WO1992002005A2 - Transition de phase d'un gel commandee par l'interaction d'un stimulus - Google Patents

Transition de phase d'un gel commandee par l'interaction d'un stimulus Download PDF

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Publication number
WO1992002005A2
WO1992002005A2 PCT/US1991/005312 US9105312W WO9202005A2 WO 1992002005 A2 WO1992002005 A2 WO 1992002005A2 US 9105312 W US9105312 W US 9105312W WO 9202005 A2 WO9202005 A2 WO 9202005A2
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WIPO (PCT)
Prior art keywords
phase
gel
transition
tranεition
modifying agent
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PCT/US1991/005312
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English (en)
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WO1992002005A3 (fr
Inventor
Toyoichi Tanaka
Etsuo Kokufuta
Yong-Quing Zhang
Atsushi Suzuki
Akira Mamada
Yoshitsugu Hirokawa
Masayuki Tokita
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Massachusetts Institute Of Technology
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Publication of WO1992002005A2 publication Critical patent/WO1992002005A2/fr
Publication of WO1992002005A3 publication Critical patent/WO1992002005A3/fr

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    • 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
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
    • C08F8/00—Chemical modification by after-treatment
    • 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
    • C08J2300/10—Polymers characterised by the presence of specified groups, e.g. terminal or pendant functional groups

Definitions

  • Gels can exhibit phase transitions, or discontinuous volume change, in response to var-iation of the surrounding conditions.
  • the fluid supporting a gel can be modified to effect a discontinuous contraction or expansion of a gel such as by changing the pH, solvent composition, relative concentration of solvents or the ion concentration of the fluid.
  • phase transition of gels typically has been a function of conditions of surrounding fluids which are unaffected by the gels, per se. Discontinuous rates of expansion and contraction of gels have generally been limited, therefore, to variation of conditions unrelated to the conditions which are to be modified by the presence of the gels. Further, the conditions under which gels exhibit phase transitions have been limited to conditions which directly affect the polymer network of the gel. Summary of the Invention
  • the present invention relates to phase-transition gels and to methods of forming phase-transition gels which undergo a significant discontinuous volume change at a desired phase-transition condition in response to a stimulus.
  • a phase-transition gel which undergoes a significant discontinuous volume change at a desired phase-transition condition in response to a stimulus includes a liquid medium gelled with a polymer network which has a phase transition condition different from that desired.
  • a phase-tran ⁇ ition- modifying agent is incorporated into the phase-transition gel in an amount sufficient to cause, in response to the stimulus, the discontinuous volume change of said gel at the desired phase-transition condition in response to the stimulus.
  • a method of forming a phase-transition gel which undergoes a significant discontinuous volume change at a desired phase-transition condition in response to a stimulus includes gelling a liquid medium with a polymer network to form a phase-transition gel which has a phase-transition condition different from that desired.
  • a phase-transition-modifying agent is incorporated in the phase-transition gel in an amount sufficient to cause, in response to the stimulus, the discontinuous volume change of said gel at the desired phase-transition condition.
  • Thi ⁇ inventions has many advantages and uses. Importantly, it provides the capabalility to engineer gels having a phase-transition at any desired condition.
  • These engineered gels have many uses. For example, they can be used as sensors of the stimulus. For example, the ratio of substrate to product can be sensed by rapid expansion of the gels when the ratio of substrate to product exceeds a maximum limit.
  • Gels of the present invention can also be used to model biological activities by triggering a phase transition of the gels in the presence of a stimulus. Also, biological function can be simulated by the gels. Examples of such functions are muscular contraction and nerve excitation. Also, actuators, transducers, memories, controlled release systems and selective pumps can be formed using gels of the present invention.
  • Figure 1 is a schematic representation of a memory device of the present invention.
  • Figure 2 is a schematic representation of a sensor device of the present invention.
  • Figure 3 is a schematic representation of an actuator device of the present invention.
  • Figure 4 is a schematic representation of a transducer of the present invention.
  • Figure 5 is a schematic representation of a light pump of the present invention.
  • Figure 6 is a schematic representation of a chemical release system of the present invention.
  • Figure 7 is a plot of the volume of an enzyme- free gel relative to the volume of the gel in a contracted phase over a temperature range during phase transition between an expanded phase and a contracted phase.
  • Figure 8 is a plot of the volume of a gel containing active enzyme and of a gel containing an inactivated enzyme relative to volumes of the gels in a contracted phase over a temperature range during phase transition between an expanded phase and a contracted phase.
  • Figure 9 is a plot of phase transition over time of a gel containing active enzyme and of an enzyme- free gel. Both gels are immersed in a solution containing a sufficient concentration of substrate to thereby cause the gels to exhibit a phase transition.
  • Figure 10 is a plot of phase transition of a gel containing a chlorophyllin during a change of temperature at various intensities of light.
  • Figure 11 is a plot of phase transition of a gel containing a chlorophyllin at constant temperature during exposure of the gel to a change of light intensity.
  • phase-transition gel and method of forming the phase-transition gel of the invention will now be ore particularly described and pointed out in the claims. It will be understood that the particular embodiments of the invention are shown by way of illustration and not as limitations of the invention. The principle features of this invention can be employed in various embodiments without departing from the scope of the invention.
  • Phase-transition of gels means a discontinuous volume change of gels between an expanded phase and a contracted phase.
  • Phase-transition gels are gels which exhibit a phase transition at a phase transition condition.
