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://www.jove.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>

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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 border="0" cellpadding="0" cellspacing="0" width="590">
	<tbody>
		<tr height="20">
			<td height="20" style="height:20px;width:216px;">Silicon wafer</td>
			<td style="width:88px;">LG Siltron</td>
			<td style="width:119px;">4&#34;, Test grade</td>
			<td style="width:167px;">Wafer for master mold fabrication</td>
		</tr>
		<tr height="60">
			<td height="60" style="height:60px;width:216px;">Acetone</td>
			<td style="width:88px;">Samchun Pure Chemical</td>
			<td style="width:119px;">A0097</td>
			<td>Cleaning silicon wafer</td>
		</tr>
		<tr height="60">
			<td height="60" style="height:60px;width:216px;">Isopropyl alcohol (IPA)</td>
			<td style="width:88px;">Daejung Chemicals &#38; Metals</td>
			<td style="width:119px;">5035-4404</td>
			<td>Cleaning silicon wafer</td>
		</tr>
		<tr height="60">
			<td height="60" style="height:60px;width:216px;">Water purification system</td>
			<td style="width:88px;">Merck Millipore</td>
			<td style="width:119px;">EMD Millipore RIOs Essential 5</td>
			<td>Prepering&#160; deionized water</td>
		</tr>
		<tr height="40">
			<td height="40" style="height:40px;width:216px;">O2 plasma machine</td>
			<td style="width:88px;">Femto Science</td>
			<td style="width:119px;">VITA-A</td>
			<td>Cleaning silicon wafer</td>
		</tr>
		<tr height="40">
			<td height="40" style="height:40px;width:216px;">SU-8 2150 negative photoresist</td>
			<td style="width:88px;">MicroChem</td>
			<td style="width:119px;">Y111077 0500L1GL</td>
			<td>Photoresist for master mold fabrication</td>
		</tr>
		<tr height="40">
			<td height="40" style="height:40px;width:216px;">Hot plate</td>
			<td style="width:88px;">Misung Scientific</td>
			<td style="width:119px;">HP330D, HP150D</td>
			<td>Baking SU-8</td>
		</tr>
		<tr height="40">
			<td height="40" style="height:40px;width:216px;">SU-8 developer</td>
			<td style="width:88px;">Microchem</td>
			<td style="width:119px;">Y020100 4000L1PE</td>
			<td>Developing SU-8</td>
		</tr>
		<tr height="40">
			<td height="40" style="height:40px;width:216px;">Mask aligner system for photolithograpy</td>
			<td style="width:88px;">Shinu Mst Co.</td>
			<td style="width:119px;">CA-6M</td>
			<td>Photolithography</td>
		</tr>
		<tr height="40">
			<td height="40" style="height:40px;width:216px;">Sylgard 184 silicone elastomer kit</td>
			<td style="width:88px;">Dow Corning</td>
			<td style="width:119px;">1064891</td>
			<td>PDMS casting</td>
		</tr>
		<tr height="80">
			<td height="80" style="height:80px;width:216px;">Laboratory Corona Treater</td>
			<td style="width:88px;">Electro-technic Products Inc.</td>
			<td style="width:119px;">Model BD-20AC</td>
			<td>PDMS air plasma treatment&#160;</td>
		</tr>
		<tr height="40">
			<td height="40" style="height:40px;width:216px;">N-isopropylacrylamide (NIPAAm)</td>
			<td style="width:88px;">Sigma-Aldrich</td>
			<td style="width:119px;">415324-50G</td>
			<td>Monomer</td>
		</tr>
		<tr height="60">
			<td height="60" style="height:60px;width:216px;">N,N&#39;-methylenebisacrylamide (MBAAm)</td>
			<td style="width:88px;">Sigma-Aldrich</td>
			<td style="width:119px;">146072-100G</td>
			<td>Crosslinker of NIPAAm</td>
		</tr>
		<tr height="60">
			<td height="60" style="height:60px;width:216px;">4-(2-hydroxyethoxy)phenyl-(2-hydroxy-2-propyl)ketone, Irgacure 2959</td>
			<td style="width:88px;">BASF</td>
			<td style="width:119px;">55047962</td>
			<td>Photoinitiator of NIPAAm</td>
		</tr>
		<tr height="40">
