온도감응성 히드록시프로필 셀룰로오스 수화젤: 다양한 가교제에 따른 특성

임규헌,김지혜,이종휘 한국고분자학회 2024 폴리머 Vol.48 No.2

In the crosslinking of hydroxypropyl cellulose (HPC), a temperature-sensitive hydrogel, there have been limited comparative studies on the effects of different crosslinking agents. This study aims to explore how the characteristics of HPC change when crosslinked with various agents. Film surface structure, swelling ratio, modulus, and diffusion coefficient are influenced by the type of crosslinking agent used. These changes are attributed to variations in the number of chain branches, chain length, and the crosslinking strength of the agents. Furthermore, in the blend films of HPC and hydroxypropyl methylcellulose (HPMC), increases in the modulus and the diffusion coefficient were observed. This understanding of HPC hydrogel properties when employing different crosslinking agents holds promise for broadening HPC's applications across various fields 온도감응성 하이드로젤인 히드록시프로필 셀룰로오스(hydroxypropyl cellulose, HPC)의 가교에서 가교제의 종류에 따른 비교 연구가 보고된 바가 드물다. 본 연구에서는 다양한 가교제를 이용해 HPC를 가교했을 때 변화하는특성을 조사하였다. 가교제의 종류에 따라 필름 표면 구조 변화, 팽윤비, 모듈러스, 확산 계수 등등이 변화하게 됨을확인하였고 이는 가교제의 사슬 가지의 개수, 사슬 길이, 가교 결합 강도에 따라서 변화하는 것으로 판단된다. 또한HPC와 hydroxypropyl methyl cellulose(HPMC)를 함께 사용해 필름을 제조하여, 증가한 모듈러스와 높은 확산계수를확인할 수 있었다. 다양한 가교제를 사용한 HPC 필름의 여러 특성에 대한 이해는 HPC의 다양한 응용분야에서의활용성을 높일 수 있을 것으로 예상된다.

Indentation and temperature response of liquid metal/hydrogel composites

Sooyeon Kim,이종휘 한국공업화학회 2022 Journal of Industrial and Engineering Chemistry Vol.110 No.-

The volume transition of thermo-responsive hydrogels has been investigated for various applicationssuch as soft actuators, sensors, drug delivery systems, and bioelectronics. Nonetheless, issues such aspoor mechanical properties, slow transition rates, and limited volume change windows have promptedthe development of hydrogel composites. Gallium (Ga), a liquid metal, is combined with poly(Nisopropylacrylamide) (PNIPAm) with varying composite structures in this work. Ga’s melting point isclose to PNIPAm’s volume transition temperature. The introduction of Ga particles into PNIPAm improvesboth the indentation resistance and the transition rate of the hydrogel. Microchannel structure can furtherimprove the transition rate by increasing the water diffusion rate. The relatively fast thermal conductionof the Ga phase in anisotropic composites causes fast deswelling of Ga-rich regions, resultingin unique double bending behavior. The double bending behavior was utilized to hold irregularly shapedobjects firmly. These results offer a useful design strategy of composites for the development of novelresponsive smart systems.

The preparation and applications of novel phosphazene crosslinked thermo and pH responsive hydrogels

Hava Ozay,Ozdem Sahin,Omer Kaan Koc,Ozgur Ozay 한국공업화학회 2016 Journal of Industrial and Engineering Chemistry Vol.43 No.-

In this study, we synthesized a novel phosphazene compound hexakis[4-(acrylamido)phenoxy]cyclotriphosphazene (HAAP) as crosslinker. The structure of compound was identified usingspectroscopic techniques. Then, HAAP was used as crosslinker for the synthesis of thermo and pHresponsive p(NIPAM-co-VI) hydrogels. The structure and swelling behavior of hydrogel was investigated. Then, HAAP-crosslinked p(NIPAM-co-VI) hydrogels were used for in vitro release of Rhodamine 6G asdrug release matrix. Additionally, HAAP-crosslinked p(NIPAM-co-VI) hydrogels were used as supportmaterial for the preparation of cobalt metal catalysts. The prepared HAAP-crosslinked p(NIPAM-co-VI)-Co composite catalyst was used as catalyst for the reduction reaction of 4-nitrophenol.