  • the difference in volume between the expanded phase of phase-transition gels and the contracted phase of the phase-transition gels can be hundreds of orders of magnitude.
  • Examples of phase-transition gels are disclosed in Tanaka, et al. , U.S. Patent No. 4,732,930 and in U.S. Patent Applications 07/425,788 and 07/470,977, the teachings of which are incorporated by reference.
  • phase-transition gel of the present invention undergoes a significant discontinuous volume change at a desired phase-transition condition in response to a stimulus.
  • the phase transition gel includes a liquid medium gelled with a polymer network which has a phase transition condition different from that desired.
  • the liquid medium is suitable if it can be gelled with a polymer network to thereby form a phase-transition gel.
  • suitable liquids include water, aqueous solutions, organic and inorganic liquids.
  • the liquid medium also can be a solution or a mixture of liquids.
  • An example of a suitable aqueous solution is a dioxane solution.
  • the polymer networks can comprise natural polymers, synthetic polymers, copolymers of natural and synthetic polymers or cross-linked synthetic and natural polymers.
  • Examples of synthetic polymer networks include N-isopropylacrylamide, N-isopropylacrylamide-acrylic acid copolymer gels, etc.
  • natural polymers include deoxyribonucleic acid, ribonucleic acid, etc.
  • Phase-transition conditions at which the phase- transition gels exhibit a discontinuous volume change include physical conditions, chemical conditions or combinations of physical and chemical conditions.
  • physical phase-transition conditions include: temperature; electromagnetic radiation, such as infrared energy, visible light and ultraviolet light; etc.
  • chemical phase-transition conditions include: concentration of ionic species, such as hydrogen and water, i.e. pH; crosslinking agents, i.e. cross-linking agents which crosslink the polymer network of the phase-transition gel; inorganic and organic solvents; etc.
  • Phase-transition conditions at which the phase-transition gels exhibit a discontinuous volume change can include combinations of physical conditions, combinations of chemical conditions, or combinations of physical and chemical conditions.
  • a phase-transition-modifying agent is disposed in the phase-transition gel which, in response to a suitable stimulus, is sufficient to cause a discontinuous volume change of said gel at the desired discontinuous volume change.
  • phase-transition-modifying agents can be employed in the phase-transition gels of the present invention. These phase-transition-modifying agents can be, for example, small chemical molecules, such as chromophores, cross-linking agents, surfactants, etc.
  • phase-transition-modifying agents can be macromolecules, such as lectins (e.g., Concanavalin A) or polymers which do not comprise the main polymer network of the gel.
  • lectins e.g., Concanavalin A
  • polymers which do not comprise the main polymer network of the gel.
  • natural polymers include proteins, such as enzymes, DNA, RNA, etc.
  • the agents can also include combinations of small chemical molecules and/or polymers.
  • the phase-transition-modifying agent can be chemically attached to the polymer network, such as by covalent bonding to the polymer network, or it can be entrapped by a suitable method, such as forming the polymer network in the presence of the phase-transition agent.
  • the phase-transition-modifying agent can comprise chemical which exhibits properties in response to a suitable stimulus sufficient to cause the discontinuous volume change of the gel at the desired phase-transition condition.
  • properties which the phase-transition agent can exhibit include enzymatic, catalytic, chelating, hydrophilic, hydrophobic and electromagnetic properties, etc.
  • Stimulus to which the phase-transition-modifying agents respond include a physical and/or chemical conditions.
  • the pha ⁇ e-transition-modifying agent causes a discontinuous phase transition of the gel at a desired phase-transition condition in response to exposure of the stimulus to the phase-transition- modifying agent.
  • suitable stimuli include: a sub ⁇ trate, when the pha ⁇ e-transition- modifying agent comprises an enzyme; an antigen, when the phase-tran ⁇ ition-modifying agent comprises an antibody; reactants, when the phase-transition- modifying agent comprise ⁇ a catalyst; etc.
  • the response of the gel to a stimulus cause ⁇ a phase transition of the phase-transition gel at a desired phase-transition condition by affecting either the interaction between polymers of the polymer network of the phase-transition gel, the interaction within the polymer network, and/or the interaction between the polymer network and the liquid medium within the gel.
  • the effect on the polymer/copolymer, polymer/polymer or polymer/solvent interaction modifies the phase-transition gel sufficient to cause, in respon ⁇ e to the ⁇ timulus, a discontinuous volume change of the phase-transition gel at the desired phase transition condition.
  • phase-transition gels of this invention can be engineered to have at a desired condition by including within the gel a suitable phase-transition-modifying agent in an amount sufficient to respond to a stimulus, whereby response of the phase-transition-modifying agent causes a discontinuous volume change of said gel at the desired condition.
  • the amount of phase-transition-modifying agent within the phase-transition gel can be selected to cause a discontinuous volume change of the gel at a temperature about 10 C C higher than the phase-transition gel would exhibit the discontinuous volume change in the absence of the phase-tran ⁇ ition- modifying agent.
  • a discontinuous phase transition is caused by respon ⁇ e of t. enzyme to the presence of a suitable substrate at a desired phase-transition condition.
  • Substrate in a liquid medium surrounding the phase-transition gel migrates to within the gel, such a ⁇ by diffusion, convection or by selective attraction of the substrate by the enzyme.
  • Respon ⁇ e of the enzyme to the presence of the substrate such as enzymatic reaction of the substrate, causes formation of substrate reaction products.
