Cholesterol-Modified Hyaluronic Acid Hydrogels With Tunable Viscoelasticity

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Solution Overview

Problem

Current methods for crosslinking hyaluronic acid (HA) hydrogels lack the ability to stoichiometrically control viscoelasticity, leading to limited tuning of hydrogel properties, and existing synthetic polymers like PEG can cause immune responses and hinder cell adhesion.

Innovation Solution

Covalently-modified hyaluronic acid polymers, functionalized with cholesterol moieties and crosslinked using click chemistry, such as strain-promoted alkyne-azide cycloaddition (SPAAC), to form nanoparticles, microparticles, and 3D viscoelastic hydrogels.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If photo-crosslinking is used to crosslink hyaluronic acid, then crosslinking efficiency is improved, but cell viability deteriorates due to UV damage

Engineering Contradiction:

Improvecrosslinking efficiencyVSAvoidcell viability

Core Design Contradiction:

ProductivityVSObject-affected harmful factors

Solution Approach 1:

The patent replaces photo-crosslinking (which uses UV light/energy) with catalyst-free thiol-ene click chemistry that proceeds under physiological conditions without UV irradiation, thereby eliminating UV damage to encapsulated cells while maintaining crosslinking efficiency

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent changes the reaction conditions from UV irradiation to physiological temperature and pH, enabling crosslinking to proceed under biocompatible conditions that preserve cell viability while achieving effective hydrogel formation

Inventive Principle:

Principle #35Parameter changes

2Reliability

If PEG is used as a synthetic polymer for hydrogels, then biocompatibility is improved, but immune response is reduced due to low-fouling nature preventing cell adhesion

Engineering Contradiction:

ImprovebiocompatibilityVSAvoidimmune response and cell adhesion

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent uses hyaluronic acid, a native biopolymer that combines biocompatibility with inherent cell-adhesive properties through CD44 receptor interactions, eliminating the need for PEG and its associated low-fouling issues while maintaining reliability

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

The patent changes from synthetic PEG polymer to native hyaluronic acid biopolymer, fundamentally altering the material's interaction with cells and immune system to provide both biocompatibility and natural cell adhesion capabilities

Inventive Principle:

Principle #35Parameter changes

3Stability of the object's composition

If covalent crosslinking is used to form HA hydrogels, then structural stability is improved, but viscoelasticity tuning capability deteriorates

Engineering Contradiction:

Improvestructural stabilityVSAvoidviscoelasticity tuning capability

Core Design Contradiction:

Stability of the object's compositionVSAdaptability or versatility

Solution Approach 1:

The patent introduces dynamic reversible crosslinks through host-guest interactions that can respond to environmental stimuli, enabling the hydrogel to dynamically adjust its viscoelastic properties while maintaining structural stability through the reversible nature of these crosslinks

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The patent incorporates functional groups with varying crosslinking densities and strengths that allow stoichiometric control over viscoelasticity, enabling precise tuning of mechanical properties while maintaining structural integrity through controlled crosslinking parameters

Inventive Principle:

Principle #35Parameter changes

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 modified HA polymers provide enhanced control over viscoelasticity and biocompatibility, enabling stable encapsulation of cells and active agents, with improved cell adhesion and proliferation, and facilitate controlled release applications.

Implementation Method 1

the dynamic ionic crosslinking or π-π stacking/hydrophobic interaction based physical crosslinking were exploited to influence encapsulated cell behavior

Methodology Applied

Scientific EffectHydrophobic interaction: Hydrophobe