Name: creating sub-50 nm nanofluidic junctions in pdms microfluidic chip via self-assembly process of colloidal particles
Uploaded: 2016-03-13T15:00:00.000+00:00
Duration: 11 min 13 s
Description: Watch this Scientific Journal Video about Creating Sub-50 Nm Nanofluidic Junctions in PDMS Microfluidic Chip via Self-Assembly Process of Colloidal Particles at JoVE.com

이 작품은 NIH R21 EB008177-01A2 뉴욕 대학 아부 다비 (NYUAD) 연구 증진 기금 2013 년 우리는 미세 동안 그들의 지원을위한 MIT MTL의 기술 직원에 대한 우리의 감사를 표현하고 제임스 웨스턴과를위한 NYUAD의 니콜라스 Giakoumidis에 의해 지원되었다 SEM의 사진을 찍고 각각 전압 분배기를 구축을 지원합니다. PDMS의 디바이스 제조가 NYUAD의 미세 코어 시설에서 실시되었다. 마지막으로, 우리는 비디오 촬영 및 편집을위한 디지털 장학금 NYUAD 센터에서 레베카 Pittam에게 감사의 말씀을 전합니다.

실리카 콜로이드 비드 정학 1. 준비 <ol><li> 300 nm 내지 500 nm의 실리카 비드 현탁액의 제조 <ol><li> 소용돌이 30 초 동안 실리카 비드 재고 서스펜션 (w 10 % / 물 V). 균일 한 현탁액을 얻었다. 1 분 동안 2,600 XG에 1.5 ML 튜브와 원심 분리기를에 600 ㎕의 재고 현탁액의 총을 피펫. </li><li> 1 mM의 인산 나트륨 완충액 (PB, pH를 7.0) 400 μL로 뜨는을 대체합니다. </li><li> 텍싱 통해 pH가 7.0에서 1 mM의 인산 나트륨 용액 15 %의 최종 농도로 실리카 비드를 일시. </li></ol></li><li> 폴리와 표면 기능화 500nm의 실리카 비드 카르복실기 (알릴 아민 염산염, PAH), 폴리로 (소듐 스티렌 설포 네이트, PSS) 고분자 전해질 <ol><li> 1 %를위한 10 ml의 1 M의 NaCl (PH 7.0) (w / v)의 비드 서스펜션이 장착 된 카르복실기 500 nm의 실리카 비드의 0.1 g을 일시 중단합니다. </li><li> 1 M NAC 0.4 % PAH (MW 65K)를 준비1 M NaCl을 15 mL의 원액을 300 μL (20 % w / 물 V)를 용해시켜 L. 20 ㎖의 1 M NaCl 용액에 0.18 g의 PSS를 용해시켜 1 M NaCl 용액에 0.9 % PSS (MW 70K)를 준비한다. 소용돌이 모두 1 분을위한 솔루션을 제공합니다. 완전히 고분자 전해질을 용해한다. </li><li> 카복실 작용기를 갖는 실리카 비드에 양전하 고분자 전해질 층을 증착하기 위해 15 ㎖의 튜브에 1 % 실리카 카복실 비드 9.8 ml의 PAH 용액 200 μL를 추가한다. 1 분 동안 비드 현탁액을 소용돌이. 60 분 동안 튜브 회전에 품어. RT에서. </li><li> 1 분 동안 1,801 XG에서 비드 현탁액을 원심 분리기. 10 mL의 탈 이온수와 바인드 PAH 다섯 번 씻어. 각 원심 분리하고 상청액을 제거한 후, 비드 조밀 튜브의 하단에 충전 하였다. 비드를 재현 탁하고, 다음 원심 분리 단계에 앞서 씻어되도록 DI 물 8 ml를 첨가하기 전에 DI 물 2 ㎖와 함께 강하게 피펫 팅 비드 덩어리를 방해. </li><li> 따르다PSS 코팅 1.2.3과 1.2.4의 단계는 구슬에 음전하 층을 증착한다. PSS 증착하기 전에 1.2.4의 5 번째 세척 단계에서 DI 물 상층 액을 제거한 후 1 M NaCl을 9.8 ml의 구슬을 다시 일시 중지합니다. <ol><li> 15 ML 튜브의 하단에있는 구슬 덩어리를 분해 한 후 1 M NaCl을 8 ml에 추가 1 M NaCl을 2 ㎖를 사용하여 동일한 활발한 피펫 팅 단계를 사용합니다. 하나의 PAH 층 증착 된 실리카 비드의 9.8 ml의 PSS 용액 200 μl를 추가합니다. 1 분 동안 텍싱 후. 60 분 동안 배양. 튜브 회전에, DI 물 5 세척 단계를 반복합니다. </li><li> 올바르게 수행 된 고분자 전해질 증착 과정을 확인 제조자 프로토콜에 따라 동적 광산란 장치를 이용하여 각각의 고분자 전해질 코팅 전후의 비드의 제타 전위를 측정한다 (표 1 참조). </li></ol></li><li> 단일 PSS 층 다음 DI 워터와 다섯 세척 단계를 반복합니다증착 및 0.05 % 트윈 20 종래의 유동성을 향상시키기 위해 미세 유체 소자에 사용하는 (V / w 15 %)와 1 mM의 인산 나트륨 완충액 650 μL의 비드를 재 - 보류. </li></ol></li><li> PSS의 단일 층을 증착하는 아민 작용기 500 나노 실리카 비드를 위해 1.2.6에 1.2.5에서 위에서 설명한 절차를 따르십시오. </li></ol> PDMS 미세 유체 칩의 제조 (2) <ol><li> 실리콘 마스터의 미세 <ol><li> 다음과 같은 미세 가공 기술을 이용하여 PDMS 성형 용 실리콘 마스터를 제작. <ol><li> 스핀 코팅 실리콘 웨이퍼 상에 4000 rpm에서 1 μm의 얇은 포토 레지스트. 