WO2016106171A1 - Extremely compliant yet tough hydrogel systems as ultrasound transmission agents - Google Patents
Extremely compliant yet tough hydrogel systems as ultrasound transmission agents Download PDFInfo
- Publication number
- WO2016106171A1 WO2016106171A1 PCT/US2015/066981 US2015066981W WO2016106171A1 WO 2016106171 A1 WO2016106171 A1 WO 2016106171A1 US 2015066981 W US2015066981 W US 2015066981W WO 2016106171 A1 WO2016106171 A1 WO 2016106171A1
- Authority
- WO
- WIPO (PCT)
- Prior art keywords
- hydrogel
- stretching
- tough
- stretched
- polymer network
- Prior art date
Links
- 239000000017 hydrogel Substances 0.000 title claims abstract description 65
- 238000002604 ultrasonography Methods 0.000 title claims description 11
- 230000005540 biological transmission Effects 0.000 title claims description 7
- 229920000642 polymer Polymers 0.000 claims abstract description 23
- 238000000034 method Methods 0.000 claims abstract description 16
- 230000008961 swelling Effects 0.000 claims abstract description 4
- FHVDTGUDJYJELY-UHFFFAOYSA-N 6-{[2-carboxy-4,5-dihydroxy-6-(phosphanyloxy)oxan-3-yl]oxy}-4,5-dihydroxy-3-phosphanyloxane-2-carboxylic acid Chemical compound O1C(C(O)=O)C(P)C(O)C(O)C1OC1C(C(O)=O)OC(OP)C(O)C1O FHVDTGUDJYJELY-UHFFFAOYSA-N 0.000 claims description 7
- 229940072056 alginate Drugs 0.000 claims description 7
- 229920000615 alginic acid Polymers 0.000 claims description 7
- 235000010443 alginic acid Nutrition 0.000 claims description 7
- 229920002401 polyacrylamide Polymers 0.000 claims description 7
- 239000003795 chemical substances by application Substances 0.000 claims description 5
- KIUKXJAPPMFGSW-DNGZLQJQSA-N (2S,3S,4S,5R,6R)-6-[(2S,3R,4R,5S,6R)-3-Acetamido-2-[(2S,3S,4R,5R,6R)-6-[(2R,3R,4R,5S,6R)-3-acetamido-2,5-dihydroxy-6-(hydroxymethyl)oxan-4-yl]oxy-2-carboxy-4,5-dihydroxyoxan-3-yl]oxy-5-hydroxy-6-(hydroxymethyl)oxan-4-yl]oxy-3,4,5-trihydroxyoxane-2-carboxylic acid Chemical compound CC(=O)N[C@H]1[C@H](O)O[C@H](CO)[C@@H](O)[C@@H]1O[C@H]1[C@H](O)[C@@H](O)[C@H](O[C@H]2[C@@H]([C@@H](O[C@H]3[C@@H]([C@@H](O)[C@H](O)[C@H](O3)C(O)=O)O)[C@H](O)[C@@H](CO)O2)NC(C)=O)[C@@H](C(O)=O)O1 KIUKXJAPPMFGSW-DNGZLQJQSA-N 0.000 claims description 3
- 229920000936 Agarose Polymers 0.000 claims description 3
- 229920001661 Chitosan Polymers 0.000 claims description 3
- 102000008186 Collagen Human genes 0.000 claims description 3
- 108010035532 Collagen Proteins 0.000 claims description 3
- 102000009123 Fibrin Human genes 0.000 claims description 3
- 108010073385 Fibrin Proteins 0.000 claims description 3
- BWGVNKXGVNDBDI-UHFFFAOYSA-N Fibrin monomer Chemical compound CNC(=O)CNC(=O)CN BWGVNKXGVNDBDI-UHFFFAOYSA-N 0.000 claims description 3
- 108010010803 Gelatin Proteins 0.000 claims description 3
- 239000002202 Polyethylene glycol Substances 0.000 claims description 3
- 229920001436 collagen Polymers 0.000 claims description 3
- 229960005188 collagen Drugs 0.000 claims description 3
- 229950003499 fibrin Drugs 0.000 claims description 3
- 239000008273 gelatin Substances 0.000 claims description 3
- 229920000159 gelatin Polymers 0.000 claims description 3
- 235000019322 gelatine Nutrition 0.000 claims description 3
- 235000011852 gelatine desserts Nutrition 0.000 claims description 3
- 229920002674 hyaluronan Polymers 0.000 claims description 3
- 229960003160 hyaluronic acid Drugs 0.000 claims description 3
- 229920003213 poly(N-isopropyl acrylamide) Polymers 0.000 claims description 3
- 229920001223 polyethylene glycol Polymers 0.000 claims description 3
- 229920002338 polyhydroxyethylmethacrylate Polymers 0.000 claims description 3
- 229920002451 polyvinyl alcohol Polymers 0.000 claims description 3
- 238000002791 soaking Methods 0.000 claims description 3
- 230000002040 relaxant effect Effects 0.000 claims description 2
- 239000002904 solvent Substances 0.000 abstract description 4
- 239000002243 precursor Substances 0.000 abstract 2
- 239000000499 gel Substances 0.000 description 8
- 238000004132 cross linking Methods 0.000 description 5
- 239000000463 material Substances 0.000 description 3
- HRPVXLWXLXDGHG-UHFFFAOYSA-N Acrylamide Chemical compound NC(=O)C=C HRPVXLWXLXDGHG-UHFFFAOYSA-N 0.000 description 2
- 239000004971 Cross linker Substances 0.000 description 2
- 239000011837 N,N-methylenebisacrylamide Substances 0.000 description 2
- OSGAYBCDTDRGGQ-UHFFFAOYSA-L calcium sulfate Chemical compound [Ca+2].[O-]S([O-])(=O)=O OSGAYBCDTDRGGQ-UHFFFAOYSA-L 0.000 description 2
