DS 및 CEC는 부분적으로는 보조금 AI053531 (NIAID, NIH)에 의해 지원되었다. SS 및 PSC는 보조금 N00014-14-1-0792 (ONR)에 의해 지원되었습니다.

저자는 공개 할 것이 없습니다.

각각의 PIP 변이체는 저농도 임에도 불구하고 특정 세포 소기관의 세포질 표면에 존재하며, 세포막 고유의 물리적 구성과 기능적 특이성의 형성에 기여합니다 1 . PIP를의 가장 중요한 용도 중 하나는 특정 세포 내 현지화 및 / 또는 활성화 6, 7을 필요로하는 단백질의 다수에 대한 특정 도킹 플랫폼이다. 세포 생리학 및 질병에서의 역할?...

무수한 상호 작용과 생화학 적 과정은 2 차원 유체 막 표면에서 일어난다. 진핵 세포의 멤브레인 - 둘러싸인 세포 기관은 생화학 적 과정과 관련 프로테옴뿐만 아니라 지질 조성에서도 독특합니다. 예외적으로 인지질의 한 종류는 phosphoinositides (PIPs)입니다. 이들이 세포질 리피도미스의 1 %만을 차지한다고 할지라도, 이들은 신호 변환,자가 식욕 (autophagy), 막 인신 매매 (membrane trafficking)에서 중요한 역할을한다. 그 중에서도 1 , 2 , 3 , 4 가 중요하다. 셀룰러 PIP 키나제하여 이노시톨 헤드 그룹의 동적 인산화 일곱 PIP 모노있다 headgroups, 비스 -, 또는 트리스 - (5)의 인산화를 일으킨다. 또한, PIP는 세포막의 세포 내 신원을 정의하고 하나 이상의 포스 포이 노를 함유하는 단백질 / 효소에 대한 특화된 막 도킹 사이트로서 작용한다예를 들어, 도메인을 itide 결합, 플렉스 트린 상 동성 (PH) Phox 동성 (PX)과 epsin N 말단 동성 (ENTH) 6,7. 가장 많이 연구 된 PIP 결합 도메인 중 하나는 특히 높은 나노 몰 낮은 마이크로 몰 범위의 친 화성 8에서 포스파티딜 이노시톨 4,5- 비스 포스페이트 (PI (4,5) P 2)과 상호 작용하는 포스 포 리파제 C (PLC) -δ1의 PH 도메인이고 , 9 , 10 , 11 . 다양한 정성 및 정량 시험관 방법이 개발되어 이러한 상호 작용의 메커니즘, 열역학 및 특이성을 연구합니다. 가장 일반적으로 사용되는 PIP 결합 분석에는 표면 플라스 몬 공명 (SPR), 등온 열량계 (ITC), 핵 자기 공명 (NMR) 분광기, 리포좀 부유 / 침강 분석법 및 지질 블롯 (Fat-blots / PIP-strips)12 , 13 . 이것들이 광범위하게 이용 되더라도 그들은 모두 많은 단점을 가지고 있습니다. 예를 들어, SPR, ITC 및 NMR은 많은 양의 시료, 값 비싼 계측 및 / 또는 숙련 된 인원 12 , 13을 필요로 합니다. 항체 기반 lipid-blots와 같은 일부 분석 형식은 PIP의 수용성 형태를 사용하고 비 생리 학적 방식으로 12 , 14 , 15 , 16로 표시 합니다. 또한, 지질 블롯은 신뢰할 수있게 정량 될 수 없으며 종종 가양 성 / 음성 관찰 12 , 17 , 18을 초래합니다. 이러한 어려움을 극복하고 현재 도구 세트를 개선하기 위해 지원되는 지질 이중층 (lipid bilayer, SLB)을 기반으로 새로운 라벨없는 방법이 am<html> ( 그림 1 ) 19 단백질 - PIP 상호 작용의 연구에 성공적으로 적용된 마이크로 유체 플랫폼. 단백질 -PIP 상호 작용을 검출하기 위해 사용 된 전략은 pH 변조 감지에 기초한다. 이것은 phosphatidylethanolamine lipid head group 20에 직접 conjugated ortho -sulforhodamine B ( o SRB)가있는 pH 민감성 염료를 포함합니다. 오의 SRB-POPE 프로브 (도 2a)는 낮은 pH에서 높은 형광 및 7.5 몰 %의 PI (4,5) P (2) 함유 SLB 수 (도 5b)에서 약 6.7의 pKa 높은 pH에서 켄칭된다. PLC-δ1 PH 도메인은 PI (4,5) P 2 ( 도 5A )에 대한 높은 특이성으로 인해 단백질 -IP 결합 방법의 유효성 확인에 광범위하게 사용되어왔다 ( 도 5A ) 21 , 22 ,&quot;&gt; 23, 24, 25 .Hence, 우리는 PLC-δ1의 PH 도메인은 그것의 PI 결합 테스트하는데 사용될 수 있다는 추론 (4,5)가 PIP 온 칩 분석을 통해 P 2. 산도 도메인 구조 본 연구에서 사용은 순 양전하 PI (8.4)을 가지며, 따라서 OH 유치 -.받는 이온 - PI (4,5) P (2) 함유 SLB 수 결합시 이온 (도 5c)를 상기 PH 도메인은 OH를 가져온다 결과적으로 계면 전위를 변조하여 O SRB-POPE (도 5C) 26. 산도 도메인 농도의 함수로서, 형광 켄칭된다 (도 6A)의 양성자 화 된 상태를 시프트 막 표면. 최종적으로, 정규화 된 데이터는 산도 도메인 PI (4,5) P (2)의 상호 작용 (도 6b,도 6c).의 친 화성을 결정하기 위해 결합 등온선에 맞게 &lt;/ p&gt; 이 연구에서는 미세 유체 플랫폼 내에서 PIP를 함유 한 SLB에 단백질 결합을 수행하기위한 상세한 프로토콜이 제공됩니다. 이 프로토콜은 독자가 microfluidic 장치와 소낭 준비를 SLB 형성과 단백질 바인딩으로 조립하는 것을 필요로합니다. 또한, 데이터 분석을위한 지시는 PLC-δ1의 PH 도메인-PI (4,5) P (2)의 상호 작용이 제공되는 선호도에 대한 정보를 추출한다.