패턴 투영 노광 (노광 시간 170 밀리 초). 700 nm의 깊이와 2 ㎛ 폭 평면 나노 채널 에칭을 이용하여 층을 반응성 이온 에칭 (실리카 비드 nanotraps 역할). </li><li> CHF 3 (45 SCCM : 3.5 ㎚ / (S)의 에칭 율을 달성하기 위해 다음의 에칭 파라미터를 사용하여), CF 4 (15 SCCM), 아르곤 (100 SCCM), 압력 100 mTorr로, RF 전력 200 W. </li></ol></li><li> 스핀 코트 제 1 μm의 두께 포토 레지스트 2,000 rpm에서 층과 이전 패턴 nanotraps에 정렬을 수행합니다. 마이크로 콘택트 리소그래피를 통해 실리콘 깊은 반응성 이온 에칭 (DRIE)에 의해 패턴. DRIE는 표 2에 26 매개 변수 사용합니다. </li></ol></li><li> PDMS 몰드의 제조 <ol><li> 진공 항아리 O의 / n에서 트리클로로 실란 (50 μL)와 실리콘 마스터를 silanization합니다. 주의 : Tricholorosilane는 독성 및 부식성 물질이다. 항상 적절한 개인 보호 장비와 화학 후드에서 사용. </li><li> 10 경화제베이스 믹스 : 실란 실리콘 마스터 1의 비율로 주조 PDMS 및 대류 오븐에서 2 시간 동안 70 ° C에서이를 경화. </li><li> PL 후 플라즈마 세정기를 사용하여 빈 웨이퍼에 칼 플라즈마 결합 그것으로 실리콘 마스터에서 PDMS의 슬래브를 제거1 분 동안 플라즈마 클리너에 ASMA 처리. 단계를 캐스팅 다음 PDMS에 대한 파티션 라인을 표시하는 가장자리를 따라 테이프를 부착합니다. </li><li> 트리클로로 실란 (50 μL) O / N과 진공 항아리에 PDMS 금형을 silanization합니다. </li><li> PDMS 캐스트 (베이스 : 1 비율 : 10 경화제) 실란 PDMS 몰드와 대류 오븐에서 2 시간 동안 70 ° C에서이를 경화. </li></ol></li><li> PDMS 소자의 제조 <ol><li> 테이프로 표시된 분할 선을 따라 PDMS 금형에서 경화 된 PDMS의 슬래브 떼어. </li><li> 테이프 깨끗한 1.5 mm 생검 펀치와 펀치 구멍 저장조, 이소 프로필 알콜 (IPA) 및 건조 질소로 씻어. </li><li> 플라즈마 본드 1 분 동안 플라즈마 세정기의 플라즈마 처리 후의 25mm X 75mm 현미경 유리 슬라이드에 PDMS 소자. </li></ol></li><li> 초음파 처리 60 분 비드 서스펜션. 충전에 초음파 목욕 전에. 10 μl의 비드 현탁액을 피펫 (300 nm의 비 기능화 된 실리카는 수광고 또는 PAH-PSS 층과 500 nm의 실리카 카복실 비드, 또는 흡입구 (4) 및 (6)에 PSS 층과 500 nm의 실리카 아민 비즈) 각각 (도 1 A, B) 바로에 PDMS 칩 플라즈마 본딩 후 볼 유리 기판. 비드 포장을 향상시키기 위해 피펫 팁과 PDMS 칩에 부드럽게 누릅니다. <ol><li> 비드 전달 채널을 충전 한 후, 테이프 1과 9 제외한 모든 입구를 다룹니다. . 사용하기 전에 4 ° C에서 3 시간 및 저장을위한 장치를 공기 - 건조 2 콜로이드 자기 조립 과정을 단계별로 개략적 도표를 제공. </li></ol></li></ol> DNA의 동 전기 농도 3. 실험 <ol><li> 저수지 3, 7 완충 용액 (1 mM의 PB의 10 μL) 및 저장 (5) DNA 샘플 (1 mM의 PB 10 nM의 10 μl를) 작성 및 저수지 2 역 피펫 팁과 부드러운 음의 압력을 , 8, 10 참조 (거품없이 솔루션 채널을 채우기 위해 <strong&gt; 그림 1B). </li><li> 압력 균형을 5 분 동안 기다려야 10 리저버 저장조 (2)와도 8 및 10 나노 DNA 10 ㎕를 1 mM의 PB 10 μL를 추가한다. 평형에 도달합니다. </li><li> 저장조 3, 5, 7, 10 편에 와이어를 삽입한다. </li><li> 소스 미터 및 Pt 와이어에 연결된 전압 분배기를 이용하여 나노 유체 접합부를 가로 질러 전압을인가한다. 우선 저수지 5, 저수지 3, 7, 10 및 GND에 30 V를 적용합니다. </li><li> ~ 30 초 후 저수지 (10)에 25 V의 전압을 낮 춥니 다. </li><li> DNA의 형광 신호를 기록 할 때 샘플의 광표백을 최소화하기 위해 매 5 년주기의 개구와 기계적 셔터를 사용한다. </li></ol>

