이 작품은 BU / CIMIT 응용 의료 공학 Predoctoral 휄로 십, 공학 참여 연구 개시 기금 (BRIGE)를 확대 국립 과학 재단 (National Science Foundation), 그리고 국립 보건원 (R21EB0094930)에 의해 지원되었다.

1. 단계 - 교대 Nanoemulsion의 준비 (PSNE) <ol><li> 11 MG DPPC와 클로로포름의 1.68 MG DSPE-PEG2000를 해산 </li><li> 유리 둥근 바닥 플라스크에 드라이 지질 필름을 형성하기 위해 유기 용매를 증발 </li><li> 밤 지질 필름을 Dessicate </li><li> 인산 버퍼 생리 (PBS)의 5.5 ML과 지질 필름을 Rehydrate </li><li> 45 ° C의 물을 욕조에 열 솔루션은 지질이 영화는 정기적으로 vortexing, 해체 할 때까지 </li><li> 7 ML의 유리 병에 지질 솔루션을 전송 </li><li> 20 % 진폭에서 2 분에 대한 지질 솔루션을 Sonicate </li><li> 2.5 ML의 두 병에 솔루션을 나눈다 각 (나머지 0.5 ML를 삭제) </li><li> 각 유리 병에 2.5 ML PBS를 추가합니다 </li><li> 0 ° C 얼음물에 각 병을 놓고 </li><li> 각 유리 병의 50 μl DDFP을 추가 </li><li> 25 % 진폭, 펄스 모드 (50 초에서 10 초), 시간에 60 초 총 : 다음 설정을 사용하여 얼음물에서 각 병을 Sonicate </li><li> TR20 ML의 섬광 병에 ansfer PSNE 솔루션 </li><li> 10 ML 최종 볼륨의 결과로, 각 유리 병에 5 ML PBS를 추가합니다 </li><li> 제조업체에서 제공 압출기 다음과 같은 지시를 조립 <ol><li> 탈 이온수 각 부분을 씻어 </li><li> 필터 지원 기지의 중심에 스테인레스 스틸 지원 디스크를 놓으십시오 </li><li> 스테인레스 스틸 지원 디스크 상단에있는 스테인리스 스틸 메쉬를 배치 </li><li> 핀셋 사용하여 스테인레스 스틸 메쉬에 압출기 배출 디스크 막 (반짝이는 사이드까지)를 배치 </li><li> 핀셋 사용하여 배수 디스크 막에 압출기 필터 (반짝이는 사이드까지)를 배치 </li><li> 조심스럽게 필터의 작은 O-링을 배치하고 지원 기지 위의 thermobarrel와 압출기의 상단에 배치 </li><li> 부분적으로 첫번째 각 날개 너트를 조여 다음, 완전히 번갈아 방식으로 손으로 날개 너트를 조여 </li><li> 에 압출기를 연결질소 가스 라인 </li><li> 상단 샘플 포트에 압출기, 피펫 10 ML 탈 이온수를 프라임하려면 시작을 한도 및 배기 밸브를 조여 </li><li> 천천히 멤브레인을 통해 샘플을 강제로 압력을 높이기 위해 질소 가스 라인을 열고 출구 튜브에서 샘플을 수집 </li><li> 사용 후, 반대 순서로 분해 탈 이온수와 압출기 부품을 헹구고, 멤브레인 필터와 멤브레인 배수 디스크를 삭제 </li></ol></li><li> 200 nm의 필터를 통해 10 배를 압출의 100 나노 미터 방울 만, 사전 조건 PSNE </li><li> 필터 100 나노 미터 또는 200 nm의를 통해 돌출 PSNE은 16 배 좁은 크기 분포를 얻을 수 </li></ol> 2. PSNE를 포함 Polyacrylamide의 히드로 겔의 작성 <ol><li> 5 ML 탈 이온수에 1.2 g BSA 가루를 diluting하여 24% BSA 솔루션을 준비 </li><li> 한 ML deionized wate에 희석 0.1 g APS 분말로 10 %의 APS 솔루션을 준비연구 </li><li> 다음과 같은 순서로, 2.1 ML의 아크릴 아미드 솔루션, 1.2 ML 트리스 버퍼, 0.1 ML 10 % APS, 4.5 ML 24% BSA 솔루션, 플라스틱 챔버에 3.6 ML 탈 이온수를 섞어 </li><li> 40 열 ° 1 시간에 진공 C 및 장소 </li><li> PSNE 480 μl를 추가하고 철저하게 부드럽게 플라스틱 챔버를 회전하여 섞는다. </li><li> 12 μl TEMED를 추가하고 2 시간에 12 ° C 물 목욕에있는 챔버를 배치 </li></ol> 3. 