Polymer Hydrogel Adhesives via Oxidative Crosslinking
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Solution Overview
Problem
Current native chemical ligation (NCL) methods for hydrogel synthesis face challenges such as slow reaction kinetics, cytotoxicity from thiol leaving groups, and hydrolytic instability, limiting their application in biological settings.
Innovation Solution
The use of oxo-ester mediated native chemical ligation (OMNCL) between NHS-activated ester and N-terminal cysteine groups in polymer precursors, forming rapid, biocompatible hydrogels through amide and disulfide bonding at physiological pH, avoiding toxic side products.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If standard NCL conditions are used with strong reducing agents, then the NCL reaction can proceed, but cytotoxicity is generated in living systems
Solution Approach 1:
The patent converts the harmful cytotoxic thiol leaving group into a beneficial disulfide crosslink by using oxidative conditions. The thiol that would normally be toxic is instead oxidized to form a stable disulfide bond, transforming a harmful byproduct into a useful crosslinking mechanism that strengthens the hydrogel network without cytotoxicity.
Solution Approach 2:
The patent changes the redox state parameter from reducing to oxidative conditions. By using oxidative agents instead of reducing agents, the reaction environment is fundamentally altered to prevent thiol release and instead promote disulfide formation, thereby eliminating cytotoxicity while maintaining reaction reliability.
2Reliability
If standard NCL conditions are used, then cross-linking can occur, but the reaction rate is slow
Solution Approach 1:
The patent changes the redox parameter from reducing to oxidative conditions, which fundamentally accelerates the reaction rate. The oxidative environment promotes faster thiol oxidation and disulfide bond formation, increasing productivity while maintaining reliable cross-linking.
Solution Approach 2:
The patent establishes continuous oxidative cross-linking that proceeds rapidly and completely. The oxidative mechanism ensures continuous and efficient cross-linking without the slow, stepwise progression of standard NCL, achieving both high productivity and reliable network formation.
3Reliability
If thioester-activated C-terminus is used in NCL, then peptide synthesis can proceed, but hydrolytic instability occurs
Solution Approach 1:
The patent converts the hydrolytically unstable thioester into a stable disulfide crosslink. The thioester that would normally be unstable and prone to hydrolysis is instead transformed through oxidative cross-linking into a stable disulfide bond, eliminating the stability problem while maintaining reaction reliability.
Solution Approach 2:
The patent changes the chemical nature from thioester-based to disulfide-based crosslinking. This parameter change fundamentally improves stability by replacing the hydrolytically labile thioester with the oxidation-resistant disulfide bond, achieving both reliable reaction and stable composition.
4Reliability
If NCL is used for hydrogel synthesis, then chemoselectivity is achieved, but adverse biological effects from thiol leaving group occur
Solution Approach 1:
The patent converts the harmful thiol leaving group into a beneficial disulfide crosslink through oxidative conditions. The thiol that causes adverse biological effects is instead oxidized to form a stable, non-toxic disulfide bond, maintaining chemoselectivity while eliminating biological harm.
Solution Approach 2:
The patent changes the redox parameter to oxidative conditions, which fundamentally alters the biological interaction. The oxidative environment prevents thiol release and promotes disulfide formation, maintaining chemoselective cross-linking while eliminating adverse biological effects associated with thiol leaving groups.
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
OMNCL hydrogels exhibit rapid formation, high biocompatibility, and strong adhesive properties, suitable for in vivo applications like wound healing and tissue engineering with minimal inflammatory response.
Implementation Method 1
forming an amide bond between the carboxyl carbon of the N-Hydroxysuccinimide (NHS) ester group of the first macromonomer and the primary amine of the terminal cysteine group of the second macromonomer
Implementation Method 2
forming a disulfide bond between primary thiol groups on two of the third macromonomers produced in step (a)
Data Source
AI summary
The present invention encompasses biocompatible reactants, biocompatible product hydrogels, methods of use thereof, and methods of synthesis thereof using a novel crosslinking mechanism between a first reactant compound including an N-Hydroxysuccinimide (NHS) ester group and a second reactant compound including a N-terminal cysteine amine group. In certain embodiments, one or more of the reactant compounds may be a macromonomer.