Name: synthesis of poly(n-isopropylacrylamide) janus microhydrogels for anisotropic thermo-responsiveness and organophilic/hydrophilic loading capability
Uploaded: 2016-02-27T13:00:00.000+00:00
Duration: 9 min 9 s
Description: Watch this Scientific Journal Video about Synthesis of PolyN-isopropylacrylamide Janus Microhydrogels for Anisotropic Thermo-responsiveness and Organophilic/Hydrophilic Loading Capability at JoVE.com

This work was supported by the National Research Foundation of Korea (NRF) grant funded by the Korea Government (MSIP (Nos. 2014R1A2A1A01006527 and 2011-0030075).

포토 리소그래피를 통해 유체 역학을 중심으로 미세 유체 장치 (HFMD)에 대한 마스터 금형 1. 제작 <ol><li> 제조 업체의 프로토콜에 따라 컴퓨터 지원 설계 (CAD) 소프트웨어를 사용하여 HFMD (그림 1a)에 대한 포토 마스크를 디자인합니다. </li><li> 웨이퍼로부터 유기 및 무기 먼지를 제거 아세톤, 이소 프로필 알코올 (IPA), 및 탈 (DI) 물 (4 &#39;)의 실리콘 웨이퍼를 씻어. </li><li> 웨이퍼와 SU-8의 접합 강도를 증가시키기 위해 5 분 동안 전력 100 W로 O 2 플라즈마로 실리콘 웨이퍼를 청소한다. </li><li> 스핀 코트 네가티브 포토 레지스트 4 ㎖, SU-8 2150, 웨이퍼 상에 30 초간 3000 rpm에서 150 μm의 (도 1b에 B1)의 막 두께를 달성한다. </li><li> 65 ° C에서 5 분 동안 열판에 SU-8 코팅 된 웨이퍼를 놓고 95 ° C까지 온도를 설정하고 부드러운 빵을 30 분 동안 열판에 웨이퍼를 둡니다. </li><li> 배치웨이퍼 위에 포토 마스크를 설계하고 마스크 얼 라이너에 자외선 (260 엠제이 cm -2, 10 mW의 형상 관리 -2 26 초)에 노출 (그림에서 B2 1B). </li><li> 핫 플레이트 (5 분 65 ° C 한 후 95 ° C 12 분)에 베이킹 후 노출을 수행합니다. </li><li> 10 분간 SU-8 현상액 욕에 침지하여 웨이퍼를 개발하고 깨끗한 표면을 얻기 위하여 5 초 동안 새로운 현상에 옮긴다. </li><li> DI 물에 20 초 동안 웨이퍼를 씻어 N 2 가스로 10 초 동안 그것을 건조 (그림에서 B3 1B). 제 2 폴리 디메틸 실록산 (PDMS) 주조 마스터 몰드로 제작 된 웨이퍼를 사용합니다. </li></ol> PDMS 주조를 통해 HFMD 2. 제작 <ol><li> PDMS 주조 마스터 주형으로서 제 1에서 얻은 패턴 웨이퍼를 사용한다. </li><li> PDMS 예비 중합체 10의 중량 비율로 균일 경화제 믹스 : 1; 예를 들어, PDMS 사전 polym 10g을위한 경화제의 1g을 사용하여어. </li><li> 마스터 주형으로 PDMS를 예비 중합체를 붓고 (도 1b에 B4)를 진공 챔버에서 1 시간을 탈기. </li><li> 3 시간 동안 65 ° C의 오븐에 PDMS 사전 폴리머와 마스터 몰드를 놓습니다. </li><li> 날카로운 메스를 사용하여 단일 칩의 크기로 경화 된 PDMS를 잘라. 조심스럽게 손으로 마스터 몰드로부터 경화 된 PDMS 복제 벗겨. </li><li> 반복 동일한 PDMS 복제를 얻기 위해 2.2 2.5 단계. </li><li> 입구 펀치와 연결 관의 외경보다 약간 작은 직경을 갖는 홀 - 펀칭기를 사용하여 레플리카 중 하나에 구멍 출구. </li><li> 코로나 treater를 사용하여 각 복제의 본딩 영역 행 플라즈마 처리를 적용한다. (34) 주의 : 오존 발생을 방지하기 위해 통풍이 잘 영역에서 코로나 treater를 사용합니다. </li><li> 에어 플라즈마 처리 영역에 메탄올 5 μl를 삭제합니다. 미세 손 manipu으로 HFMD를 제작하는 두 개의 동일한 PDMS 복제를 정렬<html> LATION, 그리고 (그림 1b에서 B5) 현미경을 통해 정렬을 확인합니다. 참고 : 공기 플라즈마 처리 된 PDMS 복제가 상당히 끈적하고 조작하기가 어렵다. 따라서, 메탄올 5 μL가 윤활제로서 기능하는 공기 플라즈마 처리 된 표면에 첨가된다. </li><li> (그림 1b에서 B6)이 PDMS 복제본 간의 유대를 강화하기 위해 65 ° C 하룻밤으로 설정 오븐에서 HFMD를 놓습니다. 본드 두 동일한 PDMS 복제본 HFMD의 마이크로 채널의 높이를 증가시키고 동작 중에 미세 유체 채널에 미세 방울의 막힘을 방지한다. </li></ol><img alt="그림 1" src="/files/ftp_upload/52813/52813fig1.jpg" /> 그림 1 : HFMD 제작 절차의 개요 HFMD에 대한 포토 마스크의 () 설계 매개 변수를 설정합니다.. HFMD에 대한 제조 과정의 (b)의 그림입니다.ftp_upload / 52813 / 52813fig1large.jpg &quot;대상 =&quot;_ 빈 &quot;&gt;이 그림의 더 큰 버전을 보려면 여기를 클릭하십시오. NIPAAm 풍부한 3. 