KR101776087B1

KR101776087B1 - Zwitterionic temperature responsive polymer and its uses as biomaterial

Info

Publication number: KR101776087B1
Application number: KR1020160010285A
Authority: KR
Inventors: 정병문; 고두영
Original assignee: 이화여자대학교 산학협력단
Priority date: 2016-01-27
Filing date: 2016-01-27
Publication date: 2017-09-07
Also published as: KR20170089701A

Abstract

Zwitterionic temperature sensitive polymers having sol-gel transition properties and their use as biomaterials for the zwitterionic temperature sensitive polymers.

Description

Zwitterionic ionic thermosensitive polymers and their use as biomaterials. &Lt; Desc / Clms Page number 1 >

The present invention relates to zwitterionic temperature sensitive polymers having sol-gel transition properties and their use as biomaterials for the zwitterionic temperature sensitive polymers.

In the study of new biomaterials, introduction to cell membrane constituents can be an attractive means. The functional group on the cell membrane surface can confer cytocompatibility and biocompatibility to the material. The major constituent of the cell membrane, such as phosphatidylcholine, phosphatidylethanolamine, phosphatidylserine, etc., possesses both negative and positive charges, and 2-methacrylolyloxoethylphosphorylcholine, sulfobetaine methacrylate, or carboxybetaine Zwitterionic molecules, a variety of zwitterionic copolymers made using acrylates, have been intensively studied for various biomedical applications. Zwitterionic polymers are applied to surface coatings of implants, biosensors, biomedical devices, vessels, nanoparticles and polymeromes due to their low protein adsorption and low cell adhesion. Zwitterionic polymers protect these materials from bio-contamination and biofilm formation. For example, a polysulfobetaine-coated catheter, when contacted with human blood, has a 2% decrease in protein adsorption compared to a commercially available catheter. As a result, the reactivity of platelets, lymphocytes, mononuclear leukocytes and neutrophils is remarkably reduced. When a cation or a part of the induced cation binds to a zwitterionic polymer, the polymer has sterilization and non-bio-contamination. The low protein adsorption of zwitterionic materials and the bactericidal properties of cations contribute synergistically to the material properties. When a polycarboxybetaine polymer having a zwitterion property binds to alpha chymotrypsin, the stability remarkably increases without decreasing the bioactivity of the protein. Therefore, it can be seen that when the protein is combined with PEG or PPG, the zwitterionic substance is more advantageous when it is combined with the protein. PEGylation is widely used in prolonging blood half-life of protein drugs, but a significant reduction in bioactivity remains a problem.

Because of the intrinsic ionic interaction of the zwitterionic polymers, many zwitterionic polymers exhibit UCST (upper critical solution temperature) in water. This behavior is due to the strong inter-ionic interaction between the zwitterionic polymers and the fact that they are insoluble in water at low temperatures. However, if the thermal energy at higher temperatures exceeds the interaction between the ions, the solubility increases. When salts are added to inhibit interactions between ions, the UCST of the zwitterionic polymer is reduced, which means that the solubility increases at lower temperatures. On the other hand, when polymerized with a hydrophobic monomer or mutated to show hydrophobicity in a zwitterionic polymer, UCST increases. Polymers showing both UCST and lower critical solution temperature (LCST) are prepared by polymerization of N-isopropylacrylamide or N-vinylcaprolactam with zwitterionic monomer. N-isopropylacrylamide copolymers are successfully used in in vitro or in vivo cell sheet engineering. However, the malformations of acrylamide monomers caused by the dissolution of polymers and the toxicity of amine molecules still add to the parenteral application of such copolymers. Most of the zwitterionic polymers are still synthesized from methyl acrylates such as 2-methacrylolyloxoethylphosphoryl choline, sulfobetaine methacrylate, and carboxybetaine methacrylate.

On the other hand, the polymers reported so far to exhibit a sol-gel transfer reaction in an aqueous solution include poloxamer, poly (N-isopropylacrylamide) and its copolymers of polyethylene glycol-polypropylene glycol-polyethylene glycol, polyethylene glycol / Poly (lactide / glycolide), polyethylene glycol / polypropylene fumarate, chitosan / glycerol phosphate, polyphosphazene, polyethylene glycol / polycaprolactone, polyethylene glycol / polyalanine, polyethylene glycol / poly . The aqueous solutions of these polymers are present in solution or sol state at or below room temperature, but transition to hydrated gel occurs at a temperature near the body temperature (37 ° C), so these polymers can be used as medicinal delivery and tissue engineering materials It is likely that there will be. In other words, after mixing with medicines or cells in a sol state, they are injected into the body through subcutaneous or intramuscular injection to make a depot instantaneously at a desired site, thereby slowly releasing the drug, Can be reproduced. These biodegradable materials can be implanted without surgery and sterilized in a sol state through a simple microfilter.

However, in the case of poloxamer, i.e., poly (ethylene glycol) -poly (propylene glycol) -poly (ethylene glycol), even a hydrogel made from 20 to 30% by weight aqueous solution is mostly dissolved within 1 to 3 days, It has been limited in the area of medicine delivery / tissue engineering.

Here, we report a new zwitterionic polymer composed of phosphorylcholine (PC) and biocompatible polypropylene glycol (PPG). PC with zwitterion is a functional group of phosphatidylcholine, which is a main component of a biological cell membrane. PPG has already been approved by the US Food and Drug Administration (FDA) for intravenous, subcutaneous, or oral administration to humans. The aqueous solution of PPG represents LCST, and the LCST is determined by the molecular weight of PPG. The LCST of the aqueous solution of PPG was 65 ° C, 33 ° C, and 20 ° C, respectively, when the molecular weights of PPG were 425, 1000 and 2000 daltons, respectively. PC-PPG-PC is expected to be a temperature-sensitive biocompatible material due to the low protein adsorption properties of PC with PPG's LCST and zwitterionic properties and PPG modified with PC's at the ends. It is also expected that the bonding between hydrophilic PC and PPG will increase the LCST of PPG. Therefore, 2700 daltons of PPG showing LCST at 20 ℃ has been considered in various aspects in the field of biomedical applications.

On the other hand, thermogel is an aqueous solution of a polymer which shows a sol-gel mutation at an increased temperature. The reaction of the thermogel is caused by a fine balance between hydrophilicity and hydrophobicity of the polymer. The drug or cell binds to the hydrogel when the polymer solution is heated to a warm environment, usually at 37 ° C. Due to the simple procedure and mild conditions in gel formation, thermosel has been proposed as a promising support for the delivery of biopharmaceuticals.

