Compliant yet tough hydrogel systems as ultrasound transmission agents

Patent metadata

Field	Value
Publication number	US-9878506-B2
Application number	US-201514970704-A
Country	US
Kind code	B2
Filing date	Dec 16, 2015
Priority date	Dec 22, 2014
Publication date	Jan 30, 2018
Grant date	Jan 30, 2018

Abstract

Method for making a tough and compliant hydrogel. A precursor hydrogel is made of a first polymer selected to maintain high elasticity and a second polymer selected to dissipate mechanical energy. The precursor hydrogel is stretched to a multiple of its original length to form a pre-stretched hydrogel. The pre-stretched hydrogel is allowed to relax and is soaked in a biocompatible solvent to reach equilibrium swelling of the pre-stretched hydrogel whereby shear modulus of the hydrogel is reduced.

First claim

What is claimed is:

1. Method for making a tough and compliant hydrogel comprising:
combining a polymer network selected to maintain elasticity and a sacrificial chain polymer network to dissipate mechanical energy to form an interpenetrating hydrogel;
stretching the interpenetrating hydrogel a first time to a first multiple of its original length to form a pre-stretched hydrogel;
allowing the pre-stretched hydrogel to relax;
soaking the relaxed hydrogel in a biocompatible solvent to reach equilibrium swelling of the hydrogel; and
stretching the interpenetrating hydrogel a second time to a second multiple of its original length wherein the second multiple is greater than the first multiple, whereby shear modulus of the hydrogel is reduced.

2. The method of claim 1 wherein the multiple of its original length is in the range of 2-10.

3. The method of claim 1 wherein the polymer network is selected from the group consisting of polyacrylamide, polyethylene glycol, poly (vinyl alcohol), poly (N-isopropyl acrylamide), and poly (2-hydroxyethylmethacrylate).

4. The method of claim 1 wherein the sacrificial chain polymer network is selected from the group consisting of alginate, hyaluronic acid, collagen, agarose, gelatin, fibrin and chitosan.

Assignees

• Massachusetts Inst Technology

Inventors

• Zhao Xuanhe
• Lin Shaoting
• Yuk Hyunwoo

Classifications

• C08J2300/208

  Interpenetrating networks [IPN] · CPC title

• C08J3/246

  Intercrosslinking of at least two polymers · CPC title

• B29K2995/0078

  Shear strength · CPC title

• C08J3/075

  Macromolecular gels · CPC title

• B29C71/0009 Primary

  using liquids, e.g. solvents, swelling agents (spectacle cases, e.g. for cleaning contact lenses A45C11/04; disinfecting or sterilising contact lenses A61L12/00, using liquid substances A61L2/20; cleaning involving the use of liquid in general B08B3/00; for hydrating contact lenses B29D11/00067) · CPC title