Super-Hydrophilic, Bio-compatible Anti-Fog Coating for Lenses in Closed Body Cavity Surgery: VitreOx™ — Scientific Model, In Vitro Experiments and In Vivo Animal Trials

Abstract

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.

Nature-Inspired Superhydrophobic Coating Materials: Drawing Inspiration from Nature for Enhanced Functionality

“…In addition to being annoying, fogging may cause additional problems in a variety of applications, including safety. Fogging, for example, might impair vision during endoscopic surgery and raise the possibility of a failure of the operation [ 179 ]. The formation of fog on moving car windscreens and motorcycle helmet visors is intimately associated with road safety.…”

Transparent laser-structured glasses with superhydrophilic properties for anti-fogging applications

“…Anti-fogging surfaces avoid the formation of scattering droplets on a surface. This can be achieved by improving the wettability of the surface such that the droplets are spread completely across the surface [1]. This wetting state is called superhydrophilic; the required water contact angle is θ < 5.…”

“…Examples of superhydrophilic surfaces can be found in nature, e.g., on various plant surfaces [4], lizards [5], or tropical flat bugs [6]. These kind of structures were mimicked on glasses by deposition of nanoparticles [7,8] or (1) cos = r cos 0 .…”