U.S. Patent Nos. 6,117,949, 6,201,072, and 6,841,617 describe polyethylene glycols / polylactides or polyglycolides and their medical applications where the transition from aqueous solution to hydrated gel takes place when the temperature is raised.

U.S. Published Patent Application 20060018949 describes polyethylene glycol / polypropylene fumarate which undergoes the transition from aqueous solution to hydrated gel when the temperature is raised, and their medical applications.

U.S. Patent No. 5,344,488 describes chitosan / glycerol phosphates and their medical applications. US Patent Publication No. 20050020808 discloses polyphosphazenes where the transition from an aqueous solution to a hydrogel takes place when the temperature is raised.

U.S. Patent Publication No. 20040077780 broadly describes polypeptide copolymers composed of polyethylene glycol / two or more kinds of amino acids in which transition from an aqueous solution to a hydrated gel takes place when the temperature is raised, and their medical applications.

Korean Patent Publication No. 2002-0023441 describes isopropylacrylamide copolymers causing sol-gel phase transition and vascular occlusion using the same.

U.S. Patent No. 20050175573 A1 describes poloxamer as a multifunctional poloxamer preparation using chemical bonding of urethane or urea.

The present invention provides a zwitterionic temperature-sensitive polymer having sol-gel transition properties and a zwitterionic temperature-sensitive polymer as a biomaterial.

However, the problems to be solved by the present invention are not limited to the above-mentioned problems, and other problems not mentioned can be clearly understood by those skilled in the art from the following description.

A first aspect of the invention provides a zwitterionic temperature responsive polymer represented by the following formula:

[Chemical Formula 1]

Z ¹ -PAG-Z ² ;

Wherein PAG is a polyalkylene glycol; Z ¹ and Z ² are each independently a zwitterionic substance selected from the group consisting of phosphoryl choline, phosphoryl ethanolamine, phosphoryl serine, sulphobetaine, carboxybetaine, and combinations thereof. (Or functional group).

A second aspect of the invention provides a drug delivery vehicle comprising a drug incorporated into a zwitterionic temperature sensitive polymer according to the first aspect of the present invention.

A third aspect of the invention provides a tissue engineering medium or scaffold comprising a zwitterionic temperature sensitive polymer according to the first aspect of the present disclosure.

According to one embodiment of the present invention, zwitterionic temperature sensitive polymers can be prepared using biocompatible polyalkylene glycols and zwitterionic materials. The zwitterionic temperature-sensitive polymer according to one embodiment of the present invention is present as an aqueous solution at a certain temperature or lower when the concentration is higher than a certain concentration, but may transition to a hydrated gel at a temperature higher than a certain temperature. Tissue engineering media, or tissue engineering supports. Particularly, the zwitterionic temperature-sensitive polymer according to one embodiment of the present invention is mixed with medicines or cells in a sol state and then injected into the body through subcutaneous or intramuscular injection, By making it instantaneously, the drug can be released slowly or the cells can grow and allow the tissue to regenerate.

According to one embodiment of the present invention, since the zwitterionic temperature-sensitive polymer has biodegradability, it is possible to make an implant without surgical operation, and it is possible to sterilize in a sol state through a simple microfilter .

According to one embodiment of the present invention, since the zwitterionic material is a biocompatible material due to low protein adsorption property, the zwitterionic material is characterized by being able to prevent inflammation and impart stability to cells or drugs when applied as a biomaterial.

1 (a) is a schematic diagram showing a process of synthesizing PC-PPG-PC in one embodiment of the present invention.
FIG. 1 (b) shows the ¹ H-NMR spectrum of PC-PPG-PC in CDCl ₃ solvent in one embodiment of the present invention.
2 (a) to 2 (d) are graphs (a) and 2 (b), respectively, of the PC-PPG-PC in which the critical micelle concentration is measured, (C) of the aggregation or self-association by dynamic light scattering of the PC-PPG-PC aqueous solution, and the TEM image (d) of PC-PPG-PC micelle.
3 (a) to 3 (d) are graphs showing the phase diagram (a) of the aqueous solution of PC-PPG-PC measured by the butting method which is a test tube in one embodiment of the present invention, (B), ¹ H-NMR spectrum (c) of PC-PPG-PC aqueous solution and FT-IR spectrum (d) of PC-PPG-PC aqueous solution.
4 (a) and 4 (b) are graphs (a) and (b) showing the storage modulus (G ') and loss modulus (G ") of PC- And PC-PPG-PC in vitro.
Figures 5 (a) -5 (c) illustrate the in vitro stem cell (TMSC) delivery profile (a) of PC-PPG-PC, the in vitro stem cells of PC-PPG- (B), and PC-PPG-PC gel after three-dimensional cell culture.
Figure 6 is H & E staining and Masson's trichrome stained images of PC-PPG-PC injected into the subcutaneous layer of rats in one embodiment of the invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art can easily carry out the present invention. It should be understood, however, that the present invention may be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. In the drawings, the same reference numbers are used throughout the specification to refer to the same or like parts.

Throughout this specification, when a part is referred to as being "connected" to another part, it is not limited to a case where it is "directly connected" but also includes the case where it is "electrically connected" do.

Throughout this specification, when a member is " on " another member, it includes not only when the member is in contact with the other member, but also when there is another member between the two members.

Throughout this specification, when an element is referred to as " including " an element, it is understood that the element may include other elements as well, without departing from the other elements unless specifically stated otherwise. The terms " about ", " substantially ", etc. used to the extent that they are used throughout the specification are intended to be taken to mean the approximation of the manufacturing and material tolerances inherent in the stated sense, Accurate or absolute numbers are used to help prevent unauthorized exploitation by unauthorized intruders of the referenced disclosure. The word " step (or step) " or " step " used to the extent that it is used throughout the specification does not mean " step for.

Throughout this specification, the term " combination (s) thereof " included in the expression of the machine form means a mixture or combination of one or more elements selected from the group consisting of the constituents described in the expression of the form of a marker, Quot; means at least one selected from the group consisting of the above-mentioned elements.

Throughout this specification, the description of "A and / or B" means "A or B, or A and B".

Hereinafter, embodiments and examples of the present invention will be described in detail with reference to the accompanying drawings. However, the present invention is not limited to these embodiments and examples and drawings.

[Chemical Formula 1]

Z ¹ -PAG-Z ² ;

Wherein PAG is a polyalkylene glycol; Z ¹ and Z ² are each independently a zwitterionic substance selected from the group consisting of phosphoryl choline, phosphoryl ethanolamine, phosphoryl serine, sulfobetaine, carboxybetaine, and combinations thereof. (Or functional group).