대표 결과 조직 - 모방의 히드로 겔 유령과 초음파 실험에 대한 설정의 개략도는 그림 1에 표시됩니다. 이 프로토콜은 적어도 일주일 솔루션 안정 좁은 크기 분포와 지질 코팅 perfluorocarbon의 방울에 결과를 표시합니다. 동적 광 분산 (90Plus 입자 크기 분석기, 브룩 헤이븐 계기, Holtsville, NY)로 측정 크기 분포는 PSNE는 압출 100와 200를 사용하기 위해 그림 2에 표시됩니다나노 필터. 동적 광 산란을 사용하여 측정 시간의 경과에 PSNE 유효 직경은, PSNE 적어도 일주일 안정적임을 입증 표 1에 표시됩니다. polyacrylamide의 히드로 겔의 기화 전후 PSNE의 B-모드 이미지는 그림 3에 표시됩니다. 또한, 병변은 알부민과 PSNE는 그림 4에 표시됩니다를 포함하는 polyacrylamide의 히드로 겔에 HIFU로 인한 난방의 15 초에 의해 형성. 병변의 비대칭 모양 초음파 경로에 거품 구름의 존재로 인해 발생 prefocal 난방의 결과입니다. 이 전송 음향 전력을 줄임으로써 최소화 할 수 prefocal 난방 시설, 거품의 분산으로 인한 병변 형성에 유의하는 것이 중요합니다. <img src="/files/ftp_upload/4308/4308fig1.jpg" alt="그림 1"/> 그림 1. 조직 - 밈과 초음파 실험에 대한 실험 설정의 개략도hydrogels을 icking. <img src="/files/ftp_upload/4308/4308fig2.jpg" alt="그림 2"/> 그림 2. 크기 100 나노 미터 또는 200 nm의 필터를 통해 압출 PSNE의 배포는 동적 광 분산을 사용하여 측정. 종좌표 축의 단위는 샘플의 총 분산 된 광 강도에 비해 특정 크기의 입자의 분산 된 빛의 강도에 따라 결정됩니다. <img src="/files/ftp_upload/4308/4308fig3.jpg" alt="그림 3"/> 그림 3. B-모드 이미지 polyacrylamide의 히드로 겔의 PSNE 기화 (A) 이전 및 (b) 후. 화살표가 거품 구름이 PSNE 기화에 의해 형성 된 초점 영역을 나타냅니다. <img src="/files/ftp_upload/4308/4308fig4.jpg" alt="그림 4"/> polyacr의 그림 4. 이미지알부민과 PSNE 포함 ylamide의 히드로 겔는 (a) HIFU로 기화와 sonication 전에하고, (b) 후 초음파 유도 가열의 결과로 병변 형성을 보여줍니다. 초음파 중심 주파수 3.3 MHz의했다. 초음파 신호가 초기 30주기로 구성, 6.4 W 펄스가 PSNE을 날려 버리기 위해, 즉시 W.은 0.77에서 지속적인 초음파의 15 초 다음 <table border="1"><tbody><tr><td rowspan="2"> 압출 후 일 </td><td colspan="2"> 200 nm의 필터 압출 </td><td colspan="2"> 100 nm의 필터 압출 </td></tr><tr><td> 디아 의미합니다. (NM) </td><td> 표준. 개발자. (NM) </td><td> 디아 의미합니다. (NM) </td><td> 표준. 개발자. (NM) </td></tr><tr><td> 1 </td><td> 182.9 </td><td> 4.9 </td><td> 118.0 </td><td> 0.9 </td></tr><tr><td> 7 </td> &lt;TD&gt; 177.7 </td><td> 2.5 </td><td> 124.8 </td><td> 3.1 </td></tr></tbody></table> 표 1. 100 nm의 200 nm의 필터를 사용 압출 차례로 7 일의 직경과 PSNE의 표준 편차를 의미합니다.

