Extremely Compliant Yet Tough Hydrogel Systems as Ultrasound Transmission Agents

Patent metadata

Field	Value
Publication number	US-2016176128-A1
Application number	US-201514970704-A
Country	US
Kind code	A1
Filing date	Dec 16, 2015
Priority date	Dec 22, 2014
Publication date	Jun 23, 2016
Grant date	—

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 long chain polymer network selected to maintain high elasticity and a sacrificial chain polymer network to dissipate mechanical energy to form an interpenetrating hydrogel; stretching the interpenetrating hydrogel to a multiple of its original length to form a pre-stretched hydrogel; allowing the pre-stretched hydrogel to relax; and soaking the relaxed hydrogel in a biocompatible medium to reach equilibrium swelling of the hydrogel whereby shear modulus of the hydrogel is reduced.

2 . The method of claim 1 including multiple stretching and relaxing steps.

3 . The method of claim 2 including a second stretching wherein the second stretching is greater than the first stretching.

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

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

6 . 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.

7 . Hydrogel made by the method of claims 1 - 6 used as an ultrasound transmission agent.

Assignees

• Massachusetts Inst Technology

Inventors

• Zhao Xuanhe
• Lin Shaoting
• Yuk Hyunwoo

Classifications

• 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

• A61K49/226

  Solutes, emulsions, suspensions, dispersions, semi-solid forms, e.g. hydrogels · CPC title

• B29K2105/0061

  Gel or sol · CPC title

• C08J2300/208

  Interpenetrating networks [IPN] · CPC title

• B29K2995/0078

  Shear strength · CPC title