			<td height="40" style="height:40px;">ABIL EM 90</td>
			<td style="width:88px;">Evonik Industries</td>
			<td style="width:119px;">201109</td>
			<td>Sufactant for oil</td>
		</tr>
		<tr height="60">
			<td height="60" style="height:60px;width:216px;">Vortex mixer</td>
			<td style="width:88px;">Scientific Industries Inc.</td>
			<td style="width:119px;">Vortex-Genie 2</td>
			<td>Mixing</td>
		</tr>
		<tr height="60">
			<td height="60" style="height:60px;width:216px;">Tygon tubing</td>
			<td style="width:88px;">Saint-Gobain</td>
			<td style="width:119px;">I.D. 1/32&#34;, O.D. 3/32&#34;, Wall 1/32&#34;</td>
			<td>Connecting tube between syringes and HFMD</td>
		</tr>
		<tr height="40">
			<td height="40" style="height:40px;width:216px;">UV light source</td>
			<td style="width:88px;">Hamamatsu</td>
			<td style="width:119px;">Spot light source LC8</td>
			<td>Polymerization from NIPAAm to PNIPAAm</td>
		</tr>
		<tr height="60">
			<td height="60" style="height:60px;width:216px;">Syringes, NORM-JECT (3ml)</td>
			<td style="width:88px;">Henke-Sass Wolf GmbH</td>
			<td style="width:119px;">22767</td>
			<td>Loading of materials</td>
		</tr>
		<tr height="40">
			<td height="40" style="height:40px;width:216px;">Syringe pump</td>
			<td style="width:88px;">KD Scientific</td>
			<td style="width:119px;">KDS model 200</td>
			<td>Perfusion of materials</td>
		</tr>
		<tr height="40">
			<td height="40" style="height:40px;width:216px;">Tegitol Type NP-10</td>
			<td style="width:88px;">Sigma-Aldrich</td>
			<td style="width:119px;">NP10-500ML</td>
			<td>Surfactant for water</td>
		</tr>
		<tr height="40">
			<td height="40" style="height:40px;width:216px;">Oil red O</td>
			<td style="width:88px;">Sigma-Aldrich</td>
			<td style="width:119px;">O0625-25G</td>
			<td>Dye for N-rich phase</td>
		</tr>
		<tr height="40">
			<td height="40" style="height:40px;width:216px;">Oil Blue N</td>
			<td style="width:88px;">Sigma-Aldrich</td>
			<td style="width:119px;">391557-5G</td>
			<td>Dye for N-rich phase</td>
		</tr>
		<tr height="40">
			<td height="40" style="height:40px;width:216px;">Yellow food dye</td>
			<td style="width:88px;">Edentown F&#38;B</td>
			<td style="width:119px;">NA</td>
			<td>Dye for N-poor phase</td>
		</tr>
		<tr height="40">
			<td height="40" style="height:40px;width:216px;">Green food dye</td>
			<td style="width:88px;">Edentown F&#38;B</td>
			<td style="width:119px;">NA</td>
			<td>Dye for N-poor phase</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Power supply</td>
			<td style="width:88px;">Agilent</td>
			<td style="width:119px;">E3649A</td>
			<td>Power soruce for thermoelectric moduel</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:216px;">Thermoelectric module</td>
			<td style="width:88px;">Peltier</td>
			<td style="width:119px;">FALC1-12710T125</td>
			<td>Temparature control</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Centrifuge machine</td>
			<td style="width:88px;">Labogene</td>
			<td style="width:119px;">1248R</td>
			<td>Settling down microhydrogels</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:216px;">24-well plate</td>
			<td style="width:88px;">SPL Life Sciences</td>
			<td style="width:119px;">32024</td>
			<td>Reservoir for observation</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:216px;">Optical microscope</td>
			<td style="width:88px;">Nikon</td>
			<td style="width:119px;">ECLIPSE 80i</td>
			<td>Optical observation</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:216px;">Image analysis software</td>
			<td style="width:88px;">IMT i-Solution Inc.</td>
			<td style="width:119px;">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 ...

