a non-invasive diagnosis of diabetes. However, most previous works still have many limitations in unstable sample collection, low sensitivity, and insufficient sample volume. Here, we report a colorimetric Schirmer Strip with preconcentration for tear glucose detection. A wax barrier on a paper Strip enables tear collection of a fixed quantity as well as biocompatible incorporation of tear collection and detection by preventing flow reversal of reagents. Additional solvent was injected on a sampling site after tear collection, which accumulates the dispersed glucose into active site by capillary-driven flow for signal amplification. Glucose concentration was quantitatively detected at 0.1-2 mM by using a simple colorimetric method without any further image processing. The color changes in glucose concentration were clearly distinguishable between normal and diabetic patient-level. The colorimetric paper Strip allows straightforward sensing platform for noninvasive diagnosis of diabetes and direct application of paper-based technology to the human body fluids.
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Plasmonic Schirmer Strip for Human Tear-Based Gouty Arthritis Diagnosis Using Surface-Enhanced Raman Scattering
ACS nano, 2016Co-Authors: Moonseong Park, Hyukjin Jung, Yong Jeong, Ki-hun JeongAbstract:Biomarkers in tear fluid have attracted much interest in daily healthcare sensing and monitoring. Recently, surface-enhanced Raman scattering (SERS) has enabled highly sensitive label-free detection of small molecules. However, a highly stable straightforward tear assay with superior sensitivity is still under development in tear collection and analysis. Here we report a plasmonic Schirmer Strip for on-demand, rapid, and simple identification of biomarkers in human tears. The diagnostic Strip features gold nanoislands directly and evenly formed on the top surface of cellulose fibers, which maintain a hygroscopic nature for an efficient collection of tear production as well as provide plasmonic enhancement in SERS signals for identification of tear molecules. The uric acid in human tears was quantitatively detected at physiological levels (25–150 μM) by using SERS. The experimental results also clearly reveal a strong linear correlation between uric acid level in both human tears and blood for gouty arthri...
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Plasmonic Schirmer Strip for Human Tear-Based Gouty Arthritis Diagnosis Using Surface-Enhanced Raman Scattering
2016Co-Authors: Moonseong Park, Hyukjin Jung, Yong Jeong, Ki-hun JeongAbstract:Biomarkers in tear fluid have attracted much interest in daily healthcare sensing and monitoring. Recently, surface-enhanced Raman scattering (SERS) has enabled highly sensitive label-free detection of small molecules. However, a highly stable straightforward tear assay with superior sensitivity is still under development in tear collection and analysis. Here we report a plasmonic Schirmer Strip for on-demand, rapid, and simple identification of biomarkers in human tears. The diagnostic Strip features gold nanoislands directly and evenly formed on the top surface of cellulose fibers, which maintain a hygroscopic nature for an efficient collection of tear production as well as provide plasmonic enhancement in SERS signals for identification of tear molecules. The uric acid in human tears was quantitatively detected at physiological levels (25–150 μM) by using SERS. The experimental results also clearly reveal a strong linear correlation between uric acid level in both human tears and blood for gouty arthritis diagnosis. This functional paper Strip enables noninvasive diagnosis of disease-related biomarkers and healthcare monitoring using human tears
Moonseong Park - One of the best experts on this subject based on the ideXlab platform.
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Colorimetric Schirmer Strip for tear glucose detection
BioChip Journal, 2017Co-Authors: Byoung-hoon Kang, Moonseong Park, Ki-hun JeongAbstract:Human tears have attracted attention with easy-accessible indicators of healthcare monitoring. Recently self-monitoring of tear glucose in place of blood glucose has been developed with microfluidic paper-based analysis for a non-invasive diagnosis of diabetes. However, most previous works still have many limitations in unstable sample collection, low sensitivity, and insufficient sample volume. Here, we report a colorimetric Schirmer Strip with preconcentration for tear glucose detection. A wax barrier on a paper Strip enables tear collection of a fixed quantity as well as biocompatible incorporation of tear collection and detection by preventing flow reversal of reagents. Additional solvent was injected on a sampling site after tear collection, which accumulates the dispersed glucose into active site by capillary-driven flow for signal amplification. Glucose concentration was quantitatively detected at 0.1-2 mM by using a simple colorimetric method without any further image processing. The color changes in glucose concentration were clearly distinguishable between normal and diabetic patient-level. The colorimetric paper Strip allows straightforward sensing platform for noninvasive diagnosis of diabetes and direct application of paper-based technology to the human body fluids.
