2 results
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
- Export citation
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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.
Electrolyte Detection by Ion Beam Analysis, in Continuous Glucose Sensors and in Microliters of Blood using a Homogeneous Thin Solid Film of Blood, HemaDrop™
- Yash Pershad, Ashley A. Mascareno, Makoyi R. Watson, Alex L. Brimhall, Nicole Herbots, Clarizza F. Watson, Abijith Krishnan, Nithin Kannan, Mark W. Mangus, Robert J. Culbertson, B. J. Wilkens, E. J. Culbertson, T. Cappello-Lee, R.A. Neglia
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- Journal:
- MRS Advances / Volume 1 / Issue 29 / 2016
- Published online by Cambridge University Press:
- 21 June 2016, pp. 2133-2139
- Print publication:
- 2016
-
- Article
- Export citation
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Percolation of blood and of interstitial fluids into implantable continuous glucose sensors (CGS) for diabetics presently limits sensor lifetime between 3 and 7 days. Na+ mobile ions in body fluids damage Si-based CGS sensors electronics. The direct detection of Na percolation is investigated by Ion Beam Analysis (IBA) and Proton Induced X-ray Emission (PIXE) in previously used CGS. Based on these results, a new technology called HemaDropTM is then tested to prepare small volume (5-10 µL) of blood for IBA. A species’s detectability by IBA scales with the square of the ratio of element’s atomic number Z to that of the substrate. Because Na has a low atomic number (Z=11), Si signals from sensor substrates can prevent Na detection in Si by 2 mega electron volt (MeV) IBA.
Using 4.7 MeV 23Na (α, α)23Na nuclear resonance (NR) can increase the 23Na scattering cross section and thus its detectability in Si. The NR energy, width, and resonance factor, is calibrated via two well-known alpha (α) particle signals with narrow energy spreads: a 5.486 ± 0.007 MeV 241Am α-source (ΔΕ = 0.12%) and the 3.038 ± 0.003 MeV 16O(α, α)16O NR (ΔΕ = 0.1%). Next, the NR cross section is calibrated via 100 nm NaF thin films on Si(100) by scanning the beam energy. The23Na (α, α) NR energy is found to be 4.696 ± 0.180 MeV, and the NR/RBS cross section 141 ± 7%. This is statistically significant but small compared to the 4.265 MeV 12C NR (1700%) and 3.038 MeV 16O NR (210%), and insufficient to detect small amounts of 23Na in Si. Next, a new method of sample preparation HemaDropTM, is tested for detection of elements in blood, such Fe, Ca, Na, Cl, S, K, C, N, and O, as an alternative to track fluid percolation and Na diffusion in damaged sensors. Detecting more abundant, heavier elements in blood and interstitial fluids can better track fluid percolation and Na+ ions in sensors. Both Na detection and accuracy of measured blood composition by IBA is greatly improved by using HemaDropTM sample preparation to create Homogeneous Thin Solid Films (HTSFs) of blood from 5-10 µL on most substrates. HTSF can be used in vacuo such as 10-8 –10-6 Torr).