Dual-Crosslinked Biodegradable Polymers for Soft Tissue Engineering
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Solution Overview
Problem
Current biodegradable polymers, such as Poly(L-lactide) and its copolymers, are inadequate for tissue engineering and regenerative medicine due to their stiffness, which makes them unsuitable for soft tissues like blood vessels, bladders, and cardiac tissues, and lack the necessary mechanical properties and degradability for these applications.
Innovation Solution
Development of poly(alkylene maleate citrates) (PAMCs) with a dual-crosslinking mechanism, featuring carbon-carbon crosslinking via UV photopolymerization and ester-bond crosslinking via polycondensation, allowing for tunable mechanical properties, degradability, and functionality, making them suitable for soft tissue engineering and drug delivery.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If current FDA approved biodegradable polymers such as PLLA are used, then the polymer provides structural support, but the polymer is too stiff to be compliant with soft tissues such as blood vessels, bladders, and cardiac tissues
Solution Approach 1:
The patent employs composite materials by combining multiple polymer components with distinct properties. Specifically, it uses a polyol matrix providing elasticity and compliance, reinforced with crosslinked networks that provide structural strength. This composite approach allows the material to simultaneously achieve both mechanical support and soft tissue compliance, resolving the contradiction between strength and adaptability.
Solution Approach 2:
The patent applies parameter changes by systematically varying the composition ratios, molecular weights, and crosslinking densities of the polymer components. By adjusting these parameters, the material properties can be tuned to achieve the desired balance between mechanical strength and softness, enabling compliance with different soft tissue requirements while maintaining structural integrity.
2Adaptability or versatility
If biodegradable polymers are used for soft tissue engineering, then the polymer should be soft and elastic, but current polymers lack the necessary mechanical properties and degradability control
Solution Approach 1:
The patent applies dynamics by incorporating hydrolyzable ester bonds into the polymer backbone that can be controlled to degrade at specific rates. The crosslinked network structure provides dynamic mechanical properties that maintain strength during the degradation process. This allows the material to transition from a purely static structure to one that evolves over time, maintaining reliability while achieving softness and elasticity.
Solution Approach 2:
The patent segments the polymer into distinct functional domains: a polyol matrix providing softness and elasticity, crosslinked networks providing mechanical strength, and hydrolyzable ester bond segments providing controlled degradability. This segmentation allows each component to independently contribute its specific property, resolving the contradiction between softness and mechanical reliability.
3Strength
If crosslinking is performed to improve mechanical properties, then the polymer strength increases, but the polymer loses its ability to degrade
Solution Approach 1:
The patent applies local quality by creating a heterogeneous crosslinked structure where crosslinks are concentrated in specific regions to provide mechanical strength, while leaving other regions with hydrolyzable ester bonds available for degradation. This local differentiation allows the material to simultaneously achieve both strength enhancement and retained degradability, resolving the contradiction between these two properties.
Solution Approach 2:
The patent extracts the degradability function by incorporating specific hydrolyzable ester bond segments that can be selectively cleaved, separating the degradation mechanism from the crosslinked network structure. This allows the crosslinked portions to provide strength while the extractable ester bond segments provide controlled degradation pathways.
4Object-affected harmful factors
If in situ polymerization is used for drug encapsulation, then the process is mild and preserves sensitive proteins, but the polymerization conditions must be precisely controlled
Solution Approach 1:
The patent replaces traditional thermal or chemical polymerization methods with photo-initiated polymerization. This substitution allows the polymerization to be initiated and controlled by light exposure rather than heat or harsh chemicals, creating a milder process that preserves sensitive proteins while providing precise spatial and temporal control over the polymerization reaction through light masking and timing.
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
PAMCs provide soft, elastic, and biocompatible scaffolds that retain mechanical properties in wet environments, enabling controlled degradation and functionalization, suitable for applications in tissue engineering, wound dressing, and drug delivery, with potential for use in blood vessels, cardiac tissues, and other soft tissue repairs.
Implementation Method 1
carbon-carbon crosslinking via UV photopolymerization
Implementation Method 2
redox initiators or photo initiators in presence of electromagnetic wave
Implementation Method 3
Hydrolyzable ester bonds are introduced into the polymer backbone to confer the degradability to the polymers
Data Source
AI summary
The present invention provides a dual crosslinked biodegradable polymer and methods of making and using the polymer. The dual crosslinked biodegradable polymer composition includes a multifunctional monomer; a diol; and an unsaturated di-acid at least partially polymerized to form a network and photocrosslinked into a dual crosslinked polymer network.