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Y., 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=High-Fidelity+Optofluidic+On-Chip+Sensors+Using+Well-Defined+Gold+Nanowell+Crystals.">High-Fidelity Optofluidic On-Chip Sensors Using Well-Defined Gold Nanowell Crystals.</a> Anal Chem. 83, 9174-9180 (2011).</li><li>Hu, Y. L., 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=Interconnected+ordered+nanoporous+networks+of+colloidal+crystals+integrated+on+a+microfluidic+chip+for+highly+efficient+protein+concentration.">Interconnected ordered nanoporous networks of colloidal crystals integrated on a microfluidic chip for highly efficient protein concentration.</a> Electrophoresis. 32, 3424-3430 (2011).</li><li>Zhang, D. -. W., 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=Microfabrication-free+fused+silica+nanofluidic+interface+for+on+chip+electrokinetic+stacking+of+DNA.">Microfabrication-free fused silica nanofluidic interface for on chip electrokinetic stacking of DNA.</a> Microfluid Nanofluid. 14, 69-76 (2013).</li><li>Syed, A., Mangano, L., Mao, P., Han, J., Song, Y. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Creating+sub-50+nm+nanofluidic+junctions+in+a+PDMS+microchip+via+self-assembly+process+of+colloidal+silica+beads+for+electrokinetic+concentration+of+biomolecules.">Creating sub-50 nm nanofluidic junctions in a PDMS microchip via self-assembly process of colloidal silica beads for electrokinetic concentration of biomolecules.</a> Lab Chip. 14, 4455-4460 (2014).</li><li>Kim, S. J., Song, Y. A., Han, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Nanofluidic+concentration+devices+for+biomolecules+utilizing+ion+concentration+polarization:+theory,+fabrication,+and+applications.">Nanofluidic concentration devices for biomolecules utilizing ion concentration polarization: theory, fabrication, and applications.</a> Chem Soc Rev. 39, 912-922 (2010).</li><li>Fu, J. P., Mao, P., Han, J. Y. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Continuous-flow+bioseparation+using+microfabricated+anisotropic+nanofluidic+sieving+structures.">Continuous-flow bioseparation using microfabricated anisotropic nanofluidic sieving structures.</a> Nat Protoc. 4, 1681-1698 (2009).</li><li>Plecis, A., Nanteuil, C., Haghiri-Gosnet, A. M., Chen, Y. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Electropreconcentration+with+Charge-Selective+Nanochannels.">Electropreconcentration with Charge-Selective Nanochannels.</a> Anal Chem. 80, 9542-9550 (2008).</li><li>Ko, S. H., 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=Nanofluidic+preconcentration+device+in+a+straight+microchannel+using+ion+concentration+polarization.">Nanofluidic preconcentration device in a straight microchannel using ion concentration polarization.</a> Lab Chip. 12, 4472-4482 (2012).</li></ol>

The authors have nothing to disclose.

nanofluidics을 연구 일반 기기 설계 방식에 따라, 우리는 나노 채널의 어레이를 패터닝하는 리소그래피 콜로이드 성 나노 입자의 증착 구동 자기 조립을 사용하는 대신 두 개의 미세 채널에서 나노 유체 사이의 접합을 제작. 비드 전달 채널, 700 nm의 깊이가 100 ㎛의 전체 폭에 비드 전달 채널의 양쪽에 2 ㎛의 폭 nanotraps의 배열 콜로이드 입자를 흐르는 경우에 흐르는 비드 현탁액을 방지 인해 nanotraps에...

10 2 나노 - Nanofluidics 10 (1)의 길이 규모에서 생물학적 과정 또는 이온의 수송 현상과 분자를 연구하는 μ의 TAS의 새로운 연구 영역 (마이크로 총 분석 시스템)입니다. 필요한 경우 이러한 나노 채널과 나노 유체 도구의 출현으로, 분자 및 이온의 수송 과정은 분리 및 검출이 길이 규모에서 사용할 수있는 기능을 이용하여, 전례없는 정밀도로 모니터링 및 조작 할 수 있습니다. 1, 2 분의 이러한 특성 나노 기능 전하 불균형을 일으켜 나노 채널 및 마이크로 채널 사이의 이온 농도 분극 (ICP)를 개시 할 수있는 나노 채널 벌크 전하 (또는 Dukhin 번호) 표면에 높은 비율이다. (3) 나노 유체 현상의 연구를위한 일반적인 장치 플랫폼은 접합 등의 나노 채널의 배열에 의해 연결된 두 개의 마이크로 시스템으로 구성되어 있습니다. 4-6 </sup&gt; 이러한 나노 유체 장치를 구축하기위한 선택의 재료로 인해 접합 과정에서 붕괴 채널을 방지 높은 강성의 실리콘이다. 7 ​​그러나, 실리콘 소자 제조 비싼 마스크와 클린 룸 시설에서 처리 상당한 양을 필요로한다. 8 때문에 성형 플라즈마 본딩, 폴리 디메틸 실록산 (PDMS)을 통해 장치의 제조의 편의 10 널리 마이크로 유체 용 건축 재료로서 허용되었으며 그것뿐만 아니라 nanofluidics 이상적인 물질 일 수있다. 그러나, 낮은 영률 360-870 KPa가 주위 플라즈마 본딩 동안 PDMS 채널을 쉽게 접을 수있다. 나노 채널의 깊이는 100 nm의 아래해야 할 경우 표준 포토 리소그래피 기술을 통해 PDMS 소자의 제조는 채널 폭을 요구하는 매우 어려운 될 것이라는 것을 의미 1 : 나노 채널 (깊이와 넓이)의 최소 종횡비는 10 미만이어야 포토리스의 전류 한계 이하에서 약 1 μm의 ography. 이러한 한계를 극복하기 위해, 플라즈마 처리 후 78 내지 11 또는 형성하는 주름의 평균 깊이와 크랙을 개시 연신 비의 리소그래피 방법을 이용하여 PDMS의 나노 채널을 생성하기위한 시도가 있었다. (12)이 기계적 압력 PDMS 채널 수 붕괴 60 나노 미터의 낮은 나노 채널의 높이입니다. (13) 이러한 고도로 발명 비 리소그래피 방법 깊이 100nm로 이하 건물 나노 채널을​​ 허용하더라도, 나노 채널 제작의 치수 제어 성이 여전히 나노 유체 장치 등의 건축 재료 PDMS의 광범위한 수용을 장애가된다. 나노 채널의 또 다른 중요한 문제는, 실리콘 또는 PDMS 여부에 이온 또는 분자의 조작에 대한 채널 벽면의 표면 전하를 변경할 필요가있는 경우에, 표면 기능화된다. 결합을 통해 장치 조립 후, 나노 채널은 매우 어렵다때문에 확산 제한 전송에 표면 기능화 도달. 높은 치수 정확도 및 용이 한 표면 기능화와 나노 스케일 채널을 생성하기 위해 마이크로 유체 소자에 증착 14-16에 의한 콜로이드 입자의 자기 조립 방법은 유망한 접근 방법 중 하나가 될 수있다. 기공 크기 및 표면 특성의 제어 외에, 튜닝 가능성은 온도 17의 pH, 18, ​​19 및 이온 세기를 조절함으로써 고분자 전해질로 코팅 된 콜로이드 입자를 사용하여 반응계 공극의 크기도있다.이 때문에 이러한 18 electrochromatography 20 바이오 센서 21 단백질 농도 22 마이크로 유체 단백질 및 DNA의 분리. 14,23 본 연구에 대한 장점, 콜로이드 입자의 자기 조립 방법은 아직 발견 애플리케이션, 우리는 구축이 자기 조립 방법을 배포 에서 동 전기 농축 장치이 마이크로 나노 유체 간의 접합을 필요 PDMS. 24 기적 농도 뒤에 기본적인 메커니즘은 이온 농도 분극 (ICP)에 기초한다. 제조 및 조립 단계 (25)의 상세한 설명은 다음의 프로토콜에 포함된다.