<table border="0" cellpadding="0" cellspacing="0" width="1638">
	<tbody>
		<tr height="20">
			<td height="20" style="height:20px;width:363px;">Coverslip</td>
			<td style="width:156px;"></td>
			<td style="width:123px;"></td>
			<td style="width:997px;"></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">Glass Coverslips: Rectangles</td>
			<td>Fisher Scientific</td>
			<td>12-544B</td>
			<td>22 x 40 x 0.16 - 0.19 mm, No. 1 1/2; Borosilicate Glass</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">7X Cleaning Solution</td>
			<td>MP Biomedicals</td>
			<td>976670</td>
			<td>Detergent</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">PYREX Crystallizing Dish</td>
			<td>Corning</td>
			<td>3140-190</td>
			<td>Borosilicate glass dish with a flat bottom; Diameter x Height (190 x 100 mm); Distributor: VWR (89090-700)</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Sentry Xpress 2.0</td>
			<td>Paragon Industries</td>
			<td>SC-2</td>
			<td>Kiln</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Name</td>
			<td>Company</td>
			<td>Catalog Number</td>
			<td>Comments</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">PDMS</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">Sylgard 184 Silicone Elastomer Kit</td>
			<td>Dow Corning&#160;</td>
			<td>4019862</td>
			<td>Polydimethylsiloxane (PDMS); Distributor: Ellsworth Adhesives</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">PYREX Desiccator</td>
			<td>VWR</td>
			<td>89134-402</td>
			<td>Vacuum Rated</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Biopsy punch</td>
			<td>Harris</td>
			<td>15110-10</td>
			<td style="width:997px;">Harris Uni-Core; 1.0 mm diameter; Miltex Biopsy Punch with Plunger (Cat. No. 15110-10) can be used as an alternative</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Name</td>
			<td>Company</td>
			<td>Catalog Number</td>
			<td>Comments</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">Device</td>
			<td></td>
			<td></td>
			<td style="width:997px;"></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">Plasma Cleaning System</td>
			<td>PlasmaEtch</td>
			<td>PE25-JW</td>
			<td>2-stage Direct Drive Oil Vacuum Pump, O2 service (Krytox Charged)</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">Digital Hot Plate</td>
			<td>Benchmark</td>
			<td>H3760-H</td>
			<td>Purchased through Denville Scientific (Cat. No. 1005640)</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Frosted Micro Slides</td>
			<td>VWR</td>
			<td>48312-003</td>
			<td>Frosted, Selected, and Precleaned; Made of Swiss Glass; Thickness: 1 mm; Dimensions: 75 x 25 mm; GR 144</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Name</td>
			<td>Company</td>
			<td>Catalog Number</td>
			<td>Comments</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">Mold</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">AutoCAD</td>
			<td>Autodesk</td>
			<td>v.2016</td>
			<td>Drafting software for the photomask design</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">Photomask</td>
			<td>CAD/Art Services</td>
			<td>N/A</td>
			<td>Design with black background and clear features was printed at 20k dpi resolution on a transparent mask (5 x 7 in) by CAD/Art Services</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">Silicone Wafers</td>
			<td>University Wafer</td>
			<td>1575</td>
			<td>Prime Grade, Single Side Polished; 100 mm (4 inch) Diameter; 525 um Thickness</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">SU-8 50</td>
			<td>MicroChem Corp.</td>
			<td>N/A</td>
			<td>Negative Tone Photoresist; Penn State Nanofabrication Facility Property</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">SU-8 Developer</td>
			<td>MicroChem Corp.</td>
			<td>N/A</td>
			<td>Penn State Nanofabrication Facility Property</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Name</td>
			<td>Company</td>
			<td>Catalog Number</td>
			<td>Comments</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">SUV</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine</td>
			<td>Avanti Polar Lipids</td>
			<td>850457C</td>
			<td>POPC</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">L-&#945;-phosphatidylinositol-4-phosphate</td>
			<td>Avanti Polar Lipids</td>
			<td>840045X</td>
			<td>PI4P</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">L-&#945;-phosphatidylinositol-4,5-bisphosphate&#160;</td>
			<td>Avanti Polar Lipids</td>
			<td>840046X</td>
			<td>PI(4,5)P2</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">1-palmitoyl-2-oleoyl-sn-glycero-3-phosphoethanolamine</td>
			<td>Avanti Polar Lipids</td>
			<td>850757C</td>
			<td>POPE; Required for the synthesis of oSRB-POPE</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">Lissamine Rhodamine B Sulfonyl Chloride (mixed isomers)</td>