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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

Synthesis, Cellular Delivery and In vivo Application of Dendrimer-based pH Sensors

The development of fluorescent indicators represented a revolution for life sciences. Genetically encoded and synthetic fluorophores with sensing abilities allowed the visualization of biologically relevant species with high spatial and temporal resolution. Synthetic dyes are of particular interest thanks to their high tunability and the wide range of measureable analytes. However, these molecules suffer several limitations related to small molecule behavior (poor solubility, difficulties in targeting, often no ratiometric imaging allowed). In this work we introduce the development of dendrimer-based sensors and present a procedure for pH measurement in vitro, in living cells and in vivo. We choose dendrimers as ideal platform for our sensors for their many desirable properties (monodispersity, tunable properties, multivalency) that made them a widely used scaffold for several biomedical devices. The conjugation of fluorescent pH indicators to the dendrimer scaffold led to an enhancement of their sensing performances. In particular dendrimers exhibit reduced cell leakage, improved intracellular targeting and allow ratiometric measurements. These novel sensors were successfully employed to measure pH in living HeLa cells and in vivo in mouse brain.

Synthesis, Cellular Delivery and In vivo Application of Dendrimer-based pH Sensors

Fluorescence sensors are powerful tools in life science. Here we describe a methodology to synthesize and use dendrimer-based fluorescent sensors to measure pH in living cells and in vivo. The dendritic scaffold enhances the properties of conjugated fluorescent dyes leading to improved sensing properties.

합성, 세포 전달 및<em&gt; 생체 내</em&gt; 덴드리머 기반 pH 센서의 응용 프로그램

The development of  fluorescent indicators represented a revolution for life sciences. Genetically  encoded and synthetic fluorophores with sensing ...

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Seeded Synthesis of CdSe/CdS Rod and Tetrapod Nanocrystals

We demonstrate a method for the synthesis of multicomponent nanostructures consisting of CdS and CdSe with rod and tetrapod morphologies. A seeded synthesis strategy is used in which spherical seeds of CdSe are prepared first using a hot-injection technique. By controlling the crystal structure of the seed to be either wurtzite or zinc-blende, the subsequent hot-injection growth of CdS off of the seed results in either a rod-shaped or tetrapod-shaped nanocrystal, respectively. The phase and morphology of the synthesized nanocrystals are confirmed using X-ray diffraction and transmission electron microscopy, demonstrating that the nanocrystals are phase-pure and have a consistent morphology. The extinction coefficient and quantum yield of the synthesized nanocrystals are calculated using UV-Vis absorption spectroscopy and photoluminescence spectroscopy. The rods and tetrapods exhibit extinction coefficients and quantum yields that are higher than that of the bare seeds. This synthesis demonstrates the precise arrangement of materials that can be achieved at the nanoscale by using a seeded synthetic approach.

A protocol for the seeded synthesis of rod-shaped and tetrapod-shaped multicomponent nanostructures consisting of CdS and CdSe is presented.

We demonstrate a method for the synthesis of multicomponent nanostructures consisting of CdS and CdSe with rod and tetrapod morphologies. A seeded ...

Synthesis of Indoxyl-glycosides for Detection of Glycosidase Activities

Indoxyl glycosides proved to be valuable and versatile tools for monitoring glycosidase activities. Indoxyls are released by enzymatic hydrolysis and are rapidly oxidized, for example by atmospheric oxygen, to indigo type dyes. This reaction enables fast and easy screening in vivo without isolation or purification of enzymes, as well as rapid tests on agar plates or in solution (e.g., blue-white screening, micro-wells) and is used in biochemistry, histochemistry, bacteriology and molecular biology. Unfortunately the synthesis of such substrates proved to be difficult, due to various side reactions and the low reactivity of the indoxyl hydroxyl function. Especially for glucose type structures low yields were observed. Our novel approach employs indoxylic acid ester as key intermediates. Indoxylic acid esters with varied substitution patterns were prepared on scalable pathways. Phase transfer glycosylations with those acceptors and peracetylated glycosyl halides can be performed under common conditions in high yields. Ester cleavage and subsequent mild silver mediated glycosylation yields the peracetylated indoxyl glycosides in high yields. Finally deprotection is performed according to Zempl&#233;n.

Indoxyl glycosides are well-established and widely used tools for enzyme screening and enzyme activity monitoring. Especially for glucose type structures previous syntheses proved to be challenging and low yielding. Our novel approach employs indoxylic acid esters as precious intermediates to yield a considerable number of indoxyl glycosides in good yields.

Indoxyl glycosides proved to be valuable and versatile tools for monitoring glycosidase activities. Indoxyls are released by enzymatic hydrolysis and are ...