<table><tbody><tr><td>Poly(Styrenesulfonic Acid) Sodium Salt</td><td>Polysciences&amp;nbsp;</td><td>08772</td><td></td></tr><tr><td>Poly(allylamine) Solution</td><td>Sigma Aldrich</td><td>479144-5G</td><td></td></tr><tr><td>Silica Microsphere - 300 nm</td><td>Polysciences&amp;nbsp;</td><td>24321</td><td></td></tr><tr><td>Silica Microsphere - 500 nm</td><td>Polysciences&amp;nbsp;</td><td>24323</td><td></td></tr><tr><td>Silica Microsphere Carboxyl Functional - 500 nm</td><td>Polysciences&amp;nbsp;</td><td>24753</td><td></td></tr><tr><td>Silica Microsphere Amine Functional - 500 nm</td><td>Polysciences&amp;nbsp;</td><td>24756</td><td></td></tr><tr><td>Sylgard 184 Silicone Elastomer kit</td><td>Dow Corning</td><td></td><td></td></tr><tr><td>Trichlorosilane</td><td>Sigma Aldrich</td><td>175552</td><td></td></tr><tr><td>Ultrasonic Cleaner</td><td>Branson</td><td>3510</td><td></td></tr><tr><td>Tube Rotator&amp;nbsp;</td><td>VWR</td><td>10136-084</td><td></td></tr><tr><td>Vortex Mixer</td><td>WiseMix</td><td>VM-10</td><td></td></tr><tr><td>Microcentrifuge</td><td>VWR</td><td>Micro 1207</td><td></td></tr><tr><td>Plasma Cleaner</td><td>Harrick Plasma</td><td>PDC-001-HP</td><td></td></tr><tr><td>PDMS Mixer</td><td>Thinky</td><td>ARE-250</td><td></td></tr><tr><td>Oven</td><td>Thermo Scientific</td><td>PR305220M</td><td></td></tr><tr><td>Epi-fluorescence Microscope</td><td>Nikon</td><td>Eclipse Ti</td><td></td></tr><tr><td>CCD Camera</td><td>Andor</td><td>Clara</td><td></td></tr><tr><td>Platinum Electrodes</td><td>Alfa Aesar</td><td>43014</td><td></td></tr><tr><td>Source Meter</td><td>Keithley</td><td>2400</td><td></td></tr><tr><td>Digital Multimeter&amp;nbsp;</td><td>Extech</td><td>410</td><td></td></tr><tr><td>Microscopy Glass Slides</td><td>Thermo Scientific</td><td>2951-001</td><td></td></tr><tr><td>Tween 20</td><td>Merck Millipore</td><td>822184</td><td></td></tr><tr><td>Sodium chloride</td><td>Fisher Scientific</td><td>7646-14-5</td><td></td></tr><tr><td>Sodium phosphate monobasic</td><td>Sigma Aldrich</td><td>71505</td><td></td></tr><tr><td>Sodium phosphate dibasic</td><td>Sigma Aldrich</td><td>S3264</td><td></td></tr><tr><td>DNA</td><td>IDT</td><td></td><td>CAA CCG ATG CCA CAT CAT TAG CTA C</td></tr><tr><td>B-Phycoerythrin</td><td>Life Technologies</td><td>P-800</td><td></td></tr><tr><td>Dynamic light scattering system for Zeta Potential Measurement</td><td>Malvern</td><td>Zetasizer Nano S</td><td></td></tr><tr><td>Photoresist&amp;nbsp;</td><td>Shipley</td><td>SPR700-1.0</td><td></td></tr><tr><td>Projection lithography</td><td>Nikon</td><td>NSR2005i9</td><td></td></tr><tr><td>Reactive Ion Etcher</td><td>Applied Materials</td><td>AME P5000</td><td></td></tr><tr><td>ICP deep reactive ion etcher</td><td>STS</td><td>STS-6&quot;</td><td></td></tr><tr><td>Contact lithography</td><td>Electronic Visions</td><td>EV620</td><td></td></tr><tr><td>Photoresist Coater Developer</td><td>SSI</td><td>SSI 150</td><td></td></tr><tr><td>Non-contact surface profiler</td><td>Wyko</td><td>NT 9800</td><td></td></tr></tbody></table>

creating sub-50 nm nanofluidic junctions in pdms microfluidic chip via self-assembly process of colloidal particles