			<td>ThermoFisher Scientific</td>
			<td>L-20</td>
			<td>Required for the synthesis of oSRB-POPE</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">pH Sensitive Fluorescent Lipid Probe (oSRB-POPE)</td>
			<td>In-house</td>
			<td>N/A</td>
			<td>In-house Synthesis (Huang D. et al. 2013)</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">Glass Scintillation Vial</td>
			<td>VWR</td>
			<td>66022-065</td>
			<td>20 mL volume capacity</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">Aquasonic 250D</td>
			<td>VWR</td>
			<td>N/A</td>
			<td>Ultrasonic Water Bath</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">Nuclepore Track-Etched Membranes</td>
			<td>Whatman</td>
			<td>110605</td>
			<td>Polycarbonate Membrane; Diameter: 25 mm; Pore Size: 0.1 um; Distributor: Sigma-Aldrich</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">Chloroform</td>
			<td>VWR</td>
			<td>CX1054-6</td>
			<td>HPLC grade</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">LIPEX Extruder</td>
			<td>Transferra Nanosciences</td>
			<td>T.001</td>
			<td>LIPEX 10 mL Thermobarrel Extruder</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Viscotek 802 DLS</td>
			<td>Malvern Instruments</td>
			<td>N/A</td>
			<td>Dynamic Light Scattering; Penn State X-Ray Crystallography Facility Property</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Name</td>
			<td>Company</td>
			<td>Catalog Number</td>
			<td>Comments</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">Data Analysis</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">GraphPad Prism</td>
			<td>GraphPad Software</td>
			<td>v.6</td>
			<td>Curve-fitting software for data analysis</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Name</td>
			<td>Company</td>
			<td>Catalog Number</td>
			<td>Comments</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">Microscope</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">Axiovert 200M Epifluorescence Microscope</td>
			<td>Carl Zeiss Microscopy</td>
			<td>N/A</td>
			<td>Microscope</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">AxioCam MRm Camera</td>
			<td>Carl Zeiss Microscopy</td>
			<td>N/A</td>
			<td>Camera</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">X-Cite 120</td>
			<td>Excelitas Technologies</td>
			<td>N/A</td>
			<td>Light Source</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">Alexa 568 Filter Set</td>
			<td>Carl Zeiss Microscopy</td>
			<td>N/A</td>
			<td>Ex/Em 576/603 nm</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">AxioVision LE64 v.4.9.1.0 Software</td>
			<td>Carl Zeiss Microscopy</td>
			<td>N/A</td>
			<td>Image Processing Software</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Name</td>
			<td>Company</td>
			<td>Catalog Number</td>
			<td>Comments</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">Other</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">Tips</td>
			<td>VWR</td>
			<td>10034-132</td>
			<td>200 uL pipette tips; Thin and smooth tip for applying the protein solution into the microfluidic channel</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">Tips</td>
			<td>VWR</td>
			<td>53509-070</td>
			<td>10 uL pipette tips; Thin and smooth tip for applying the vesicle solution into the microfluidic channel</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">Orion Star A321 pH meter</td>
			<td>Thermo Scientific</td>
			<td>STARA3210</td>
			<td>pH meter</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">Orion micro pH probe</td>
			<td>Thermo Scientific</td>
			<td>8220BNWP</td>
			<td>micro pH probe</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">N-(2-Hydroxyethyl)-Piperazine-N&#39;-(2-Ethanesulfonic Acid)</td>
			<td>VWR</td>
			<td>VWRB30487</td>
			<td>HEPES, Free Acid</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">Sodium Chloride</td>
			<td>VWR</td>
			<td>BDH8014-2.5KGR</td>
			<td>NaCl</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">Tubing</td>
			<td>Allied Wire &#38; Cable</td>
			<td>TFT-200-24 N</td>
			<td>Internal Diameter: 0.020-0.026 inches (0.051-0.066 cm); Wall Thickness: 0.010 inches (0.025 cm); Flexible Polytetrafluoroethylene Thin-Wall Tubing; Natural Color</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">Nitrogen Gas - Industrial</td>
			<td>Praxair</td>
			<td>N/A</td>
			<td>Local Provider</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;">Oxygen Gas - Industrial</td>
			<td>Praxair</td>
			<td>N/A</td>
			<td>Local Provider</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Liquid Nitrogen</td>
			<td>Praxair</td>
			<td>N/A</td>
			<td>Local Provider</td>
		</tr>
	</tbody>
</table>