준비 (N 리치) 및 (N-가난한) 과포화 NIPAAm의 상 분리에 의한 페이즈 NIPAAm 가난한 <ol><li> 볼텍스 믹서를 사용하여 1; 1 AW / w 비로 DI 물 NIPAAm 단량체 녹이고 예를 들어, DI 물 10ml에 NIPAAm의 10g (도 2a의 제 화상)을 녹인다. 주 : NIPAAm 단량체가 완전히 실온에서 용해되면, 용액을 혼탁 (도 2a의 제 화상)을 보인다. 이 현상은 과포화 NIPAAm 단량체의 용해도 유도 상분리 성공적 발생 제 큐이다. </li><li> 단량체 용액을 적어도 15 분 동안 실온에서 수직 자세로 안정 할 수있다. 상부상은 N 리치 상이며, 밀도 하부상은 N 부족한 위상 (도 2a의 세번째 이미지)이다. 일의 밀도전자 N-풍부하고 N-가난한 단계는 각각 0.93 ± 0.01 및 0.99 ± 0.01 g cm -3이다. (15) </li><li> 두 단계를 분리 인터페이스가 분명해진다 때, 조심스럽게 피펫을 사용하여이 인터페이스를 방해하지 않고 N-풍부하고 N-가난한 단계에서 단량체 용액 2 ㎖의 압축을 풉니 다. </li><li> 상기 추출 된 N-N에 풍부한 광개시제 N 4 mg의 추가, N &#39;가교제로서 -methylenebisacrylamide (MBAAm) 및 4- (2- 히드 록시에 톡시) 페닐 4 mg의 (2- 히드 록시 -2- 프로필) 케톤, 불쌍한 단량체 솔루션은 낮은 가교제 농도의 핵심 유체 1과 2 (2 mg을 ml의-1) 샘플 (B1 및도 2b 그림에서 B2)를 제조 하였다. </li><li> 이전 단계 3.3를 반복하고 코어 유체를 제조 추출 N - 풍부 및 N 부족한 단량체 용액의 각각에 MBAAm 80 mg의 4- (2- 히드 록시에 톡시) 페닐 (2- 히드 록시 -2- 프로필) 케톤 4 mg을 추가 도 1 및 높은 가교제 농도가 2 (40 mg을 용액 1) 시료 (B3 및 B4도URE 2B). </li><li> (도 2b에서 B5) 피복 액을 제조 광유로 오일의 계면 활성제 10 중량 %를 녹인다. </li></ol><img alt="그림 2" src="/files/ftp_upload/52813/52813fig2.jpg" /> 그림 2 :. 야누스 Microhydrogel 합성 자재 준비 () 과포화 NIPAAm의 상 분리를 통해 N-풍부하고 N-가난한 단량체 솔루션의 준비. (b)는 재료 및 프로토콜에 사용 된 실험 장치의 세부 사항입니다. <a href="https://jove.unicartagenaproxy.elogim.com/files/ftp_upload/52813/52813fig2large.jpg" target="_blank">이 그림의 더 큰 버전을 보려면 여기를 클릭하십시오.</a> 야누스 Microhydrogels 4. 합성 HFMD를 사용하여 <ol><li> 로드 핵심 유체의 2 ml의 1, 2 (B1, B2 또는 B3, B4에서 인터넷 gure 2B) 세 개의 분리 된 3 ㎖ 주사기로하고 칼집 유체 (그림 2b에 B5). </리&gt; <li> 주사기 펌프에 주사기를 탑재하고 튜브 (그림을 사용하는 (B). 수집 저수지에 HFMD의 유체 출구를 연결하는 튜브를 사용하여 HFMD의 적절한 유체 입구에 각 주사기를 연결합니다. </li><li> 각각의 주사기 펌프 세트 2, 2, 10 μL 분 -1의 유량으로 코어 (1) 및 액체 (2)와 피복 유체를 주입. </li><li> (선택적) 조정은 코어 (1) 및 (2) 유체의 유량 야누스 microdroplet 양쪽의 상대적 음량 비율을 조정한다. </li><li> 수직으로 1cm 정도 떨어진 수집 저장조로부터 UV 광원을 배치. UV 광원에 전환하고 시각적으로 야누스 microhydrogels의 지속적인 생산을 모니터링 할 수 있습니다. 주의 : UV 보호 - 고글 microhydrogel 생산을 모니터링. </li><li> 원뿔 튜브로 제작 된 야누스 microhydrogels를 수집하고 IPA를 사용하여 세척한다. 그런 다음, 원뿔 튜브 (5 분 780g)을 해결하기 위해 원심 분리microhydrogels. </li><li> 반복 단계 4.6 여러번 완전 야누스 microhydrogels 주변 광유를 제거한다. </li><li> 0.005 %의 물 계면 활성제와 단계를 반복 4.6 만 사용 DI 물 (v / v)로 대신 IPA의 야누스 microhydrogels 주위에 남은 IPA를 제거합니다. </li><li> 10 ㎖의 유리 병 포함 DI 물에 완전히 세척 야누스 microhydrogels를 저장합니다. </li></ol> 야누스 Microhydrogels의 이방성 열 응답 성 5. 분석 <ol><li> 24 웰 플레이트에 제 4 절에서 합성 야누스 microhydrogels을 배치 피펫을 사용합니다. 단층 웰의 바닥면에 형성 될 때까지 15 초 microhydrogels 정착 할 수있다. </li><li> 5 배 대물 렌즈와 수직 광학 현미경을 사용하여 24 ° C에서 야누스 microhydrogel의 이미지를 얻습니다. </li><li> 웰 플레이트에 따라 열전 모듈을 설정하고 야누스 마이크로 함유 용액의 온도를 증가시키기 위해이 모듈의 전압을 제어32 ° C에 하이드로 겔. </li><li> 32 ℃에서 다시 한번 5 배 대물 렌즈와 수직 광학 현미경을 사용하여 야누스 microhydrogel의 이미지를 얻습니다. </li><li> 반복 통계 분석에 대해 다른 야누스 microhydrogel을 선택 돌보는, 5.2-5.4 24 번 단계를 반복합니다. </li><li> 24 및 32 ℃에서 여러 야누스 microhydrogels 25의 이미지에서, 제조자의 지시에 따른 이미지 분석 소프트웨어를 사용 야누스 microhydrogels의 PN-풍부한 PN 부족한 부분의 반경을 측정한다. </li></ol>

