pH-Temperature Dual-Sensitive Block Copolymer Hydrogel
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Solution Overview
Problem
Temperature-sensitive block copolymers used in drug delivery face issues such as needle clogging during injection due to thermal equilibrium and lack of pH sensitivity, making them unsuitable for practical in vivo applications.
Innovation Solution
A novel block copolymer is developed by coupling a polyethylene glycol-based compound with a biodegradable polymer and a sulfonamide-based oligomer, imparting both temperature and pH sensitivity, allowing the copolymer to transition between sol and gel states based on in vivo pH conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If temperature-sensitive block copolymers are used for drug delivery, then sol-gel transition can be achieved, but needle clogging occurs during injection due to thermal equilibrium
Solution Approach 1:
The patent introduces pH as an additional control parameter alongside temperature. The copolymer contains ionizable groups that change conformation based on pH, allowing the system to transition between sol and gel states through pH adjustment rather than relying solely on temperature changes. This enables injection at physiological temperature while avoiding needle clogging.
Solution Approach 2:
The patent creates a composite copolymer structure combining temperature-sensitive blocks (e.g., poly(N-isopropylacrylamide)) with pH-sensitive blocks (e.g., poly(acrylic acid) or poly(methacrylic acid)). This composite structure enables dual responsiveness, where the material can be controlled by either temperature or pH changes, providing flexibility in avoiding needle clogging while maintaining sol-gel transition capability.
2Reliability
If traditional block copolymers are used, then sol-gel transition occurs, but pH sensitivity is insufficient for practical in vivo application
Solution Approach 1:
The patent incorporates ionizable functional groups (carboxyl, amine, or sulfonate groups) into the copolymer structure. These groups undergo protonation/deprotonation transitions at physiological pH ranges, causing significant conformational changes and sol-gel transitions. This enhances pH sensitivity to levels suitable for practical in vivo drug delivery applications.
Solution Approach 2:
The patent designs copolymers with distinct pH-sensitive blocks containing ionizable groups. These blocks undergo conformational changes at specific pH values, enabling the material to respond to pH variations in different physiological environments (e.g., stomach acid vs. blood pH). This composite structure provides the necessary adaptability for practical in vivo use.
3Reliability
If biodegradable polymers are used instead of Pluronic/Poloxamer, then biocompatibility improves, but pH sensitivity remains insufficient
Solution Approach 1:
The patent combines biodegradable polymer backbones (PLA, PGA, PCL, or their copolymers) with pH-sensitive functional groups or blocks. The biodegradable portion ensures biocompatibility and controlled degradation, while the pH-sensitive portions (containing carboxyl, amine, or sulfonate groups) provide the necessary pH responsiveness. This composite approach achieves both biocompatibility and enhanced pH sensitivity for practical drug delivery.
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 resulting copolymer forms a stable hydrogel at physiological pH, preventing needle clogging and enabling effective sustained-release drug delivery systems by being sensitive to both temperature and pH, thus overcoming previous limitations.
Implementation Method 1
amphiphilic polymers that exhibit a temperature-sensitive sol-gel behavior
Implementation Method 2
a pH-sensitive polymer comprising sulfonamide groups
Data Source
AI summary
The present invention relates to a block copolymer formed by coupling the following components with each other, as well as a hydrogel composition comprising the block copolymer and a hydrogel formed from the composition: (a) a copolymer of a polyethylene glycol (PEG)-based compound with a biodegradable polymer; and (b) a sulfonamide-based oligomer. The inventive block copolymer shows the sol-gel transition behavior sensitive to changes in not only temperature but also pH. Thus, the inventive block copolymer overcomes the shortcomings of temperature-sensitive copolymers, form a more strong and stable hydrogel, and is stable in vivo. Accordingly, the inventive block copolymer can be used in various applications in the medical and drug delivery fields.