폴리 디메틸 실록산 (PDMS)의 성형으로 인해 결합의 용이성뿐만 아니라 투명성 마이크로 유체 장치를 만드는 일반적인 건축 재료이다. 때문에 PDMS 재료의 부드러움, 그러나 나노 채널을​​ 구축 PDMS를 사용하기 어려운 것이다. 채널 플라즈마 본딩시 쉽게 붕괴되는 경향이있다. 본 논문에서는 하위 50 개의 마이크로 사이에 기공 나노와 나노 유체 접합을 만들 수있는 실리카 콜로이드 나노 입자의 증발 중심의 자기 조립 방법을 제시한다. 기공 크기뿐만 아니라 나노 유체 접합 표면 전하 단순히 자기 조립 공정 전에 바이알 조립 미세 유동 장치의 외부 콜로이드 실리카 비드 크기 및 표면 작용을 변화시킴으로써 튜닝된다. 300 내지 500 나노 미터, 900 나노 미터의 비드 크기를 갖는 나노 입자의 자기 조립 (self-assembly)을 사용하여, 각각의 기공 (45) 내지 ~의 크기, ~ 75 nm이고, ~ 135 nm의 다공질 막을 제조하는 것이 가능했다. 전기에서알 전위 양이온 - 선택성 막으로서,이 나노 다공성 막을 개시 이온 농도 분극 (ICP) 작용을 15 분 이내에 ~ 1,700 배까지 농축하는 DNA. 이 아닌 나노 리소그래피 처리는 PDMS 마이크로 유체 칩 내부 이온 및 분자의 나노 전송 프로세스 연구를위한 가변 나노 유체 접합을 구축하기 위해 새로운 기회를 열어.

두 마이크로 간의 자기 조립 된 나노 유체 접합을 포함 PDMS에 집중 기적 칩)는도 1a에 도시된다. 장치의 중앙 채널은 50 ㎛ 폭 비드 전달 채널 (도 1b)을 통해 DNA 시료 용액으로 채워지고 양쪽에 각각 2 완충액 채널 어귀된다. 실리카 콜로이드 현탁액 샘플 완충액 나노 유체 채널 간의 접합을 만들 즉시 플라즈마 본딩 후 비드 전달 채널로 유입된다. 깊...

Watch this Scientific Journal Video about Creating Sub-50 Nm Nanofluidic Junctions in PDMS Microfluidic Chip via Self-Assembly Process of Colloidal Particles at JoVE.com

Creating Sub-50 Nm Nanofluidic Junctions in PDMS Microfluidic Chip via Self-Assembly Process of Colloidal Particles

We propose a simple self-assembly technique of silica colloidal nanoparticles to create a nanofluidic junction between two microchannels in polydimethylsiloxane (PDMS). Using this technique, a nanoporous bead membrane with a pore size down to ~45 nm was built inside a microchannel and applied to electrokinetic preconcentration of DNA samples.

콜로이드 입자의 자기 조립 과정을 통해 PDMS 미세 유체 칩의 하위 50 Nm의 나노 유체 접합 만들기

Polydimethylsiloxane (PDMS) is the prevailing building material to make microfluidic devices due to its ease of molding and bonding as well as its ...

creating-sub-50-nm-nanofluidic-junctions-pdms-microfluidic-chip-via

Universidad San Sebastian

Research

JoVE Journal

Engineering

10.6K 조회수.  New York University Abu Dhabi (NYUAD). We propose a simple self-assembly technique of silica colloidal nanoparticles to create a nanofluidic junction between two microchannels in polydimethylsiloxane (PDMS). Using this technique, a nanoporous bead membrane with a pore size down to ~45 nm was built inside a microchannel and applied to electrokinetic preconcentration of DNA samples.

비디오: Creating Sub-50 Nm Nanofluidic Junctions in PDMS Microfluidic Chip via Self-Assembly Process of Colloidal Particles

A Microfluidic-based Hydrodynamic Trap for Single Particles

The ability to confine and manipulate single particles in free solution is a key enabling technology for fundamental and applied science. Methods for particle trapping based on optical, magnetic, electrokinetic, and acoustic techniques have led to major advancements in physics and biology ranging from the molecular to cellular level. In this article, we introduce a new microfluidic-based technique for particle trapping and manipulation based solely on hydrodynamic fluid flow. Using this method, we demonstrate trapping of micro- and nano-scale particles in aqueous solutions for long time scales. The hydrodynamic trap consists of an integrated microfluidic device with a cross-slot channel geometry where two opposing laminar streams converge, thereby generating a planar extensional flow with a fluid stagnation point (zero-velocity point). In this device, particles are confined at the trap center by active control of the flow field to maintain particle position at the fluid stagnation point. In this manner, particles are effectively trapped in free solution using a feedback control algorithm implemented with a custom-built LabVIEW code. The control algorithm consists of image acquisition for a particle in the microfluidic device, followed by particle tracking, determination of particle centroid position, and active adjustment of fluid flow by regulating the pressure applied to an on-chip pneumatic valve using a pressure regulator. In this way, the on-chip dynamic metering valve functions to regulate the relative flow rates in the outlet channels, thereby enabling fine-scale control of stagnation point position and particle trapping. The microfluidic-based hydrodynamic trap exhibits several advantages as a method for particle trapping. Hydrodynamic trapping is possible for any arbitrary particle without specific requirements on the physical or chemical properties of the trapped object. In addition, hydrodynamic trapping enables confinement of a "single" target object in concentrated or crowded particle suspensions, which is difficult using alternative force field-based trapping methods. The hydrodynamic trap is user-friendly, straightforward to implement and may be added to existing microfluidic devices to facilitate trapping and long-time analysis of particles. Overall, the hydrodynamic trap is a new platform for confinement, micromanipulation, and observation of particles without surface immobilization and eliminates the need for potentially perturbative optical, magnetic, and electric fields in the free-solution trapping of small particles.