  • the enzymatic re ⁇ pon ⁇ e causes a discontinuous volume change of the phase-tran ⁇ ition gel at the desired phase-transition condition.
  • Suitable enzymes include rabbit liver esterase, urea ⁇ e, amyla ⁇ e, lipase, galactosidase, catalase, protease, etc.
  • substrates include sugar ⁇ , lipid ⁇ , protein ⁇ , hydrogen peroxide, etc.
  • an enzyme inhibitor can be used to interact with the enzyme to thereby cause the discontinuou ⁇ pha ⁇ e tran ⁇ ition.
  • urease for example, is dispo ⁇ ed in an N-i ⁇ oprpylacrylamide-acrylic acid copolymer network
  • a pha ⁇ e tran ⁇ ition can be caused at a desired phase- tran ⁇ ition condition by enzymatic reaction with urea to form carbon dioxide and ammonium ion. It i ⁇ believed that the ammonium ion ionizes the acrylic acid to thereby induce the phase transition of the gel.
  • phase-transition-modifying agent co prise ⁇ a chromophore
  • the phase-tran ⁇ ition gel can exhibit a di ⁇ continuou ⁇ volume change at the desired phase-tran ⁇ ition condition in by respon ⁇ e to visible light as a suitable stimulus. It is believed that, in some case ⁇ , heat generated by the chrompohore raises the temperature of the phase-transition gel and thereby increases the osmotic pre ⁇ ure within the gel, thereby causing the phase tran ⁇ ition.
  • An example of a suitable chromophore i ⁇ tri ⁇ odium salt of coppered chlorophyllin.
  • the phase-tran ⁇ ition-modifying agent within the gel can co pri ⁇ e a photoactive material which isomerizes during exposure to light.
  • the stimulus is light.
  • isomerization of the photoactive material alter ⁇ the polymer/copolymer or interpolymer interaction and thereby change ⁇ the pha ⁇ e-tran ⁇ ition condition ⁇ .
  • An example of a photoactive material includes diazobenzene.
  • a suitable hydrophobic gel is contacted with a suitable surface chemical, such as surfactant molecules comprising both hydrophobic groups and hydrophilic groups. It is believed that the surfactants form a coating on the polymer gel which acts to ionize the polymer, thereby causing it to become a hydrophilic gel, whereby the environmental conditions at which the gel exhibit a phase transition are changed.
  • surfactants include sodium dodecyl sulfate (CH_ (CH.) ..SO ⁇ )Na ) (anionic) and dodecyl trimethyl ammonium chloride ( (CH 3 (CH 2 ) 1;L N) + (CH 3 )C1) ⁇ ) - (cationic) .
  • phase-transition-modifying agent comprise ⁇ a cro ⁇ slinking agent
  • a stimulus present in a given amount in the surrounding solvent causes crosslinking of the polymer network.
  • the pha ⁇ e tran ⁇ ition can be markedly altered by ⁇ uch crosslinking.
  • crosslinking agents include ethylene diamine, polyethylene diamine. It is believed that the catalytic reaction modifies the polymer/polymer interaction, intrapolymer interaction or polymer/fluid interaction to thereby cau ⁇ e a phase transition at environmental conditions at which phase transition of the gel would not otherwise occur.
  • An example of a suitable polymer network is polyacrylamide and an example of a suitable cataly ⁇ t i ⁇ poly(4-vinylimidazole) .
  • An example of a suitable reactant includes p-nitrophenylacetate.
  • Memory device 44 illustrated in Figures 1A and IB, includes phase-transition gel 46 disposed within cylinder 48.
  • Cylinder 48 includes aperture 52 for exposing phase-tran ⁇ ition gel 46 to environment 54.
  • Panel 55 is slidably engaged with guides 56 0 wherein panel 55 is in non-interfering relation with migration of stimulus 58 from environment 54 to phase-transition gel 46 through aperture 52.
  • Phase-transition gel 46 includes a phase-transition- modifying agent 59 which causes a phase transition of phase-transition gel 46 at a desired phase transition condition during exposure of gel body 46 to a sufficient concentration of stimulus 58.
  • Piston 60 is disposed in cylinder 48 adjacent to gel body 46 for movement from a first position, shown in Figure o 1A, where phase-transition gel 46 i ⁇ in a contracted pha ⁇ e, to a ⁇ econd po ⁇ ition, ⁇ hown in Figure IB, where gel 46 is in an expanded phase. Piston 60 i ⁇ connected by wire 62 to panel 5 . Upon sufficient expo ⁇ ure to ⁇ timulus 58 by migration of stimulus 58 5 through aperture 52 to gel 46, gel 46 exhibits a phase transition from the contracted phase to the expanded phase.
  • gel 46 moves piston 60 0 from the first po ⁇ ition to the ⁇ econd position. Movement of piston 60 from the first position to the second position causes piston 60 to pull panel 55 along guides 56 by wire 62 to thereby seal gel 46 from environment 54. Sealing of gel 46 from environment 54 prevents gel body 46 from exhibiting a phase transition from an expanded phase to a contracted phase during subsequent changes in the presence of stimulus 58 in environment 54, thereby causing memory device 44 to retain a memory of the occurrence of a change in the concentration of stimulu ⁇ 58 in environment 54.
  • Sen ⁇ or device 64 illu ⁇ trated in Figure ⁇ 2A and 2B, include ⁇ phase-transition gel 66.