pip-on-a-chip: a label-free study of protein-phosphoinositide interactions

수많은 세포 단백질이 막 표면과 상호 작용하여 필수 세포 과정에 영향을줍니다. 이러한 상호 작용은 phosphoinositides (PIPs)의 경우처럼 특정 세포 내 지방화 및 / 또는 활성화를 보장하기 위해 멤브레인 내의 특정 지질 성분을 향하게 할 수 있습니다. PIP와 세포질 PIP 결합 도메인은 세포 생리학에서 그들의 역할을 더 잘 이해하기 위해 광범위하게 연구되어 왔습니다. 우리는 protein-PIP 상호 작용을 연구하기위한 도구로서지지 된 지질 이중층 (SLBs)에 pH 조절 분석을 적용했습니다. 이 연구에서, pH 민감성 ortho- sulforhodamine B conjugated phosphatidylethanolamine은 protein-PIP 상호 작용을 검출하는 데 사용됩니다. 단백질이 PIP 함유 멤브레인 표면에 결합하면, 계면 전위가 조절되어 ( 즉 , 국소 pH 변화), 프로브의 양성자 화 상태가 변하게됩니다. pH 조절 분석의 성공적인 사용에 대한 사례 연구는 phospholipase C delta1 Pleckstr상동 (PLC-δ1의 PH) 도메인 및 예로서, 포스파티딜 이노시톨 -4,5- 비스 포스페이트 (PI (4,5) P 2)의 상호 작용이다. 이 상호 작용에 대한 겉보기 해리 상수 ( K d, app )는 0.39 ± 0.05 μM이었고 , 다른 것들에 의해 얻어진 K d 값과 유사했다. 이전에 관찰 된 바와 같이, PLC-δ1 PH 도메인은 PI (4,5) P 2 특이 적이며, 포스파티딜 이노시톨 4- 인산염에 대한 약한 결합을 나타내며, 순수한 포스파티딜콜린 SLB에 대한 결합은 보이지 않는다. PIP-on-a-chip 분석은 낮은 샘플 부피 및 리간드 / 수용체 표지 요구 사항이 없지만 작은 및 낮은 친화도 막 상호 작용을 테스트 할 수있는 능력을 포함하되 이에 국한되지 않는 전통적인 PIP 결합 분석보다 유리합니다. 큰 분자 및 개선 된 신호 대 잡음비. 따라서, PIP-on-a-chip 접근법의 사용은 광범위한 막 상호 작용 메커니즘의 해명을 용이하게 할 것이다. 또한이 방법은 잠재적으로세포막과 상호 작용할 수있는 단백질의 능력을 조절하는 치료제를 확인하는데있어

우리는 PIP-on-a-chip 마이크로 디바이스 ( 그림 1 ) 내에서 PLC-δ1 PH 도메인 -PI (4,5) P 2 상호 작용을 연구하기 위해 pH 변조 분석을 사용했습니다. 상세한 프로토콜을 통해 마이크로 유체 소자 구성 요소를 준비 및 조립하고 소형 단층 소포 (SUV)를 만들고 ( 그림 2 ) 장치 내 SLB를 형성하고 ( 그림 3 ) PIP를 ?...

Watch this Scientific Journal Video about PIP-on-a-chip: A Label-free Study of Protein-phosphoinositide Interactions at JoVE.com

PIP-on-a-chip: A Label-free Study of Protein-phosphoinositide Interactions

여기서 우리는 pH 조절에 기반한 라벨없는 방법을 사용하여 단백질 - 포스 포이 노시 티드 상호 작용을 연구하기위한 마이크로 유체 플랫폼의 맥락에서지지 된 지질 이중층을 제시합니다.

PIP-on-a-chip : 단백질 - 포스 포이 노시 티드 상호 작용에 대한 라벨없는 연구

Numerous cellular proteins interact with membrane surfaces to affect essential cellular processes. These interactions can be directed towards a specific ...

pip-on-chip-label-free-study-protein-phosphoinositide

Research

JoVE Journal

Bioengineering

9.4K 조회수.  The Pennsylvania State University.  여기서 우리는 pH 조절에 기반한 라벨없는 방법을 사용하여 단백질 - 포스 포이 노시 티드 상호 작용을 연구하기위한 마이크로 유체 플랫폼의 맥락에서지지 된 지질 이중층을 제시합니다. 