In one embodiment of the present invention, Z ¹ and Z ^{2, which} are ^two zwitterionic substances bonded to both ends of the PAG, may be the same or different from each other, but may not be limited thereto.

In one embodiment of the present invention, the polyalkylene glycol (PAG) can be a polymer known to be usable as a temperature-sensitive polymer. For example, the polyalkylene glycol (PAG) may include, but is not limited to, polyethylene glycol, polypropylene glycol, polybutylene glycol, or copolymers thereof.

Also, in one embodiment of the invention, the polyalkylene glycol (PAG) may be a copolymer comprising blocks of monomers other than glycolic acid. For example, the polyalkylene glycol (PAG) may be a copolymer of ethylene glycol / Propylene glycol copolymer, lactic acid / glycolic acid copolymer, lactic acid / ethylene glycol copolymer, lactic acid-glycolic acid-ethylene glycol copolymer, lactic acid-glycolic acid-propylene glycol-ethylene glycol copolymer,? -Caprolactone / ethylene Glycol copolymers, 3-hydroxybutyric acid / propylene glycol copolymers, fumarated propylene / ethylene glycol copolymers, organic phosphazene / ethylene glycol copolymers, polypeptide block copolymers, or copolymers comprising two or more of these But may not be limited thereto.

Also, in one embodiment of the present invention, the polyalkylene glycol (PAG) may be a block copolymer, for example, a typical block copolymer is an ABA type block copolymer, and a temperature sensitive hydrated gel is formed Many examples of block copolymers that are more complex than the ABA type are known.

The ABA type block copolymer capable of forming a hydrogel usually has both a hydrophilic block or segment and a hydrophobic block or segment. The thermosensitive polymer forming the hydrogel at the time of heating does not include chemical crosslinking. Therefore, the gel is reversibly formed or disassembled depending on the temperature, and the driving force for forming the hydrogel at a high temperature is the magnitude of the hydrophobic interaction Increase. These polymers usually self-assemble and form physical bridges.

Organic polymers capable of forming hydrated gels are well known in the art and are not described further herein. Those skilled in the art will be able to select among the above-mentioned types of polymers a phase in which the phase transition occurs at a suitable phase transition temperature according to the specific use of the zwitterionic temperature responsive polymer and the temperature range within which the gel is maintained is in the appropriate range , And if necessary, can be modified and designed.

For example, as an example of the block copolymer, polyethylene glycol-polypropylene glycol-polyethylene glycol (PEG-PPG-PEG) 3 block copolymer is available. As the commercially available three-block copolymer, Pluronic P188 (BASF) has an average composition of (EG) _80- (PG) _27- (EG) ₈₀ (molecular weight = 8,400). Pluronic P188 is a biocompatible, bioabsorbable polymer approved by the US Food and Drug Administration (FDA) for human use.

In one embodiment herein, the polyalkylene glycol has a number average molecular weight of about 500 to about 20,000 daltons, about 500 to about 15,000 daltons, about 500 to about 10,000 daltons, about 1,000 to about 20,000 daltons, about From about 2,000 to about 20,000 daltons, from about 3,000 to about 20,000 daltons, from about 4,000 to about 20,000 daltons, from about 5,000 to about 20,000 daltons, or from about 10,000 to about 20,000 daltons.

In one embodiment of the present invention, the zwitterionic temperature sensitive polymer may have sol-gel transition properties at a temperature of about 5 캜 to about 60 캜 in an aqueous solution thereof at a certain concentration or above, . For example, the zwitterionic temperature responsive polymer can be heated to a temperature of from about 5 캜 to about 60 캜, from about 5 캜 to about 50 캜, from about 5 캜 to about 40 캜, from about 5 캜 to about 30 캜, From about 10 캜 to about 30 캜, from about 10 캜 to about 20 캜, from about 5 캜 to about 10 캜, from about 10 캜 to about 60 캜, from about 10 캜 to about 50 캜, About 20 ° C to about 60 ° C, about 20 ° C to about 50 ° C, about 20 ° C to about 40 ° C, about 20 ° C to about 30 ° C, Sol-gel transition properties in the temperature range from about 30 캜 to about 40 캜, from about 40 캜 to about 60 캜, from about 40 캜 to about 50 캜, from about 50 캜 to about 60 캜, or from about 35 캜 to about 40 캜 But it may not be limited thereto.

In one embodiment of the present invention, the zwitterionic temperature sensitive polymer may have a sol-gel transition property at a temperature not lower than a body temperature in an aqueous solution thereof, but it may not be limited thereto. For example, at low temperatures, specifically below about 25 占 폚, the zwitterionic temperature responsive polymer can be prepared from the polyalkylene glycol and the zwitterionic material due to the hydrophilic nature of the polyalkylene glycol and the zwitterionic material, As the polyalkylene glycol changes to hydrophobic, it forms micelles, and mutation may occur in the hydrogel. At this time, the temperature at which the zwitterionic temperature responsive polymer undergoes micelle mutation is referred to as a critical micelle temperature (CMT).

In one embodiment of the present invention, the zwitterionic material may have a protein non-adsorptive property, but the present invention is not limited thereto. For example, due to the non-adsorptive nature of the zwitterionic material, the zwitterionic temperature sensitive polymer may be biocompatible, but may not be limited thereto.

In one embodiment of the present invention, the zwitterionic temperature sensitive polymer may be applied to biomaterials due to sol-gel transition properties at body temperature or above, but may not be limited thereto. For example, the zwitterionic temperature-sensitive polymers may be applied to biomaterials such as medicinal carriers or cell carriers due to the sol-gel transfer characteristics and the non-adsorbed nature of the zwitterionic materials. But may not be limited thereto.

In one embodiment herein, the zwitterionic temperature sensitive polymer may exhibit multiple sol-gel-sol-gel-gel transitions at a certain concentration range with increasing temperature, but is not limited thereto . For example, the zwitterionic temperature responsive polymer is a transparent, low viscous sol state at a temperature range of about 20 ° C. or less, a semi-transparent semi-solid gel state at a temperature range of about 20 ° C. to about 50 ° C., But may be, but not limited to, a sol-gel state having a translucent viscosity at a temperature range of from about 50 DEG C to about 65 DEG C, and a gel state of a transparent semi-solid at a temperature range of about 65 DEG C or higher.

In one embodiment of the invention, the polyalkylene glycol may include, but is not limited to, polyethylene glycol, polypropylene glycol, or copolymers thereof.