<ol>
	<li>Hoffman, A. S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Hydrogels+for+biomedical+applications.">Hydrogels for biomedical applications.</a> Adv. Drug Delivery Rev. 54 (1), 3-12 (2002).</li><li>Qiu, Y., Park, K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Environment-sensitive+hydrogels+for+drug+delivery.">Environment-sensitive hydrogels for drug delivery.</a> Adv. Drug Delivery Rev. 53 (3), 321-339 (2001).</li><li>Hirokawa, Y., Tanaka, T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Volume+phase+transition+in+a+nonionic+gel.">Volume phase transition in a nonionic gel.</a> J. Chem. Phys. 81 (12), 6379-6380 (1984).</li><li>Bae, Y. H., Okano, T., Hsu, R., Kim, S. W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Thermo-sensitive+polymers+as+on-off+switches+for+drug+release.">Thermo-sensitive polymers as on-off switches for drug release.</a> Macromol. Rapid Commun. 8 (10), 481-485 (1987).</li><li>Yoshida, R., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Comb-type+grafted+hydrogels+with+rapid+deswelling+response+to+temperature+changes.">Comb-type grafted hydrogels with rapid deswelling response to temperature changes.</a> Nature. 374 (6519), 240-242 (1995).</li><li>Tanaka, T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Collapse+of+gels+and+the+critical+endpoint.">Collapse of gels and the critical endpoint.</a> Phys. Rev. Lett. 40 (12), 820-823 (1978).</li><li>Tanaka, T., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Phase+transitions+in+ionic+gels.">Phase transitions in ionic gels.</a> Phys. Rev. Lett. 45 (20), 1636-1639 (1980).</li><li>Zhao, Y. L., Stoddart, J. F. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Azobenzene-based+light-responsive+hydrogel+system.">Azobenzene-based light-responsive hydrogel system.</a> Langmuir. 25 (15), 8442-8446 (2009).</li><li>Alvarez-Lorenzo, C., Bromberg, L., Concheiro, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Light-sensitive+intelligent+drug+delivery+systems.">Light-sensitive intelligent drug delivery systems.</a> Photochem. Photobiol. 85 (4), 848-860 (2009).</li><li>Tanaka, T., Nishio, I., Sun, S. T., Ueno-Nishio, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Collapse+of+gels+in+an+electric+field.">Collapse of gels in an electric field.</a> Science. 218 (4571), 467-469 (1982).</li><li>Kwon, I. C., Bae, Y. H., Kim, S. W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Electrically+credible+polymer+gel+for+controlled+release+of+drugs.">Electrically credible polymer gel for controlled release of drugs.</a> Nature. 354 (6351), 291-293 (1991).</li><li>Obaidat, A. A., Park, K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Characterization+of+protein+release+through+glucose-sensitive+hydrogel+membranes.">Characterization of protein release through glucose-sensitive hydrogel membranes.</a> Biomaterials. 18 (11), 801-806 (1997).</li><li>Kataoka, K., Miyazaki, H., Bunya, M., Okano, T., Sakurai, Y. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Totally+synthetic+polymer+gels+responding+to+external+glucose+concentration:+their+preparation+and+application+to+on-off+regulation+of+insulin+release.">Totally synthetic polymer gels responding to external glucose concentration: their preparation and application to on-off regulation of insulin release.</a> J. Am. Chem. Soc. 120 (48), 12694-12695 (1998).</li><li>Heskins, M., Guillet, J. E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Solution+properties+of+poly(N-isopropylacrylamide).">Solution properties of poly(N-isopropylacrylamide).</a> J. Macromol. Sci. Part A Pure Appl. Chem. 2 (8), 1441-1455 (1968).</li><li>Sasaki, S., Okabe, S., Miyahara, Y. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Thermodynamic+properties+of+N-isopropylacrylamide+in+water:+solubility+transition,+phase+separation+of+supersaturated+solution,+and+glass+formation.">Thermodynamic properties of N-isopropylacrylamide in water: solubility transition, phase separation of supersaturated solution, and glass formation.</a> J. Phys. Chem. B. 114 (46), 14995-15002 (2010).</li><li>Bromberg, L., Alakhov, V. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Effects+of+polyether-modified+poly(acrylic+acid)+microgels+on+doxorubicin+transport+in+human+intestinal+epithelial+Caco-2+cell+layers.">Effects of polyether-modified poly(acrylic acid) microgels on doxorubicin transport in human intestinal epithelial Caco-2 cell layers.</a> J. Controlled Release. 88 (1), 11-22 (2003).</li><li>Coughlan, D. C., Quilty, F. P., Corrigan, O. I. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Effect+of+drug+physicochemical+properties+on+swelling/deswelling+kinetics+and+pulsatile+drug+release+from+thermoresponsive+poly(N-isopropylacrylamide)+hydrogels.">Effect of drug physicochemical properties on swelling/deswelling kinetics and pulsatile drug release from thermoresponsive poly(N-isopropylacrylamide) hydrogels.</a> J. Controll. Release. 98 (1), 97-114 (2004).</li><li>Bergbreiter, D. E., Case, B. L., Liu, Y. S., Caraway, J. W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Poly(N-isopropylacrylamide)+soluble+polymer+supports+in+catalysis+and+synthesis.">Poly(N-isopropylacrylamide) soluble polymer supports in catalysis and synthesis.</a> Macromolecules. 31 (18), 6053-6062 (1998).</li><li>Lapeyre, V., Gosse, I., Chevreux, S., Ravaine, V. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Monodispersed+glucose-responsive+microgels+operating+at+physiological+salinity.">Monodispersed glucose-responsive microgels operating at physiological salinity.</a> Biomacromolecules. 7 (12), 3356-3363 (2006).</li><li>Hoare, T., Pelton, R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Engineering+glucose+swelling+responses+in+poly(N-isopropylacrylamide)-based+microgels.">Engineering glucose swelling responses in poly(N-isopropylacrylamide)-based microgels.</a> Macromolecules. 40 (3), 670-678 (2007).</li><li>Xu, S., Zhang, J., Paquet, C., Lin, Y., Kumacheva, E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=From+hybrid+microgels+to+photonic+crystals.">From hybrid microgels to photonic crystals.</a> Adv. Funct. Mater. 13 (6), 468-472 (2003).</li><li>Clarke, J., Vincent, B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Stability+of+non-aqueous+microgel+dispersions+in+the+presence+of+free+polymer.">Stability of non-aqueous microgel dispersions in the presence of free polymer.</a> J. Chem. Soc., Faraday Trans. 1. 77 (8), 1831-1843 (1981).</li><li>Mears, S. J., Deng, Y., Cosgrove, T., Pelton, R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Structure+of+sodium+dodecyl+sulfate+bound+to+a+poly+(NIPAM)+microgel+particle.">Structure of sodium dodecyl sulfate bound to a poly (NIPAM) microgel particle.</a> Langmuir. 13 (7), 1901-1906 (1997).</li><li>Shah, R. K., Kim, J. W., Agresti, J. J., Weitz, D. A., Chu, L. Y. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Fabrication+of+monodisperse+thermosensitive+microgels+and+gel+capsules+in+microfluidic+devices.">Fabrication of monodisperse thermosensitive microgels and gel capsules in microfluidic devices.</a> Soft Matter. 4 (12), 2303-2309 (2008).</li><li>Jack, C. R., Forbes, G., Dewanjee, M. K., Brown, M. L., Earnest, F. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Polyvinyl+alcohol+sponge+for+embolotherapy:+particle+size+and+morphology.">Polyvinyl alcohol sponge for embolotherapy: particle size and morphology.</a> Am. J. Neuroradiol. 6 (4), 595-597 (1985).</li><li>Derdeyn, C. P., Moran, C. J., Cross, D. T., Dietrich, H. H., Dacey, R. G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Polyvinyl+alcohol+particle+size+and+suspension+characteristics.">Polyvinyl alcohol particle size and suspension characteristics.</a> Am. J. Neuroradiol. 16 (6), 1335-1343 (1995).</li><li>Han, K., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Effect+of+flow+rates+on+generation+of+monodisperse+clay-poly(N-isopropylacrylamide)+embolic+microspheres+using+hydrodynamic+focusing+microfluidic+device.">Effect of flow rates on generation of monodisperse clay-poly(N-isopropylacrylamide) embolic microspheres using hydrodynamic focusing microfluidic device.</a> Jpn. J. Appl. Phys. 50 (6), 06-12 (2011).</li><li>Seo, K. D., Doh, J., Kim, D. S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=One-step+microfluidic+synthesis+of+Janus+microhydrogels+with+anisotropic+thermo-responsive+behavior+and+organophilic/hydrophilic+loading+capability.">One-step microfluidic synthesis of Janus microhydrogels with anisotropic thermo-responsive behavior and organophilic/hydrophilic loading capability.</a> Langmuir. 29 (49), 15137-15141 (2013).</li><li>Seo, K. D., Kim, D. S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Microfluidic+synthesis+of+thermo-responsive+poly(N-isopropylacrylamide)-poly(ethylene+glycol)+diacrylate+microhydrogels+as+chemo-embolic+microspheres.">Microfluidic synthesis of thermo-responsive poly(N-isopropylacrylamide)-poly(ethylene glycol) diacrylate microhydrogels as chemo-embolic microspheres.</a> J. Micromech. Microeng. 24 (8), 085001 (2014).</li><li>Seo, K. D., Kwak, B. K., Kim, D. S., S&#225;nchez, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Microfluidic-assisted+fabrication+of+flexible+and+location+traceable+organo-motor.">Microfluidic-assisted fabrication of flexible and location traceable organo-motor.</a> IEEE Trans. Nanobiosci. 14 (3), 298-304 (2015).</li><li>Seo, K. D., Kim, D. S., S&#225;nchez, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Fabrication+and+application+of+complex-shaped+microparticles+via+microfluidics.">Fabrication and application of complex-shaped microparticles via microfluidics.</a> Lab Chip. , (2015).</li><li>Shah, R. K., Kim, J. W., Weitz, D. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Janus+supraparticles+by+induced+phase+separation+of+nanoparticles+in+droplets.">Janus supraparticles by induced phase separation of nanoparticles in droplets.</a> Adv. Mater. 21 (19), 1949-1953 (2009).</li><li>Lone, S., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Microfluidic+synthesis+of+Janus+particles+by+UV-directed+phase+separation.">Microfluidic synthesis of Janus particles by UV-directed phase separation.</a> Chem. Commun. 47 (9), 2634-2636 (2011).</li><li>Hauber, K., Drier, T., Beebe, D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=PDMS+bonding+by+means+of+a+portable,+low-cost+corona+system.">PDMS bonding by means of a portable, low-cost corona system.</a> Lab chip. 6 (12), 1548-1549 (2006).</li><li>Nisisako, T., Torii, T., Takahashi, T., Takizawa, Y. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Synthesis+of+monodisperse+bicolored+Janus+particles+with+electrical+anisotropy+using+a+microfluidic+co-flow+system.">Synthesis of monodisperse bicolored Janus particles with electrical anisotropy using a microfluidic co-flow system.</a> Adv. Mater. 18 (9), 1152-1156 (2006).</li><li>Seiffert, S., Romanowsky, M. B., Weitz, D. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Janus+microgels+produced+from+functional+precursor+polymers.">Janus microgels produced from functional precursor polymers.</a> Langmuir. 26 (18), 14842-14847 (2010).</li><li>Peppas, N. A., Hilt, J. Z., Khademhosseini, A., Langer, R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Hydrogels+in+biology+and+medicine:+from+molecular+principles+to+bionanotechnology.">Hydrogels in biology and medicine: from molecular principles to bionanotechnology.</a> Adv. Mater. 18 (11), 1345-1360 (2006).</li></ol>