비디오: PIP-on-a-chip: A Label-free Study of Protein-phosphoinositide Interactions

Micropatterned Surfaces to Study Hyaluronic Acid Interactions with Cancer Cells

Cancer invasion and progression involves a motile cell phenotype, which is under complex regulation by growth factors/cytokines and extracellular matrix (ECM) components within the tumor microenvironment. Hyaluronic acid (HA) is one stromal ECM component that is known to facilitate tumor progression by enhancing invasion, growth, and angiogenesis1. Interaction of HA with its cell surface receptor CD44 induces signaling events that promote tumor cell growth, survival, and migration, thereby increasing metastatic spread2-3. HA is an anionic, nonsulfated glycosaminoglycan composed of repeating units of D-glucuronic acid and D-N-acetylglucosamine. Due to the presence of carboxyl and hydroxyl groups on repeating disaccharide units, native HA is largely hydrophilic and amenable to chemical modifications that introduce sulfate groups for photoreative immobilization 4-5. Previous studies involving the immobilizations of HA onto surfaces utilize the bioresistant behavior of HA and its sulfated derivative to control cell adhesion onto surfaces6-7. In these studies cell adhesion preferentially occurs on non-HA patterned regions.
To analyze cellular interactions with exogenous HA, we have developed patterned functionalized surfaces that enable a controllable study and high-resolution visualization of cancer cell interactions with HA. We utilized microcontact printing (uCP) to define discrete patterned regions of HA on glass surfaces. A "tethering" approach that applies carbodiimide linking chemistry to immobilize HA was used 8. Glass surfaces were microcontact printed with an aminosilane and reacted with a HA solution of optimized ratios of EDC and NHS to enable HA immobilization in patterned arrays. Incorporating carbodiimide chemistry with mCP enabled the immobilization of HA to defined regions, creating surfaces suitable for in vitro applications. Both colon cancer cells and breast cancer cells implicitly interacted with the HA micropatterned surfaces. Cancer cell adhesion occurred within 24 hours with proliferation by 48 hours. Using HA micropatterned surfaces, we demonstrated that cancer cell adhesion occurs through the HA receptor CD44. Furthermore, HA patterned surfaces were compatible with scanning electron microscopy (SEM) and allowed high resolution imaging of cancer cell adhesive protrusions and spreading on HA patterns to analyze cancer cell motility on exogenous HA.

A novel approach that allows the high-resolution analysis of cancer cell interactions with exogenous hyaluronic acid (HA) is described. Patterned surfaces are fabricated by combining carbodiimide chemistry and microcontact printing.

Micropatterned 표면은 암세포와 Hyaluronic 산성 상호 작용을 연구하기 위해

Cancer invasion and progression involves a motile cell phenotype, which is under complex regulation by growth factors/cytokines and extracellular matrix ...

연구

생체공학

Non-contact, Label-free Monitoring of Cells and Extracellular Matrix using Raman Spectroscopy

Non-destructive, non-contact and label-free technologies to monitor cell and tissue cultures are needed in the field of biomedical research.1-5 However, currently available routine methods require processing steps and alter sample integrity. Raman spectroscopy is a fast method that enables the measurement of biological samples without the need for further processing steps. This laser-based technology detects the inelastic scattering of monochromatic light.6 As every chemical vibration is assigned to a specific Raman band (wavenumber in cm-1), each biological sample features a typical spectral pattern due to their inherent biochemical composition.7-9 Within Raman spectra, the peak intensities correlate with the amount of the present molecular bonds.1 Similarities and differences of the spectral data sets can be detected by employing a multivariate analysis (e.g. principal component analysis (PCA)).10
Here, we perform Raman spectroscopy of living cells and native tissues. Cells are either seeded on glass bottom dishes or kept in suspension under normal cell culture conditions (37 &deg;C, 5% CO2) before measurement. Native tissues are dissected and stored in phosphate buffered saline (PBS) at 4 &deg;C prior measurements. Depending on our experimental set up, we then either focused on the cell nucleus or extracellular matrix (ECM) proteins such as elastin and collagen. For all studies, a minimum of 30 cells or 30 random points of interest within the ECM are measured. Data processing steps included background subtraction and normalization.

Raman spectroscopy is a suitable technique for the non-contact, label-free analysis of living cells, tissue-engineered constructs and native tissues. Source-specific spectral fingerprints can be generated and analyzed using multivariate analysis.

라만 분광학을 사용하여 세포와 세포외 기질의 비 접촉, 레이블이없는 모니터링

Non-destructive, non-contact and label-free technologies to monitor cell and tissue cultures are needed in the field of biomedical research.1-5 However, ...