In one embodiment of the invention, the polyalkylene glycol is a biodegradable polymer selected from the group consisting of esters, oleo esters, acetals, anhydrides, amides, urethanes, thioketals, Functional group, but may not be limited thereto.

In one embodiment of the present invention, the biodegradable functional group may be one for promoting or inducing biodegradation of the polyalkylene glycol, but the present invention is not limited thereto.

In one embodiment of the present invention, the zwitterionic temperature-sensitive polymer may be applied to cell culture, but the present invention is not limited thereto. For example, the cells may be embryonic stem cells, mesenchymal stem cells, liver cells, cardiac stem cells, myocardial cells, endothelial cells, or fibroblasts, but the present invention is not limited thereto.

A second aspect of the invention provides a drug delivery system comprising a drug incorporated into a zwitterionic temperature sensitive polymer according to the first aspect of the present invention. Although the description of the drug delivery system according to the second aspect of the present invention is omitted from the description of the first aspect of the present invention, the description of the first aspect of the present application is not limited to the second aspect of the present invention The same can be applied.

In one embodiment of the present invention, the zwitterionic temperature sensitive polymer may be represented by the following formula (1), but is not limited thereto:

[Chemical Formula 1]

Z ¹ -PAG-Z ² ;

Wherein PAG is a polyalkylene glycol; Z ¹ and Z ² are each independently a zwitterionic substance selected from the group consisting of phosphoryl choline, phosphoryl ethanolamine, phosphoryl serine, sulfobetaine, carboxybetaine, and combinations thereof. .

In one embodiment of the present invention, the zwitterionic temperature sensitive polymer may have a sol-gel transition property at a temperature not lower than a body temperature in an aqueous solution thereof, but it may not be limited thereto.

In one embodiment of the present invention, the zwitterionic material may have a protein non-adsorptive property, but the present invention is not limited thereto. For example, due to the non-adsorptive nature of the zwitterionic materials, the zwitterionic temperature sensitive polymers can have biocompatibility and thus can be applied to biomaterials such as medicinal carriers or cell carriers But may not be limited thereto.

In one embodiment of the invention, the drug delivery vehicle comprising the zwitterionic temperature responsive polymer may be injected into the body via subcutaneous or intramuscular injection after being mixed with the drug in a sol state, have. For example, the drug delivery vehicle containing the zwitterionic temperature sensitive polymer may be injected into the body to instantly produce a hydrogel at a desired site, thereby slowly releasing the drug. However, have.

In one embodiment of the invention, the drug can be selected from the group consisting of an anti-cancer agent, a hormone, an antibiotic, an analgesic, an anti-infective agent, a protein or peptide medicament, a nucleic acid, and combinations thereof. .

In one embodiment, the protein or peptide medicament is selected from the group consisting of oxytocin, vasopressin, ruthening hormone releasing hormone, growth hormone, insulin, glucagon, interleukin, interferon, gastrin, calcitonin, erythropoietin, endorphin, (TNF), nerve growth factor (NGF), bone morphogenetic polypeptide (BMP), angiogenic growth factor (VEGF), granulocyte colony stimulating factor (GCSF), renin or an antibody However, the present invention is not limited thereto.

In one embodiment of the invention, the nucleic acid may be, but is not limited to, DNA, plasmid DNA, RNA, RNAi, or siRNA.

In one embodiment of the invention, the anti-cancer agent may be one comprising taxol, adriamycin, bleomycin, cisplatin, carboplatin, doxorubicin, 5-fluorouracil, methotrexate or antinomycin D, .

A third aspect of the invention provides a tissue engineering medium or scaffold comprising a zwitterionic temperature responsive polymer according to the first aspect of the present invention. Although a detailed description has been omitted for the tissue engineering medium or scaffold according to the third aspect of the present invention, the description of the first and second aspects of the present invention is omitted, The same can be applied to the third aspect of the present application.

In one embodiment herein, the number average molecular weight of the polyalkylene glycol may be from about 500 to about 20,000 daltons (Da), but is not limited thereto.

In one embodiment of the invention, the tissue engineering medium or support comprising the zwitterionic temperature responsive polymer may be injected into the body via subcutaneous or intramuscular injection after being mixed with cells in the sol state, . For example, a tissue engineering medium or supporter containing the zwitterionic temperature-sensitive polymer may be injected into the body to instantly produce a hydrated gel at a desired site, thereby inducing cells to regenerate tissue, But may not be limited thereto.

In one embodiment of the present invention, the zwitterionic temperature-sensitive polymer may be used as a support for tissue engineering since it has a property of transitioning to a hydrated gel at a temperature higher than body temperature and being stably maintained in the body, .

In one embodiment of the invention, the tissue engineering media or scaffold can be, but is not limited to, produce implants without surgery. For example, the tissue engineering media or scaffold may be capable of producing implants without surgical procedures due to zwitterionic materials having biodegradability, and may be sterilized in a sol state using a microfilter, but not limited thereto .

In one embodiment of the invention, the tissue engineering medium or support comprises a chondroitin, embryonic stem cell, mesenchymal stem cell, liver cell, cardiac stem cell, myocardium But are not limited to, one or more cells selected from the group consisting of cells, endothelial cells, fibroblasts, and combinations thereof.

In one embodiment of the present invention, the zwitterionic temperature sensitive polymer may be applied as a scanning type tissue engineering material, but it is not limited thereto. For example, the sol-gel transfer characteristics of the zwitterionic temperature responsive polymer may be used to maximize cartilage regeneration ability by injecting it into a specific cartilage area, but the present invention is not limited thereto.

EXAMPLES Hereinafter, the present invention will be described in more detail with reference to the following examples. However, the following examples are given to aid understanding of the present invention, and the present invention is not limited to the following examples.

[ Example ]

Zwitter The ionic temperature sensitive polymer (PC- PPG -PC) Synthesis

The polypropylene glycol (MW = 2,700 daltons), 2-chloro-2-oxo-1,3,2-dioxaphospholane ), Triethylamine, trimethylamine, anhydrous toluene, and anhydrous acetonitrile were purchased from Sigma-Aldrich, USA.