The authors declare that they have no competing financial interests.

두 비혼 화성 기재는 일반적으로 야누스 microhydrogels를 합성하는데 사용된다. 최근까지, 동일한 기재로 이루어지는 야누스 microhydrogels이 드물게보고하고,보고 야누스 microhydrogels 인해 성분 물질의 혼 화성에 의한 외란에 투명한 내부 형태를 가지고 있지 않았다.이 프로토콜 35, 36, 우리는 방법을 보여 명확 실형 구조 전적으로 단일 모재 PNIPAAm 이루어지는 야누스 microhydrogels를 합성. <p clas...

Hydrogels are a network of hydrophilic polymer chains.1 An increasing amount of research in the field of hydrogels has promoted significant advances and revealed their similarity to biological tissues; the properties of hydrogels allow the uptake of large amounts of water while maintaining their structure. Environmentally responsive hydrogels have also been studied extensively because of their ability to swell or shrink reversibly in response to external stimuli.2 Several triggers, including temperature,3-5 pH,6,7 light,8,9 electric fields,10,11 and specific molecules, such as glucose,12,13 have been suggested to control the geometric shape of hydrogels. Among the many environmentally responsive hydrogels currently available, poly(N-isopropylacrylamide) (PNIPAAm), a well-known thermo-responsive hydrogel, exhibits volume shrinkage above a low critical solution temperature (LCST) of 32 &#176;C.14 A recent study by Sasaki et al.15 reported the intriguing liquid-liquid phase separation of supersaturated NIPAAm, which is the monomer of PNIPAAm. According to this report, supersaturated NIPAAm was dissolved with a 10-fold molar excess of H2O, and soon after, the solution separated into two liquid phases when allows to stand at a temperature above 25 &#176;C; by contrast, dilute NIPAAm was dissolved homogeneously under the same conditions.
Microparticles made of environmentally responsive hydrogels are fascinating candidates for application in drug delivery,16,17 catalysis,18 sensing,19,20 and photonics.21 Traditional synthetic methods including emulsion polymerization, are used to produce hydrogel microparticles with polydispersity.22,23 However, certain applications require microparticles with a narrow size distribution, for example, to stabilize the pharmacokinetics of drug delivery.24 Irregularly shaped or polydisperse embolic microparticles aggregate proximally into clusters, leading to chronic inflammatory responses in embolic particles for cancer therapeutic treatment.25,26
The microfluidic approach is at the forefront of research as a means of fabricating micro-sized particles with narrow size distributions and complex shapes.27-31 The advantages of fabricating microparticles in the microfluidic device are predicated by the small characteristic length of the microfluidic device, which results in a low Reynolds number. In contrast to traditional bulk emulsification where drops are formed in parallel, microdroplets produced in microfluidic devices are generated in series and subsequently polymerized into microparticles upon exposure to UV irradiation. The fundamental principle of droplet formation using a microfluidic device is balance between the interfacial tension and the shear force of the sheath fluid acting on the core fluid. 
Despite the obvious advantages of microfluidic fabrication of droplets/particles, Janus droplets/particles consisting of the same base material are rarely reported because the internal morphology of these droplets/particles is generally disturbed by the diffusion and perturbation of the core fluids. To circumvent this intrinsic limitation, two groups recently reported the preparation of the Janus microparticles by employing heat-induced phase separation of colloidal nanoparticles and UV-directed phase separation.32,33
To this end, we report a microfluidic approach to synthesize Janus microhydrogels entirely composed of a single base material and obtain a product with clearly compartmentalized morphology. Our approach is based on the primary concept of liquid-liquid phase separation of supersaturated NIPAAm monomer. The resulting Janus microhydrogels were found to possess unique properties including anisotropic thermo-responsiveness and organophilic/hydrophilic loading capability.