  • Phase-tran ⁇ ition-modifying agent 68 and indicator 70 are di ⁇ posed in gel 66.
  • Pha ⁇ e-transition-modifying agent 68 causes a phase transition of gel 66 from a contracted phase, shown in Figures 2A, to an expanded phase, shown in Figure 2B, upon exposure of sensor 64 to a sufficient concentration of stimulus 71 in environment 72.
  • gel 66 Upon exposure of sensor 64 to a sufficient concentration of stimulu ⁇ 71 in environment 72, gel 66 exhibits a phase transition from the contracted phase to an expanded pha ⁇ e.
  • Phase transition of gel 66 releases indicator 70, such as a dye, to environment 72, thereby indicating the presence of stimulus 71.
  • Actuator device 74 illustrated in Figures 3A and 3B, includes cylinder 76 and phase-tran ⁇ ition gel 78 disposed in cylinder 76.
  • Piston 80 is dispo ⁇ ed in cylinder 76 adjacent to gel 78.
  • Piston 80 is moveable between a first position, shown in figure 3A, and a second piston, shown in Figure 3B.
  • Push rod 82 extends from piston 80 and is fixed to switch 84 of electrical circuit 86.
  • Phase-tran ⁇ ition- odifying agent 88 is disposed in gel 78.
  • Phase-transition-modifying agent 88 cau ⁇ e ⁇ gel 78 to exhibit a pha ⁇ e tran ⁇ ition from a contracted phase to an expanded pha ⁇ e upon expo ⁇ ure of gel 78 to a ⁇ ufficient concentration of stimulus 90 in environment 92.
  • Aperture 94 at cylinder 76 provides fluid communication between environment 92 and gel 78. Increasing concentration of stimulus 90 in environment 92 causes stimulu ⁇ 90 to migrate through aperture 94.
  • Exposure of gel 78 to stimulus 90 causes gel 78 to exhibit a phase transition from a contracted phase, shown in Figure 3A, to an expanded phase, shown in Figure 3B. Phase transition of gel 78 within cylinder 76 causes gel 78 to move from the first position to the second position.
  • Movement of piston 80 directs push rod 82 against ⁇ witch 84, thereby moving ⁇ witch 84 from an open position, shown in Figure 3A, to a close position, shown in Figure 3B.
  • Moving switch 84 to the closed position closes electrical circuit 86, thereby actuating electrical circuit 86.
  • Reduction of the amount of stimulus 90 in environment 92 causes gel 78 to exhibit a phase transition from the expanded phase to the contracted phase, thereby opening electrical circuit 86.
  • Transducer device 96 illustrated in Figures 4A and 4B, includes cylinder 98 and phase-transition gel 100 disposed within cylinder 98. Electrically conductive coil 102 extends around cylinder 98. Apertures 104 in cylinder 98 provide fluid communication between fluid 106 and gel body 100. Pha ⁇ e-tran ⁇ ition-modifying agent 108 i ⁇ di ⁇ po ⁇ ed in gel 100. Phase-transition-modifying agent 108 comprises a suitable electromagnetic responsive material which, upon exposure to sufficient electromagnetic radiation, cause ⁇ gel 100 to exhibit a pha ⁇ e transition from a contracted phase, shown in Figure 4A, to an expanded phase, shown in Figure 4B. Piston 110 is disposed adjacent gel 100. Push rod 112 extends from piston 110.
  • Light pump 114 includes cylinder 116 and phase-transition gel 118 disposed within cylinder 116.
  • Phase-transition- modifying agent 120 is disposed in gel 118.
  • Agent 120 upon exposure to sufficient visible light, cause ⁇ gel 118 to exhibit a phase transition from a contracted phase, shown in Figure 5A, to an expanded phase, shown in Figure 5B.
  • Cylinder 116 is translucent.
  • Aperture 121 in cylinder 116 provide fluid communication between fluid 122 and gel 118.
  • Piston 124 is disposed within cylinder 116 and is adjacent gel 118.
  • Push rod 126 extends from piston 124 to diaphragm pump 128.
  • Push rod 126 is fixed to diaphragm 129 of diaphragm pump 128.
  • Expo ⁇ ure of gel to a sufficient intensity of visible light 130 from light source 131 causes gel 118 to exhibit a phase tran ⁇ ition from a contracted pha ⁇ e to an expanded pha ⁇ e.
  • Phase transition of gel 118 to the expanded phase moves piston 124 and push rod 126 from a first position, shown in Figure 5A, to a second position, shown in Figure 5B.
  • the inten ⁇ ity of visible light is then reduced by suitable means to below an amount sufficient to maintain gel 11.8 in an expanded phase, whereby gel 118 exhibits a phase transition from an expanded phase to a contracted phase, thereby causing piston 124 and push rod 126 to move from the second postion to the first position.
  • Repeated increase and decrea ⁇ e of visible light intensity cause ⁇ repetitive expansion and contraction of gel body 126 and operation of diaphragm pump by consequent movement of piston 124 and push rod 126 between the first and second positions.
  • Chemical release system 132 illustrated in Figures 6A and 6B, includes pha ⁇ e-tran ⁇ ition gel 134 di ⁇ po ⁇ ed within fluid 136.
  • Phase-transition- modifying agent 138 and chemical 142 are disposed in gel 134.
  • Agent 138 causes gel 134 to exhibit a phase transition from a contracted phase to an expanded phase upon exposure of gel 134 to a sufficient amount of a suitable stimulus 142.