Correlative Microscopy for 3D Structural Analysis of Dynamic Interactions

Cryo-electron tomography (cryoET) allows 3D visualization of cellular structures at molecular resolution in a close-to-physiological state1. However, direct visualization of individual viral complexes in their host cellular environment with cryoET is challenging2, due to the infrequent and dynamic nature of viral entry, particularly in the case of HIV-1. While time-lapse live-cell imaging has yielded a great deal of information about many aspects of the life cycle of HIV-13-7, the resolution afforded by live-cell microscopy is limited (~ 200 nm). Our work was aimed at developing a correlation method that permits direct visualization of early events of HIV-1 infection by combining live-cell fluorescent light microscopy, cryo-fluorescent microscopy, and cryoET. In this manner, live-cell and cryo-fluorescent signals can be used to accurately guide the sampling in cryoET. Furthermore, structural information obtained from cryoET can be complemented with the dynamic functional data gained through live-cell imaging of fluorescent labeled target.
In this video article, we provide detailed methods and protocols for structural investigation of HIV-1 and host-cell interactions using 3D correlative high-speed live-cell imaging and high-resolution cryoET structural analysis. HeLa cells infected with HIV-1 particles were characterized first by confocal live-cell microscopy, and the region containing the same viral particle was then analyzed by cryo-electron tomography for 3D structural details. The correlation between two sets of imaging data, optical imaging and electron imaging, was achieved using a home-built cryo-fluorescence light microscopy stage. The approach detailed here will be valuable, not only for study of virus-host cell interactions, but also for broader applications in cell biology, such as cell signaling, membrane receptor trafficking, and many other dynamic cellular processes.

We describe a correlative microscopy method that combines high-speed 3D live-cell fluorescent light microscopy and high-resolution cryo-electron tomography. We demonstrate the capability of the correlative method by imaging dynamic, small HIV-1 particles interacting with host HeLa cells.

동적 상호 작용의 3 차원 구조 분석을위한 상호 현미경

Cryo-electron tomography (cryoET) allows 3D visualization of cellular structures at molecular resolution in a close-to-physiological state1. However, ...

Determination of the Transport Rate of Xenobiotics and Nanomaterials Across the Placenta using the ex vivo Human Placental Perfusion Model

Decades ago the human placenta was thought to be an impenetrable barrier between mother and unborn child. However, the discovery of thalidomide-induced birth defects and many later studies afterwards proved the opposite. Today several harmful xenobiotics like nicotine, heroin, methadone or drugs as well as environmental pollutants were described to overcome this barrier. With the growing use of nanotechnology, the placenta is likely to come into contact with novel nanoparticles either accidentally through exposure or intentionally in the case of potential nanomedical applications. Data from animal experiments cannot be extrapolated to humans because the placenta is the most species-specific mammalian organ 1. Therefore, the ex vivo dual recirculating human placental perfusion, developed by Panigel et al. in 1967 2 and continuously modified by Schneider et al. in 1972 3, can serve as an excellent model to study the transfer of xenobiotics or particles.
Here, we focus on the ex vivo dual recirculating human placental perfusion protocol and its further development to acquire reproducible results.
The placentae were obtained after informed consent of the mothers from uncomplicated term pregnancies undergoing caesarean delivery. The fetal and maternal vessels of an intact cotyledon were cannulated and perfused at least for five hours. As a model particle fluorescently labelled polystyrene particles with sizes of 80 and 500 nm in diameter were added to the maternal circuit. The 80 nm particles were able to cross the placental barrier and provide a perfect example for a substance which is transferred across the placenta to the fetus while the 500 nm particles were retained in the placental tissue or maternal circuit. The ex vivo human placental perfusion model is one of few models providing reliable information about the transport behavior of xenobiotics at an important tissue barrier which delivers predictive and clinical relevant data.

Determination of the Transport Rate of Xenobiotics and Nanomaterials Across the Placenta using the ex vivo Human Placental Perfusion Model

The ex vivo dual recirculating human placental perfusion model can be used to investigate the transfer of xenobiotics and nanoparticles across the human placenta. In this video protocol we describe the equipment and techniques required for a successful execution of a placenta perfusion.

태반의 맞은 편에 생체이 물과 나노 물질의 전송 속도의 결정을 사용하여<em&gt; 생체</em&gt; 인간 태반 관류 모델

Decades ago the human placenta was thought to be an impenetrable barrier between mother and unborn child. However, the discovery of thalidomide-induced ...

Use of Label-free Optical Biosensors to Detect Modulation of Potassium Channels by G-protein Coupled Receptors

Ion channels control the electrical properties of neurons and other excitable cell types by selectively allowing ions to flow through the plasma membrane1. To regulate neuronal excitability, the biophysical properties of ion channels are modified by signaling proteins and molecules, which often bind to the channels themselves to form a heteromeric channel complex2,3. Traditional assays examining the interaction between channels and regulatory proteins require exogenous labels that can potentially alter the protein&#39;s behavior and decrease the physiological relevance of the target, while providing little information on the time course of interactions in living cells. Optical biosensors, such as the X-BODY Biosciences BIND Scanner system, use a novel label-free technology, resonance wavelength grating (RWG) optical biosensors, to detect changes in resonant reflected light near the biosensor. This assay allows the detection of the relative change in mass within the bottom portion of living cells adherent to the biosensor surface resulting from ligand induced changes in cell adhesion and spreading, toxicity, proliferation, and changes in protein-protein interactions near the plasma membrane. RWG optical biosensors have been used to detect changes in mass near the plasma membrane of cells following activation of G protein-coupled receptors (GPCRs), receptor tyrosine kinases, and other cell surface receptors. Ligand-induced changes in ion channel-protein interactions can also be studied using this assay. In this paper, we will describe the experimental procedure used to detect the modulation of Slack-B sodium-activated potassium (KNa) channels by GPCRs.

