Week 3: Comparative Anti-Fog Trials, Experiment Design, and Surgical Insights
Hello everyone, and welcome to Week 3 of my blog series on KnoxFog™ – the hyper-hydrophilic, semi-solid anti-fog gel designed to improve visualization in endoscopic procedures.
The last couple weeks have been long as I was on vacation and just came back from the senior trip. We all had a great time! 🙂
This week, I’m focusing on three big areas of progress as promised:
- Comparative trials vs. other anti-fogging methods under realistic surgical conditions
- Detailed experiment design to ensure reproducibility and unbiased results
- Collaboration with surgeons at Banner Health to bridge lab findings and actual OR workflows
1. Comparative Trials: Testing KnoxFog™ vs. Heated Lenses, Alcohol-Based Coatings, and No Coating
In the research, we’ve conducted multiple in vitro experiments to benchmark KnoxFog™ against:
- Heated Lenses (where an endoscope is warmed to body temperature to reduce condensation)
- Alcohol-Based Coatings (quick-drying solutions that often evaporate rapidly and can irritate tissue)
- No Coating (the control/baseline condition)
Key Observations
- No Coating: Fog typically forms within seconds to a few minutes, showing inconsistent “time-to-fog.”
- Heated Lenses: While raising lens temperature can delay fogging, it often requires re-heating every 5–20 minutes.
- Alcohol-Based Anti-Fog: Evaporates quickly and may need frequent reapplication; some surgeons also worry about chemical irritation.
- KnoxFog™: Combining super-hydrophilicity (flattening water droplets into a uniform film) with water-absorbing nanopores has repeatedly demonstrated extended fog-free durations, often exceeding an hour or even multiple hours when applied as a semi-solid coating.
By running parallel trials on multiple endoscopes, each connected to a separate camera feed for time-stamped imaging, we track exactly how long each lens remains free of condensation. So far, KnoxFog™ has consistently shown the longest “time-to-fog,” thanks to its hyper-hydrophilic surface energy and ability to absorb rather than merely repel water.
2. Experimentation Procedure and Design
To ensure that the comparative results are scientifically sound and repeatable, we use a standardized test setup. Below is a simplified look at how these experiments typically run:
- Closed-Body Cavity Simulation
- We replicate human body temperature (≈ 38 °C) in a controlled environment – often a Pyrex dish with water heated on a hot plate.
- Aluminum foil may be used to insulate the setup, maintaining consistent temperature and humidity around each endoscope.
- Calibration and Checkerboard Targets
- Before each test, we verify the clarity of each endoscope using an optical tester (a checkerboard or resolution chart). This establishes a “fog-free baseline.”
- Once the lens is in the heated environment, we monitor how the image degrades over time.
- Multiple Endoscopes in Parallel
- Typically, four or eight endoscopes are tested at once. Some are coated with KnoxFog™, some with an alternative method (heated or alcohol-based), and at least one is left uncoated for control.
- Each lens is time-stamped when fog first appears (the point at which the checkerboard becomes obscured).
- Data Collection and Analysia
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- Repeated at 5-minute intervals (or more frequent snapshots) until the lens is visibly fogged.
- “Time-to-fog” values are averaged across multiple runs, ensuring that slight variations in temperature or lens positioning don’t skew the results.
- This yields a robust data set for side-by-side comparisons.
3. Design of Experiments & Experimental Procedure
To simulate the closed body cavity, a shallow 7 inches diameter borosilicate Pyrex dish– was used and was covered a polypropylene circular plate called the plenum
A. The plenum was cleanly drilled with eight apertures, carefully cleaned, and sanitized thereafter using a 12% chlorine solution, then alcohol 99%.
It was followed by three careful rinses in sterile, distilled water with Totally Dissolved Solid (TDS) reading of 1 ppm, thus 1 Megaohm DI water.
B. Four apertures were drilled in the plenum in a symmetric, circular pattern (N-W-S -E, labeled E1, E2, E3, E4 on the plenum as shown 1 (a)
The purpose of the symmetrically located apertures is to insert in the closed cavity four endoscopes E1, E2, E3, and E4 at approximately 45° angles in geometrically equivalent positions.
C. Four ADDITIONAL apertures were drilled in the plenum to insert the four endoscopes in four symmetrical positions on a circle centered on the circular vessel used as the in vitro closed cavity.
These four additional apertures NW -SW-SE- NE, are labeled on Fig. 1 (b) . The four labeled temperature probes; T1, T2, T3, T4, are positioned at approximately 45-degree angles to measure temperature near each endoscope on the same circular symmetrical isotherm.
D. Additional apertures were drilled to help regulate the cavity temperature.
E. The plenum was filled with 500mL sterile H20, heated to 38°C on a hot plate.
Why This Matters?
A key takeaway is that test reproducibility matters as much as raw performance. By standardizing procedures, employing multiple identical endoscopes, and carefully documenting temperature/humidity levels, we get dependable data that surgeons and regulators can trust.
Wrapping Up
Comparative testing has proven that KnoxFog™ significantly outperforms traditional anti-fogging strategies (heated lenses, alcohol-based sprays, or nothing at all) by maintaining a clear, distortion-free lens for extended periods. The experiment design – using multiple endoscopes, precisely controlled temperatures, and clear definitions of “time-to-fog” – ensures robust, reproducible data.
Stay tuned for next week, where I’ll delve into extended data analysis from our largest multi-endoscope study yet and share initial feedback from the Banner Health team on the ClearEndoscope™ applicator prototype. Thank you once again to Professor Herbots and Mr. Schaffer for all the supprt and help. Thanks for reading, and feel free to reach out with any questions!
I also will have a mini quiz next week to do a check on all the information we have talked about.
Happy readings!
Shreyash
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