- 230000003111 delayed effect Effects 0.000 description 2
- 239000007788 liquid Substances 0.000 description 2
- 238000012986 modification Methods 0.000 description 2
- 230000004048 modification Effects 0.000 description 2
- ZIUHHBKFKCYYJD-UHFFFAOYSA-N n,n'-methylenebisacrylamide Chemical compound C=CC(=O)NCNC(=O)C=C ZIUHHBKFKCYYJD-UHFFFAOYSA-N 0.000 description 2
- 239000004160 Ammonium persulphate Substances 0.000 description 1
- ROOXNKNUYICQNP-UHFFFAOYSA-N ammonium persulfate Chemical compound [NH4+].[NH4+].[O-]S(=O)(=O)OOS([O-])(=O)=O ROOXNKNUYICQNP-UHFFFAOYSA-N 0.000 description 1
- 235000019395 ammonium persulphate Nutrition 0.000 description 1
- 230000008094 contradictory effect Effects 0.000 description 1
- 238000007872 degassing Methods 0.000 description 1
- 238000010894 electron beam technology Methods 0.000 description 1
- 239000003999 initiator Substances 0.000 description 1
- 150000002500 ions Chemical class 0.000 description 1
- 239000011159 matrix material Substances 0.000 description 1
- 238000005259 measurement Methods 0.000 description 1
- 230000007246 mechanism Effects 0.000 description 1
- 238000010526 radical polymerization reaction Methods 0.000 description 1
- 230000002441 reversible effect Effects 0.000 description 1
- 239000000523 sample Substances 0.000 description 1
- 238000010257 thawing Methods 0.000 description 1
- 238000011282 treatment Methods 0.000 description 1
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
- B29C71/00—After-treatment of articles without altering their shape; Apparatus therefor
- B29C71/0009—After-treatment of articles without altering their shape; Apparatus therefor using liquids, e.g. solvents, swelling agents
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
- A61B8/00—Diagnosis using ultrasonic, sonic or infrasonic waves
- A61B8/42—Details of probe positioning or probe attachment to the patient
- A61B8/4272—Details of probe positioning or probe attachment to the patient involving the acoustic interface between the transducer and the tissue
- A61B8/4281—Details of probe positioning or probe attachment to the patient involving the acoustic interface between the transducer and the tissue characterised by sound-transmitting media or devices for coupling the transducer to the tissue
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61K—PREPARATIONS FOR MEDICAL, DENTAL OR TOILETRY PURPOSES
- A61K49/00—Preparations for testing in vivo
- A61K49/22—Echographic preparations; Ultrasound imaging preparations ; Optoacoustic imaging preparations
- A61K49/222—Echographic preparations; Ultrasound imaging preparations ; Optoacoustic imaging preparations characterised by a special physical form, e.g. emulsions, liposomes
- A61K49/226—Solutes, emulsions, suspensions, dispersions, semi-solid forms, e.g. hydrogels
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
- C08J3/00—Processes of treating or compounding macromolecular substances
- C08J3/02—Making solutions, dispersions, lattices or gels by other methods than by solution, emulsion or suspension polymerisation techniques
- C08J3/03—Making solutions, dispersions, lattices or gels by other methods than by solution, emulsion or suspension polymerisation techniques in aqueous media
- C08J3/075—Macromolecular gels
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
- C08J3/00—Processes of treating or compounding macromolecular substances
- C08J3/24—Crosslinking, e.g. vulcanising, of macromolecules
- C08J3/246—Intercrosslinking of at least two polymers
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
- A61B17/00—Surgical instruments, devices or methods, e.g. tourniquets
- A61B17/22—Implements for squeezing-off ulcers or the like on the inside of inner organs of the body; Implements for scraping-out cavities of body organs, e.g. bones; Calculus removers; Calculus smashing apparatus; Apparatus for removing obstructions in blood vessels, not otherwise provided for
- A61B17/225—Implements for squeezing-off ulcers or the like on the inside of inner organs of the body; Implements for scraping-out cavities of body organs, e.g. bones; Calculus removers; Calculus smashing apparatus; Apparatus for removing obstructions in blood vessels, not otherwise provided for for extracorporeal shock wave lithotripsy [ESWL], e.g. by using ultrasonic waves