Optical biosensor techniques can detect changes in mass near the plasma membrane in living cells and allow one to follow cellular responses in both individual cells and populations of cells. This protocol will describe detection of the modulation of potassium channels by G-protein coupled receptors in intact cells using this approach.

G-단백질 결합 수용체에 의해 칼륨 채널의 변조를 감지하기 위해 라벨이없는 광 바이오 센서의 사용

Ion channels control the electrical properties of neurons and other excitable cell types by selectively allowing ions to flow through the plasma ...

A Microfluidic-based Electrochemical Biochip for Label-free DNA Hybridization Analysis

Miniaturization of analytical benchtop procedures into the micro-scale provides significant advantages in regards to reaction time, cost, and integration of pre-processing steps. Utilizing these devices towards the analysis of DNA hybridization events is important because it offers a technology for real time assessment of biomarkers at the point-of-care for various diseases. However, when the device footprint decreases the dominance of various physical phenomena increases. These phenomena influence the fabrication precision and operation reliability of the device. Therefore, there is a great need to accurately fabricate and operate these devices in a reproducible manner in order to improve the overall performance. Here, we describe the protocols and the methods used for the fabrication and the operation of a microfluidic-based electrochemical biochip for accurate analysis of DNA hybridization events. The biochip is composed of two parts: a microfluidic chip with three parallel micro-channels made of polydimethylsiloxane (PDMS), and a 3 x 3 arrayed electrochemical micro-chip. The DNA hybridization events are detected using electrochemical impedance spectroscopy (EIS) analysis. The EIS analysis enables monitoring variations of the properties of the electrochemical system that are dominant at these length scales. With the ability to monitor changes of both charge transfer and diffusional resistance with the biosensor, we demonstrate the selectivity to complementary ssDNA targets, a calculated detection limit of 3.8 nM, and a 13% cross-reactivity with other non-complementary ssDNA following 20 min&#160;of incubation. This methodology can improve the performance of miniaturized devices by elucidating on the behavior of diffusion at the micro-scale regime and by enabling the study of DNA hybridization events.

We present a microfluidic-based electrochemical biochip for DNA hybridization detection. Following ssDNA probe functionalization, the specificity, sensitivity, and detection limit are studied with complementary and non-complementary ssDNA targets. Results illustrate the influence of the DNA hybridization events on the electrochemical system, with a detection limit of 3.8 nM.

라벨없는 DNA의 혼성화 분석 용 미세 유체 기반 전기 바이오칩

Miniaturization of analytical benchtop procedures into the micro-scale provides significant advantages in regards to reaction time, cost, and integration ...

A Label-free Technique for the Spatio-temporal Imaging of Single Cell Secretions

Inter-cellular communication is an integral part of a complex system that helps in maintaining basic cellular activities. As a result, the malfunctioning of such signaling can lead to many disorders. To understand cell-to-cell signaling, it is essential to study the spatial and temporal nature of the secreted molecules from the cell without disturbing the local environment. Various assays have been developed to study protein secretion, however, these methods are typically based on fluorescent probes which disrupt the relevant signaling pathways. To overcome this limitation, a label-free technique is required.
In this paper, we describe the fabrication and application of a label-free localized surface plasmon resonance imaging (LSPRi) technology capable of detecting protein secretions from a single cell. The plasmonic nanostructures are lithographically patterned onto a standard glass coverslip and can be excited using visible light on commercially available light microscopes. Only a small fraction of the coverslip is covered by the nanostructures and hence this technique is well suited for combining common techniques such as fluorescence and bright-field imaging.
A multidisciplinary approach is used in this protocol which incorporates sensor nanofabrication and subsequent biofunctionalization, binding kinetics characterization of ligand and analyte, the integration of the chip and live cells, and the analysis of the measured signal. As a whole, this technology enables a general label-free approach towards mapping cellular secretions and correlating them with the responses of nearby cells.

Inter-cellular communication is critical for controlling various physiological activities within and outside the cell. This paper describes a protocol for measuring the spatio-temporal nature of single cell secretions. To achieve this, a multidisciplinary approach is used which integrates label-free nanoplasmonic sensing with live cell imaging.

단일 세포 분비물의 공간 - 시간 영상의 레이블이없는 기술

Inter-cellular communication is an integral part of a complex system that helps in maintaining basic cellular activities. As a result, the malfunctioning ...