<table><tbody><tr><td>Silicon wafer</td><td>LG Siltron</td><td>4&quot;, Test grade</td><td>Wafer for master mold fabrication</td></tr><tr><td>Acetone</td><td>Samchun Pure Chemical</td><td>A0097</td><td>Cleaning silicon wafer</td></tr><tr><td>Isopropyl alcohol (IPA)</td><td>Daejung Chemicals &amp;amp; Metals</td><td>5035-4404</td><td>Cleaning silicon wafer</td></tr><tr><td>Water purification system</td><td>Merck Millipore</td><td>EMD Millipore RIOs Essential 5</td><td>Prepering&amp;nbsp; deionized water</td></tr><tr><td>O&lt;sub&gt;2&lt;/sub&gt; plasma machine</td><td>Femto Science</td><td>VITA-A</td><td>Cleaning silicon wafer</td></tr><tr><td>SU-8 2150 negative photoresist</td><td>MicroChem</td><td>Y111077 0500L1GL</td><td>Photoresist for master mold fabrication</td></tr><tr><td>Hot plate</td><td>Misung Scientific</td><td>HP330D, HP150D</td><td>Baking SU-8</td></tr><tr><td>SU-8 developer</td><td>Microchem</td><td>Y020100 4000L1PE</td><td>Developing SU-8</td></tr><tr><td>Mask aligner system for photolithograpy</td><td>Shinu Mst Co.</td><td>CA-6M</td><td>Photolithography</td></tr><tr><td>Sylgard 184 silicone elastomer kit</td><td>Dow Corning</td><td>1064891</td><td>PDMS casting</td></tr><tr><td>Laboratory Corona Treater</td><td>Electro-technic Products Inc.</td><td>Model BD-20AC</td><td>PDMS air plasma treatment&amp;nbsp;</td></tr><tr><td>&lt;em&gt;N&lt;/em&gt;-isopropylacrylamide (NIPAAm)</td><td>Sigma-Aldrich</td><td>415324-50G</td><td>Monomer</td></tr><tr><td>&lt;em&gt;N,N&#039;&lt;/em&gt;-methylenebisacrylamide (MBAAm)</td><td>Sigma-Aldrich</td><td>146072-100G</td><td>Crosslinker of NIPAAm</td></tr><tr><td>4-(2-hydroxyethoxy)phenyl-(2-hydroxy-2-propyl)ketone, Irgacure 2959</td><td>BASF</td><td>55047962</td><td>Photoinitiator of NIPAAm</td></tr><tr><td>ABIL EM 90</td><td>Evonik Industries</td><td>201109</td><td>Sufactant for oil</td></tr><tr><td>Vortex mixer</td><td>Scientific Industries Inc.</td><td>Vortex-Genie 2</td><td>Mixing</td></tr><tr><td>Tygon tubing</td><td>Saint-Gobain</td><td>I.D. 1/32&quot;, O.D. 3/32&quot;, Wall 1/32&quot;</td><td>Connecting tube between syringes and HFMD</td></tr><tr><td>UV light source</td><td>Hamamatsu</td><td>Spot light source LC8</td><td>Polymerization from NIPAAm to PNIPAAm</td></tr><tr><td>Syringes, NORM-JECT (3 ml)</td><td>Henke-Sass Wolf GmbH</td><td>22767</td><td>Loading of materials</td></tr><tr><td>Syringe pump</td><td>KD Scientific</td><td>KDS model 200</td><td>Perfusion of materials</td></tr><tr><td>Tegitol Type NP-10</td><td>Sigma-Aldrich</td><td>NP10-500ML</td><td>Surfactant for water</td></tr><tr><td>Oil red O</td><td>Sigma-Aldrich</td><td>O0625-25G</td><td>Dye for N-rich phase</td></tr><tr><td>Oil Blue N</td><td>Sigma-Aldrich</td><td>391557-5G</td><td>Dye for N-rich phase</td></tr><tr><td>Yellow food dye</td><td>Edentown F&amp;amp;B</td><td>NA</td><td>Dye for N-poor phase</td></tr><tr><td>Green food dye</td><td>Edentown F&amp;amp;B</td><td>NA</td><td>Dye for N-poor phase</td></tr><tr><td>Power supply</td><td>Agilent</td><td>E3649A</td><td>Power source for thermoelectric module</td></tr><tr><td>Thermoelectric module</td><td>Peltier</td><td>FALC1-12710T125</td><td>Temparature control</td></tr><tr><td>Centrifuge machine</td><td>Labogene</td><td>1248R</td><td>Settling down microhydrogels</td></tr><tr><td>24-well plate</td><td>SPL Life Sciences</td><td>32024</td><td>Reservoir for observation</td></tr><tr><td>Optical microscope</td><td>Nikon</td><td>ECLIPSE 80i</td><td>Optical observation</td></tr><tr><td>Image analysis software</td><td>IMT i-Solution Inc.</td><td>iSolutions DT</td><td>Measurement of radius</td></tr></tbody></table>

synthesis of poly(n-isopropylacrylamide) janus microhydrogels for anisotropic thermo-responsiveness and organophilic/hydrophilic loading capability

Janus microparticles are compartmentalized particles with differing molecular structures and/or functionality on each of their two sides. Because of this unique property, Janus microparticles have been recognized as a new class of materials, thereby attracting a great deal of attention from various research fields. The versatility of these microparticles has been exemplified through their uses as building blocks for self-assembly, electrically responsive actuators, emulsifiers for painting and cosmetics, and carriers for drug delivery. This study introduces a detailed protocol that explicitly describes a synthetic method for designing novel Janus microhydrogels composed of a single base material, poly(N-isopropylacrylamide) (PNIPAAm). Janus microdroplets are firstly generated via a hydrodynamic focusing microfluidic device (HFMD) based on the separation of a supersaturated aqueous NIPAAm monomer solution and subsequently polymerized through exposure to UV irradiation. The resulting Janus microhydrogels were found to be entirely composed of the same base material, featured an easily identifiable compartmentalized morphology, and exhibited anisotropic thermo-responsiveness and organophilic/hydrophilic loading capability. We believe that the proposed method introduces a novel hydrogel platform with the potential for advanced synthesis of multi-functional Janus microhydrogels.

도 3a는 HFMD 통해 야누스 microhydrogels를 합성하는 데 사용되는 실험 장치의 개략도를 나타낸다. N - 풍부 및 N 부족한 상 정확하게 코어 유체 1 및 2로 HFMD에 주입 한 후 병합 때문에 레일리 모세관 불안정 광유 시스 액에 의한 오리피스에서 야누스 미세 방울로 분해 하였다. 도 3b에 도시 된 바와 같이 결과적으로, N-N 풍부한 부족한 상 이루어지?...

Watch this Scientific Journal Video about Synthesis of PolyN-isopropylacrylamide Janus Microhydrogels for Anisotropic Thermo-responsiveness and Organophilic/Hydrophilic Loading Capability at JoVE.com

Synthesis of PolyN-isopropylacrylamide Janus Microhydrogels for Anisotropic Thermo-responsiveness and Organophilic/Hydrophilic Loading Capability

We present a protocol to synthesize Janus microhydrogels composed entirely of the same base material, poly(N-isopropylacrylamide) (PNIPAAm), with a clearly compartmentalized structure base on the phase separation of a supersaturated NIPAAm monomer solution. The synthesized Janus microhydrogels show unique properties such as anisotropic thermo-responsiveness and organophilic/hydrophilic loading capability.

폴리의 합성 (<em&gt; N</em&gt; 이소 프로필 아크릴 아미드) 이방성 열 응답 성 및 유기화 / 친수성로드 기능에 대한 야누스 Microhydrogels

Janus microparticles are compartmentalized particles with differing molecular structures and/or functionality on each of their two sides. Because of this ...

synthesis-poly-n-isopropylacrylamide-janus-microhydrogels-for

Universidad de Cartagena UDEC

Research

JoVE Journal

Chemistry

Synthesis of Poly(N-isopropylacrylamide) Janus Microhydrogels for Anisotropic Thermo-responsiveness and Organophilic/Hydrophilic Loading Capability

9.9K 조회수.  Pohang University of Science and Technology (POSTECH). We present a protocol to synthesize Janus microhydrogels composed entirely of the same base material, poly(N-isopropylacrylamide) (PNIPAAm), with a clearly compartmentalized structure base on the phase separation of a supersaturated NIPAAm monomer solution. The synthesized Janus microhydrogels show unique properties such as anisotropic thermo-responsiveness and organophilic/hydrophilic loading capability.