- A61B17/2251—Implements for squeezing-off ulcers or the like on the inside of inner organs of the body; Implements for scraping-out cavities of body organs, e.g. bones; Calculus removers; Calculus smashing apparatus; Apparatus for removing obstructions in blood vessels, not otherwise provided for for extracorporeal shock wave lithotripsy [ESWL], e.g. by using ultrasonic waves characterised by coupling elements between the apparatus, e.g. shock wave apparatus or locating means, and the patient, e.g. details of bags, pressure control of bag on patient
- A61B2017/2253—Implements for squeezing-off ulcers or the like on the inside of inner organs of the body; Implements for scraping-out cavities of body organs, e.g. bones; Calculus removers; Calculus smashing apparatus; Apparatus for removing obstructions in blood vessels, not otherwise provided for for extracorporeal shock wave lithotripsy [ESWL], e.g. by using ultrasonic waves characterised by coupling elements between the apparatus, e.g. shock wave apparatus or locating means, and the patient, e.g. details of bags, pressure control of bag on patient using a coupling gel or liquid
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29K—INDEXING SCHEME ASSOCIATED WITH SUBCLASSES B29B, B29C OR B29D, RELATING TO MOULDING MATERIALS OR TO MATERIALS FOR MOULDS, REINFORCEMENTS, FILLERS OR PREFORMED PARTS, e.g. INSERTS
- B29K2105/00—Condition, form or state of moulded material or of the material to be shaped
- B29K2105/0058—Liquid or visquous
- B29K2105/0061—Gel or sol
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29K—INDEXING SCHEME ASSOCIATED WITH SUBCLASSES B29B, B29C OR B29D, RELATING TO MOULDING MATERIALS OR TO MATERIALS FOR MOULDS, REINFORCEMENTS, FILLERS OR PREFORMED PARTS, e.g. INSERTS
- B29K2995/00—Properties of moulding materials, reinforcements, fillers, preformed parts or moulds
- B29K2995/0037—Other properties
- B29K2995/0078—Shear strength
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
- C08J2300/00—Characterised by the use of unspecified polymers
- C08J2300/14—Water soluble or water swellable polymers, e.g. aqueous gels
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
- C08J2300/00—Characterised by the use of unspecified polymers
- C08J2300/20—Polymers characterized by their physical structure
- C08J2300/208—Interpenetrating networks [IPN]
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
- C08J2333/00—Characterised by the use of homopolymers or copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and only one being terminated by only one carboxyl radical, or of salts, anhydrides, esters, amides, imides, or nitriles thereof; Derivatives of such polymers
- C08J2333/24—Homopolymers or copolymers of amides or imides
- C08J2333/26—Homopolymers or copolymers of acrylamide or methacrylamide
Definitions
- This invention relates to a method for making a tough and compliant hydrogel with a low shear modulus that is extremely tough and robust. It is desirable to have hydrogels be both resilient and tough. A particular use for such a hydrogel is as a transmission agent for ultrasound because resiliency allows it to conform to a body part. Resilience and toughness appear to be intrinsically contradictory properties but can be achieved according to the methods disclosed herein. Summary of the Invention
- the method for making a tough and compliant hydrogel according to the invention includes combining a long chain polymer network to maintain high elasticity and a sacrificial chain polymer network to dissipate mechanical energy to form an interpenetrating hydrogel.
- the interpenetrating hydrogel is prestretched to a prescribed multiple of its original length and then relaxed for multiple cycles. Thereafter, the pre-stretched hydrogel is soaked in a biocompatible medium to reach equilibrium swelling of the hydrogel. As a result, the shear modulus of the hydrogel is significantly reduced. To achieve extremely low modulus, multiple loading-unloading steps are performed to deplete most of the sacrificial polymer network to a control led degree.
- the long chain network may be selected from a group consisting of polyacrylamide, polyethylene glycol, poly (vinyl alcohol), poly (N-isopropyl acrylamide), and poly (2- hydroxyethyl methacrylate).
- the sacrificial cliain network may be selected from the group consisting of alginate, hyaluronic acid, collagen, agarose, gelatin, fibrin and chitosan.