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Plasmonic Schirmer Strip for Human Tear-Based Gouty Arthritis Diagnosis Using Surface-Enhanced Raman Scattering
ACS nano, 2016Co-Authors: Moonseong Park, Hyukjin Jung, Yong Jeong, Ki-hun JeongAbstract:Biomarkers in tear fluid have attracted much interest in daily healthcare sensing and monitoring. Recently, surface-enhanced Raman scattering (SERS) has enabled highly sensitive label-free detection of small molecules. However, a highly stable straightforward tear assay with superior sensitivity is still under development in tear collection and analysis. Here we report a plasmonic Schirmer Strip for on-demand, rapid, and simple identification of biomarkers in human tears. The diagnostic Strip features gold nanoislands directly and evenly formed on the top surface of cellulose fibers, which maintain a hygroscopic nature for an efficient collection of tear production as well as provide plasmonic enhancement in SERS signals for identification of tear molecules. The uric acid in human tears was quantitatively detected at physiological levels (25–150 μM) by using SERS. The experimental results also clearly reveal a strong linear correlation between uric acid level in both human tears and blood for gouty arthri...
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Plasmonic Schirmer Strip for Human Tear-Based Gouty Arthritis Diagnosis Using Surface-Enhanced Raman Scattering
2016Co-Authors: Moonseong Park, Hyukjin Jung, Yong Jeong, Ki-hun JeongAbstract:Biomarkers in tear fluid have attracted much interest in daily healthcare sensing and monitoring. Recently, surface-enhanced Raman scattering (SERS) has enabled highly sensitive label-free detection of small molecules. However, a highly stable straightforward tear assay with superior sensitivity is still under development in tear collection and analysis. Here we report a plasmonic Schirmer Strip for on-demand, rapid, and simple identification of biomarkers in human tears. The diagnostic Strip features gold nanoislands directly and evenly formed on the top surface of cellulose fibers, which maintain a hygroscopic nature for an efficient collection of tear production as well as provide plasmonic enhancement in SERS signals for identification of tear molecules. The uric acid in human tears was quantitatively detected at physiological levels (25–150 μM) by using SERS. The experimental results also clearly reveal a strong linear correlation between uric acid level in both human tears and blood for gouty arthritis diagnosis. This functional paper Strip enables noninvasive diagnosis of disease-related biomarkers and healthcare monitoring using human tears
Naresh Kumar - One of the best experts on this subject based on the ideXlab platform.
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Application of Scanning Electron Microscopy With Energy-Dispersive X-Ray Spectroscopy for Analyzing Ocular Surface Particles on Schirmer Strips
Cornea, 2017Co-Authors: Anuroop Avula, Anat Galor, Patricia Blackwelder, Melissa Carballosa-gautam, Abigail S. Hackam, Bennie Jeng, Naresh KumarAbstract:PURPOSE To demonstrate the application of scanning electron microscopy with energy-dispersive x-ray spectroscopy (SEM/EDS) for analyzing Schirmer Strips for particle concentration, size, morphology, and type distribution. METHODS A cross-sectional design was used. Patients were prospectively recruited from the Miami Veterans Affairs (VA) Healthcare System eye clinic, and they underwent a complete ocular surface examination. The size, type, and chemical composition of particulate matter on Schirmer Strips (from the left eye) were analyzed using SEM/EDS. RESULTS Schirmer Strips from all 6 patients showed particle loading, ranging from 1 to 33 particles, whereas the blank Schirmer Strip that served as a control showed no particle loading. Most particles were coarse, with an average size of 19.7 μm (95% confidence interval 15-24.4 μm). All samples contained organic particles (eg, pollen and mold), and 5 of the 6 samples contained nonorganic particles. The nonorganic particles were composed of silicon, minerals, and metals, including gold and titanium. The size of aluminum and iron particles was ≥62 μm, whereas the size of 2 other metals, zinc and gold, was smaller, that is,
Clayton J. Radke - One of the best experts on this subject based on the ideXlab platform.
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Human Lacrimal Production Rates from Modified Schirmer-Tear Test.