Protocol for the Synthesis of Ortho-trifluoromethoxylated Aniline Derivatives

Molecules bearing trifluoromethoxy (OCF3) group often show desired pharmacological and biological properties. However, facile synthesis of trifluoromethoxylated aromatic compounds remains a formidable challenge in organic synthesis. Conventional approaches often suffer from poor substrate scope, or require use of highly toxic, difficult-to-handle, and/or thermally labile reagents. Herein, we report a user-friendly protocol for the synthesis of methyl 4-acetamido-3-(trifluoromethoxy)benzoate using 1-trifluoromethyl-1,2-benziodoxol-3(1H)-one (Togni reagent II). Treating methyl 4-(N-hydroxyacetamido)benzoate (1a) with Togni reagent II in the presence of a catalytic amount of cesium carbonate (Cs2CO3) in chloroform at RT afforded methyl 4-(N-(trifluoromethoxy)acetamido)benzoate (2a). This intermediate was then converted to the final product methyl 4-acetamido-3-(trifluoromethoxy)benzoate (3a) in nitromethane at 120 &#176;C. This procedure is general and can be applied to the synthesis of a broad spectrum of ortho-trifluoromethoxylated aniline derivatives, which could serve as useful synthetic building blocks for the discovery and development of new pharmaceuticals, agrochemicals, and functional materials.

Protocol for the Synthesis of Ortho-trifluoromethoxylated Aniline Derivatives

An operationally simple procedure for the synthesis of ortho-trifluoromethoxylated aniline derivatives via a two-step sequence of O-trifluoromethylation of N-aryl-N-hydroxyacetamide followed by thermally induced intramolecular OCF3-migration is reported.

의 합성을위한 프로토콜<em&gt; 직교</em&gt; -trifluoromethoxylated 아닐린 파생 상품

Molecules bearing trifluoromethoxy (OCF3) group often show desired pharmacological and biological properties. However, facile synthesis of ...

Synthesis and Characterization of Supramolecular Colloids

Control over colloidal assembly is of utmost importance for the development of functional colloidal materials with tailored structural and mechanical properties for applications in photonics, drug delivery and coating technology. Here we present a new family of colloidal building blocks, coined supramolecular colloids, whose self-assembly is controlled through surface-functionalization with a benzene-1,3,5-tricarboxamide (BTA) derived supramolecular moiety. Such BTAs interact via directional, strong, yet reversible hydrogen-bonds with other identical BTAs. Herein, a protocol is presented that describes how to couple these BTAs to colloids and how to quantify the number of coupling sites, which determines the multivalency of the supramolecular colloids. Light scattering measurements show that the refractive index of the colloids is almost matched with that of the solvent, which strongly reduces the van der Waals forces between the colloids. Before photo-activation, the colloids remain well dispersed, as the BTAs are equipped with a photo-labile group that blocks the formation of hydrogen-bonds. Controlled deprotection with UV-light activates the short-range hydrogen-bonds between the BTAs, which triggers the colloidal self-assembly. The evolution from the dispersed state to the clustered state is monitored by confocal microscopy. These results are further quantified by image analysis with simple routines using ImageJ and Matlab. This merger of supramolecular chemistry and colloidal science offers a direct route towards light- and thermo-responsive colloidal assembly encoded in the surface-grafted monolayer.

A protocol for the synthesis and characterization of colloids coated with supramolecular moieties is described. These supramolecular colloids undergo self-assembly upon the activation of the hydrogen-bonds between the surface-anchored molecules by UV-light.

Control over colloidal assembly is of utmost importance for the development of functional colloidal materials with tailored structural and mechanical ...

Synthesis of Protein Bioconjugates via Cysteine-maleimide Chemistry

The chemical linking or bioconjugation of proteins to fluorescent dyes, drugs, polymers and other proteins has a broad range of applications, such as the development of antibody drug conjugates (ADCs) and nanomedicine, fluorescent microscopy and systems chemistry. For many of these applications, specificity of the bioconjugation method used is of prime concern. The Michael addition of maleimides with cysteine(s) on the target proteins is highly selective and proceeds rapidly under mild conditions, making it one of the most popular methods for protein bioconjugation.
We demonstrate here the modification of the only surface-accessible cysteine residue on yeast cytochrome c with a ruthenium(II) bisterpyridine maleimide. The protein bioconjugation is verified by gel electrophoresis and purified by aqueous-based fast protein liquid chromatography in 27% yield of isolated protein material. Structural characterization with MALDI-TOF MS and UV-Vis is then used to verify that the bioconjugation is successful. The protocol shown here is easily applicable to other cysteine - maleimide coupling of proteins to other proteins, dyes, drugs or polymers.