<ol>
	<li>Hynynen, K., Darkazanli, A., Unger, E., Schenck, J. F. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=MRI-guided+noninvasive+ultrasound+surgery.">MRI-guided noninvasive ultrasound surgery.</a> Med. Phys. 20, 107-115 (1993).</li><li>Baban, D. F., Seymour, L. W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Control+of+tumour+vascular+permeability.">Control of tumour vascular permeability.</a> Adv. Drug Deliv. Rev. 34, 109-119 (1998).</li><li>Maeda, H., Wu, J., Sawa, T., Matsumura, Y., Hori, K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Tumor+vascular+permeability+and+the+EPR+effect+in+macromolecular+therapeutics:+a+review.">Tumor vascular permeability and the EPR effect in macromolecular therapeutics: a review.</a> J. Control. Release. 65, 271-284 (2000).</li><li>Schadlich, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Tumor+accumulation+of+NIR+fluorescent+PEG-PLA+nanoparticles:+impact+of+particle+size+and+human+xenograft+tumor+model.">Tumor accumulation of NIR fluorescent PEG-PLA nanoparticles: impact of particle size and human xenograft tumor model.</a> ACS Nano. 5, 8710-8720 (2011).</li><li>Williams, R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Convertible+perfluorocarbon+droplets+for+cancer+detection+and+therapy.">Convertible perfluorocarbon droplets for cancer detection and therapy.</a> 2010 IEEE Ultrasonics Symposium. , (2010).</li><li>Martz, T. D., Sheeran, P. S., Bardin, D., Lee, A. P., Dayton, P. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Precision+manufacture+of+phase-change+perfluorocarbon+droplets+using+microfluidics.">Precision manufacture of phase-change perfluorocarbon droplets using microfluidics.</a> Ultrasound Med. Biol. 37, 1952-1957 (2011).</li><li>Giesecke, T., Hynynen, K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Ultrasound-mediated+cavitation+thresholds+of+liquid+perfluorocarbon+droplets+in+vitro.">Ultrasound-mediated cavitation thresholds of liquid perfluorocarbon droplets in vitro.</a> Ultrasound Med. Biol. 29, 1359-1365 (2003).</li><li>Sheeran, P. S., Luois, S., Dayton, P. A., Matsunaga, T. O. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Formulation+and+Acoustic+Studies+of+a+New+Phase-Shift+Agent+for+Diagnostic+and+Therapeutic+Ultrasound.">Formulation and Acoustic Studies of a New Phase-Shift Agent for Diagnostic and Therapeutic Ultrasound.</a> Langmuir. 27, 10412-10420 (2011).</li><li>Sheeran, P. S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Decafluorobutane+as+a+phase-change+contrast+agent+for+low-energy+extravascular+ultrasonic+imaging.">Decafluorobutane as a phase-change contrast agent for low-energy extravascular ultrasonic imaging.</a> Ultrasound Med. Biol. 37, 1518-1530 (2011).</li><li>Zhang, P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> The Application of Phase-Shift Nanoemulsion in High Intensity Focused Ultrasound: An In Vitro Study [Doctoral Dissertation]. , (2011).</li><li>Allen, T. M., Hansen, C., Martin, F., Redemann, C., Yau-Young, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Liposomes+containing+synthetic+lipid+derivatives+of+poly(ethylene+glycol)+show+prolonged+circulation+half-lives+in+vivo.">Liposomes containing synthetic lipid derivatives of poly(ethylene glycol) show prolonged circulation half-lives in vivo.</a> Biochim. Biophys. Acta. 1066, 29-36 (1991).</li><li>Klibanov, A. L., Maruyama, K., Beckerleg, A. M., Torchilin, V. P., Huang, L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Activity+of+amphipathic+poly(ethylene+glycol)+5000+to+prolong+the+circulation+time+of+liposomes+depends+on+the+liposome+size+and+is+unfavorable+for+immunoliposome+binding+to+target.">Activity of amphipathic poly(ethylene glycol) 5000 to prolong the circulation time of liposomes depends on the liposome size and is unfavorable for immunoliposome binding to target.</a> Biochim. Biophys. Acta. 1062, 142-148 (1991).</li><li>Klibanov, A. L., Maryama, K., Torchilin, V. P., Huang, L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Amphipathic+polyethyleneglycols+effectively+prolong+the+circulation+time+of+liposomes.">Amphipathic polyethyleneglycols effectively prolong the circulation time of liposomes.</a> FEBS Lett. 268, 235-237 (1990).</li><li>Gabizon, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Prolonged+circulation+time+and+enhanced+accumulation+in+malignant+exudates+of+Doxorubicin+encapsulated+in+polyethylene-glycol+coated+liposomes.">Prolonged circulation time and enhanced accumulation in malignant exudates of Doxorubicin encapsulated in polyethylene-glycol coated liposomes.</a> Cancer Res. 54, 987-992 (1994).</li><li>Awasthi, V. D., Garcia, D., Goins, B. A., Philips, W. T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Circulation+and+biodistribution+profiles+of+long-circulating+PEG-liposomes+of+various+sizes+in+rabbits.">Circulation and biodistribution profiles of long-circulating PEG-liposomes of various sizes in rabbits.</a> Int. J. Pharm. 253, 121-132 (2003).</li><li>Zhang, P., Porter, T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=An+in+vitro+study+of+a+phase-shift+nanoemulsion:+a+potential+nucleation+agent+for+bubble-enhanced+HIFU+tumor+ablation.">An in vitro study of a phase-shift nanoemulsion: a potential nucleation agent for bubble-enhanced HIFU tumor ablation.</a> Ultrasound Med. Biol. 36, 1856-1866 (2010).</li><li>Lafon, C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Gel+phantom+for+use+in+high-intensity+focused+ultrasound+dosimetry.">Gel phantom for use in high-intensity focused ultrasound dosimetry.</a> Ultrasound Med. Biol. 31, 1383-1389 (2005).</li></ol>