비디오: Synthesis of PolyN-isopropylacrylamide Janus Microhydrogels for Anisotropic Thermo-responsiveness and Organophilic/Hydrophilic Loading Capability

Microwave-assisted Functionalization of Poly(ethylene glycol) and On-resin Peptides for Use in Chain Polymerizations and Hydrogel Formation

One of the main benefits to using poly(ethylene glycol) (PEG) macromers in hydrogel formation is synthetic versatility. The ability to draw from a large variety of PEG molecular weights and configurations (arm number, arm length, and branching pattern) affords researchers tight control over resulting hydrogel structures and properties, including Young&#8217;s modulus and mesh size. This video will illustrate a rapid, efficient, solvent-free, microwave-assisted method to methacrylate PEG precursors into poly(ethylene glycol) dimethacrylate (PEGDM). This synthetic method provides much-needed starting materials for applications in drug delivery and regenerative medicine. The demonstrated method is superior to traditional methacrylation methods as it is significantly faster and simpler, as well as more economical and environmentally friendly, using smaller amounts of reagents and solvents. We will also demonstrate an adaptation of this technique for on-resin methacrylamide functionalization of peptides. This on-resin method allows the N-terminus of peptides to be functionalized with methacrylamide groups prior to deprotection and cleavage from resin. This allows for selective addition of methacrylamide groups to the N-termini of the peptides while amino acids with reactive side groups (e.g.&#160;primary amine of lysine, primary alcohol of serine, secondary alcohols of threonine, and phenol of tyrosine) remain protected, preventing functionalization at multiple sites. This article will detail common analytical methods (proton Nuclear Magnetic Resonance spectroscopy (;H-NMR) and Matrix Assisted Laser Desorption Ionization Time of Flight mass spectrometry (MALDI-ToF)) to assess the efficiency of the functionalizations. Common pitfalls and suggested troubleshooting methods will be addressed, as will modifications of the technique which can be used to further tune macromer functionality and resulting hydrogel physical and chemical properties. Use of synthesized products for the formation of hydrogels for drug delivery and cell-material interaction studies will be demonstrated, with particular attention paid to modifying hydrogel composition to affect mesh size, controlling hydrogel stiffness and drug release.

Microwave-assisted Functionalization of Polyethylene glycol and On-resin Peptides for Use in Chain Polymerizations and Hydrogel Formation

This video will illustrate a rapid, efficient method to methacrylate poly(ethylene glycol), enabling chain polymerizations and hydrogel synthesis. It will demonstrate how to similarly introduce methacrylamide functionalities into peptides, detail common analytical methods to assess functionalization efficiency, provide suggestions for troubleshooting and advanced modifications, and demonstrate typical hydrogel characterization techniques.

전자 레인지를 이용한 폴리의 기능화 (에틸렌 글리콜) 및 체인 중합 및 하이드로 겔 형성에있는 사용을위한 온 수지 펩티드

One of the main benefits to using poly(ethylene glycol) (PEG) macromers in hydrogel formation is synthetic versatility. The ability to draw from a large ...

연구

화학

Controlled Synthesis and Fluorescence Tracking of Highly Uniform Poly(N-isopropylacrylamide) Microgels

Stimuli-sensitive poly(N-isopropylacrylamide) (PNIPAM) microgels have various prospective practical applications and uses in fundamental research. In this work, we use single particle tracking of fluorescently labeled PNIPAM microgels as a showcase for tuning microgel size by a rapid non-stirred precipitation polymerization procedure. This approach is well suited for prototyping new reaction compositions and conditions or for applications that do not require large amounts of product. Microgel synthesis, particle size and structure determination by dynamic and static light scattering are detailed in the protocol. It is shown that the addition of functional comonomers can have a large influence on the particle nucleation and structure. Single particle tracking by wide-field fluorescence microscopy allows for an investigation of the diffusion of labeled tracer microgels in a concentrated matrix of non-labeled microgels, a system not easily investigated by other methods such as dynamic light scattering.

Controlled Synthesis and Fluorescence Tracking of Highly Uniform PolyN-isopropylacrylamide Microgels

Non-stirred precipitation polymerization provides a rapid, reproducible prototyping approach to the synthesis of stimuli-sensitive poly(N-isopropylacrylamide) microgels of narrow size distribution. In this protocol synthesis, light scattering characterization and single particle fluorescence tracking of these microgels in a wide-field microscopy setup are demonstrated.

제어 합성 및 매우 균일 한 폴리 형광 추적 (<em&gt; N</em&gt; 이소 프로필 아크릴 아미드) 미크로 겔

Stimuli-sensitive poly(N-isopropylacrylamide) (PNIPAM) microgels have various prospective practical applications and uses in fundamental research. In this ...

Preparation of Hydroxy-PAAm Hydrogels for Decoupling the Effects of Mechanotransduction Cues

It is now well established that many cellular functions are regulated by interactions of cells with physicochemical and mechanical cues of their extracellular matrix (ECM) environment. Eukaryotic cells constantly sense their local microenvironment through surface mechanosensors to transduce physical changes of ECM into biochemical signals, and integrate these signals to achieve specific changes in gene expression. Interestingly, physicochemical and mechanical parameters of the ECM can couple with each other to regulate cell fate. Therefore, a key to understanding mechanotransduction is to decouple the relative contribution of ECM cues on cellular functions.
Here we present a detailed experimental protocol to rapidly and easily generate biologically relevant hydrogels for the independent tuning of mechanotransduction cues in vitro. We chemically modified polyacrylamide hydrogels (PAAm) to surmount their intrinsically non-adhesive properties by incorporating hydroxyl-functionalized acrylamide monomers during the polymerization. We obtained a novel PAAm hydrogel, called hydroxy-PAAm, which permits immobilization of any desired nature of ECM proteins. The combination of hydroxy-PAAm hydrogels with microcontact printing allows to independently control the morphology of single-cells, the matrix stiffness, the nature and the density of ECM proteins. We provide a simple and rapid method that can be set up in every biology lab to study in vitro cell mechanotransduction processes. We validate this novel two-dimensional platform by conducting experiments on endothelial cells that demonstrate a mechanical coupling between ECM stiffness and the nucleus.

We present a new polyacrylamide hydrogel, called hydroxy-PAAm, that allows a direct binding of ECM proteins with minimal cost or expertise. The combination of hydroxy-PAAm hydrogels with microcontact printing facilitates independent control of many cues of the natural cell microenvironment for studying cellular mechanostransduction.

mechanotransduction의 큐의 영향 디커플링에 대한 히드 록시 PAAm 히드로 겔의 제조

It is now well established that many cellular functions are regulated by interactions of cells with physicochemical and mechanical cues of their ...

생체공학

An Injectable and Drug-loaded Supramolecular Hydrogel for Local Catheter Injection into the Pig Heart

Regeneration of lost myocardium is an important goal for future therapies because of the increasing occurrence of chronic ischemic heart failure and the limited access to donor hearts. An example of a treatment to recover the function of the heart consists of the local delivery of drugs and bioactives from a hydrogel. In this paper a method is introduced to formulate and inject a drug-loaded hydrogel non-invasively and side-specific into the pig heart using a long, flexible catheter. The use of 3-D electromechanical mapping and injection via a catheter allows side-specific treatment of the myocardium. To provide a hydrogel compatible with this catheter, a supramolecular hydrogel is used because of the convenient switching from a gel to a solution state using environmental triggers. At basic pH this ureido-pyrimidinone modified poly(ethylene glycol) acts as a Newtonian fluid which can be easily injected, but at physiological pH the solution rapidly switches into a gel. These mild switching conditions allow for the incorporation of bioactive drugs and bioactive species, such as growth factors and exosomes as we present here in both in vitro and in vivo experiments. The in vitro experiments give an on forehand indication of the gel stability and drug release, which allows for tuning of the gel and release properties before the subsequent application in vivo. This combination allows for the optimal tuning of the gel to the used bioactive compounds and species, and the injection system.