  • Chemical 140 upon release from gel body 134, inhibits the activity of stimulus 142.
  • chemical 140 can be insulin and stimulus 142 can be glucose.
  • gel 134 Upon exposure of gel 134 to a sufficient concentration of stimulu ⁇ 142, gel 134 exhibits a phase transition from a contracted phase, shown in Figure 6A, to an expanded phase, shown in Figure 6B.
  • Chemical 140 is released from gel 134 while gel 134 is in the expanded phase until the stimulu ⁇ diminishes to below an amount sufficient to maintain gel 134 in an expanded phase.
  • Gel 134 then exhibits a phase transition from the expanded phase to the contracted phase, whereby release of chemical 140 from gel 134 stops. Release of chemical 140 form gel 134 stops. Release of chemical 140 is thereby controlled by controlled chemical release system 132.
  • the gels described can be designed to exhibit a phase transition from an expanded phase to a contracted pha ⁇ e upon exposure to a stimulus.
  • the present invention has many other applications.
  • gels of the present invention can by used as desiccating agents or as sponges.
  • Sponges employing the gels have many applications, such as for cleanup of oil spill ⁇ .
  • the gel ⁇ can al ⁇ o be u ⁇ ed for expelling fluid.
  • Moisturizers can be formed using gels of the pre ⁇ ent invention to relea ⁇ e moi ⁇ ture upon drying of a ⁇ urrounding layer.
  • Example ⁇ of such moisturizers include gels which could be applied to leaves of plants, or moisturizers which also include sun block for application to human skin.
  • Chelating agents disposed in gels can form gel ⁇ which respond to the existance of metals as contaminants, thereby causing selective reaction of the chelating agents to concentrate and to purify liquids.
  • Gels of the present invention can also absorb impurities and to neutralize fluids.
  • Biological materials such as Salmonella
  • the gels can be detected by causing the gel ⁇ of the present invention to release a dye upon phase transition.
  • the gels can also be used for flavoring upon exposure to sufficient environmental conditions, such as heat.
  • fragrances can be disposed from a gel of the present invention during exposure of gel to noxious odors, such as for use with diapers.
  • a finely tuned array of gels in micropores can by formed, whereby the gels are tuned to exhibit a phase transition upon exposure to infrared energy. The array can thereby act as a sensor of infrared energy by, for example, expanding to close a gap.
  • Gels of the present invention can be used for laboratory testing, such as immunoas ⁇ ay systems and ovulation testing. Actuators can be constructed using the gels, such a ⁇ an energy efficient window, wherein a blind i ⁇ controlled in response to light by a mechanical ⁇ yste operated by expansion of the gel ⁇ in response to light.
  • Fire retardant gels for use in clothing can also be formed, whereby the gels release fire retarding chemicals upon exposure to extreme heat.
  • Physical barriers can be formed by expansion of gels in response to stimulus.
  • Reaction can also be triggered by phase transition of the gels, wherein gels expand to thereby allow chemicals to combine. Also, chemicals can be selectively combined, which chemicals would deteriorate rapidly if not otherwise kept separate.
  • the gels can be employed to release insecticide upon exposure during period ⁇ of daylight, when in ⁇ ect activity typically i ⁇ highest.
  • Color ⁇ can be selectively released in an emulsion upon exposure of the emulsion upon a sub ⁇ trate to variou ⁇ wavelength ⁇ of light, thereby acting a ⁇ a photgraphic film.
  • Carbonle ⁇ copying can be performed by impregnating a gel, containing a dye, in paper, whereby ⁇ elective expo ⁇ ure of the paper to light release ⁇ the dye to form an image on the paper.
  • Gels which expand upon exposure to light can be employed for self repairing opaque containers.
  • the gels of the present invention can also be used to concentrate chemicals, including some food ⁇ , for transport.
  • Osmotic pumps can be constructed with gels ⁇ uch as for desalinization of water.
  • Detergents can employ the gels for controlled release of detergent in response to temperature, for example, during a wash cycle.
  • a gel can be designed to respond to certain stimuli, such as high glucose, that undergoes phase transition upon seeing this stimuli and releases a drug, such as insulin, that has been loaded into the gel.
  • the gel could mechanically push a drug, such as insulin, out of a reservoir upon encountering a stimuli, such as glucose, by undergoing a phase transition.
  • a gel material could be designed that changes its mechanical properties upon encountering the proper stimuli.
  • a gel valve can be created where the gel is designed to undergo phase transition (and close or open depending on how it is designed) when it sees a particular chemical ⁇ pecies. This valve might be u ⁇ ed to shut down a process upon encountering a contaminant.
  • Custom polymer gels can be designed to undergo phase transition upon encountering a chemical at a certain stage of manufacturing. This might be useful in a process where it is important to remove a polymer intermediary. This intermediary could be removed by phase transition.
  • a light-triggered polymer gel containing ink could be used for instant photography. THe ink would be released upon encountering light.
  • a gel can be cu ⁇ tom-designed to undergo phase transition when encountering a contaminant or waste and thereby soak up the waste.
  • Another version of this application would involve creating a gel that undergoes phase transition through chelating (which could remove contaminating metals (i.e. chromium 6) from a process.
  • a custom gel could be created to absorb certain chemicals, for example, blood in a gel tampon, by undergoing phase tran ⁇ ition.