- the hydrogel made by the method of the invention may be used as an ultrasound transmission agent.
- Fig. 1 is a schematic illustration of the steps performed according to the invention to transform a tough and stiff hydrogel into a tough and compliant hydrogel by pre-stretching the gel, relaxing and soaking it in a solvent such media or PBS.
- Fig. 2 is a graph of modulus against pre-stretch. One can see that soaking the pre-stretched hydrogel in solvent can significantly reduce the shear modulus of the hydrogel from over 10 kPa to approximately 1 kPa.
- Fig. 3 is a comparison graph of stress versus stretch for hydrogels with different treatments.
- Figs. 4a and 4b are photographs of the soft and tough hydrogel of the invention conformally attached to different regions of a human body.
- Figs. 5a and 5b are ultrasound images of a phantom object measured through conventional liquid hydrogel as shown in Fig. 5a and the extremely compliant and tough hydrogel of the invention shown in Fig. 5b. Description of the Preferred Embodiment
- hydrogels of the invention can be formed and printed into various shapes with different dimensions. As a result of their low rigidity and high robustness, the gels of the invention can be con formally attached to different regions of the human body. This aspect is important when the novel gel system of the invention is used as an ultrasound transmission agent.
- materials from which the hydrogels are made according to the invention are from two types of polymers.
- One type of polymer maintains high elasticity of the hydrogel and the other type of polymer dissipates mechanical energy when the hydrogel is deformed.
- the first type of polymers include polyacrylamide, polyethylene glycol, poly (vinyl alcohol), poly (N-isopropyl acrylamide), and poly (2-hydroxyethyl methacrylate).
- the second type of polymers include alginate, hyaluronic acid, collagen, agarose, gelatin * fibrin, and chitosan, which are generally capable of reversible crosslinking.
- the first type of polymers are usually crosslinked by methods including free-radical polymerization, UV crosslinking, gamma irradiation, electron beam irradiation and freeze thawing.
- the second type of polymers are usually crosslinked by methods including adding multivalent ions, changing ambient temperature and varying pH of the solution.
- the chain length between two adjacent crosslinkings of the first type polymers is generally much longer than that of the second type polymers.
- the volume concentration of the first type of polymers in the hydrogel can range from 5% to 40%, and that of the second type is usually lower than the first type, ranging from 0.15% to 10%. Therefore, the crosslinking density of the second type polymers is usually much larger than the first type polymers.
- a pre-gel solution was prepared by mixing alginate (Sigma, A20330) and acrylamide (sigma, A8887) into a solution with one to five weight percent of alginate and 5- 40 weight percent of acrylamide.
- the concentration of the N, N-methylenebisacrylamide needs to be very low (i.e., less than 4 x 10-4 g per 10 mL of the polymer solution) to enable the low modulus of the hydrogels in future steps.
- the pre-gel solution After degassing the pre-gel solution in a vacuum chamber, we added calcium sulfate (Sigma, C3771) as the crosslinker for alginate and N, N, N ⁇ N'-tetramethylemylenediamine (Sigma, T7024-50M) as the crosslinking accelerator for polyacrylamide. Thereafter, the pre-gel solution was infused into molds of different shapes and was subjected to ultraviolet light for 60 minutes with 8W power and 254nm wavelength to fabricate the initial hydrogel.
- calcium sulfate Sigma, C3771
- N, N, N ⁇ N'-tetramethylemylenediamine Sigma, T7024-50M
- the as-fabricated pre-gel hydrogels are relatively stiff with a shear modulus over 10 kPa and up to 100 kPa as shown in Fig. 2.
- the inventors have developed an innovative and practical method to reduce the modulus of the hydrogel while maintaining its high fracture toughness. With reference first to Fig. 1, we first prc-stretch the hydrogel for a prescribed time to a multiple of its original length and then relax for multiple cycles.
- the extremely soft and tough hydrogel disclosed herein can be conformally attached to different regions of a human body.
- the material can also conformally deform and wrap around ultrasound probes of various shapes.
- the hydrogel is elastic and extremely tough, it will not flow or fracture as commonly used ultrasound gels do.
- the shear modulus of the hydrogel is very low (approximately 1 kPa). it is expected to give excellent transmission efficiency for ultrasound.
- the extremely compliant and tough hydrogel of the invention gives high quality ultrasound images.
- conventional liquid hydrogel flows away or dehydrates after approximately one minute of measurement
- the novel compliant and tough hydrogel of the invention can last 30 minutes to hours.
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.
Description
EXTREMELY COMPLIANT YET TOUGH HYDROGEL SYSTEMS AS
ULTRASOUND TRANSMISSION AGENTS
Sponsorship Information
This invention was made with government support under grant number N00014-14-1 -
0619 awarded by the Office of Naval Research. The government has certain rights in the invention.