Supramolecular hydrogelators based on ureido-pyrimidinones allow full control over the macroscopic gel properties and the sol&#8211;gel switching behavior using pH. Here, we present a protocol for formulating and injecting such a supramolecular hydrogelator via a catheter delivery system for local delivery directly in relevant areas in the pig heart.

돼지 심장에 현지 카테터 주입 용 주사 및 약물로드 초분자 히드로 겔

Regeneration of lost myocardium is an important goal for future therapies because of the increasing occurrence of chronic ischemic heart failure and the ...

Simple Polyacrylamide-based Multiwell Stiffness Assay for the Study of Stiffness-dependent Cell Responses

Currently, most of the in vitro cell research is performed on rigid tissue culture polystyrene (~1 GPa), while most cells in the body are attached to a matrix that is elastic and much softer (0.1 &#8211; 100 kPa). Since such stiffness mismatch greatly affects cell responses, there is a strong interest in developing hydrogel materials that span a wide range of stiffness to serve as cell substrates. Polyacrylamide gels, which are inexpensive and cover the stiffness range of all soft tissues in the body, are the hydrogel of choice for many research groups. However, polyacrylamide gel preparation is lengthy, tedious, and only suitable for small batches. Here, we describe an assay which by utilizing a permanent flexible plastic film as a structural support for the gels, enables the preparation of polyacrylamide gels in a multiwell plate format. The technique is faster, more efficient, and less costly than current methods and permits the preparation of gels of custom sizes not otherwise available. As it doesn&#8217;t require any specialized equipment, the method could be easily adopted by any research laboratory and would be particularly useful in research focused on understanding stiffness-dependent cell responses.

Here, a method that enables quick, efficient, and inexpensive preparation of polyacrylamide gels in a multiwell plate format is described. The method does not require any specialized equipment and could be easily adopted by any research laboratory. It would be particularly useful in research focused on understanding stiffness-dependent cell responses.

간단한 폴리 아크릴 아미드 기반 강성 의존 세포 반응의 연구를위한 멀티 웰 강성 분석

Currently, most of the in vitro cell research is performed on rigid tissue culture polystyrene (~1 GPa), while most cells in the body are attached to a ...

Preparation of Thermoresponsive Nanostructured Surfaces for Tissue Engineering

Thermoresponsive poly(N-isopropylacrylamide) (PIPAAm)-immobilized surfaces for controlling cell adhesion and detachment were fabricated by the Langmuir-Schaefer method. Amphiphilic block copolymers composed of polystyrene and PIPAAm (St-IPAAms) were synthesized by reversible addition-fragmentation chain transfer (RAFT) radical polymerization. A chloroform solution of St-IPAAm molecules was gently dropped into a Langmuir-trough apparatus, and both barriers of the apparatus were moved horizontally to compress the film to regulate its density. Then, the St-IPAAm Langmuir film was horizontally transferred onto a hydrophobically modified glass substrate by a surface-fixed device. Atomic force microscopy images clearly revealed nanoscale sea-island structures on the surface. The strength, rate, and quality of cell adhesion and detachment on the prepared surface were modulated by changes in temperature across the lower critical solution temperature range of PIPAAm molecules. In addition, a two-dimensional cell structure (cell sheet) was successfully recovered on the optimized surfaces. These unique PIPAAm surfaces may be useful for controlling the strength of cell adhesion and detachment.

Nanoscaled sea-island surfaces composed of thermoresponsive block copolymers were fabricated by the Langmuir-Schaefer method for controlling spontaneous cell adhesion and detachment. Both the preparation of the surface and the adhesion and detachment of cells on the surface were visualized.

조직 공학 Thermoresponsive 나노 구조 표면의 제조

Thermoresponsive poly(N-isopropylacrylamide) (PIPAAm)-immobilized surfaces for controlling cell adhesion and detachment were fabricated by the ...

Synthesis of Thermogelling Poly(N-isopropylacrylamide)-graft-chondroitin Sulfate Composites with Alginate Microparticles for Tissue Engineering

Injectable biomaterials are defined as implantable materials that can be introduced into the body as a liquid and solidify in situ. Such materials offer the clinical advantages of being implanted minimally invasively and easily forming space-filling solids in irregularly shaped defects. Injectable biomaterials have been widely investigated as scaffolds for tissue engineering. However, for the repair of certain load-bearing areas in the body, such as the intervertebral disc, scaffolds should possess adhesive properties. This will minimize the risk of dislocation during motion and ensure intimate contact with the surrounding tissue, providing adequate transmission of forces. Here, we describe the preparation and characterization of a scaffold composed of thermally sensitive poly(N-isopropylacrylamide)-graft-chondroitin sulfate (PNIPAAM-g-CS) and alginate microparticles. The PNIPAAm-g-CS copolymer forms a viscous solution in water at RT, into which alginate particles are suspended to enhance adhesion. Above the lower critical solution temperature (LCST), around 30 &#176;C, the copolymer forms a solid gel around the microparticles. We have adapted standard biomaterials characterization procedures to take into account the reversible phase transition of PNIPAAm-g-CS. Results indicate that the incorporation of 50 or 75 mg/ml&#160;alginate particles into 5% (w/v) PNIPAAm-g-CS solutions quadruple the adhesive tensile strength of PNIPAAm-gCS alone (p&#60;0.05). The incorporation of alginate microparticles also significantly increases swelling capacity of PNIPAAm-g-CS (p&#60;0.05), helping to maintain a space-filling gel within tissue defects. Finally, results of the in vitro toxicology assay kit, 2,3-bis-(2-methoxy-4-nitro-5-sulfophenyl)-2H-tetrazolium-5-carboxanilide (XTT) and Live/Dead viability assay indicate that the adhesive is capable of supporting the survival and proliferation of encapsulated Human Embryonic Kidney (HEK) 293 cells over 5 days.

Synthesis of Thermogelling PolyN-isopropylacrylamide-graft-chondroitin Sulfate Composites with Alginate Microparticles for Tissue Engineering

An injectable tissue engineering scaffold composed of poly(N-isopropylacrylamide)-graft-chondroitin sulfate (PNIPAAm-g-CS)-containing alginate microparticles was prepared. The adhesive strength, swelling properties and in vitro biocompatibility are analyzed in this study. The characterization techniques developed here may be applicable to other thermogelling systems.

조직 공학 알긴산 미세 입자와 Thermogelling 폴리 (N- 이소 프로필) -graft - 콘드로이틴 황산 복합 재료의 합성

Injectable biomaterials are defined as implantable materials that can be introduced into the body as a liquid and solidify in situ. Such materials offer ...