  • the gel could be used to absorb toxins from the gastrointestinal tract, such as toxins released by e_ ⁇ coli in Traveler's Diarrhea. This could be a non-antibiotic agent to relieve the diarrhea.
  • the gel could also be used in robotics for response by robotics to environmental conditions.
  • the aqueous solution containing the rabbit liver estera ⁇ e was then exposed to vacuum for a period of time sufficient to degas the aqueous solution.
  • Ten microliters of four percent aqueous ammonium persulfate solution initiator, commercially available from Mallinckropt was combined with the degassed aqueous solution to form a reaction solution.
  • the reaction solution was transferred to a glas ⁇ capillary tube having a length of twenty centimeter ⁇ and an internal diameter of 0.1 millimeter.
  • Deactivated Enzyme Gel 2 was formed by the method described above and sub ⁇ equently wa ⁇ expo ⁇ ed to a temperature of about 100°C for a ⁇ ufficient period of time to inactivate the enzyme.
  • Gel 3 was formed by the same method described above but without dis ⁇ olving an enzyme into the aqueou ⁇ solution. Gel 3 was cut to form a right cylinder having the same dimensions as the above gel ⁇ and wa ⁇ then di ⁇ po ⁇ ed in a third gla ⁇ s micropipette.
  • Aqueous solutions were prepared of ethylbutylate as a substrate stimulus and/or butyric acid and ethanol, which were products of hydrolysis of ethylbutylate catalyzed by the rabbit liver esterase.
  • the size and shape of the gels in the micropipettes were monitored at different temperatures using a Model C1966 AVEC image proces ⁇ or commercially available from Hamamat ⁇ u Photonics, Inc.
  • the concentration of ethanol, butyric acid and ethylbutylate in the aqueous solution was determined by using a Model 588OA gas chromatograph, commercially available from Hewlett Packard Inc.
  • Figure 7 is a plot of the volume of Gel 3, containing no enzyme, relative to the volume of Gel 3 in a contracted phase over a temperature range during expansion and contraction Gel 3.
  • Curves A and B represent the volume of Gel 3 during expansion and contraction, respectively, in an aqueous solution containing 47.3 mM of substrate, i.e. ethylbutylate, and no substrate reaction product, i.e. butyric acid or ethanol.
  • the gel changes phase as the temperature of the aqueous solution is raised or lowered in a temperature range of from about 27.9'C to about 28.4*C.
  • Curves C and D represent the volume of the same gel during phase transition of expansion and contrac ⁇ tion, respectively, in an aqueous solution containing 47.3 mM each of ethanol and butyric acid, but containing no stimulus, i.e., ethylbutylate.
  • the temperatures of volume change are higher when the aqueous solution is relatively rich in product of hydrolyzed substrate than when the solution is relatively rich in sub ⁇ strate.
  • Curves E and F represent the volume of the same gel during phase transition of expansion and contrac ⁇ tion, respectively, in an aqueou ⁇ solution containing neither substrate nor product of hydrolyzed sub- strate.
  • FIG. 8 is a plot of the volume of Gel 1 (containing active enzyme) and Gel 2 (containing inactivated enzyme) in their expanded phases during gradual reduction and increase of temperature relative to the same gels in their contracted phases.
  • Curves A and B represent plots of expansion and contraction, respectively, of Gel 2, containing inactivated enzyme.
  • Curves C and D represent plots of expansion and contraction, re ⁇ pectively, of Gel 1, containing activated enzyme.
  • polymer network of the gel increased the temperature at which the gel exhibited a phase transition in a solution saturated with the substrate.
  • Figure 9 is a plot of the phase transition of
  • Curve A is a plot of the time of phase transition of Gel 1, following immersion of the gel in a solution at 28.9*C. The concentration of substrate in the solution was 47.3 illimoles per liter of solution.
  • Curve B is a plot of the phase
  • the gel undergoes a pha ⁇ e tran ⁇ ition at below 34'C in water.
  • the transition temperature of the gel 40°C.
  • the concentration of dextran ⁇ odium ⁇ ulfate wa ⁇ below 0.1 percent, the gel wa ⁇ in an expanded phase at 40"C.
  • the concentration of dextran sodium sulfate wa ⁇ above 0.1 percent the gel was in a contracted phase at 40"C.
  • the dextran ⁇ odium sulfate was then replaced with an nonionized inhibitor, manno pyranose, to thereby cause the gel to exhibit a phase transition at below 34°C.
  • N-isopropylacrylamide gel prepared as in Example II but included 20 mg/ml of urease incorporated into the polymer network rather than dextran sodium sulfonate.
  • Urea was used as a substrate, which was decomposed into carbon dioxide and ammonium ion. The latter ionized the acrylic acid and altered the phase transition temperature. For 10 -2M urea concentration the change in the transition temperature was approximately 20*C.
  • the gel when in a collapsed state at a temperature-of
  • Bio-Rad Laboratories and 240 milliliters of tetra- methylethylenediamine accelerator, commercially available from Bio-Rad Laboratories were dissolved in one hundred milliliters of water to from an aqueous solution.
  • 0.722 gm of trisodium salt of coppered chlorophyllin, commercially available from Aldrich, Inc. was di ⁇ olved in one hundred milliliters of degased water at O'C
  • the aqueous solution containing the rabbit liver estera ⁇ e was then exposed to vacuum for a period of time sufficient to degas the aqueous solution.
  • 0.2 gms of four percent aqueous ammonium persulfate solution initiator commercially available from Mallinckrott, Inc.