PC-PPG-PC was synthesized through the reaction between alcohol and 2-chloro-2-oxo-1,3,2-dioxaphosphorane. Polypropylene glycol (10 g, 3.70 mmol) and triethylamine (1.3 mL, 9.33 mmol) were dissolved in anhydrous toluene (100 mL). 2-Chloro-2-oxo-1,3,2-dioxaphosphorane (0.68 mL, 7.40 mmol) was added to the solution and the reaction mixture was stirred at room temperature for 20 hours. Precipitated trimethyl ammonium chloride was filtered off and the remaining solvent was removed. The product was dissolved in anhydrous acetonitrile (25 mL) in a pressure reactor. The reactor was immersed in a dry ice-acetone bath followed by the addition of trimethylamine (0.88 mL, 9.38 mmol). After the pressure reactor was sealed, the reaction was allowed to proceed at 65 占 폚 for 72 hours. The reaction mixture was cooled to room temperature and the residual trimethylamine and solvent were removed by evaporation. After bubbling with nitrogen for 24 h, the product was purified by a filtration method (cut-off molecular weight 1,000 daltons). The purified product was then lyophilized. The final yield is 84%.

NMR of temperature sensitive polymers and FTIR analysis

The structure of the PC-PPG-PC prepared above was CDCl ₃ Was confirmed by ¹ H- / ³¹ P-NMR spectroscopy (500 MHz NMR spectrometer; Varian, USA) and FTIR spectrometer (FTIR spectrophotometer FTS-800; Varian, USA) in the solvent. Further, ¹ H-NMR and FTIR spectra of PC-PPG-PC (45.0 wt%, D ₂ O solvent) were examined at a temperature range of 10 ° C to 80 ° C. The PC-PPG-PC was equilibrated at each temperature for 5 minutes.

Gel permeation chromatography, GPC )

The molecular weight and molecular weight distribution of the polymer were measured using a GPC system consisting of a pump (SP930D; Younglin, Korea) and a refractive index detector (RI750F; Younglin, Korea). N, N-dimethylformamide was used as an eluent and analyzed using an OHpak SB-803QH column (Shodex, Japan). Polyethylene glycol (Polysciences, USA) having a molecular weight in the range of 200 to 20,000 daltons was used in standard molecular weights.

Dynamic light scattering (DLS) analysis

The size and self-assembly of PC-PPG-PC were investigated with a dynamic light scattering machine (Zetasizer Nano; Malvern Instruments Inc., USA). A 200-YAG DPSS laser (Lange, Germany) operating at 532 nm was used as the light source. The scattering intensity of the aqueous polymer solution was measured as a concentration function at a range of 0.0005 to 1.0% by weight at 25 캜. In addition, the approximate size of the polymeric and polymeric self-assemblies was measured as a function of temperature at 10, 25, and 40 C at a fixed concentration of 0.10 wt%. Scattering intensity was measured with an incident beam angle of 173 ^o. Dynamic light scattering results were analyzed by CONTIN normalization method. From the diffusion coefficient, the hydrodynamic size of the polymer assembly was obtained by the Stokes-Einstein equation.

Criticality Micelle The critical micelle temperature, CMT ) Measure

In order to measure the critical micelle temperature of the PC-PPG-PC thus prepared, a hydrophobic dye (1,6-diphenyl-1,3,5-hexatriene, DPH) (0.10% by weight). The change in the UV-visible spectrum of the dye was measured with a UV-visible spectroscope (S3100, Sinco, Korea) as a function of temperature in the temperature range from 10 캜 to 80 캜. PC-PPG-PC was equilibrated at each temperature for 5 minutes.

Transmission electron microscopy (transmission electron microscopy, TEM ) analysis

A PC-PPG-PC aqueous solution (10 mL, 0.10 wt%) was placed over a 200 mesh carbon coated copper grid and water was slowly evaporated at room temperature. Micrographs were obtained using a JEM-2100F microscope (JEOL, Japan) at an accelerating voltage of 200 kV.

PC- PPG -PC Phase equilibrium Phase diagram

The sol - gel transition temperature of the aqueous polymer solution was measured by the butting method which is a test tube. An aqueous polymer solution (0.5 mL) was injected into a test tube having an inner diameter of 11 mm. The transition temperature was measured on a flow (sol) and non-flow (gel) basis with increasing the temperature step by step. Each data point is an average value measured three times.

Dynamic mechanical analysis

As a function of temperature, the dynamic modulus of elasticity of PC-PPG-PC aqueous solution was determined with a Rheometer RS 1 (Thermo Haake, USA). A water soluble polymer solution (45.0 wt%) was placed between parallel plates having a diameter of 25 mm. The space between the parallel plates of the gap was maintained at 0.5 mm. Prior to performing dynamic mechanical analysis, a wetted surface was placed inside the chamber to minimize water evaporation of the sample. The data were collected under controlled stress (4.0 dyne / cm ² ) at a heating rate of 0.2 ° C / min at a frequency of 1.0 rad / s.

In vitro drug release

Insulin was dissolved in PC-PPG-PC aqueous solution (45.0 wt%). A glass bottle containing 0.5 mL of each formulation was preincubated at 37 DEG C for 10 minutes. Phosphate buffered saline (pH = 7.4, 3.0 mL) was then added to the top of the gel at 37 占 폚. At 37 째 C fresh medium (3.0 mL) was carefully replaced at designated time intervals. The recovered sample was analyzed with an HPLC system (Waters 1525B, Korea) at a wavelength of 214 nm. A Jupiter 5m C18 300A column (250 x 4.60 mm 5 micron, Phenomenex, USA) and acetonitrile / water (30/70, v / v) co-solvent systems were used as eluent solvents.

In vivo Insulin delivery

5-week-old male SD rats were purchased from a central laboratory animal (Central Lab Animal Inc., Korea). The rats were stabilized for one week and then injected into rat abdominal cavity by dissolving streptozotocin (65 mg / Kg-rat) in 0.01 M citrate buffer at pH 4.5 for the induction of diabetes. Diabetes mellitus was diagnosed in rats whose blood glucose level was more than 350 mg / dL for 5 consecutive days. The insulin dose of 13.8 mg / Kg-rat was then injected into the subcutaneous layer of diabetic rats in the form of insulin / PC-PPG-PC (45.0 wt%, 0.5 mL). As a control group, saline and PC-PPG-PC aqueous solution were injected into the subcutaneous layer of diabetic rats. Water was always supplied, and all rats were maintained under light / dark (12 hours / 12 hours) system. After fasting for 2 hours, the blood glucose levels of the rats were monitored using a glucose meter (Accu-Chek, Roche, Switzerland). Blood glucose levels in non-diabetic rats were monitored as a positive control, with n being 4 in each group.

