pH-Switchable Supramolecular Hydrogel for Injectable Gel-Sol Reversal
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Solution Overview
Problem
Existing hydrogels face challenges such as the need for chemical cross-linking, limited mechanical properties, biodegradability, and instability in varying pH and temperature conditions, making them unsuitable for efficient drug delivery and medical applications.
Innovation Solution
Development of supramolecular polymers that can switch between a liquid and gelled state using pH and temperature, with improved mechanical and elastic performances, allowing for injectable formulations at low concentrations without chemical cross-linking.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If chemical cross-linking is used to obtain hydrogels, then mechanical strength is improved, but biodegradability deteriorates and toxicity increases
Solution Approach 1:
The patent changes the chemical parameters of the polymer system by using poly(L-lactic acid) with specific molecular weights and compositions that enable physical cross-linking through hydrophobic interactions and crystallization, eliminating the need for toxic chemical cross-linkers while maintaining mechanical strength
Solution Approach 2:
The patent utilizes phase transitions of poly(L-lactic acid) blocks, specifically crystallization and melting transitions, to create reversible physical cross-links in the hydrogel network, providing mechanical strength without chemical cross-linking and enabling biodegradability
2Strength
If chemical cross-linking is used to obtain hydrogels, then mechanical strength is improved, but reversibility deteriorates
Solution Approach 1:
The patent employs reversible phase transitions of poly(L-lactic acid) blocks, where crystallization provides cross-linking at lower temperatures and melting restores fluidity at higher temperatures, enabling reversible gel-sol transitions while maintaining mechanical strength through the crystalline network
3Object-affected harmful factors
If natural polymers like collagen are used for hydrogels, then biocompatibility is improved, but mechanical strength deteriorates
Solution Approach 1:
The patent creates a composite block copolymer system combining hydrophilic polyethylene glycol blocks with hydrophobic poly(L-lactic acid) blocks, where the PLLA segments provide mechanical strength through crystallization while the PEG segments ensure biocompatibility and hydrophilicity
Solution Approach 2:
The patent modifies the molecular weight and composition parameters of the block copolymer to optimize the balance between biocompatibility (through PEG content) and mechanical strength (through crystalline PLLA domains), achieving both properties simultaneously
4Reliability
If hydrogels are made stable across wide pH and temperature ranges, then reliability is improved, but adaptability to physiological conditions deteriorates
Solution Approach 1:
The patent utilizes the thermoreversible phase transitions of poly(L-lactic acid) blocks to create hydrogels that are stable at physiological temperatures (37°C) through crystallization but can be reversibly converted to sol state at elevated temperatures for injection, then re-gel upon cooling
Solution Approach 2:
The patent designs the block copolymer with specific molecular weight ratios and compositions that enable the hydrogel to maintain stability at physiological pH and temperature while allowing controlled transitions under external stimuli, achieving both reliability and adaptability
5Ease of operation
If prepolymers are dissolved in water for administration, then ease of administration is improved, but mechanical properties of the resulting hydrogel deteriorate
Solution Approach 1:
The patent uses thermoreversible phase transitions where the polymer solution remains fluid at injection temperature, then undergoes crystallization upon cooling in the body to form a mechanically strong hydrogel, achieving both ease of administration and mechanical strength
Solution Approach 2:
The patent optimizes the molecular weight and composition parameters of the block copolymer to ensure adequate solubility for injection while maintaining the ability to form strong crystalline networks upon gelation, balancing ease of administration with mechanical properties
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 supramolecular polymers provide stable, injectable hydrogels with favorable mechanical properties, suitable for drug delivery, barrier films, and other medical applications, maintaining stability across a wide range of temperatures and pH levels.
Implementation Method 1
supramolecular polymers that can switch between a liquid and gelled state using pH and temperature
Implementation Method 2
Hydrogels based on natural polymers, especially collagen, are biocompatible and mostly thermally reversible
Implementation Method 3
physically by the formation of e.g. hydrogen bonds or ionic interactions between different polymer chains
Implementation Method 4
physically by the formation of e.g. hydrogen bonds or ionic interactions between different polymer chains
Data Source
AI summary
The invention relates to a supramolecular polymer comprising polymer chains according to Formula (I):wherein the average n in the supramolecular polymer is between 2 and 16, and wherein building block *-Q-* represents:wherein the average i in the supramolecular polymer is between 1.5 and 6.0, and wherein building block *-T-* represents:wherein the average j in the supramolecular polymer is between 1 and 6, wherein the supramolecular polymer has an average molecular weight Mn of about 15 kDa to about 150 kDa, wherein POL is a linear hydrophilic polymeric group having an average molecular weight Mn of about 1 kDa to about 30 kDa, wherein L and K represent linker groups and wherein A represents hydrogen bonding units.