  • reaction solution was combined with the degassed aqueous solution to form a reaction solution.
  • the reaction solution was transferred to a glass capillary tube having a length of twenty centimeters and an internal diameter of one hundred millimeters.
  • the reaction solution gelled in the glass capillary tube, whereby the monomer and cross ⁇ linking agent reacted to form a polymer network which entrapped a substantial portion of the chlorophyllin in the polymer network, thereby forming a gel of a polymer network and trapped enzyme.
  • the gel was removed from the capillary tube and washed with deionized, distilled water. The washed gel was dispo ⁇ ed in a gla ⁇ s micropipette having an internal diameter of one millimeter.
  • the cylindrical gel was immersed in water, having a pH of 11.9 in a sealed rectangular glas ⁇ microcapillary, who ⁇ e temperature was regulated within 0.1°C.
  • An argon ion laser emitting light at a wavelength of 480 nm was used as a light source.
  • the light intensity at the gel was adjusted using a polarizer and ranged from zero to 130mW.
  • the inci ⁇ dent beam with a Gaussian width of approximately seven millimeters was focused with a lens of focal length nineteen centimeters, which produced a focu ⁇ ed beam having a diameter of twenty,micrometer ⁇ and a focal depth of 0.8 micrometers.
  • the size and shape of the gel were monitored and analyzed using the AVEC image processor (Model C1966, Hamamatsu Photonics) .
  • the diameter of the gel was plotted as a func ⁇ tion of temperature in Figure 10 for three values of light intensity.
  • the gel underwent a sharp, but continuous volume change at approximately 35*C.
  • the volume change became sharper and the transition temperature wa ⁇ lowered to 33 ⁇ C.
  • the gel exhibited a discontinuous volume change, or phase transition, at 31.5*C.
  • the gel was then maintained at a constant temperature of 31.5'C and exposed to increasing light intensity which ranged from zero to 120 W. As can be seen in Figure 11, the gel exhibited a phase tran ⁇ ition at a light intensity of 100 mW.
  • the gel formed was removed from the capillary, washed with copious amounts of water and then cut to a length of one millimeter.
  • the temperature at which the gel exhibits a phase transition in water was 34*C.
  • the gel was then exposed to a 0.1 percent by weight solution of sodium dodecyl sulfate. The gel then exhibited a phase transition at a temperature of 60°C.

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Abstract

L'invention se rapporte à un gel à transition de phase et à un procédé de formation d'un gel à transition de phase, lequel subit un changement de volume discontinu important dans une condition de transition de phase désirée en réaction à un stimulus. Le gel à transition de phase se compose d'un milieu liquide gélifié au moyen d'un réseau polymère qui se trouve dans une condition de transition de phase différente de celle désirée et qui contient une quantité d'un agent modificateur de transition de phase suffisante pour produire, en réaction au stimulus, un changement de volume dicontinu du gel jusqu'à ce que celui-ci présente la condition de transition de phase désirée.
PCT/US1991/005312 1990-07-26 1991-07-26 Transition de phase d'un gel commandee par l'interaction d'un stimulus WO1992002005A2 (fr)

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DE19812436A1 (de) * 1998-03-22 1999-09-30 Univ Dresden Tech Funktionselement für die Fluid- oder Aerosoltechnik
US5976648A (en) * 1995-12-14 1999-11-02 Kimberly-Clark Worldwide, Inc. Synthesis and use of heterogeneous polymer gels
WO2000000151A1 (fr) * 1998-06-29 2000-01-06 The Procter & Gamble Company Article absorbant jetable comprenant un systeme de reaction a actionneur electrique
WO2000000148A1 (fr) 1998-06-29 2000-01-06 The Procter & Gamble Company Article jetable pourvu d'un systeme sensible
WO2000000137A3 (fr) * 1998-06-29 2000-04-13 Procter & Gamble Article jetable pourvu d'un dispositif d'isolation de matieres corporelles
WO2000066880A1 (fr) * 1999-04-29 2000-11-09 Shell Internationale Research Maatschappij B.V. Dispositif de fond de trou permettant de reguler l'ecoulement de fluide dans un puits
US6149636A (en) * 1998-06-29 2000-11-21 The Procter & Gamble Company Disposable article having proactive sensors
US6160198A (en) * 1998-06-29 2000-12-12 The Procter & Gamble Company Disposable article having a discontinuous responsive system
US6186991B1 (en) 1998-06-29 2001-02-13 The Procter & Gamble Company Disposable article having a responsive system including a mechanical actuator
US6342037B1 (en) 1998-06-29 2002-01-29 The Procter & Gamble Company Device having fecal component sensor
US6359190B1 (en) 1998-06-29 2002-03-19 The Procter & Gamble Company Device for measuring the volume of a body cavity
US6372951B1 (en) 1998-06-29 2002-04-16 The Procter & Gamble Company Disposable article having sensor to detect impending elimination of bodily waste
US6395955B1 (en) 1998-06-29 2002-05-28 The Procter & Gamble Company Diaper including feces modification agent
