Reversible PEG Hydrogel Dressing for Painless Removal
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Solution Overview
Problem
Existing hydrogel wound dressings and ocular applications face challenges with irreversible cross-linking, making them difficult to remove and limiting their conformability and drug delivery efficacy.
Innovation Solution
Development of a reversibly cross-linked hydrogel composition using polyethylene glycol (PEG) with sulfhydryl or mercaptan moieties, forming disulfide bonds that can be easily broken for painless removal, combined with RGD peptides for enhanced adhesion and drug retention.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If hydrogel wound dressings use irreversible cross-linking to provide structural integrity and adhesion, then the dressing maintains its form and sticks to skin, but the dressing becomes difficult to remove and causes pain during removal
Solution Approach 1:
The patent changes the chemical state of cross-links from irreversible to reversible by using dynamic covalent chemistry. The hydrogel incorporates boronic acid ester bonds that can form and break under specific pH conditions, allowing the dressing to adhere strongly during wound healing then dissolve easily during removal when exposed to physiological pH or specific solutions.
Solution Approach 2:
The patent introduces dynamic reversibility to the cross-linked hydrogel network. The cross-links can dynamically form and break based on environmental conditions (pH, temperature, presence of specific molecules), enabling the dressing to transition from a stable adherent state during use to a soluble removable state after use.
2Stability of the object's composition
If hydrogel uses high polymer concentration for in situ gel formation, then the gel forms properly at application site, but the gel becomes viscous and flows, making it difficult to retain at specific body surfaces
Solution Approach 1:
The patent utilizes phase transition of polymers from soluble to insoluble state at specific temperatures. The hydrogel is applied as a cold soluble solution that can be easily administered, then undergoes phase transition to form a gel at body temperature, providing retention without requiring high concentrations or complex application procedures.
3Stability of the object's composition
If thermally gelling polymers are used for in situ gel formation, then the polymer gels at body temperature, but the polymer gels before administration due to temperature change during packaging or storage
Solution Approach 1:
The patent changes the triggering parameter for gelation from temperature to pH or specific chemical conditions. The polymer remains soluble during storage and administration regardless of temperature changes, then gels in situ when exposed to specific pH conditions or biochemical triggers at the application site, ensuring reliable timing control.
4Strength
If adhesive gauze or patch products are used to maintain integrity, then the product stays intact during use, but the product is difficult to remove when peeling off from skin
Solution Approach 1:
The patent changes the chemical nature of adhesive bonds from permanent to reversible. The hydrogel uses dynamic covalent bonds that maintain strong adhesion during wound healing but can be reversed by changing pH or adding specific breaking agents, allowing painless removal without peeling.
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 hydrogel provides a conformable, easily removable dressing with prolonged drug release and improved bioadhesive properties, enhancing wound healing and ocular residence time while allowing for controlled drug delivery.
Implementation Method 1
polyethylene glycol (PEG) with sulfhydryl or mercaptan moieties, forming disulfide bonds
Data Source
AI summary
Described is a spray-on hydrogel comprising water-soluble PEG polymers that cross-link in situ to form a hydrogel such that the cross-links are reversible. The hydrogel can be useful as a drug delivery composition, wound dressing or surgery adjuvant. Polyethylene glycol polymer and cross-linker solutions are sprayed simultaneously through a common orifice. Cross-linking via formation of thioether or disulfide bonds is initiated upon mixing, providing rapid gelation. The hydrogel components can be derivatized with RGD peptides or analogs thereof to promote retention in/on a body compartment such as the skin, surface of the eye, or a mucosa such as the vaginal mucosa. The cross-links are reversed using a reducing solution enabling easy removal of the hydrogel by dissolution. Processes for preparation of the cross-linker, RGD derivatized PEG and RGD-linked agents are also disclosed.