In this article, we present a microfluidic-based method for particle confinement based on hydrodynamic flow. We demonstrate stable particle trapping at a fluid stagnation point using a feedback control mechanism, thereby enabling confinement and micromanipulation of arbitrary particles in an integrated microdevice.

단일 입자 Microfluidic 기반 유체 트랩

The ability to confine and manipulate single particles in free solution is a key enabling technology for fundamental and applied science.  Methods for ...

연구

생체공학

Fluorescence detection methods for microfluidic droplet platforms

The development of microfluidic platforms for performing chemistry and biology has in large part been driven by a range of potential benefits that accompany system miniaturisation. Advantages include the ability to efficiently process nano- to femoto- liter volumes of sample, facile integration of functional components, an intrinsic predisposition towards large-scale multiplexing, enhanced analytical throughput, improved control and reduced instrumental footprints.1
In recent years much interest has focussed on the development of droplet-based (or segmented flow) microfluidic systems and their potential as platforms in high-throughput experimentation.2-4 Here water-in-oil emulsions are made to spontaneously form in microfluidic channels as a result of capillary instabilities between the two immiscible phases. Importantly, microdroplets of precisely defined volumes and compositions can be generated at frequencies of several kHz. Furthermore, by encapsulating reagents of interest within isolated compartments separated by a continuous immiscible phase, both sample cross-talk and dispersion (diffusion- and Taylor-based) can be eliminated, which leads to minimal cross-contamination and the ability to time analytical processes with great accuracy. Additionally, since there is no contact between the contents of the droplets and the channel walls (which are wetted by the continuous phase) absorption and loss of reagents on the channel walls is prevented.
Once droplets of this kind have been generated and processed, it is necessary to extract the required analytical information. In this respect the detection method of choice should be rapid, provide high-sensitivity and low limits of detection, be applicable to a range of molecular species, be non-destructive and be able to be integrated with microfluidic devices in a facile manner. To address this need we have developed a suite of experimental tools and protocols that enable the extraction of large amounts of photophysical information from small-volume environments, and are applicable to the analysis of a wide range of physical, chemical and biological parameters. Herein two examples of these methods are presented and applied to the detection of single cells and the mapping of mixing processes inside picoliter-volume droplets. We report the entire experimental process including microfluidic chip fabrication, the optical setup and the process of droplet generation and detection.

Droplet-based microfluidic platforms are promising candidates for high throughput experimentation since they are able to generate picoliter, self-compartmentalized vessels inexpensively at kHz rates. Through integration with fast, sensitive and high resolution fluorescence spectroscopic methods, the large amounts of information generated within these systems can be efficiently extracted, harnessed and utilized.

microfluidic 비말 플랫폼 형광 검출 방법

The development of microfluidic platforms for performing chemistry and biology has in large part been driven by a range of potential benefits that ...

Microfluidic Chips Controlled with Elastomeric Microvalve Arrays

Miniaturized microfluidic systems provide simple and effective solutions for low-cost point-of-care diagnostics and high-throughput biomedical assays. Robust flow control and precise fluidic volumes are two critical requirements for these applications. We have developed microfluidic chips featuring elastomeric polydimethylsiloxane (PDMS) microvalve arrays that: 1) need no extra energy source to close the fluidic path, hence the loaded device is highly portable; and 2) allow for microfabricating deep (up to 1 mm) channels with vertical sidewalls and resulting in very precise features.

The PDMS microvalves-based devices consist of three layers: a fluidic layer containing fluidic paths and microchambers of various sizes, a control layer containing the microchannels necessary to actuate the fluidic path with microvalves, and a middle thin PDMS membrane that is bound to the control layer. Fluidic layer and control layers are made by replica molding of PDMS from SU-8 photoresist masters, and the thin PDMS membrane is made by spinning PDMS at specified heights. The control layer is bonded to the thin PDMS membrane after oxygen activation of both, and then assembled with the fluidic layer. The microvalves are closed at rest and can be opened by applying negative pressure (e.g., house vacuum). Microvalve closure and opening are automated via solenoid valves controlled by computer software.

Here, we demonstrate two microvalve-based microfluidic chips for two different applications. The first chip allows for storing and mixing precise sub-nanoliter volumes of aqueous solutions at various mixing ratios. The second chip allows for computer-controlled perfusion of microfluidic cell cultures.

The devices are easy to fabricate and simple to control. Due to the biocompatibility of PDMS, these microchips could have broad applications in miniaturized diagnostic assays as well as basic cell biology studies.

We demonstrate protocols for manufacturing and automating elastomeric polydimethylsiloxane (PDMS)-based microvalve arrays that need no extra energy to close and feature photolithographically defined precise volumes. A parallel subnanoliter-volume mixer and an integrated microfluidic perfusion system are presented.

Microfluidic 칩은 탄성 Microvalve의 배열을 제어

Miniaturized microfluidic systems provide simple and effective solutions for low-cost point-of-care diagnostics and high-throughput biomedical assays.  ...