US6407308B1 (en) 1998-06-29 2002-06-18 The Procter & Gamble Company Disposable article having sensor to detect impending elimination of bodily waste
US6433244B1 (en) 1998-06-29 2002-08-13 The Procter & Gamble Company Disposable treatment article having a responsive system
US6679324B2 (en) 1999-04-29 2004-01-20 Shell Oil Company Downhole device for controlling fluid flow in a well
EP1877761A2 (fr) * 2005-04-29 2008-01-16 AMBROZY, Rel S. Indication de stimulus utilisant des gels polymeres
WO2008059274A1 (fr) * 2006-11-18 2008-05-22 University Of Sheffield Dispositifs de capteurs
US7940605B2 (en) 2005-04-29 2011-05-10 Prasidiux, Llc Stimulus indicating device employing polymer gels
US8077554B2 (en) 2005-04-29 2011-12-13 Ambrozy Rel S Stimulus indicating device employing polymer gels
US8166906B2 (en) 2005-04-29 2012-05-01 Ambrozy Rel S Stimulus indicating device employing polymer gels

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US9182292B2 (en) 2005-04-29 2015-11-10 Prasidiux, Llc Stimulus indicating device employing polymer gels

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US4174952A (en) * 1978-01-23 1979-11-20 Massachusetts Institute Of Technology Immunoassay by light scattering intensity anisotropy measurements
US4732930A (en) * 1985-05-20 1988-03-22 Massachusetts Institute Of Technology Reversible, discontinuous volume changes of ionized isopropylacrylamide cells

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Publication number Priority date Publication date Assignee Title
US6194073B1 (en) 1995-12-14 2001-02-27 Kimberly-Clark Worldwide, Inc Synthesis and use of heterogeneous polymer gels
US5976648A (en) * 1995-12-14 1999-11-02 Kimberly-Clark Worldwide, Inc. Synthesis and use of heterogeneous polymer gels
DE19812436A1 (de) * 1998-03-22 1999-09-30 Univ Dresden Tech Funktionselement für die Fluid- oder Aerosoltechnik
US6384296B1 (en) 1998-06-29 2002-05-07 The Procter & Gamble Company Disposable article having a responsive system including an electrical actuator
US6407308B1 (en) 1998-06-29 2002-06-18 The Procter & Gamble Company Disposable article having sensor to detect impending elimination of bodily waste
US6570053B2 (en) 1998-06-29 2003-05-27 The Procter & Gamble Company Disposable article having a proactive sensor
US6149636A (en) * 1998-06-29 2000-11-21 The Procter & Gamble Company Disposable article having proactive sensors
US6160198A (en) * 1998-06-29 2000-12-12 The Procter & Gamble Company Disposable article having a discontinuous responsive system
US6186991B1 (en) 1998-06-29 2001-02-13 The Procter & Gamble Company Disposable article having a responsive system including a mechanical actuator
WO2000000148A1 (fr) 1998-06-29 2000-01-06 The Procter & Gamble Company Article jetable pourvu d'un systeme sensible
US6266557B1 (en) 1998-06-29 2001-07-24 The Procter & Gamble Company Biofeedback device for an incontinent person
US6342037B1 (en) 1998-06-29 2002-01-29 The Procter & Gamble Company Device having fecal component sensor
US6359190B1 (en) 1998-06-29 2002-03-19 The Procter & Gamble Company Device for measuring the volume of a body cavity
US6372951B1 (en) 1998-06-29 2002-04-16 The Procter & Gamble Company Disposable article having sensor to detect impending elimination of bodily waste
WO2000000151A1 (fr) * 1998-06-29 2000-01-06 The Procter & Gamble Company Article absorbant jetable comprenant un systeme de reaction a actionneur electrique
US6395955B1 (en) 1998-06-29 2002-05-28 The Procter & Gamble Company Diaper including feces modification agent
WO2000000137A3 (fr) * 1998-06-29 2000-04-13 Procter & Gamble Article jetable pourvu d'un dispositif d'isolation de matieres corporelles
JP2002519110A (ja) * 1998-06-29 2002-07-02 ザ、プロクター、エンド、ギャンブル、カンパニー 電気アクチュエーターを含む反応システムを有する使い捨て吸収体
US6433244B1 (en) 1998-06-29 2002-08-13 The Procter & Gamble Company Disposable treatment article having a responsive system
AU760852B2 (en) * 1999-04-29 2003-05-22 Shell Internationale Research Maatschappij B.V. Downhole device for controlling fluid flow in a well
WO2000066880A1 (fr) * 1999-04-29 2000-11-09 Shell Internationale Research Maatschappij B.V. Dispositif de fond de trou permettant de reguler l'ecoulement de fluide dans un puits
US6679324B2 (en) 1999-04-29 2004-01-20 Shell Oil Company Downhole device for controlling fluid flow in a well
EP1877761A2 (fr) * 2005-04-29 2008-01-16 AMBROZY, Rel S. Indication de stimulus utilisant des gels polymeres
EP1877761A4 (fr) * 2005-04-29 2010-03-24 Rel S Ambrozy Indication de stimulus utilisant des gels polymeres
US7940605B2 (en) 2005-04-29 2011-05-10 Prasidiux, Llc Stimulus indicating device employing polymer gels
US8077554B2 (en) 2005-04-29 2011-12-13 Ambrozy Rel S Stimulus indicating device employing polymer gels
US8166906B2 (en) 2005-04-29 2012-05-01 Ambrozy Rel S Stimulus indicating device employing polymer gels
US9063015B2 (en) 2005-04-29 2015-06-23 Prasidiux Llp Stimulus indication employing polymer gels
WO2008059274A1 (fr) * 2006-11-18 2008-05-22 University Of Sheffield Dispositifs de capteurs

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