Degradable Coating Ureteral Stent for Bacterial Adhesion
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Solution Overview
Problem
Existing ureteral stents face issues with bacterial adhesion, biofilm formation, urinary salt accumulation, discomfort due to bladder pressure, and the need for invasive removal procedures, which are not effectively addressed by current materials and designs.
Innovation Solution
A controllable, operation-free ureteral stent with a degradable coating and a traction wire system, featuring a nondegradable base layer and a degradable coating made from materials like polylactic acid and polyglycolic acid, combined with a hydrophilic coating and an anti-reflux water-retaining soft sleeve, allowing for controlled degradation and reduced bladder pressure, facilitating easy removal without surgery.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a drug coating is added on the outer wall of the ureteral stent to achieve antibacterial effect, then bacterial adhesion is inhibited, but once the drug is completely released, the ureteral stent has no inhibitory ability
Solution Approach 1:
The patent changes the physical-chemical parameters of the coating material from non-degradable to biodegradable, allowing the coating to gradually decompose and release antibacterial agents over time. This transforms the antibacterial mechanism from immediate high-concentration release to sustained controlled release, extending the duration of antibacterial effect while preventing bacterial adhesion throughout the indwelling period.
2Strength
If polyurethane material is used for the ureteral stent to ensure strength, then structural integrity is maintained, but the biocompatibility is poor leading to formation of urinary salts
Solution Approach 1:
The patent employs a composite material structure consisting of a polyurethane base layer providing mechanical strength and a biodegradable coating layer (polylactic acid or polyglycolic acid) providing biocompatibility. This composite structure combines the advantages of both materials: the polyurethane ensures stent strength and structural integrity, while the biodegradable coating prevents urinary salt formation and reduces tissue irritation through controlled degradation and antibacterial release.
3Object-affected harmful factors
If silicone material is used for the ureteral stent to improve biocompatibility, then tissue compatibility is enhanced, but the bacterial adhesion rate is high and friction coefficient is high making operation difficult
Solution Approach 1:
The patent creates a composite structure where the silicone base layer provides excellent biocompatibility and tissue compatibility, while the biodegradable coating layer (polylactic acid or polyglycolic acid) reduces bacterial adhesion and friction. The coating acts as an intermediate layer that maintains the mechanical properties of silicone for ease of operation while adding antibacterial and low-friction characteristics through its degradation products and surface properties.
4Duration of action of stationary object
If the ureteral stent is left in the body for long term, then continuous ureteral obstruction relief is achieved, but urine reflux occurs due to increase of bladder pressure causing waist swelling and discomfort
Solution Approach 1:
The patent applies the disposable concept to the coating layer, which is designed to be temporary and biodegradable. The biodegradable coating (polylactic acid or polyglycolic acid) provides protective and antibacterial functions during the critical early indwelling period, then gradually degrades and is absorbed by the body. This temporary coating prevents urine reflux and bacterial adhesion during the period when the stent is most needed, while its degradation eliminates long-term harmful effects without requiring removal surgery.
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 solution effectively prevents bacterial adhesion and biofilm formation, reduces discomfort from bladder pressure, and allows for non-invasive removal of the stent, improving patient comfort and reducing medical expenses by eliminating the need for secondary cystoscopy surgery.
Implementation Method 1
the degradable coating on the surface of the ureteral stent within a certain period of time
Implementation Method 2
a ureteral stent with a silica gel hydrophilic coating
Implementation Method 3
anti-reflux water-retaining soft sleeve is added to prevent reflux
Data Source
AI summary
A controllable operation-free take-out ureteral stent with a degradable coating includes a ureteral stent, a traction wire, a discharged body, and a degradable fixture, where the discharged body is fixed on one end of the traction wire, and the degradable fixture fixes the discharged body on the other end of the traction wire and is arranged close to one end of the ureteral stent within a limited period of time; the ureteral stent comprises a nondegradable base layer and a degradable coating which are sequentially arranged from inside to outside; the problem of bacterial adhesion on the surface of the ureteral stent caused by long indwelling time or patients' special allergies can be solved by automatic degradation and peeling off of the degradable coating on the surface of the ureteral stent within a certain period of time.