온도 감응성 고분자를 이용한 유전자 전달

남궁란,김원종 한국생체재료학회 2010 생체재료학회지 Vol.14 No.2

A successful gene therapy is considerably dependent on the vector types that allow an efficient gene delivery to cells. Recently stimuli-responsive polymers are obtaining great interest because of the potential to deliver therapeutic gene with high efficacy. Among the various stimuli-responsive polymers, temperature-responsive polymers are the most widely investigated smart systems in gene delivery as temperature is an efficient stimulus that is easy to control and has practical advantages both in vitro and in vivo. In this review, we discuss the properties of representative a temperature-responsive polymers and their recent applications for gene delivery.

Development of bioresorbable smart injectable hydrogels based on thermo-responsive copolymer integrated bovine serum albumin bioconjugates for accelerated healing of excisional wounds

V. H. Giang Phan,Thai Minh Duy Le,고피나단 자나르다난,Phuong-Khanh Thi Ngo,이두성,Thavasyappan Thambi 한국공업화학회 2021 Journal of Industrial and Engineering Chemistry Vol.96 No.-

One of the major challenges in wound healing is the development of suitable hydrogels that areinjectable, biocompatible with multiple functionalities and properties such as high mechanical, tissueadhesiveness, and swelling properties. However, these hydrogels should not elicit any immunologicalresponse and synthesis steps should be easier and tunable according to the requirements. Consideringthese properties, we synthesized a thermo-sensitive triblock copolymer consisting of bovine serumalbumin (BSA) protein capable of leveraging the needs for a proper wound closure and tissueregeneration on excisional injuries. Firstly, the triblock copolymer consisting of poly(e-caprolactone-colactide)-b-poly(ethylene glycol)-b-poly(e-caprolactone-co-lactide (PCLA) was synthesized and then thecopolymer was grafted with BSA to yield BSA-PCLA bioconjugates. Aqueous solutions of free-flowingbioconjugate sol at room temperature can transform to gel at physiological temperature with highviscoelastic properties. Subcutaneous injection of BSA-PCLA bioconjugate sol into the back of Sprague-Dawley rats formed gel immediately and found to be bioresorbable after 5 weeks without significanttoxicity at implantation sites. BSA-PCLA bioconjugate gel exhibited good adhesive property to majororgans including liver, heart, and spleen when compared with control PCLA gel. When tested for in vivowound closure trials, the BSA-PCLA gels showed rapid wound contraction compared to the PCLA and thecontrol. The increased angiogenesis and collagen deposition were confirmed from the histological studiesof the samples. These highly adhesive, biocompatible, biodegradable, thermos-sensitive bioconjugategels show promising potential in wound healing and tissue regeneration without any additionalbiofactors or inorganic nanoparticles.

Synthesis and Characterization of Biodegradable Elastic Hydrogels Based on Poly(ethylene glycol) and Poly(${\varepsilon}-caprolactone$) Blocks

Im, Su-Jin,Choi, You-Mee,Subramanyam, Elango,Huh, Kang-Moo,Park, Ki-Nam The Polymer Society of Korea 2007 Macromolecular Research Vol.15 No.4

Novel biodegradable elastic hydrogels, based on hydrophilic and hydrophobic polymer blocks, were synthesized via the radical crosslinking reaction of diacrylates of poly(ethylene glycol) (PEG) and poly(${\varepsilon}-caprolactone$) (PCL). PEG and PCL diols were diacrylated with acryloyl chloride in the presence of triethylamine, with the reaction confirmed by FT-IR and $^1H-NMR$ measurements. The diacrylate polymers were used as building-blocks for the syntheses of a series of hydro gels, with different block compositions, by simply varying the feed ratios and molecular weights of the block components. The swelling ratio of the hydrogels was controlled by the balance between the hydrophilic and hydrophobic polymer blocks. Usually, the swelling ratio increases with increasing PEG content and decreasing block length within the network structure. The hydrogels exhibited negative thermo-sensitive swelling behavior due to the coexistence of hydrophilic and hydrophobic polymer components in their network structure, and such thermo-responsive swelling/deswelling behavior could be repeated using a temperature cycle, without any significant change in the swelling ratio. In vitro degradation tests showed that degradation occurred over a 3 to 8 month period. Due to their biodegradability, biocompatibility, elasticity and functionality, these hydrogels could be utilized in various biomedical applications, such as tissue engineering and drug delivery systems.

