2 results
Optimizing Homogeneous Thin Solid Films (HTSFs) from µL-Blood Droplets via Hyper-Hydrophilic Coatings (HemaDropTM) for Accurate Compositional Analysis via IBA, XRF, and XPS
- Nicole Herbots, Nikhil C. Suresh, Shaurya Khanna, Saaketh R. Narayan, Amber A. Chow, Mohammed Sahal, Sukesh Ram, Jack M. Day, Yash W. Pershad, Harshini L. Thinakaran, Robert J. Culbertson, Eric J. Culbertson, Karen L. Kavanagh
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- Journal:
- MRS Advances / Volume 4 / Issue 46-47 / 2019
- Published online by Cambridge University Press:
- 23 October 2019, pp. 2489-2513
- Print publication:
- 2019
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- Article
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Liquid phase analysis dominates the field of blood diagnostics and requires drawing blood volumes of several ml for each test. To achieve acceptable accuracy, each single liquid blood test requires ∼7 mL per blood sample, and repeated blood tests are often needed. Frequent testing ca result in Hospital Acquired Anemia for infants, chronically ill, and critically ill patients. Blood testing methods that can be utilized with small amounts of blood are a critical need to save lives. Theranos claimed to have developed novel methods requiring only a few nL of blood. However, Theranos’ techniques led to errors that exceeded beyond the medically acceptable threshold of 10%. This work investigates solid state blood analysis using low volumes of several µL. The most common blood tests used as first line for diagnostics and monitoring patients’ status, always include blood electrolytes, iron, and in some cases, heavy metals.
The present work investigates the formation of rapidly solidified Homogeneous Thin Solid Films (HTSFs) formed from blood drops, in order to make them suitable for solid state analysis in vacuo and in air. The solidification of ∼5 micro-liter (µL)-sized blood droplets into HTSFs is studied with two goals: achieve reproducible HTSFs optimized for producing accurate analysis, and successfully measure the potential accuracy of measurements made on HTSFs for blood electrolytes Na, K, Mg, Ca, and Cl and heavy metals such as Fe.
The blood volumes selected for this work are in the µL range, one thousandth volumes drawn for current liquid phase analysis. Balanced Saline Solution (BSS) is used as an initial liquid for testing solidification uniformity and a potential calibration material. Next, canine and human blood are studied on two types of HemaDropTM coatings for solidification: super-hydrophilic and hyper-hydrophilic. HTSF formation from BSS and blood drops are compared on both coated and uncoated surfaces.
Three solid state analytical methods are investigated in parallel to probe composition at different depths and test each for reproducibility and accuracy: Ion Beam Analysis (IBA), X-ray Fluorescence (XRF), and X-ray Photoelectron Spectroscopy (XPS). The results show that using solid films of blood yields composition, which can be reproducibly measured by IBA, XPS and XRF to varying degrees. XPS’s depth of analysis, limited to ∼5 nm, probes a small fraction of the HTSF, but provides insights into the range of thickness for homogeneous compositions in HTSFs. Statistical and error analysis help establish whether measurements taken in sets of three typically used in lab fall below the medically accepted error threshold (<10%) for each technique and element detected. Measurements are repeated and taken at various locations and on different HTSFs to establish reproducibility. XRF is of particular interest, because it is fast, accurate, portable and can be conducted in air, making it ideal for areas with limited resources.
Super-Hydrophilic, Bio-compatible Anti-Fog Coating for Lenses in Closed Body Cavity Surgery: VitreOxTM – Scientific Model, In Vitro Experiments and In Vivo Animal Trials
- Nicole Herbots, Clarizza F. Watson, Eric J. Culbertson, Ajjya J. Acharya, Pierre R. Thilmany, Steven Marsh, Raymond T. Marsh, Igor P.O. Martins, Gabriel P.K. Watson, A.M. Mascareno, Saloni Sinha, Mayuri Gupta, Nehal Gupta, Abijith Krishnan
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- Journal:
- MRS Advances / Volume 1 / Issue 29 / 2016
- Published online by Cambridge University Press:
- 22 June 2016, pp. 2141-2146
- Print publication:
- 2016
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- Article
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Lenses in laparoscopes, arthroscopes, and laryngoscopes fog during closed body surgery due to humidity from bodily fluids and differences between body and operating room temperatures.1,2 Surgeons must repeatedly remove, clean, and reinsert scopes that are obscured by fog. As a result, surgery duration, infection risks, and scarring from air exposure increase.3,4 Current methods to address fogging introduce other complications. Acidic alcohol-based coatings scar tissue and quickly evaporate, and heated lenses require reheating every 5 to 20 minutes.3,4 This paper presents a new super-hydrophilic, biocompatible, non-toxic, pH neutral (7.2-7.4), and long-lasting anti-fog coating called VitreOx™.5-7 VitreOx™ can be used wet or dry, without use of alcohol, heat, or fluid evacuation. When applied as a liquid, it easily espouses lenses’ surfaces and edges, and dries within seconds to form a permanently super-hydrophilic surface on silica and polymer surfaces. VitreOx™ avoids current shortfalls by eliminating frequent reapplications, avoiding reapplication for surgeries lasting up to 72 hours.
VitreOx™'s anti-fog properties can be explained by nucleation and growth theory for thin films condensation: 1) 3-D droplets, resulting in fogging; 2) 2-D sheets resulting in a flat transparent film; or 3) mixed 3-D on 2-D, resulting in optical distortion. On hydrophobic surfaces (e.g. lenses), condensation occurs with fogging via spherical 3-D droplets, as in the Volmer-Weber model. 3-D droplets scatter light in all directions through refraction yielding opaque or translucent films (fog). VitreOx™ applied to hydrophobic lenses renders them super-hydrophilic. Similar to the 2-D Frank Van-der-Merwe Growth Mode, condensation with uniform wetting yields transparent 2-D films that do not distort optical images transmission.
In vitro and in vivo studies of VitreOx™ were conducted to measure performance and duration of anti-fog effectiveness and bio-compatibility. In vitro tests spanned from 3 to 72 hours over a 3-year range. Side-by-side in vivo gastro-endoscopies were conducted on Yucatan™ swine for 90 minutes using 1) VitreOx™, 2) bare lens, and 3) Covidien Clearify™ surfactant with warmer. VitreOx™ coated lenses did not fog nor need reapplication for 90 minutes, while Covidien Clearify™ lasted 38 minutes without fogging, requiring retreatment. No adverse reaction was observed on swines exposed toVitreOx™, in surgery and 12 months thereafter.