Biodegradable Block Copolymer Sutures for Prolonged Wound Support
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Solution Overview
Problem
Existing sutures do not provide sufficient tensile strength for an extended period, particularly in immune-compromised patients, leading to a high risk of Post Operative Ventral Hernia (POVH) due to inadequate tissue support during wound healing.
Innovation Solution
Development of a novel class of biodegradable tri-block and di-block polymers with a central polypropylene oxide (PPO) segment and lateral biodegradable segments, such as polycaprolactone (PCL), which exhibit a reversed degradation behavior compared to traditional hydrophilic polymers, providing enhanced tensile strength and flexibility for wound closure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of moving object
If traditional absorbable sutures are used, then the suture degrades quickly (within 2 months), but the tensile strength is insufficient for immune-compromised patients who need prolonged support (3-5 months)
Solution Approach 1:
The patent uses a triblock copolymer structure (A-B-A) combining hydrophilic polyethylene oxide blocks with hydrophobic polypropylene oxide central block. This composite structure enables the suture to maintain tensile strength for 3-5 months while providing controlled degradation, resolving the contradiction between prolonged support duration and maintaining strength in immune-compromised patients.
Solution Approach 2:
The patent modifies the polymer composition parameters by adjusting the ratio of hydrophilic to hydrophobic blocks and the molecular weight distribution. This parameter optimization allows the suture to achieve both extended duration (3-5 months) and sufficient tensile strength, overcoming the limitation of traditional sutures that degrade too quickly.
2Duration of action of stationary object
If the suture remains in tissue for prolonged period (3-5 months), then tissue support is extended, but the absorption rate decreases
Solution Approach 1:
The patent creates a dynamic degradation profile where the suture maintains stability during the critical 3-5 month support period, then accelerates degradation afterward. The triblock structure allows the suture to transition from a stable, strength-providing state to a rapid degradation state, achieving both prolonged support and eventual absorption.
Solution Approach 2:
The suture exhibits periodic behavior with an initial stable phase (3-5 months of support) followed by a degradation phase. This periodic action pattern allows the suture to fulfill its support function for the required duration while ensuring eventual absorption, resolving the contradiction between extended duration and absorption rate.
3Reliability
If hydrophilic polymers are used, then degradation rate increases, but tensile strength decreases
Solution Approach 1:
The patent applies local quality by assigning different properties to different blocks: the hydrophobic polypropylene oxide central block provides tensile strength and structural integrity, while the hydrophilic polyethylene oxide blocks control degradation through water interaction. This spatial differentiation of properties resolves the contradiction between degradation control and tensile strength.
Solution Approach 2:
The triblock copolymer combines materials with opposing properties (hydrophilic and hydrophobic) to achieve both controlled degradation and sufficient tensile strength. The composite structure allows each block to contribute its advantageous property, resolving the trade-off between degradation rate and strength.
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 polymers maintain sufficient tensile strength for 3-5 months, supporting tissue healing in immune-compromised patients and reducing the risk of POVH by ensuring prolonged support to the abdominal wall.
Implementation Method 1
more hydrophilic polymers attract more (or more rapidly) water molecules that hydrolyze the groups responsible for the degradation; such groups may be aliphatic ester groups, which are present along the polymeric backbone, resulting in chain cleavage
Implementation Method 2
the diffusion of water molecules into the crystalline phase is significantly hindered
Data Source
Figure 1A
Figure 1B~2
Figure 3
AI summary
The invention provides a class of polymeric materials being ABA tri-block or AB di- block, comprised of biodegradable segments and poly(propylene oxide) (PPO) segment and uses thereof.