3D 3D cell culture and delivery analysis

The TMSC was separated from the 11-year-old female donor's palatal tract according to the ethical guidelines of the Ewha Womans University Mokdong Hospital (Seoul, Korea) (IRB approval code: ETC 11-53-02). After obtaining consent from the donor, the tonsil was collected from the patient through tonsillectomy. For stem cell proliferation, stem cells of passage 5 or higher were cultured in DMEM (high glucose Dulbecco's modified eagle media, Hyclone, USA), 10% (v / v) Hyclone ^™ penicillin / streptomycin solution, And cultured two-dimensionally on polystyrene culture plates under 5% CO ₂ conditions using Gibco® antibiotic-antimitotic solution. The collected TMSCs (passage 6, 0.4 x 10 ⁶ cells) were suspended in an aqueous solution of PC-PPG-PC (45.0 wt%; 0.20 mL) and then injected into a 24-well culture dish at 37 ° C. In these conditions, TMSC was encapsulated by gel by sol-gel transfer. Sheets under the 10% FBS and 1% penicillin / streptomycin containing the azithromycin DMEM (1.0 mL, 37 ℃) a cell encapsulated by PC-PPG-PC writing was added to Mauser (thermogel), 37 ℃, 5 % CO 2 atmosphere The medium was changed every 3 days.

Cell viability and proliferation analysis

Cell viability was measured by Live / Dead kit (Life Technologies, USA) after 0 day (1 hour), 1 day, 3 days and 7 days of culture in PC-PPG-PC thermoplastic. TMSCs encapsulated in thermogels were prepared by using ethidium homodimer-1 (4.0 μM) and calcein AM (2.0 μM) using phosphate buffered saline as a solvent and incubating the cells for 15 min at 37 ° C. Lt; / RTI > The cells displayed were imaged and photographed using an Olympus IX71 fluorescence microscope and an Olympus DP2-BSW. The living cells were stained green with curcane AM and the dead cells were stained red by ethidium homodimer-1. Cell proliferation was monitored with a cell counting kit-8 (CCK-8, Dojindo Co. Ltd., Kumamoto, Japan) (n = 3). CCK-8 solution (1.5 mL, 10% v / v in medium) was added to each well. After incubation for 3 hours, the sample was measured at 450 nm using an ELISA reader (Model 550; Bio-Rad, USA) and 655 nm was used as the baseline.

Analysis of tissue compatibility

The mice were stabilized for one week and then injected with PC-PPG-PC aqueous solution (45.0 wt%, 0.5 mL / rat) into the subcutaneous layer of the rats. After 5 days of culture, the implanted surrounding tissue was harvested for analysis. The tissue was then fixed in 4% paraformaldehyde solution for 24 hours. Finally, the fixed tissue was hardened in paraffin. The paraffin block was sectioned to a thickness of 6 μm using a microtome. Samples were fixed on a microscope slide and then stained with Mayer's hematoxylin-eoisin (H & E) method and Masson's trichrome staining method.

PC-PPG-PC was synthesized by treating trimethylamine in the reaction between the dihydroxy terminal group of PPG and 2-chloro-2-oxo-1,3,2-dioxaphosphorane (Fig. 1 (a) ]. The ¹ H-NMR spectrum of PC-PPG-PC (in CDCl ₃ solvent) shows the methyl group peak of polypropylene glycol at 1.0 to 1.2 ppm. ^The peak seen at 1.2 to 1.4 ppm of the ¹ H-NMR spectrum also indicates a small peak of the methyl group of the polypropylene glycol connected to the terminal phosphoryl group. The peak at 4.4 to 4.5 ppm is the peak due to the methylene group of the PC group linked to the oxygen of the phosphoryl group. The 3.2 to 3.7 ppm peak originates from the methyl group of PC, and the methylene group of PC is linked to nitrogen, the methine group of PPG and the methylene group of PPG (Fig. 1 (b)). By comparing the peaks of 1.0 to 1.4 ppm (methylene peak of PPG) with 4.4 to 4.5 ppm (methylene peak of PC), it was confirmed that both ends of PPG were capped with PC groups. ^{In the 31} P-NMR spectrum, a single peak also showed the correct structure of PC-PPG-PC. The FTIR spectrum of the clean polymer showed the phosphorylcholine group at 1242 cm ^-1 (P = O stretching). The GPC chromatogram of PC-PPG-PC showed a mean molecular weight of 1300 and a molecular weight distribution of 1.1 for the PEG standard as a single bar.

Dynamic light scattering spectroscopy, dissolution of hydrophobic dyes, and transmission electron microscopy (TEM) were used to investigate the self-assembly behavior of low concentration PC-PPG-PC polymer solutions. Due to the amphipathic nature of PC-PPG-PC at 25 캜, the polymer formed micelles. When the concentration of the polymer was increased, the scattering intensity began to increase, and PC-PPG-PC micelle formation at PPG core and PC shell at 25 ° C was proposed. The critical micelle concentration (CMC) of PC-PPG-PC was measured at about 25 ° C at 0.05 to 0.10 wt% (Fig. 2 (a)). PPG-PC (0.10% by weight) aqueous solution containing hydrophobic dyes of 1,6-diphenyl-1,3,5-hexatriene (DHP) Self-assembly was measured as a function of temperature. The dyes show characteristic triple bands at 300 nm to 400 nm in the hydrophobic environment, while they exhibit maximum absorbance at 300 nm in the hydrophilic environment. The appearance of a triple band at 300 nm to 400 nm suggests that a hydrophobic domain is formed, that is, it represents micelles. When the temperature of the PC-PPG-PC aqueous solution was increased to 25 ° C or more, triple bands of dyes appeared at 337 nm, 356 nm, and 375 nm (FIG. 2 (b)). Above 60 ° C, the triple band disappeared and significant scattering was observed in the UV-vis spectrum. The UV-vis spectrum shows that the micelle structure is preserved in the temperature range of 25 캜 to 60 캜. Below 25 ℃, the polymer remained a random coil structure due to the hydrophilic nature of both PC and PPG. As the temperature is increased, the PPG remains hydrophobic while the PC remains hydrophilic, thus PC-PPG-PC forms micelles. The critical micelle temperature (CMT) of PC-PPG-PC aqueous solution (0.10 wt%) was confirmed to be about 25 캜. The conversion of temperature-sensitive unimers to micelles is a unique feature of the current PC-PPG-PC and PEG-PPG-PEG systems. Above 60 ℃, PPG was further dehydrated and thermal energy weakened PC ion interaction. Temperature - sensitive micelle formation was also confirmed by dynamic light scattering method. The apparent self-assembled size of the PC-PPG-PC was 220 nm (peak average) at 25 ° C and was 2 to 5 nm (unit) at 10 ° C in the light scattering study of PC-PPG-PC aqueous solution (0.10% (Fig. 2 (c)). At 40 캜, larger polymer aggregation was observed at 500 to 1200 nm. Spherical PC-PPG-PC micelles of 100 nm to 250 nm in size were identified by TEM image from aqueous polymer solution (0.10 wt%). The micelle size in the TEM image was similar to that obtained in the dynamic light scattering study (Fig. 2 (d)), although the shape or size of these polymer assemblies may be damaged by moisture evaporation during the TEM experiment.