Effect of end-block chain length on rheological properties of ABA triblock copolymer hydrogels

Hyunjoon Jung,Taeshik Earmme,Soo-Hyung Choi 한국유변학회 2021 Korea-Australia rheology journal Vol.33 No.2

End-block length dependence of the hydrogel relaxation dynamics was investigated using PEO-based ABA triblock copolymer solutions in an aqueous solvent. Both ends of PEO were capped with hydrophobic poly(isopropyl glycidyl ether-co-ethyl glycidyl ether) exhibiting a lower critical solution temperature (LCST) behavior, resulting in the transition between sol and gel with temperature. Despite the nearly identical hydrophobicity of the end-blocks, the sol-to-gel transition temperature is found to be significantly dependent on the end-block length. Particularly, a small increment of the end-block length leads to significantly slower relaxation dynamics which is attributed to the thermodynamic barrier of end-block extraction. Hydrogels with an appropriate relaxation time show excellent injectability and self-healing ability, yet extremely slow relaxation dynamics result in brittle hydrogels. These results are discussed in terms of current understanding of the hydrogel relaxation dynamics and particular attention is paid to the issue of the chain dynamics between aggregated cores.

Spermine Modified PNIPAAm Nano-Hydrogel Serving as Thermo-Responsive System for Delivery of Cisplatin

Soheila Ghasemi,Marzieh Owrang,Farzad Javaheri,Fatemeh Farjadian 한국고분자학회 2022 Macromolecular Research Vol.30 No.5

Poly(N-isopropylacrylamide) (PNIPAAm) hydrogel as a temperatureresponsive polymer was prepared through controlled process using reversible addition fragmentation chain transfer (RAFT) polymerization. The hydrogel was then amino modified using a biocompatible polyamine i.e. spermine and next the antitumor cisplatin drug was conjugated to the modified hydrogel via pH-sensitive spermine linkage. This system had a pH dependency and temperature sensitivity at lower critical solution temperature (LCST). Cisplatin potentially is liberated from the carrier in the acidic environment. However, the release of cisplatin from this polymeric system is increased considerably around the transition temperature of the polymer. The drug release manner of the prepared hydrogel was determined at two pH values (5.5 and 7.4) and three temperatures (37, 40 and 42℃) at different time intervals. The in vitro toxicity assessment was conducted on MCF-7 cell line which showed the system efficiency in killing breast cancer cells.

온도 반응성 하이드로젤로 제작된 마이크로 필라의 가역적 군집 효과

최지성(Ji Seong Choi),유진영(Jin Young Yu),강성민(Seong Min Kang) 대한기계학회 2021 대한기계학회 춘추학술대회 Vol.2021 No.11

We demonstrate a controllable clustering effect using high aspect ratio structure composed of thermo-responsive hydrogel by modulating the elastic modulus of a material. High-aspect-ratio polymer micropillar, made of materials with low elastic modulus, was easily clustered by a capillary force and surface adhesion. This clustering effect was used to trap small particles or for biological analysis. Conversely, straight shape of high-aspect-ratio pillar with high elastic modulus was applied to sensors and energy harvesting devices to increase efficiency. Therefore, it was needed to reversibly control the clustering behavior. By controlling the crosslinker density of the thermo-responsive hydrogel, the high-aspect-ratio pillar was fabricated to control the clustering behavior by capillary of water and an ambient temperature. Through experiments and theoretical analysis, the repeatable control of the clustering and recovery behavior of the pillars was confirmed, and the potential for optical applications was demonstrated by showing the smart window.

Preparation of Catechol-Anchored Polymer Crosslinked to Dopamine-Conjugated Pluronic for Temperature Sensitive and Adhesive Hydrogels

노상규,박성영 한국공업화학회 2018 한국공업화학회 연구논문 초록집 Vol.2018 No.1