관심 없음 충돌이 선언 없습니다.

높은 강도 집중 초음파 (HIFU)이 열 종양 어블 레이션하기 위해 임상 적으로 사용됩니다. 1 지역화 난방을 개선하고 종양의 열 절제를 개선하려면 지질 코팅 perfluorocarbon의 방울은 HIFU에 의해 기화 할 수있는 개발되었습니다. 많은 종양의 vasculature는 인해 빠른 성장을 비정상적으로 새는 것입니다. 따라서 2 나노 입자는 fenestrations을 관통하고 수동적으로 종양 내에 축적 할 수 있으며,...

<table border="1"><tbody><tr><td> 일반 이름 </td><td> 제조업 자 </td><td> 고양이. 수 </td><td> 전체 이름 / 설명 </td></tr><tr><td> DPPC </td><td> 벤티의 지질, 설화 석고, AL, 미국 </td><td> 850355P </td><td> 1,2 - dipalmitoyl-SN-glycero-3-phosphocholine </td></tr><tr><td> DSPE-PEG2000 </td><td> 벤티의 지질, 설화 석고, AL, 미국 </td><td> 880120P </td><td> 1,2 - distearoyl-SN-glycero-3-phosphoethanolamine-N-[메 톡시 (폴리에틸렌 글리콜) -2000] (암모니아 염) </td></tr><tr><td> DDFP </td><td> Fluoromed, 라운드 록, TX, USA </td><td> CAS : ​​138495-42-8 </td><td> Dodecafluoropentane (C 5 F 12) </td></tr><tr><td> PBS </td><td> 시그마 - 알드리치, 세인트 루이스, MO, USA </td><td> P2194 </td><td> 생리 인산 버퍼 </td></tr><tr><td> 클로로포름 </td><td> 시그마 - 알드리치, 세인트. 루이, MO, USA </td><td> 372978 </td><td> 클로로포름 </td></tr><tr><td> 아크릴 아미드 </td><td> 시그마 - 알드리치, 세인트 루이스, MO, USA </td><td> A9926 </td><td> 40% 19시 1분 아크릴 아미드 / 비스 - 아크릴 아미드 </td></tr><tr><td> 트리스 버퍼 </td><td> 시그마 - 알드리치, 세인트 루이스, MO, USA </td><td> T2694 </td><td> 1M, 산도 8, trizma 히드로 클로라이드와 trizma 기지 </td></tr><tr><td> BSA </td><td> 시그마 - 알드리치, 세인트 루이스, MO, USA </td><td> A3059 </td><td> 소 혈청 알부민 </td></tr><tr><td> APS </td><td> 시그마 - 알드리치, 세인트 루이스, MO, USA </td><td> A3678 </td><td> 암모늄 persulfate 솔루션 </td></tr><tr><td> TEMED </td><td> 시그마 - 알드리치, 세인트 루이스, MO, USA </td><td> 87,689 </td><td> N, N, N &#39;, N&#39;-Tetramethylethylenediamine </td></tr><tr><td></td><td></td><td></td><td> 장비 </td></tr><tr><td> Sonicator (3mm 팁) </TD&gt; <td> Sonics &amp; 자료, 주식회사, 뉴타운, CT, USA </td><td> Vibra-셀 </td><td></td></tr><tr><td> 열탕 목욕 </td><td> 온도 피셔 과학, Waltham, MA, USA </td><td> Neslab EX-7 </td><td></td></tr><tr><td> 압출기 </td><td> 북부 지질, 버나비, BC, 캐나다 </td><td> LIPEX </td><td></td></tr><tr><td> 압출기 필터 </td><td> 워트 먼지, Piscataway, NJ, USA </td><td> # 110605와 # 110606을 Nuclepore </td><td></td></tr><tr><td> 압출기 흡수 디스크 </td><td> Sterlitech 공사, 켄트, WA, USA </td><td> # PETEDD25100 </td><td></td></tr><tr><td> 플라스틱 챔버 </td><td> 미국 플라스틱 회사, 리마, OH, USA </td><td> # 55,288, 1 3 / 16 &quot;1 개 16분의 3&quot;X2 16분의 7 &quot; </td><td></td></tr></tbody></table>

synthesis of phase-shift nanoemulsions with narrow size distributions for acoustic droplet vaporization and bubble-enhanced ultrasound-mediated ablation

높은 강도 집중 초음파 (HIFU)는 열 종양 어블 레이션하기 위해 임상 적으로 사용됩니다. 현지화 난방을 개선하고 종양의 열 절제를 개선하려면 지질 코팅 perfluorocarbon의 방울은 HIFU에 의해 기화 할 수있는 개발되었습니다. 많은 종양의 vasculature는 인해 빠른 성장을 비정상적으로 새는 있으며, 나노 입자는 fenestrations을 관통하고 수동적으로 종양 내에 축적 할 수 있습니다. 따라서 방울의 크기를 조절하는 종양에서 더 축적 될 수 있습니다. 이 보고서에서는 좁은 크기 분포와 위상 편이 nanoemulsion (PSNE)에서 안정 방울의 준비가 설명되어 있습니다. PSNE는 액체 perfluorocarbon의 존재에 지질 솔루션을 sonicating에 의해 합성되었다. 좁은 크기 분포는 100 또는 200 nm의 기공 크기의 필터를 사용하여 PSNE을 여러 번 압출하여 얻은 것입니다. 크기 분포는 동적 광 산란을 사용하여 7 일 동안 측정되었습니다. PolyacPSNE을 포함 rylamide의 hydrogels은 체외 실험에서 준비되었다. hydrogels의 PSNE 방울은 초음파와 지역화 난방 개선 결과 거품과 기화되었습니다. 기화 PSNE 더 빠른 난방이 가능하며 열 절제에 필요한 초음파 강도를 줄일 수 있습니다. 따라서, PSNE는 잠재적으로 HIFU로 인한 열 절제 트리트먼트 치료 결과를 개선, 종양의 열 절제를 강화 할 예정이다.

