Flexible Plasma Generator for Endoscope Channel Sterilization

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Solution Overview

Problem

Current endoscope reprocessing methods, particularly for flexible endoscopes, are inadequate in sterilizing narrow lumens due to limitations in chemical disinfection efficacy and the difficulty in delivering plasma effectively, leading to residual contamination and increased risk of healthcare-associated infections.

Innovation Solution

A flexible elongate atmospheric plasma generator is inserted into the endoscope channel to generate a transverse plasma along its length, using a dielectric body with centrally located and externally meshed electrodes, enabling non-thermal plasma sterilization without chemicals, capable of deactivating biofilms and prions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If chemical disinfection methods are used for sterilization, then the sterilization process can be applied to flexible endoscopes, but the efficacy against established biofilms is limited and chemical residues remain

Engineering Contradiction:
Improvesterilization efficacyVSAvoidchemical residues and toxicity
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent replaces chemical disinfection methods with a physical plasma-based sterilization system. The plasma generator uses dielectric barrier discharge to create reactive oxygen and nitrogen species that effectively kill microorganisms and degrade biofilms without leaving harmful chemical residues, thus substituting chemical action with physical plasma processes

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The invention changes the sterilization parameter from chemical concentration and contact time to plasma power and exposure duration. By controlling the plasma generation parameters (power input, gas flow rate, treatment time), the system achieves effective sterilization while avoiding the limitations of chemical methods such as residue formation and biofilm resistance

Inventive Principle:
Principle #35Parameter changes

2Reliability

If conventional plasma generation methods are used, then sterilization can be achieved, but the plasma jet length is limited to a couple of tens of centimetres due to fast dissociative recombination

Engineering Contradiction:
Improvesterilization capabilityVSAvoidplasma jet length
Core Design Contradiction:
ReliabilityVSLength of stationary object

Solution Approach 1:

The patent segments the plasma generation along the entire length of the endoscope channel by incorporating a distributed electrode system. Multiple electrode segments are arranged axially along the channel, each generating local plasma zones that collectively cover the full length of the endoscope, thus overcoming the limitation of short plasma jet length

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The dielectric barrier acts as an intermediary that enables plasma generation throughout the channel. The dielectric material allows the plasma to be sustained along the electrode length by controlling the discharge process, preventing direct contact between the plasma and the conductive endoscope channel while maintaining effective sterilization

Inventive Principle:
Principle #24Intermediary (Mediator)

3Adaptability or versatility

If the endoscope channel is narrow (2-3 mm diameter and 1.5 m length), then flexible endoscopy can be performed, but conventional plasma delivery methods are not suitable for this geometry

Engineering Contradiction:
Improveendoscope applicationVSAvoidplasma delivery difficulty
Core Design Contradiction:
Adaptability or versatilityVSEase of operation

Solution Approach 1:

The plasma generator is nested within the endoscope channel itself. The electrode system is integrated into the channel structure, with the first electrode centrally located and the second electrode forming the channel wall. This nested configuration allows plasma generation directly within the narrow channel geometry without requiring external plasma delivery equipment

Inventive Principle:
Principle #7Nested doll (Nesting)

Solution Approach 2:

The patent transitions from linear plasma jet delivery to a transverse plasma generation approach. By generating plasma perpendicular to the channel axis (transverse discharge between concentric electrodes), the system overcomes the length and diameter constraints that limit conventional linear plasma jet methods

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

4Reliability

If manual washing and chemical disinfection are used, then cleaning can be performed, but the process is time-consuming and requires multiple steps

Engineering Contradiction:
Improvecontamination removalVSAvoidreprocessing time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The patent merges multiple reprocessing steps (cleaning, disinfection, drying) into a single plasma treatment process. The plasma simultaneously achieves organic contaminant degradation, microbial sterilization, and surface drying through its reactive species and energy input, eliminating the need for separate sequential steps

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The plasma treatment provides continuous sterilization and cleaning action throughout the endoscope channel during a single pass. Unlike intermittent chemical disinfection that requires soaking and rinsing cycles, the plasma maintains continuous reactive species generation along the channel length, achieving thorough decontamination in one continuous operation

Inventive Principle:
Principle #20Continuity of useful action

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

The method achieves thorough and repeatable sterilization of endoscope channels, reducing residual contamination and infection risk, while being safer and more efficient than traditional chemical methods, with potential to replace High-Level Disinfection protocols.

Implementation Method 1

A flexible elongate atmospheric plasma generator is inserted into the endoscope channel to generate a transverse plasma along its length

Methodology Applied
Scientific EffectPlasma: Plasma

Implementation Method 2

reactive species can initiate and catalyse peroxidation and oxidation processes, which can degrade biological contaminants

Methodology Applied
Scientific EffectOxidation: Oxidation

Implementation Method 3

The exterior surface of the plasma generator can be cleaned using microscopic ultrasonic bubbles

Methodology Applied
Scientific EffectUltrasonic vibration: Ultrasonic Vibration

Data Source

PatentEP4135782B1Sterilisation of endoscopes
Publication Date: 2025.11.12 UNIV OF SOUTHAMPTON
  • EP4135782B1 patent drawingFigure 1~3
  • EP4135782B1 patent drawingFigure 4~6
  • EP4135782B1 patent drawingFigure 7~8b

AI summary

An apparatus for sterilising an interior surface of an elongate endoscope tube by an atmospheric plasma, the apparatus comprising a flexible elongate atmospheric plasma generator for generating a transverse atmospheric plasma within, and along a length of, an elongate endoscope tube into which the atmospheric plasma generator has, in use, been inserted, the flexible elongate atmospheric plasma generator being configured for insertion into an end of, and along a length of, an internal channel of an elongate endoscope tube, the flexible elongate atmospheric plasma generator comprising an elongate body of dielectric material, an elongate first electrode centrally located within the body of dielectric material and an elongate second electrode around an elongate external surface of the body of dielectric material, wherein the second electrode comprises a plurality of electrically conductive elements forming a mesh defining holes in the second electrode, wherein the atmospheric plasma generator is configured such that application of a potential difference across the first and second electrodes can generate a plasma within atmospheric air surrounding the atmospheric plasma generator.