생물학

Endothelialized Microfluidics for Studying Microvascular Interactions in Hematologic Diseases

Advances in microfabrication techniques have enabled the production of inexpensive and reproducible microfluidic systems for conducting biological and biochemical experiments at the micro- and nanoscales 1,2. In addition, microfluidics have also been specifically used to quantitatively analyze hematologic and microvascular processes, because of their ability to easily control the dynamic fluidic environment and biological conditions3-6. As such, researchers have more recently used microfluidic systems to study blood cell deformability, blood cell aggregation, microvascular blood flow, and blood cell-endothelial cell interactions6-13.However, these microfluidic systems either did not include cultured endothelial cells or were larger than the sizescale relevant to microvascular pathologic processes. A microfluidic platform with cultured endothelial cells that accurately recapitulates the cellular, physical, and hemodynamic environment of the microcirculation is needed to further our understanding of the underlying biophysical pathophysiology of hematologic diseases that involve the microvasculature.
Here, we report a method to create an "endothelialized" in vitro model of the microvasculature, using a simple, single mask microfabrication process in conjunction with standard endothelial cell culture techniques, to study pathologic biophysical microvascular interactions that occur in hematologic disease. This "microvasculature-on-a-chip" provides the researcher with a robust assay that tightly controls biological as well as biophysical conditions and is operated using a standard syringe pump and brightfield/fluorescence microscopy. Parameters such as microcirculatory hemodynamic conditions, endothelial cell type, blood cell type(s) and concentration(s), drug/inhibitory concentration etc., can all be easily controlled. As such, our microsystem provides a method to quantitatively investigate disease processes in which microvascular flow is impaired due to alterations in cell adhesion, aggregation, and deformability, a capability unavailable with existing assays.

A method to culture an endothelial cell monolayer throughout the entire inner 3D surface of a microfluidic device with microvascular-sized channels (&lt;30 &mu;m) is described. This in vitro microvasculature model enables the study of biophysical interactions between blood cells, endothelial cells, and soluble factors in hematologic diseases.

Hematologic 질환의 Microvascular 상호 작용 유학을위한 Endothelialized Microfluidics

Advances in  microfabrication techniques have enabled the production of inexpensive and  reproducible microfluidic systems for conducting biological and ...

Non-plasma Bonding of PDMS for Inexpensive Fabrication of Microfluidic Devices

In this video, we demonstrate how to use the neuron microfluidic device without plasma bonding.  In some cases it may be desirable to reversibly bond devices to the Corning No. 1 cover glass.  This could be due, perhaps, to a plasma cleaner not being available.  In other instances, it may be desirable to remove the device from the glass after the culturing of neurons for certain types of microscopy or for immunostaining, though it is not necessary to remove the device for immunostaining since the neurons can be stained in the device.  Some researchers, however, still prefer to remove the device.  In this case, reversible bonding of the device to the cover glass makes that possible.  There are some disadvantages to non-plasma bonding of the devices in that not as tight of a seal is formed.  In some cases axons may grow under the grooves rather than through them.  Also, because the glass and PDMS are hydrophobic, liquids do not readily enter the device making it necessary at times to force media and other reagents into the device.  Liquids will enter the device via capillary action, but it takes significantly longer as compared to devices that have been plasma bonded.  The plasma cleaner creates temporary hydrophilic charges on the glass and device that facilitate the flow of liquids through the device after bonding within seconds.  For non-plasma bound devices, liquid flow through the devices takes several minutes.  It is also important to note that the devices to be used with non-plasma bonding need to be sterilized first, whereas plasma treated devices do not need to be sterilized prior to use because the plasma cleaner will sterilize them.

In this video we demonstrate how to use the neuron microfluidic device without plasma bonding.

Microfluidic 장치의 저렴한 제작에 대한 PDMS의 비 플라즈마 본딩

In this video, we demonstrate how to use the neuron microfluidic device without plasma bonding.  In some cases it may be desirable to reversibly bond ...

Microfluidic Pneumatic Cages: A Novel Approach for In-chip Crystal Trapping, Manipulation and Controlled Chemical Treatment

The precise localization and controlled chemical treatment of structures on a surface are significant challenges for common laboratory technologies. Herein, we introduce a microfluidic-based technology, employing a double-layer microfluidic device, which can trap and localize in situ and ex situ synthesized structures on microfluidic channel surfaces. Crucially, we show how such a device can be used to conduct controlled chemical reactions onto on-chip trapped structures and we demonstrate how the synthetic pathway of a crystalline molecular material and its positioning inside a microfluidic channel can be precisely modified with this technology. This approach provides new opportunities for the controlled assembly of structures on surface and for their subsequent treatment.

Herein, we describe the fabrication and operation of a double-layer microfluidic system made of polydimethylsiloxane (PDMS). We demonstrate the potential of this device for trapping, directing the coordination pathway of a crystalline molecular material and controlling chemical reactions onto on-chip trapped structures.

미세 유체 압축 공기를 넣은 케이지 : A의 칩 크리스탈 트래핑, 조작에 대한 새로운 접근 방식 및 제어 화학 처리

The precise localization and controlled chemical treatment of structures on a surface are significant challenges for common laboratory technologies. ...

화학

High Throughput Microfluidic Rapid and Low Cost Prototyping Packaging Methods

In this work, 3 different packaging and assembly techniques are presented. They can be classified into two categories: one-time use and reusable packaging techniques.
The one-time use packaging technique employs UV-based and temperature curing epoxies to connect microtubes to access holes, wire-bonding for integrated circuit connections, and silver epoxy for electrical connections. This method is based on a robust assembly technique that can support relatively high pressure close to 1 psi and does not need any support to strengthen the microfluidic architecture.
Reusable packaging techniques consist of PDMS-based microtube interconnectors and anisotropic adhesive films for electrical connections. These devices are more sensitive and fragile. Consequently, Plexiglas support is added to the microfluidic structure to improve the electrical contact when anisotropic adhesive films are used, and also to strengthen the microfluidic architecture. In addition, a micromanipulator is needed to maintain tubes while using a thin PDMS layer to connect them to the access holes. Different PDMS layer thicknesses, ranging from 0.45-3 mm, are tested to compare the best adherence versus injection rates. Applied injection rates are varied from 50-300 &#956;l/hr for 0.45-3 mm PDMS layers, respectively. These techniques are mainly applicable for low-pressure applications. However, they can be extended for high-pressure ones through plasma-oxygen process to permanently seal the PDMS to glass substrates. The main advantage of this technique, besides the fact that it is reusable, consists of keeping the device observable when the microchannel length is very short (in the range of 3 mm or lower).