Fabricating Degradable Thermoresponsive Hydrogels on Multiple Length Scales via Reactive Extrusion, Microfluidics, Self-assembly, and Electrospinning

While various smart materials have been explored for a variety of biomedical applications (e.g., drug delivery, tissue engineering, bioimaging, etc.), their ultimate clinical use has been hampered by the lack of biologically-relevant degradation observed for most smart materials. This is particularly true for temperature-responsive hydrogels, which are almost uniformly based on polymers that are functionally non-degradable (e.g., poly(N-isopropylacrylamide) (PNIPAM) or poly(oligoethylene glycol methacrylate) (POEGMA)). As such, to effectively translate the potential of thermoresponsive hydrogels to the challenges of remote-controlled or metabolism-regulated drug delivery, cell scaffolds with tunable cell-material interactions, theranostic materials with the potential for both imaging and drug delivery, and other such applications, a method is required to render the hydrogels (if not fully degradable) at least capable of renal clearance following the required lifetime of the material. To that end, this protocol describes the preparation of hydrolytically-degradable hydrazone-crosslinked hydrogels on multiple length scales based on the reaction between hydrazide and aldehyde-functionalized PNIPAM or POEGMA oligomers with molecular weights below the renal filtration limit. Specifically, methods to fabricate degradable thermoresponsive bulk hydrogels (using a double barrel syringe technique), hydrogel particles (on both the microscale through the use of a microfluidics platform facilitating simultaneous mixing and emulsification of the precursor polymers and the nanoscale through the use of a thermally-driven self-assembly and cross-linking method), and hydrogel nanofibers (using a reactive electrospinning strategy) are described. In each case, hydrogels with temperature-responsive properties similar to those achieved via conventional free radical cross-linking processes can be achieved, but the hydrazone cross-linked network can be degraded over time to re-form the oligomeric precursor polymers and enable clearance. As such, we anticipate these methods (which may be generically applied to any synthetic water-soluble polymer, not just smart materials) will enable easier translation of synthetic smart materials to clinical applications.

Protocols are described for the fabrication of degradable thermoresponsive hydrogels based on hydrazone cross-linking of polymeric oligomers on the bulk scale, microscale, and nanoscale, the latter for preparation of both gel nanoparticles and nanofibers.

자기 조립, 분해 Thermoresponsive Hydrogels 반응 압출, 마이크로, 통해 여러 길이 가늠 자에를 조작 하 고 전기

While various smart materials have been explored for a variety of biomedical applications (e.g., drug delivery, tissue engineering, bioimaging, etc.), ...

Magnetic and Thermal-sensitive Poly(N-isopropylacrylamide)-based Microgels for Magnetically Triggered Controlled Release

Magnetically and thermally sensitive poly(N-isopropylacrylamide) (PNIPAAm)/Fe3O4-NH2 microgels with the encapsulated anti-cancer drug curcumin (Cur) were designed and fabricated for magnetically triggered release. PNIPAAm-based magnetic microgels with a spherical structure were produced via a temperature-induced emulsion followed with physical-crosslinking by mixing PNIPAAm, polyethylenimine (PEI), and Fe3O4-NH2 magnetic nanoparticles. Because of their dispersity, the Fe3O4-NH2 nanoparticles were embedded inside the polymer matrix. The amine groups exposed on the Fe3O4-NH2 and PEI surface supported the spherical structure by physically crosslinking with the amide groups of the PNIPAAm. The hydrophobic anti-cancer drug curcumin can be dispersed in water after encapsulation into the microgels. The microgels were characterized by transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FT-IR), and UV-Vis spectral analysis. Furthermore, magnetically triggered release was studied under an external high frequency magnetic field (HFMF). A significant &#34;burst release&#34; of curcumin was observed after applying the HFMF to the microgels due to the magnetic inductive heating (hyperthermia) effect. This manuscript describes the magnetically triggered controlled release of Cur-PNIPAAm/Fe3O4-NH2 encapsulated curcumin, which can be potentially applied for tumor therapy.

Magnetic and Thermal-sensitive PolyN-isopropylacrylamide-based Microgels for Magnetically Triggered Controlled Release

This manuscript describes the preparation of magnetic and thermal-sensitive microgels via a temperature-induced emulsion without chemical reaction. These sensitive microgels were synthesized by mixing poly(N-isopropylacrylamide) (PNIPAAm), polyethylenimine (PEI) and Fe3O4-NH2 nanoparticles for the potential use in magnetically and thermally triggered drug-release.

자기 및 열에 민감한 폴리 (<em&gt; N</em&gt; - 이소 프로필 아크릴 아미드) 기반의 마그네틱 트리거 리간드 용 젤

Magnetically and thermally sensitive poly(N-isopropylacrylamide) (PNIPAAm)/Fe3O4-NH2 microgels with the encapsulated anti-cancer drug curcumin (Cur) were ...

Synthesis of Stimuli-responsive Nanogels using Aqueous One-step Crosslinking and Co-nanopolymerization

Nanogels consisting of crosslinked-polymeric nanoparticles have been developed for the delivery of numerous chemical and biological therapeutics, owing to their versatile bottom-up synthesis and biocompatibility. While various methods have been employed for nanogel synthesis to date, very few have achieved it without the use of harsh organic solvents or high temperatures that can damage the integrity of the biological payload. In contrast, the methodology presented here accomplishes the synthesis of sub-100 nm sized, protein-loaded nanogels using mild reaction conditions. Here, we present a method for the non-covalent encapsulation of protein-based payloads within nano-gels that were synthesized using an aqueous-based, single-step, crosslinking copolymerization technique. In this technique, we initially electrostatically bind a protein-based payload to a cationic quaternary ammonium monomer and simultaneously cross-link and co-polymerize it using ammonium persulfate and N,N,N&#39;,N&#39;-tetramethylethylenediamine to form nanogels that entrap the protein payload. The size and polydispersity index of the nanogels is determined using dynamic light scattering (DLS), while the surface morphology is assessed by transmission electron microscopy (TEM). The mass of protein entrapped within nanogels is determined by calculating the encapsulation efficiency. Furthermore, the controlled-release ability of the nanogels via the gradual degradation of redox-responsive structural elements is also assessed in bioreduction assays. We provide examples of nanoparticle optimization data to demonstrate all caveats of nanogel synthesis and characterization using this technique. In general, uniformly sized nanogels were obtained with an average size of 57 nm and a polydispersity index value of 0.093. A high encapsulation efficiency of 76% was achieved. Furthermore, the nanogels exhibited controlled release of up to 86% of the encapsulated protein by gradual degradation of novel redox-responsive components in the presence of glutathione over 48 h.

Nanogels are an excellent and versatile nanoparticle platform for the delivery of biologics. Stimuli-responsive poly(ethylene) glycol-based polymeric nano-gels, capable of encapsulating protein-based payloads, were synthesized using a one-step cross-linking co-nanopolymerization strategy in aqueous conditions. The optimal fabrication and characterization of these novel nanoparticles are presented here.

Aqueous One-step Crosslinking 및 Co-nanopolymerization을 이용한 Stimuli-responsive Nanogel 합성

Nanogels consisting of crosslinked-polymeric nanoparticles have been developed for the delivery of numerous chemical and biological therapeutics, owing to ...

폴리의 합성 (

요약

더 많은 비디오 탐색

이 비디오의 챕터