Watch this Scientific Journal Video about Synthesis of Phase-shift Nanoemulsions with Narrow Size Distributions for Acoustic Droplet Vaporization and Bubble-enhanced Ultrasound-mediated Ablation at Jo

Synthesis of Phase-shift Nanoemulsions with Narrow Size Distributions for Acoustic Droplet Vaporization and Bubble-enhanced Ultrasound-mediated Ablation

위상 시프트 nanoemulsions (PSNE)는 지역화 된 난방을 개선하고 종양의 열 절제를 개선하기 위해 높은 강도 집중 초음파를 사용하여 기화 할 수 있습니다. 이 보고서에서는 좁은 크기 분포와 안정 PSNE의 준비가 설명되어 있습니다. 또한, 초음파로 인한 박리에 기화의 PSNE의 영향은 조직 - 모방의 유령에서 증명된다.

음향 액적 기화 및 버블이 강화 된 초음파로 인한 박리에 대한 좁은 크기 분포와 위상 - 교대 Nanoemulsions의 합성

High-intensity  focused ultrasound (HIFU) is used clinically to thermally ablate tumors. To  enhance localized heating and improve thermal ablation in ...

synthesis-phase-shift-nanoemulsions-with-narrow-size-distributions

Research

JoVE Journal

Engineering

11.0K 조회수.  Boston University. 위상 시프트 nanoemulsions (PSNE)는 지역화 된 난방을 개선하고 종양의 열 절제를 개선하기 위해 높은 강도 집중 초음파를 사용하여 기화 할 수 있습니다. 이 보고서에서는 좁은 크기 분포와 안정 PSNE의 준비가 설명되어 있습니다. 또한, 초음파로 인한 박리에 기화의 PSNE의 영향은 조직 - 모방의 유령에서 증명된다.

비디오: Synthesis of Phase-shift Nanoemulsions with Narrow Size Distributions for Acoustic Droplet Vaporization and Bubble-enhanced Ultrasound-mediated Ablation

Controlling the Size, Shape and Stability of Supramolecular Polymers in Water

For aqueous based supramolecular polymers, the simultaneous control over shape, size and stability is very difficult1. At the same time, the ability to do so is highly important in view of a number of applications in functional soft matter including electronics, biomedical engineering, and sensors. In the past, successful strategies to control the size and shape of supramolecular polymers typically focused on the use of templates2,3, end cappers4 or selective solvent techniques5. 
Here we disclose a strategy based on self-assembling discotic amphiphiles that leads to the control over stack length and shape of ordered, chiral columnar aggregates. By balancing electrostatic repulsive interactions on the hydrophilic rim and attractive non-covalent forces within the hydrophobic core of the polymerizing building block, we manage to create small and discrete spherical objects6,7. Increasing the salt concentration to screen the charges induces a sphere-to-rod transition. Intriguingly, this transition is expressed in an increase of cooperativity in the temperature-dependent self-assembly mechanism, and more stable aggregates are obtained. 
For our study we select a benzene-1,3,5-tricarboxamide (BTA) core connected to a hydrophilic metal chelate via a hydrophobic, fluorinated L-phenylalanine based spacer (Scheme 1). The metal chelate selected is a Gd(III)-DTPA complex that contains two overall remaining charges per complex and necessarily two counter ions. The one-dimensional growth of the aggregate is directed by &pi;-&pi; stacking and intermolecular hydrogen bonding. However, the electrostatic, repulsive forces that arise from the charges on the Gd(III)-DTPA complex start limiting the one-dimensional growth of the BTA-based discotic once a certain size is reached. At millimolar concentrations the formed aggregate has a spherical shape and a diameter of around 5 nm as inferred from 1H-NMR spectroscopy, small angle X-ray scattering, and cryogenic transmission electron microscopy (cryo-TEM). The strength of the electrostatic repulsive interactions between molecules can be reduced by increasing the salt concentration of the buffered solutions. This screening of the charges induces a transition from spherical aggregates into elongated rods with a length &gt; 25 nm. Cryo-TEM allows to visualise the changes in shape and size. In addition, CD spectroscopy permits to derive the mechanistic details of the self-assembly processes before and after the addition of salt. Importantly, the cooperativity -a key feature that dictates the physical properties of the produced supramolecular polymers- increases dramatically upon screening the electrostatic interactions. This increase in cooperativity results in a significant increase in the molecular weight of the formed supramolecular polymers in water.

The goal of this experiment is to determine and control the size, shape and stability of self-assembled discotic amphiphiles in water. For aqueous based supramolecular polymers such level of control is very difficult. We apply a strategy using both repulsive and attractive interactions. The experimental techniques applied to characterize this system are broadly applicable.