Label-free Single Molecule Detection Using Microtoroid Optical Resonators

Detecting small concentrations of molecules down to the single molecule limit has impact on areas such as early detection of disease, and fundamental studies on the behavior of molecules. Single molecule detection techniques commonly utilize labels such as fluorescent tags or quantum dots, however, labels are not always available, increase cost and complexity, and can perturb the events being studied. Optical resonators have emerged as a promising means to detect single molecules without the use of labels. Currently the smallest particle detected by a non-plasmonically-enhanced bare optical resonator system in solution is a 25 nm polystyrene sphere1. We have developed a technique known as Frequency Locking Optical Whispering Evanescent Resonator (FLOWER) that can surpass this limit and achieve label-free single molecule detection in aqueous solution2. As signal strength scales with particle volume, our work represents a &#62; 100x improvement in the signal to noise ratio (SNR) over the current state of the art. Here the procedures behind FLOWER are presented in an effort to increase its usage in the field.

We have developed a label-free biosensing system based on optical resonator technology known as Frequency Locking Optical Whispering Evanescent Resonator (FLOWER) that is capable of detecting single molecules in solution. Here the procedures behind this work are described and presented.

Microtoroid 광 공진기를 사용하여 라벨이없는 단일 분자 검출

Detecting small concentrations of molecules down to the single molecule limit has impact on areas such as early detection of disease, and fundamental ...

Preparation of 3D Collagen Gels and Microchannels for the Study of 3D Interactions In Vivo

Historically, most cellular processes have been studied in only 2 dimensions. While these studies have been informative about general cell signaling mechanisms, they neglect important cellular cues received from the structural and mechanical properties of the local microenvironment and extracellular matrix (ECM). To understand how cells interact within a physiological ECM, it is important to study them in the context of 3 dimensional assays. Cell migration, cell differentiation, and cell proliferation are only a few processes that have been shown to be impacted by local changes in the mechanical properties of a 3-dimensional ECM. Collagen I, a core fibrillar component of the ECM, is more than a simple structural element of a tissue. Under normal conditions, mechanical cues from the collagen network direct morphogenesis and maintain cellular structures. In diseased microenvironments, such as the tumor microenvironment, the collagen network is often dramatically remodeled, demonstrating altered composition, enhanced deposition and altered fiber organization. In breast cancer, the degree of fiber alignment is important, as an increase in aligned fibers perpendicular to the tumor boundary has been correlated to poorer patient prognosis1. Aligned collagen matrices result in increased dissemination of tumor cells via persistent migration2,3. The following is a simple protocol for embedding cells within a 3-dimensional, fibrillar collagen hydrogel. This protocol is readily adaptable to many platforms, and can reproducibly generate both aligned and random collagen matrices for investigation of cell migration, cell division, and other cellular processes in a tunable, 3-dimensional, physiological microenvironment.

Preparation of 3D Collagen Gels and Microchannels for the Study of 3D Interactions In Vivo

Collagen is a core component of the ECM, and provides essential cues for several cellular processes ranging from migration to differentiation and proliferation. Provided here is a protocol for embedding cells within 3D collagen hydrogels, and a more advanced technique for generating randomized or aligned collagen matrices using PDMS microchannels.

3D 상호 작용의 연구에 대한 3D 콜라겐 젤과 마이크로 채널 준비<em&gt; 생체</em

Historically, most cellular processes have been studied in only 2 dimensions.  While these studies have been informative about general cell signaling ...

Assessing Collagen and Elastin Pressure-dependent Microarchitectures in Live, Human Resistance Arteries by Label-free Fluorescence Microscopy

The pathogenic contribution of resistance artery remodeling is documented in essential hypertension, diabetes and the metabolic syndrome. Investigations and development of microstructurally motivated mathematical models for understanding the mechanical properties of human resistance arteries in health and disease have the potential to aid understanding how disease and medical treatments affect the human microcirculation. To develop these mathematical models, it is essential to decipher the relationship between the mechanical and microarchitectural properties of the microvascular wall. In this work, we describe an ex vivo method for passive mechanical testing and simultaneous label-free three-dimensional imaging of the microarchitecture of elastin and collagen in the arterial wall of isolated human resistance arteries. The imaging protocol can be applied to resistance arteries of any species of interest. Image analyses are described for quantifying i) pressure-induced changes in internal elastic lamina branching angles and adventitial collagen straightness using Fiji and ii) collagen and elastin volume densities determined using Ilastik software. Preferably all mechanical and imaging measurements are performed on live, perfused arteries, however, an alternative approach using standard video-microscopy pressure myography in combination with post-fixation imaging of re-pressurized vessels is discussed. This alternative method provides users with different options for analysis approaches. The inclusion of the mechanical and imaging data in mathematical models of the arterial wall mechanics is discussed, and future development and additions to the protocol are proposed.

We describe simultaneous mechanical testing and 3D-imaging of the arterial wall of isolated, live human resistance arteries, and Fiji and Ilastik image analyses for the quantification of elastin and collagen spatial organization and volume densities. We discuss the use of these data in mathematical models of arterial wall mechanics.

레이블 없는 형광 현미경 검사 법에 의해, 인간의 저항 동맥에 콜라겐과 엘라 스 틴 압력 종속 마이크로아키텍처가 평가

The pathogenic contribution of resistance artery remodeling is documented in essential hypertension, diabetes and the metabolic syndrome. Investigations ...