Synthesis of Protein Bioconjugates via Cysteine-maleimide Chemistry

This protocol details the important steps required for the bioconjugation of a cysteine containing protein to a maleimide, including reagent purification, reaction conditions, bioconjugate purification and bioconjugate characterization.

The chemical linking or bioconjugation of proteins to fluorescent dyes, drugs, polymers and other proteins has a broad range of applications, such as the ...

Hydroquinone Based Synthesis of Gold Nanorods

Gold nanorods are an important kind of nanoparticles characterized by peculiar plasmonic properties. Despite their widespread use in nanotechnology, the synthetic methods for the preparation of gold nanorods are still not fully optimized. In this paper we describe a new, highly efficient, two-step protocol based on the use of hydroquinone as a mild reducing agent. Our approach allows the preparation of nanorods with a good control of size and aspect ratio (AR) simply by varying the amount of hexadecyl trimethylammonium bromide (CTAB) and silver ions (Ag+) present in the "growth solution". By using this method, it is possible to markedly reduce the amount of CTAB, an expensive and cytotoxic reagent, necessary to obtain the elongated shape. Gold nanorods with an aspect ratio of about 3 can be obtained in the presence of just 50 mM of CTAB (versus 100 mM used in the standard protocol based on the use of ascorbic acid), while shorter gold nanorods are obtained using a concentration as low as 10 mM.

This paper describes a protocol for the synthesis of gold nanorods, based on the use of hydroquinone as reducing agent, plus the different mechanisms for controlling their size and aspect ratio.

금 나노 막대의 하이드로 퀴논 기반 합성

Gold nanorods are an important kind of nanoparticles characterized by peculiar plasmonic properties. Despite their widespread use in nanotechnology, the ...

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 ...

Facet-to-facet Linking of Shape-anisotropic Colloidal Cadmium Chalcogenide Nanostructures

Here, we describe a protocol that allows for shape-anisotropic cadmium chalcogenide nanocrystals (NCs), such as nanorods (NRs) and tetrapods (TPs), to be covalently and site-specifically linked via their end facets, resulting in polymer-like linear or branched chains. The linking procedure begins with a cation-exchange process in which the end facets of the cadmium chalcogenide NCs are first converted to silver chalcogenide. This is followed by the selective removal of ligands at their surface. This results in cadmium chalcogenide NCs with highly reactive silver chalcogenide end facets that spontaneously fuse upon contact with each other, thereby establishing an interparticle facet-to-facet attachment. Through the judicious choice of precursor concentrations, an extensive network of linked NCs can be produced. Structural characterization of the linked NCs is carried out via low- and high-resolution transmission electron microscopy (TEM), as well as energy-dispersive X-ray spectroscopy, which confirm the presence of silver chalcogenide domains between chains of cadmium chalcogenide NCs.

A protocol detailing how shape-anisotropic colloidal cadmium chalcogenide nanocrystals can be covalently linked via their end facets is presented here.

면 대 면 모양 이방성 콜 로이드 카드뮴 칼코게나이드 Nanostructures의 연결

Here, we describe a protocol that allows for shape-anisotropic cadmium chalcogenide nanocrystals (NCs), such as nanorods (NRs) and tetrapods (TPs), to be ...

Grafting Multiwalled Carbon Nanotubes with Polystyrene to Enable Self-Assembly and Anisotropic Patchiness

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A procedure for the synthesis of polystyrene-grafted multiwalled carbon nanotubes using successive chemical modification steps to selectively introduce the polymer chains to the sidewalls and their self-assembly via anisotropic patchiness is presented.

자기 집합에 있도록 폴리스 티 렌과 이방성 Patchiness Multiwalled 탄소 나노튜브를 접목

We demonstrate a straightforward protocol to graft pristine multiwalled carbon nanotubes (MWCNTs) with polystyrene (PS) chains at the sidewalls through a ...