Priority Information
This application claims priority to United States utility application serial number
14/970,704 filed on December 16, 2015 and to provisional application serial number 62/095243 filed on December 22, 2014, the contents of which are incorporated herein by reference. Background of the Invention
This invention relates to a method for making a tough and compliant hydrogel with a low shear modulus that is extremely tough and robust. It is desirable to have hydrogels be both resilient and tough. A particular use for such a hydrogel is as a transmission agent for ultrasound because resiliency allows it to conform to a body part. Resilience and toughness appear to be intrinsically contradictory properties but can be achieved according to the methods disclosed herein. Summary of the Invention
The method for making a tough and compliant hydrogel according to the invention includes combining a long chain polymer network to maintain high elasticity and a sacrificial chain polymer network to dissipate mechanical energy to form an interpenetrating hydrogel. The interpenetrating hydrogel is prestretched to a prescribed multiple of its original length and then relaxed for multiple cycles. Thereafter, the pre-stretched hydrogel is soaked in a biocompatible medium to reach equilibrium swelling of the hydrogel. As a result, the shear modulus of the hydrogel is significantly reduced. To achieve extremely low modulus, multiple loading-unloading steps are performed to deplete most of the sacrificial polymer network to a control led degree.
The long chain network may be selected from a group consisting of polyacrylamide, polyethylene glycol, poly (vinyl alcohol), poly (N-isopropyl acrylamide), and poly (2- hydroxyethyl methacrylate). The sacrificial cliain network may be selected from the group consisting of alginate, hyaluronic acid, collagen, agarose, gelatin, fibrin and chitosan. The hydrogel made by the method of the invention may be used as an ultrasound transmission agent.
Brief Description of the Drawing
Fig. 1 is a schematic illustration of the steps performed according to the invention to transform a tough and stiff hydrogel into a tough and compliant hydrogel by pre-stretching the gel, relaxing and soaking it in a solvent such media or PBS.
Fig. 2 is a graph of modulus against pre-stretch. One can see that soaking the pre-stretched hydrogel in solvent can significantly reduce the shear modulus of the hydrogel from over 10 kPa to approximately 1 kPa.
Fig. 3 is a comparison graph of stress versus stretch for hydrogels with different treatments.
Figs. 4a and 4b are photographs of the soft and tough hydrogel of the invention conformally attached to different regions of a human body.
Figs. 5a and 5b are ultrasound images of a phantom object measured through conventional liquid hydrogel as shown in Fig. 5a and the extremely compliant and tough hydrogel of the invention shown in Fig. 5b.
Description of the Preferred Embodiment
We have invented a method and material system to make new hydrogels that have a shear modulus as low as 1 kPa but are extremely tough and robust. The extraordinary properties of the hydrogels are achieved through the mechanisms of delayed stiffening and mechanical dissipation. The hydrogels of the invention can be formed and printed into various shapes with different dimensions. As a result of their low rigidity and high robustness, the gels of the invention can be con formally attached to different regions of the human body. This aspect is important when the novel gel system of the invention is used as an ultrasound transmission agent.
Tn general, materials from which the hydrogels are made according to the invention are from two types of polymers. One type of polymer maintains high elasticity of the hydrogel and the other type of polymer dissipates mechanical energy when the hydrogel is deformed. The first type of polymers include polyacrylamide, polyethylene glycol, poly (vinyl alcohol), poly (N-isopropyl acrylamide), and poly (2-hydroxyethyl methacrylate). The second type of polymers include alginate, hyaluronic acid, collagen, agarose, gelatin* fibrin, and chitosan, which are generally capable of reversible crosslinking.
The first type of polymers are usually crosslinked by methods including free-radical polymerization, UV crosslinking, gamma irradiation, electron beam irradiation and freeze thawing. The second type of polymers are usually crosslinked by methods including adding multivalent ions, changing ambient temperature and varying pH of the solution. The chain length between two adjacent crosslinkings of the first type polymers is generally much longer than that of the second type polymers. In addition, the volume concentration of the first type of polymers in the hydrogel can range from 5% to 40%, and that of the second type is usually lower than the first type, ranging from 0.15% to 10%. Therefore, the crosslinking density of the second type polymers is usually much larger than the first type polymers. The possible combination of different polymers to form tough hydrogels are summarized in the matrix shown in Table 1.