물에 Supramolecular 폴리머의 크기, 모양과 안정성을 제어

For aqueous based supramolecular polymers, the simultaneous control over shape, size and stability is very difficult1. At the same time, the ability to do ...

연구

공학

Synthesis and Operation of Fluorescent-core Microcavities for Refractometric Sensing

This paper discusses fluorescent core microcavity-based sensors that can operate in a microfluidic analysis setup. These structures are based on the formation of a fluorescent quantum-dot (QD) coating on the channel surface of a conventional microcapillary. Silicon QDs are especially attractive for this application, owing in part to their negligible toxicity compared to the II-VI and II-VI compound QDs, which are legislatively controlled substances in many countries. While the ensemble emission spectrum is broad and featureless, an Si-QD film on the channel wall of a capillary features a set of sharp, narrow peaks in the fluorescence spectrum, corresponding to the electromagnetic resonances for light trapped within the film. The peak wavelength of these resonances is sensitive to the external medium, thus permitting the device to function as a refractometric sensor in which the QDs never come into physical contact with the analyte. The experimental methods associated with the fabrication of the fluorescent-core microcapillaries are discussed in detail, as well as the analysis methods. Finally, a comparison is made between these structures and the more widely investigated liquid-core optical ring resonators, in terms of microfluidic sensing capabilities.

Fluorescent-core microcavity sensors employ a high-index quantum-dot coating in the channel of silica microcapillaries. Changes in the refractive index of fluids pumped into the capillary channel cause shifts in the microcavity fluorescence spectrum that can be used to analyze the channel medium.

Refractometric 감지 용 형광 코어 Microcavities의 합성 및 운영

This paper discusses  fluorescent core microcavity-based sensors that can operate in a microfluidic  analysis setup. These structures are based on the ...

Process of Making Three-dimensional Microstructures using Vaporization of a Sacrificial Component

Vascular structures in natural systems are able to provide high mass transport through high surface areas and optimized structure. Few synthetic material fabrication techniques are able to mimic the complexity of these structures while maintaining scalability. The Vaporization of a Sacrificial Component (VaSC) process is able to do so. This process uses sacrificial fibers as a template to form hollow, cylindrical microchannels embedded within a matrix. Tin (II) oxalate (SnOx) is embedded within poly(lactic) acid (PLA) fibers which facilitates the use of this process. The SnOx catalyzes the depolymerization of the PLA fibers at lower temperatures. The lactic acid monomers are gaseous at these temperatures and can be removed from the embedded matrix at temperatures that do not damage the matrix. Here we show a method for aligning these fibers using micromachined plates and a tensioning device to create complex patterns of three-dimensionally arrayed microchannels. The process allows the exploration of virtually any arrangement of fiber topologies and structures.

The Vaporization of a Sacrificial Component (VaSC) process is used to fabricate microvascular structures. This procedure uses sacrificial poly(lactic) acid fibers to form hollow microchannels with precise 3D geometric positioning provided by laser micromachined guide plates.

희생 구성 요소의 증발을 사용하여 세 가지 차원 미세 만들기의 과정

Vascular structures in natural systems are able to provide high mass transport through high surface areas and optimized structure. Few synthetic material ...

Fabrication, Operation and Flow Visualization in Surface-acoustic-wave-driven Acoustic-counterflow Microfluidics

Surface acoustic waves (SAWs) can be used to drive liquids in portable microfluidic chips via the acoustic counterflow phenomenon. In this video we present the fabrication protocol for a multilayered SAW acoustic counterflow device. The device is fabricated starting from a lithium niobate (LN) substrate onto which two interdigital transducers (IDTs) and appropriate markers are patterned. A polydimethylsiloxane (PDMS) channel cast on an SU8 master mold is finally bonded on the patterned substrate. Following the fabrication procedure, we show the techniques that allow the characterization and operation of the acoustic counterflow device in order to pump fluids through the PDMS channel grid. We finally present the procedure to visualize liquid flow in the channels. The protocol is used to show on-chip fluid pumping under different flow regimes such as laminar flow and more complicated dynamics characterized by vortices and particle accumulation domains.