In this article we describe different techniques for microfluidic rapid prototyping platforms. The proposed techniques are based on ultraviolet (UV) sensitive and temperature curing epoxies, polydimethylsiloxane (PDMS) based tubing, wire-bonding, and anisotropic adhesive films. The assembling procedures presented are developed for both one-time use devices as well as reusable microfluidic systems.

높은 처리량 마이크로 유체 신속하고 저렴한 비용으로 프로토 타입 포장 방법

In this work, 3 different packaging and assembly techniques are presented. They can be classified into two categories: one-time use and reusable packaging ...

Patterning of Microorganisms and Microparticles through Sequential Capillarity-assisted Assembly

Controlled patterning of microorganisms into defined spatial arrangements offers unique possibilities for a broad range of biological applications, including studies of microbial physiology and interactions. At the simplest level, accurate spatial patterning of microorganisms would enable reliable, long-term imaging of large numbers of individual cells and transform the ability to quantitatively study distance-dependent microbe-microbe interactions. More uniquely, coupling accurate spatial patterning and full control over environmental conditions, as offered by microfluidic technology, would provide a powerful and versatile platform for single-cell studies in microbial ecology. 
This paper presents a microfluidic platform to produce versatile and user-defined patterns of microorganisms within a microfluidic channel, allowing complete optical access for long-term, high-throughput monitoring. This new microfluidic technology is based on capillarity-assisted particle assembly and exploits the capillary forces arising from the controlled motion of an evaporating suspension inside a microfluidic channel to deposit individual microsized objects in an array of traps microfabricated onto a polydimethylsiloxane (PDMS) substrate. Sequential depositions generate the desired spatial layout of single or multiple types of micro-sized objects, dictated solely by the geometry of the traps and the filling sequence. 
The platform has been calibrated using colloidal particles of different dimensions and materials: it has proven to be a powerful tool to generate diverse colloidal patterns and perform surface functionalization of trapped particles. Furthermore, the platform was tested on microbial cells, using Escherichia coli cells as a model bacterium. Thousands of individual cells were patterned on the surface, and their growth was monitored over time. In this platform, the coupling of single-cell deposition and microfluidic technology allows both geometric patterning of microorganisms and precise control of environmental conditions. It thus opens a window into the physiology of single microbes and the ecology of microbe-microbe interactions, as shown by preliminary experiments.

We present a technology that uses capillarity-assisted assembly in a microfluidic platform to pattern micro-sized objects suspended in a liquid, such as bacteria and colloids, into prescribed arrays on a polydimethylsiloxane substrate.

순차모세혈관 보조 어셈블리를 통한 미생물 및 미생물 입자의 패터닝

Controlled patterning of microorganisms into defined spatial arrangements offers unique possibilities for a broad range of biological applications, ...

공학

Pneumatically Driven Microfluidic Platform for Micro-Particle Concentration

The present article introduces a method for fabricating and operating a pneumatic valve to control particle concentration using a microfluidic platform. This platform has a three-dimensional (3D) network with curved fluid channels and three pneumatic valves, which create networks, channels, and spaces through duplex replication with polydimethylsiloxane (PDMS). The device operates based on the transient response of a fluid flow rate controlled by a pneumatic valve in the following order: (1) sample loading, (2) sample blocking, (3) sample concentration, and (4) sample release. The particles are blocked by thin diaphragm layer deformation of the sieve valve (Vs) plate and accumulate in the curved microfluidic channel. The working fluid is discharged by the actuation of two on/off valves. As a result of the operation, all particles of various magnifications were successfully intercepted and disengaged. When this technology is applied, the operating pressure, the time required for concentration, and the concentration rate may vary depending on the device dimensions and particle size magnification.

The present protocol describes a pneumatic microfluidic platform that can be used for efficient microparticle concentration.

미세입자 농도를 위한 공압 구동 미세유체 플랫폼

The present article introduces a method for fabricating and operating a pneumatic valve to control particle concentration using a microfluidic platform. ...

조합 플러그 생산을 위한 미세유체 장치 설정

Bilayer Microfluidic Device for Combinatorial Plug Production

Droplet microfluidics is a versatile tool that allows the execution of a large number of reactions in chemically distinct nanoliter compartments. Such systems have been used to encapsulate a variety of biochemical reactions - from incubation of single cells to implementation of PCR reactions, from genomics to chemical synthesis. Coupling the microfluidic channels with regulatory valves allows control over their opening and closing, thereby enabling the rapid production of large-scale combinatorial libraries consisting of a population of droplets with unique compositions. In this paper, protocols for the fabrication and operation of a pressure-driven, PDMS-based bilayer microfluidic device that can be utilized to generate combinatorial libraries of water-in-oil emulsions called plugs are presented. By incorporating software programs and microfluidic hardware, the flow of desired fluids in the device can be controlled and manipulated to generate combinatorial plug libraries and to control the composition and quantity of constituent plug populations. These protocols will expedite the process of generating combinatorial screens, particularly to study drug response in cells from cancer patient biopsies.

저자 스포트라이트: Integrating Computational and Experimental Approaches in Precision Oncology

The fabrication of a polydimethylsiloxane (PDMS)-based bilayer device for the production of combinatorial libraries in water-in-oil emulsions (plugs) is presented here. The necessary hardware and software required to automate plug production are detailed in the protocol, and the production of a quantitative library of fluorescent plugs is also demonstrated.

조합 플러그 생산을 위한 이중층 미세유체 장치

Droplet microfluidics is a versatile tool that allows the execution of a large number of reactions in chemically distinct nanoliter compartments. Such ...