An example protocol for making a specific hydrogel with polyacrylamide and alginate is now described. A pre-gel solution was prepared by mixing alginate (Sigma, A20330) and acrylamide (sigma, A8887) into a solution with one to five weight percent of alginate and 5- 40 weight percent of acrylamide. We then added N, N-methylenebisacrylamide (Sigma, 146072) as the crosslinker for polyacrylamide and ammonium persulphate (Sigma, 248614) as photo initiator for polyacrylamide. The concentration of the N, N-methylenebisacrylamide needs to be very low (i.e., less than 4 x 10-4 g per 10 mL of the polymer solution) to enable the low modulus of the hydrogels in future steps. After degassing the pre-gel solution in a vacuum chamber, we added calcium sulfate (Sigma, C3771) as the crosslinker for alginate and N, N, N\ N'-tetramethylemylenediamine (Sigma, T7024-50M) as the crosslinking accelerator for polyacrylamide. Thereafter, the pre-gel solution was infused into molds of different shapes and was subjected to ultraviolet light for 60 minutes with 8W power and 254nm wavelength to fabricate the initial hydrogel.
The as-fabricated pre-gel hydrogels are relatively stiff with a shear modulus over 10 kPa and up to 100 kPa as shown in Fig. 2. The inventors have developed an innovative and practical method to reduce the modulus of the hydrogel while maintaining its high fracture toughness. With reference first to Fig. 1, we first prc-stretch the hydrogel for a prescribed time to a multiple of its original length and then relax for multiple cycles.
We then soak the pre-stretched hydrogel in a biocompatible solvent such as PBS or media over a period of time to reach equilibrium swelling of the hydrogel. We then stretched the hydrogel again to a ratio higher than the first pre-stretch
and then relax for multiple cycles. As a result, the shear modulus of the hydrogel will be significantly reduced as shown in Fig. 2. For example, when the ratio of the second stretch , the shear
modulus of the hydrogel is reduced to approximately 1 kPa. Although the resultant hydrogel has a very low shear modulus, it is still very tough as indicated by the stress versus strain curve of the hydrogel under loading and unloading. With reference to Fig. 3 it can be seen that the pre-stretched and soaked hydrogel still provides very high stretchability (over 1 1 times) and significant mechanical dissipation indicated by the hysteresis loop. The combination of high stretchability and mechanical dissipation give high fracture toughness to the resulting compliant hydrogel.
As shown in Figs. 4a and 4b, the extremely soft and tough hydrogel disclosed herein can be conformally attached to different regions of a human body. The material can also conformally deform and wrap around ultrasound probes of various shapes. In addition, because the hydrogel is elastic and extremely tough, it will not flow or fracture as commonly used ultrasound gels do. Furthermore, since the shear modulus of the hydrogel is very low (approximately 1 kPa). it is expected to give excellent transmission efficiency for ultrasound. As shown in figs. 5a and 5 b, the extremely compliant and tough hydrogel of the invention gives high quality ultrasound images. However, whereas conventional liquid hydrogel flows away or dehydrates after approximately one minute of measurement, the novel compliant and tough hydrogel of the invention can last 30 minutes to hours.
Additional information concerning this invention may be found in Lin et al., "Designing Extremely Resilient and Tough Mydrogels via Delayed Dissipation", Extreme Mechanics Letters 1 (2014) 70-75. Reference may also be made to international publication number WO2013/103956. The contents of both of these references are incorporated herein by reference.
It is recognized that modifications and variations of the invention will be apparent to those of ordinary skill in the art and it is intended that all such modifications and variations be included within the scope of the appended claims.
Claims
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.
Applications Claiming Priority (4)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US201462095243P | 2014-12-22 | 2014-12-22 | |
US62/095,243 | 2014-12-22 | ||
US14/970,704 US9878506B2 (en) | 2014-12-22 | 2015-12-16 | Compliant yet tough hydrogel systems as ultrasound transmission agents |
US14/970,704 | 2015-12-16 |
Publications (1)
Publication Number | Publication Date |
---|---|
WO2016106171A1 true WO2016106171A1 (en) | 2016-06-30 |
Family
ID=56128456
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