As the temperature increased, PC-PPG-PC aqueous solution exhibited multiple sol-gel-sol-gel transition at a specific concentration range of 40-60 wt% (Fig. For example, the aqueous polymer solution at 45 wt% is transparent and has a low viscous sol state at 22 [deg.] C or lower. However, the polymer aqueous solution turned into a translucent semi-solid gel at a temperature range of 22 to 56 占 폚. The polymer aqueous solution was then transferred to a semitransparent viscous sol at a temperature range of 56 [deg.] C to 66 [deg.] C. At a temperature of 66 캜 or higher, the aqueous polymer solution changed to a transparent semi-solid gel. At a concentration of 40.0% by weight or less, the viscosity of PC-PPG-PC aqueous solution changed with increasing temperature, but it was regarded as a sol because it did not form a strong gel that does not flow against the stress of the test tube. On the other hand, at a concentration of 60.0 wt% or more, the PC-PPG-PC aqueous solution was present as a non-flowable gel in a temperature range of 0 ° C to 80 ° C. The phase behavior of the aqueous polymer solution was clearly shown in the photograph as 10 캜 (transparent sol), 25 캜 (translucent gel), 60 캜 (translucent sol), and 70 캜 (transparent gel) ]. Molecular behavior studies involving multiple transfer of PC-PPG-PC aqueous solutions were investigated as a function of temperature in ¹ H-NMR spectra and FTIR spectra of PC-PPG-PC aqueous solution (45.0 wt%, solvent D ₂ O). The ¹ H-NMR spectrum of PC-PPG-PC aqueous solution (45.0 wt%, solvent D ₂ O) showed a PPG peak at 0.8 to 1.4 ppm (-CH ₃ ) and 3.2 to 3.8 ppm (-OCHCH ₂ - And the small PC [-N ⁺ (CH ₃ ) ₃ ] peaks at ~ 3.2 ppm showed that both were disrupted in the first gel region by increasing the temperature [Gel (tl)]. However, at a temperature of 60 캜 or higher, the intensity of the peaks increased and the shape changed sharply (Fig. 3 (c)). In addition, a new peak of PPG appeared at 3.2 to 3.4 ppm, indicating a change in the autochemical environment due to significant dehydration of PPG. Peak disruption and sharpening in the ¹ H-NMR spectrum are related to the molecular motion of the corresponding moiety. The ¹ H-NMR spectrum of PC-PPG-PC suggested a reduction of PPG molecular motion in the first gel region. However, it increases again when the temperature is increased to 60 ° C or more. As the temperature increased, the 4.7 to 5.0 ppm water peak in the ¹ H-NMR spectrum shifted steadily from 4.0 to 4.4 ppm. PC-PPG-PC aqueous solution (45.0 wt%, solvent: D ₂ O) was monitored by a temperature function using the FTIR spectrum (Fig. 3 (d)). The PPG aqueous solution (45.0 wt.%) And the FTIR spectrum of the literature can assign a P = O stretching vibration band at 1230 cm ^-1 . When the temperature was increased from 10 ° C to 80 ° C, the band was shifted from 1230 cm ^-1 to 1249 cm ^-1 . As the temperature increased, the intermolecular ionic interaction between the negatively charged phospholyl group and the positively charged choline group was consequently attenuated by the enhancement of the P = O stretching band. It is well known that the change in force constant or band position in the FTIR spectrum is related to intermolecular hydrogen bonding to the carbonyl group (C = O) of the polypeptide. The 1630 cm ^-1 band in the carbonyl beta sheet peptides configured to hydrogen bond to systematically, and go to 1640 cm ^-1 in the random coil peptide.

The phase behavior of the PC-PPG-PC aqueous solution was determined by the reaction of poly (N-isopropylacrylamide-co-sulphobetaine methacrylate) and poly (N-vinylcaprolactam-co-sulphobetaine Methacrylate) aqueous solution. The ionic interactions between zwitterion ion are weakened with increasing temperature and lead to the UCST behavior of the aqueous polymer solution as the solubility of the polymer increases with increasing temperature. At the same time, as the temperature increases, the solubility of the poly (N-isopropylacrylamide) moiety decreases, leading to LCST at higher temperatures. A multiple gel-gel-upper gel transition was reported in aqueous solution of polyethylene glycol-polycaprolactone-polyethylene glycol (EG ₁₃ CL ₂₃ EG ₁₃ ). Melting of crystalline polycaprolactone blocks and dehydration of PEG were proposed as multiple transfer mechanisms of aqueous polymer solutions. In the upper gel state, the PCL is in the amorphous state, while in the lower gel state, it is in the crystalline state. In aqueous solution of polyethyleneglycol-polypropylene glycol-polyethyleneglycol (EG ₁₇ PG ₆₀ EG ₁₇ ), a lower gel-upper gel transition appeared at increasing temperature. Micelle packing and phase separation models have been proposed as mechanisms of the lower gel transition and the upper gel transition, respectively. The unique sol-gel-sol-gel transition of PC-PPG-PC of the present invention is related to the dehydration of PPG in water and the change of ionic interaction of PC residue.

The thermosyphelling PC-PPG-PC system was identified as a continuous delivery system for protein drugs and stem cells. First, the possibility of the system as a scan carrier was tested by monitoring the modulus change of the aqueous polymer solution (45.0 wt%) as a function of temperature (Fig. 4A). The first sol - gel transition temperature was close to 20 ℃ and the increase in storage modulus (G ') and loss modulus (G ") were obvious. In particular, at this temperature, the G "cross over G 'represents an apparent sol-gel transition. G 'and G "are the viscous and elastic component elements of the composite modulus, respectively. The gel maintains the elastic modulus in the body temperature range of 36 캜 to 43 캜. It can therefore be used as a biomedical injection system. The in-vitro system of insulin was prepared by injecting insulin / PC-PPG-PC aqueous solution into warm wells at 37 ° C. Insulin was released from the gel formed in situ by diffusion control for over 7 days (Fig. 4 (a)). The gel has been preserved in its physical integrity. The zwitterionic polymers, as discussed above, exhibit low protein adsorption properties, which facilitates the steady release of insulin. In vivo, the insulin secretion system was prepared by injecting an aqueous solution of PC-PPG-PC containing insulin (45.0 wt%) into the subcutaneous layer of diabetic rats. Insulin dose was fixed at 13.8 mg / Kg-rat. Control experiments were performed by injecting a negative, insulin-free aqueous polymer solution (45.0 wt%) (gel only) into the subcutaneous layer of diabetic rats. Normal rats without diabetes were tested in the same manner as positive control. The insulin / PC-PPG-PC formulation showed a therapeutic efficacy in rats of about 3 days with a single infusion.