Optometry and vision science : official publication of the American Academy of Optometry, 2018Co-Authors: Young Hyun Kim, Meng C. Lin, Clayton J. RadkeAbstract:Author(s): Li, Songhao; Kim, Young Hyun; Li, Wing; Lin, Meng C; Radke, Clayton J | Abstract: SIGNIFICANCE:A simple methodology is presented to quantify basal tear production with a modified Schirmer-tear test. PURPOSE:We introduce a simple clinical procedure to measure quantitative basal tear-production flowrates, QL, from a modified Schirmer-tear test (STT). METHODS:Eight healthy subjects aged at least 18 years underwent modified STTs on both eyes for two visits each. Schirmer Strips were sheathed with transparent tape before insertion. Topical anesthetic minimized reflex tearing. Wetting lengths were measured every 30 s for 5 min; QL was calculated from the linear slope of wetting length versus time. Determination of QL requires mass-balance equations on the tear prism and Schirmer Strip with Strip imbibition kinetics obeying Darcy and Young-Laplace laws. RESULTS:Basal tear production rates varied from essentially 0 to about 2 μl/min. With some exceptions, right and left eyes showed similar tear production rates. CONCLUSIONS:By following the modified STT, QL is established with minimal additional effort over a standard Schirmer test. We predict and observe four different subtypes of imbibition kinetics depending on how short or long the time is for first appearance of the wetting front and on how fast or slow is tear production. For slow lacrimal production rates, the standard 5-min wetting length does not correlate with basal tear production.
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Human tear-production rate from closed-eye Schirmer-Strip capillary dynamics
Colloids and Surfaces A: Physicochemical and Engineering Aspects, 2017Co-Authors: R. Telles, Thomas J. Dursch, Meng C. Lin, Clayton J. RadkeAbstract:Abstract A Schirmer tear test (STT) is commonly used to gauge human tear production, especially when dry-eye symptoms present. In an STT, the rounded tip of a standardized paper Strip is inserted into the lower fornix of the eye, and the wetted length extending out from the lower lid is recorded after 5 min of eye closure. Longer wetted lengths suggest higher tear production rates. To date, however, there is no methodology to transform STT transient wetting lengths into basal tear- production rates. We develop a physical model to elucidate wetting kinetics in a Schirmer Strip. Tear evaporation from the exposed portion of the Strip and gravity are accounted for. Careful consideration of the initial depletion of tear in the closed-eye tear prism reveals an initial fast increase in wetted length followed by slower growth. Excellent agreement of the proposed model is achieved with experimental observation. When evaporation is negligible, the slow-growth regime exhibits a linear increase of wetted length in time. The linear-length-growth time regime permits simple calculation of quantitative tear-production rates. We suggest measuring several dynamic wetting lengths along a sheathed Schirmer Strip and near the 5-min insertion duration followed by fitting to a straight line. The slope of the length-versus-time data gives the basal lacrimal-supply rate.
Iris F. F. Benzie - One of the best experts on this subject based on the ideXlab platform.
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Water-soluble antioxidants in human tears : effect of the collection method
Investigative ophthalmology & visual science, 2001Co-Authors: Camus Kar Man Choy, Pauline Cho, Wai-yuen Chung, Iris F. F. BenzieAbstract:Purpose To resolve differences in published data on tear antioxidant levels by comparing the concentration of water-soluble antioxidants in human reflex tears collected by capillary tube and by the Schirmer Strip collection method and in basal and reflex tears collected using the Schirmer Strip method. Methods Yawn-induced reflex tears (collected simultaneously by capillary tubes and by Schirmer Strips) and basal tears (by Schirmer Strips and using local anesthetic) were collected from 12 healthy subjects. Tear cysteine, ascorbate, glutathione, urate, and tyrosine were measured by high-performance liquid chromatography within a few minutes of collection. Results Cysteine, ascorbate, glutathione, and tyrosine were 5 to 10 times higher (P 0.05). Conclusions The conflict in published data on tear antioxidants is caused by differences in collection methods. With the exception of urate, antioxidants accumulate to very high levels in corneal cells. Spuriously high antioxidant levels in tears collected using Schirmer Strips, therefore, are most probably caused by contamination with intracellular constituents. The capillary tube collection method is proposed as the method of choice for reflex tear collection for biochemical studies. This less-invasive method facilitates the evaluation of tear antioxidant levels as a biomonitoring tool for corneal health. Although moderately increased antioxidant levels may be beneficial, the authors hypothesize that marked increases may indicate damage to the ocular surface.