PCT/US2015/066981 WO2016106171A1 (en) | 2014-12-22 | 2015-12-21 | Extremely compliant yet tough hydrogel systems as ultrasound transmission agents |
Country Status (2)
Country | Link |
---|---|
US (2) | US9878506B2 (en) |
WO (1) | WO2016106171A1 (en) |
Cited By (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CN109054052A (en) * | 2018-07-24 | 2018-12-21 | 武汉工程大学 | A kind of preparation method of high tenacity dual network physical crosslinking selfreparing hydrogel |
US10872736B2 (en) | 2018-05-29 | 2020-12-22 | City University Of Hong Kong | Robust electrical component and an electrolyte for use in an electrical component |
US11362367B2 (en) | 2019-04-15 | 2022-06-14 | City University Of Hong Kong | Electrical energy storage device and a method of preparing the same |
US11387456B2 (en) | 2019-05-23 | 2022-07-12 | City University Of Hong Kong | Energy storage device and a method of preparing the device |
Families Citing this family (13)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US8939909B2 (en) | 2011-10-28 | 2015-01-27 | Decision Sciences International Corporation | Spread spectrum coded waveforms in ultrasound imaging |
US9844359B2 (en) | 2013-09-13 | 2017-12-19 | Decision Sciences Medical Company, LLC | Coherent spread-spectrum coded waveforms in synthetic aperture image formation |
US10743838B2 (en) * | 2015-02-25 | 2020-08-18 | Decision Sciences Medical Company, LLC | Acoustic signal transmission couplants and coupling mediums |
CA3001315C (en) | 2015-10-08 | 2023-12-19 | Decision Sciences Medical Company, LLC | Acoustic orthopedic tracking system and methods |
CN108938089A (en) * | 2017-05-19 | 2018-12-07 | 新加坡国立大学 | The manufacturing method of soft robot |
US11154274B2 (en) | 2019-04-23 | 2021-10-26 | Decision Sciences Medical Company, LLC | Semi-rigid acoustic coupling articles for ultrasound diagnostic and treatment applications |
JP7262329B2 (en) * | 2019-07-05 | 2023-04-21 | 富士フイルムヘルスケア株式会社 | Acoustic coupler gel and manufacturing method thereof |
CN111701035B (en) * | 2020-06-28 | 2022-09-06 | 南京超维景生物科技有限公司 | Ultrasonic contrast agent composition, ultrasonic contrast agent, preparation method of ultrasonic contrast agent and application of acoustic deformation material |
EP4243696A1 (en) | 2020-11-13 | 2023-09-20 | Decision Sciences Medical Company, LLC | Systems and methods for synthetic aperture ultrasound imaging of an object |
CN113652050B (en) * | 2021-06-30 | 2023-07-25 | 广东粤港澳大湾区国家纳米科技创新研究院 | Hydrogel film, preparation method thereof and ultrasonic coupling patch |
CN115477767B (en) * | 2022-10-17 | 2024-03-29 | 四川大学 | Conductive polymer hydrogel and preparation method and application thereof |
CN116549675B (en) * | 2023-05-10 | 2024-01-23 | 苏州大学附属儿童医院 | Non-irritating medical ultrasonic coupling agent and preparation method thereof |
CN116271113B (en) * | 2023-05-24 | 2023-08-08 | 四川大学华西医院 | Multifunctional photo-curing sound guide gel and preparation method and application thereof |
Citations (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US20100055184A1 (en) * | 2008-09-04 | 2010-03-04 | Zeitels Steven M | Hydrogels for vocal cord and soft tissue augmentation and repair |
WO2013103956A1 (en) | 2012-01-05 | 2013-07-11 | President And Fellows Of Harvard College | Interpenetrating networks with covalent and ionic crosslinks |
CN104311841A (en) * | 2014-09-30 | 2015-01-28 | 江南大学 | Method for preparing high-intensity covalence/ion interpenetrating polymer network easily molded gel |
Family Cites Families (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US8978570B2 (en) | 2012-01-05 | 2015-03-17 | Oceaneering International, Inc. | Lifting floor for bodies of water |
-
2015
- 2015-12-16 US US14/970,704 patent/US9878506B2/en active Active
- 2015-12-21 WO PCT/US2015/066981 patent/WO2016106171A1/en active Application Filing
-
2017
- 2017-12-19 US US15/846,301 patent/US20180126677A1/en not_active Abandoned
Patent Citations (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US20100055184A1 (en) * | 2008-09-04 | 2010-03-04 | Zeitels Steven M | Hydrogels for vocal cord and soft tissue augmentation and repair |
WO2013103956A1 (en) | 2012-01-05 | 2013-07-11 | President And Fellows Of Harvard College | Interpenetrating networks with covalent and ionic crosslinks |
CN104311841A (en) * | 2014-09-30 | 2015-01-28 | 江南大学 | Method for preparing high-intensity covalence/ion interpenetrating polymer network easily molded gel |
Non-Patent Citations (6)
Title |
---|
CHANGCHENG HE ET AL: "Tough and super-resilient hydrogels synthesized by using peroxidized polymer chains as polyfunctional initiating and cross-linking centers", SOFT MATTER, vol. 9, no. 10, 24 January 2013 (2013-01-24), GB, pages 2837, XP055266080, ISSN: 1744-683X, DOI: 10.1039/c2sm27605d * |
