TPU Stent with Covalently Attached Silk Particles for Drug Delivery
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Solution Overview
Problem
Urethral healing after surgery or trauma is hindered by complications such as strictures, fistulas, infections, and stones, resulting in significant healthcare costs and patient suffering, with existing treatments being inadequate in providing sustained therapeutic benefits.
Innovation Solution
A stent comprising thermoplastic polyurethane (TPU) material with covalently attached silk particles, which serve as a carrier for urological therapeutic agents, providing an elastic modulus of 1 MPa to 20 MPa and enabling extended release of the agents for up to 168 hours, manufactured through enrichment with carboxylic acid groups and coupling with carbodiimide-activated silk particles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of moving object
If existing stents are used for urethral healing, then the stent provides structural support, but the therapeutic agent release duration is insufficient (less than 168 hours)
Solution Approach 1:
The stent combines thermoplastic polyurethane (TPU) material with silk particles to create a composite structure. The TPU provides structural support and flexibility with elastic modulus of 1-20 MPa, while the silk particles serve as carriers for urological therapeutic agents. This composite approach enables both mechanical functionality and extended drug delivery (up to 168 hours) simultaneously, resolving the contradiction between structural support and prolonged therapeutic action.
Solution Approach 2:
The patent modifies the TPU material by enriching it with carboxylic acid groups through photooxidation, then covalently coupling silk particles to these groups. This parameter change in the material composition transforms the stent from a simple structural device to an active drug delivery system, extending the therapeutic agent release duration while maintaining structural integrity and healing effectiveness.
2Duration of action of stationary object
If the stent provides extended release for up to 168 hours, then the therapeutic benefit is sustained, but the device complexity increases due to covalent coupling mechanisms
Solution Approach 1:
The patent uses carboxylic acid groups as intermediary functional groups on the TPU surface, which are then activated by carbodiimide chemistry to covalently bind silk particles. This intermediary approach provides a systematic method for attaching drug carriers, enabling extended release (up to 168 hours) while managing the complexity through a well-defined chemical coupling protocol rather than complex mechanical structures.
3Reliability
If silk particles are covalently attached to TPU material, then the therapeutic agent delivery is sustained, but the manufacturing process complexity increases
Solution Approach 1:
The manufacturing process performs preliminary enrichment of TPU with carboxylic acid groups through photooxidation before the actual silk particle attachment. This preliminary action prepares the TPU surface in advance, creating ready-to-couple functional groups that simplify the subsequent silk particle attachment step. The pre-functionalized TPU can then be manufactured with consistent therapeutic agent delivery (0.001-0.4 mg per 1 mg silk particles) through a more straightforward covalent coupling process.
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 stent provides sustained and effective delivery of urological therapeutic agents, enhancing urethral healing by maintaining therapeutic levels for an extended period, thereby reducing complications and healthcare costs.
Implementation Method 1
Enriching the TPU material with a plurality of carboxylic acid groups may comprise photooxidation of the TPU material with an oxidizing agent
Implementation Method 2
Covalently coupling the silk particles to the carboxylic acid groups may comprise activating the carboxylic acid groups by reacting the groups with a carbodiimide, then reacting the silk particles with the activated carboxylic acid groups
Implementation Method 3
activating the carboxylic acid groups by reacting the groups with a carbodiimide
Implementation Method 4
The stent may provide extended release of the urological therapeutic agent for up to 168 hours
Data Source
AI summary
Materials, methods, and techniques herein relate to stents. More specifically, the instant disclosure relates to stents, such as catheters, for slow-release drug delivery of urological therapeutic agents.