The PC-PPG-PC thermosel was studied as a delivery system of TMSCs derived from one side. Cell suspension The water-soluble polymer solution formed a cell-encapsulated hydrated gel matrix upon injection into the well at 37 ° C. Since PC is a major functional group in biological membranes, PC-PPG-PC is expected to provide a cell-friendly environment for stem cells. TMSCs retained their original spherical shape in in situ formed PC-PPG-PC gel. Dead cells were not observed in the gel for 7 days. However, the cell density steadily decreased from PC-PPG-PC gel for 7 days (Fig. 5 (a) to Fig. 5 (c)). The total number of viable cells in the cell culture wells was measured by the CCK-8 method. The total number of living cells increased for 7 days, suggesting that the cells were slowly delivered outside the gel and proliferated for 7 days. These results indicate that the PC-PPG-PC thermoplastic is providing cell-friendly, continuous delivery of stem cells.

Biocompatibility of the PC-PPG-PC thermoplastic was confirmed by injecting a polymer aqueous solution (45.0 wt%) into the subcutaneous layer of the rat and using the gel formed in situ. The gel showed very weak tissue response in the tissues surrounding the implant. Hematoxylin and eosin (H & E) staining revealed slight inflammatory cells around the implant on the fifth day after injection into the rat (left side of FIG. 6). PC-PPG-PC thermogels exhibited a very mild inflammatory response (Fig. 6, right), even in Masson's trichrome (MT) staining, where the collagen layer was blue, cytoplasm red, and nuclei black. At 37 캜, the positive ion PC portion was exposed to the tissue while the PPG portion became the hydrophobic group to form the core of the micelle. Zwitterionic polymers tend to have low protein adsorption properties, as mentioned above. Because protein adsorption is the first step in the formation of collagen capsules, zwitterionic PC-PPG-PC can reduce the foreign-body reaction and improve the biocompatibility of the thermosel. The long gel duration of PC-PPG-PC is compared to the short gel duration of PEG-PPG-PEG thermogels lasting less than 1 day in the subcutaneous layer of rats. This contributed to the persistence of the biocompatibility of the in situ formed thermoplasm as well as the ionic interactions between the zwitterion of PCs.

According to the present invention, temperature-sensitive Z ¹ -PAG-Z ^2, which is promising for pharmaceutical delivery or tissue engineering applications, was prepared (in the Z ¹ -PAG-Z ² , PAG is a polyalkylene glycol and Z ¹ and Z ² comprises a zwitterionic substance selected from the group consisting of phosphoryl choline, phosphoryl ethanolamine, phosphoryl serine, sulphobetaine, carboxybetaine, and combinations thereof. The aqueous solution of Z ¹ -PAG-Z ² according to the present invention is present as an aqueous solution at a certain temperature or lower when the concentration is higher than a certain concentration, but the transition to hydrated gel occurs at a temperature higher than the certain temperature. Since the zwitterionic substance is used as a terminal and the affinity to biomolecules or cells is very excellent, the zwitterionic temperature-sensitive polymer is a remarkable substance which has proved its applicability to the biomedical field. It can be applied as a medium.

It will be understood by those of ordinary skill in the art that the foregoing description of the embodiments is for illustrative purposes and that those skilled in the art can easily modify the invention without departing from the spirit or essential characteristics thereof. It is therefore to be understood that the above-described embodiments are illustrative in all aspects and not restrictive. For example, each component described as a single entity may be distributed and implemented, and components described as being distributed may also be implemented in a combined form.

The scope of the present invention is defined by the appended claims rather than the detailed description, and all changes or modifications derived from the meaning and scope of the claims and their equivalents should be construed as being included within the scope of the present invention.

Claims

1. A zwitterionic temperature responsive polymer represented by the following formula (1): < EMI ID =
[Chemical Formula 1]
Z ¹ -PAG-Z ² ;
In Formula 1,
The PAG may be selected from the group consisting of polyethylene glycol, polypropylene glycol, polybutylene glycol, ethylene glycol / propylene glycol copolymer, lactic acid / glycolic acid copolymer, lactic acid / ethylene glycol copolymer, lactic acid- -Propylene glycol-ethylene glycol copolymer,? -Caprolactone / ethylene glycol copolymer, 3-hydroxybutyric acid / propylene glycol copolymer, fumarated propylene / ethylene glycol copolymer, organic phosphazene / ethylene glycol copolymer, Block copolymers, or copolymers comprising two or more of them each linked together and having a number average molecular weight of from 500 to 20,000 daltons (Da);
Z ¹ and Z ² are each independently a zwitterionic substance selected from the group consisting of phosphoryl choline, phosphoryl ethanolamine, phosphoryl serine, sulfobetaine, carboxybetaine, and combinations thereof. .

delete

The method according to claim 1,
Wherein the zwitterionic temperature responsive polymer has a sol-gel transition property at a temperature of from 5 占 폚 to 60 占 폚 in an aqueous solution thereof.

The method according to claim 1,
Wherein the zwitterionic temperature responsive polymer has sol-gel transition properties at temperatures above body temperature in its aqueous solution.

The method according to claim 1,
Wherein the PAG further comprises a biodegradable functional group selected from the group consisting of esters, oleo esters, acetals, anhydrides, amides, urethanes, thioketals, and combinations thereof. Temperature thermally responsive polymer.

7. A drug delivery system comprising a drug incorporated into a zwitterionic temperature sensitive polymer according to any one of claims 1 to 6.

8. The method of claim 7,
Wherein the medicament is selected from the group consisting of an anti-cancer agent, a hormone, an antibiotic, an analgesic, an anti-infective agent, a protein or peptide medicament, a nucleic acid, and combinations thereof.

7. A composition comprising a zwitterionic temperature responsive polymer according to any one of claims 1 to 6,
Tissue engineering medium or scaffold.