DATABASE WPI Week 201523, Derwent World Patents Index; AN 2015-18829N, XP002756618 * |
HOSSEIN OMIDIAN ET AL: "Elastic, Superporous Hydrogel Hybrids of Polyacrylamide and Sodium Alginate", MACROMOLECULAR BIOSCIENCE, vol. 6, no. 9, 15 September 2006 (2006-09-15), pages 703 - 710, XP055054987, ISSN: 1616-5187, DOI: 10.1002/mabi.200600062 * |
LIN ET AL.: "Designing Extremely Resilient and Tough Hydrogels via Delayed Dissipation", EXTREME MECHANICS LETTERS, vol. 1, 2014, pages 70 - 75 |
QUNWEI TANG ET AL: "Fabrication of a high-strength hydrogel with an interpenetrating network structure", COLLOIDS AND SURFACES. A, PHYSICACHEMICAL AND ENGINEERING ASPECTS, vol. 346, no. 1-3, 9 June 2009 (2009-06-09), NL, pages 91 - 98, XP055266081, ISSN: 0927-7757, DOI: 10.1016/j.colsurfa.2009.05.031 * |
SHAOTING LIN ET AL: "Designing extremely resilient and tough hydrogels via delayed dissipation", EXTREME MECHANICS LETTERS, vol. 1, 24 December 2014 (2014-12-24), pages 70 - 75, XP055265648, ISSN: 2352-4316, DOI: 10.1016/j.eml.2014.11.002 * |
Cited By (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US10872736B2 (en) | 2018-05-29 | 2020-12-22 | City University Of Hong Kong | Robust electrical component and an electrolyte for use in an electrical component |
CN109054052A (en) * | 2018-07-24 | 2018-12-21 | 武汉工程大学 | A kind of preparation method of high tenacity dual network physical crosslinking selfreparing hydrogel |
US11362367B2 (en) | 2019-04-15 | 2022-06-14 | City University Of Hong Kong | Electrical energy storage device and a method of preparing the same |
US11387456B2 (en) | 2019-05-23 | 2022-07-12 | City University Of Hong Kong | Energy storage device and a method of preparing the device |
Also Published As
Publication number | Publication date |
---|---|
US20160176128A1 (en) | 2016-06-23 |
US20180126677A1 (en) | 2018-05-10 |
US9878506B2 (en) | 2018-01-30 |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
US9878506B2 (en) | Compliant yet tough hydrogel systems as ultrasound transmission agents | |
US4480642A (en) | Dilation device for the cervix | |
JP6338263B2 (en) | Low hydrous soft device and manufacturing method thereof | |
US4452776A (en) | Hydrogel implant article and method | |
JP5432133B2 (en) | Monomer composition for silicon hydrogel for soft contact lens and soft contact lens produced by the monomer composition | |
JP5096793B2 (en) | Polymer composition and ophthalmic lens body | |
RU2011127047A (en) | OPHTHALMIC DEVICES FOR DELIVERY OF HYDROPHOBIC ENSURING COMFORT AGENTS | |
RU2013126920A (en) | POLYMER HYDROGELS AND METHODS FOR THEIR PREPARATION | |
JPH01503072A (en) | Wettable, hydrophilic, flexible and oxygen permeable copolymer composition | |
RU2014152725A (en) | CONTACT LENSES containing water-soluble polymers or copolymers of N- (2-hydroxyalkyl) methacrylamide | |
US20100318185A1 (en) | Biomedical Devices | |
JP2011522934A (en) | Silicone-containing copolymer-based hydrogels | |
JPWO2011102356A1 (en) | Low hydrous soft ophthalmic lens and manufacturing method thereof | |
JPWO2013024801A1 (en) | Medical device and manufacturing method thereof | |
JP6070193B2 (en) | Medical device and manufacturing method thereof | |
GB2199672A (en) | Swellable synthetic intraocular lens | |
Zhuang et al. | High‐strength, tough, rapidly self‐recoverable, and fatigue‐resistant hydrogels based on multi‐network and multi‐bond toughening mechanism | |
JPWO2013024856A1 (en) | Medical device and manufacturing method thereof | |
CN114409930B (en) | Gel material with skin-like characteristics and preparation method and application thereof | |
CN115197522B (en) | High-water-content high-oxygen-permeability silicon hydrogel, cornea contact lens and preparation method of cornea contact lens | |
Zhang et al. | Strengthening poly (2-hydroxyethyl methacrylate) hydrogels using biochars and hydrophobic aggregations | |
EP0034174A4 (en) | Hydrogel implant article and method. | |
EP2178931A1 (en) | High ion and metabolite flux lenses and materials | |
EP3662809A1 (en) | Hood for endoscope | |
JP2005160565A (en) | Intraocular lens |
Legal Events
Date | Code | Title | Description |
---|---|---|---|
121 | Ep: the epo has been informed by wipo that ep was designated in this application |
Ref document number: 15834777 Country of ref document: EP Kind code of ref document: A1 |
|
NENP | Non-entry into the national phase |
Ref country code: DE |
|
122 | Ep: pct application non-entry in european phase |
Ref document number: 15834777 Country of ref document: EP Kind code of ref document: A1 |