In this video we first describe fabrication and operation procedures of a surface acoustic wave (SAW) acoustic counterflow device. We then demonstrate an experimental setup that allows for both qualitative flow visualization and quantitative analysis of complex flows within the SAW pumping device.

Surface acoustic waves (SAWs) can be used to drive liquids in portable microfluidic chips via the acoustic counterflow phenomenon. In this video we ...

Characterization of Nanocrystal Size Distribution using Raman Spectroscopy with a Multi-particle Phonon Confinement Model

Analysis of the size distribution of nanocrystals is a critical requirement for the processing and optimization of their size-dependent properties. The common techniques used for the size analysis are transmission electron microscopy (TEM), X-ray diffraction (XRD) and photoluminescence spectroscopy (PL). These techniques, however, are not suitable for analyzing the nanocrystal size distribution in a fast, non-destructive and a reliable manner at the same time. Our aim in this work is to demonstrate that size distribution of semiconductor nanocrystals that are subject to size-dependent phonon confinement effects, can be quantitatively estimated in a non-destructive, fast and reliable manner using Raman spectroscopy. Moreover, mixed size distributions can be separately probed, and their respective volumetric ratios can be estimated using this technique. In order to analyze the size distribution, we have formulized an analytical expression of one-particle PCM and projected it onto a generic distribution function that will represent the size distribution of analyzed nanocrystal. As a model experiment, we have analyzed the size distribution of free-standing silicon nanocrystals (Si-NCs) with multi-modal size distributions. The estimated size distributions are in excellent agreement with TEM and PL results, revealing the reliability of our model.

We demonstrate how to determine the size distribution of semiconductor nanocrystals in a quantitative manner using Raman spectroscopy employing an analytically defined multi-particle phonon confinement model. Results obtained are in excellent agreement with the other size analysis techniques like transmission electron microscopy and photoluminescence spectroscopy.

다중 입자 Phonon은 감금 모델 라만 분광학을 이용하여 나노 결정 크기 분포의 특성

Analysis of the size distribution of nanocrystals is a critical requirement for the processing and optimization of their size-dependent properties. The ...

Characterization of Full Set Material Constants and Their Temperature Dependence for Piezoelectric Materials Using Resonant Ultrasound Spectroscopy

During the operation of high power electromechanical devices, a temperature rise is unavoidable due to mechanical and electrical losses, causing the degradation of device performance. In order to evaluate such degradations using computer simulations, full matrix material properties at elevated temperatures are needed as inputs. It is extremely difficult to measure such data for ferroelectric materials due to their strong anisotropic nature and property variation among samples of different geometries. Because the degree of depolarization is boundary condition dependent, data obtained by the IEEE (Institute of Electrical and Electronics Engineers) impedance resonance technique, which requires several samples with drastically different geometries, usually lack self-consistency. The resonant ultrasound spectroscopy (RUS) technique allows the full set material constants to be measured using only one sample, which can eliminate errors caused by sample to sample variation. A detailed RUS procedure is demonstrated here using a lead zirconate titanate (PZT-4) piezoceramic sample. In the example, the complete set of material constants was measured from room temperature to 120 &#176;C. Measured free dielectric constants <img alt="Equation 1" src="/files/ftp_upload/53461/image001.jpg" /> and&#160;<img alt="Equation 2" src="/files/ftp_upload/53461/image002.jpg" /> were compared with calculated ones based on the measured full set data, and piezoelectric constants d15 and d33 were also calculated using different formulas. Excellent agreement was found in the entire range of temperatures, which confirmed the self-consistency of the data set obtained by the RUS.

This protocol describes the procedure of measuring the temperature dependence of the full set material constants of piezoelectric materials using resonant ultrasound spectroscopy (RUS).

풀 세트 재질 상수의 특성 및 공명 초음파​​ 분광법을 사용하여 압전 재료에 대한 그들의 온도 의존성

During the operation of high power electromechanical devices, a temperature rise is unavoidable due to mechanical and electrical losses, causing the ...

Capillary-based Centrifugal Microfluidic Device for Size-controllable Formation of Monodisperse Microdroplets

Here, we demonstrate a simple method for the rapid production of size-controllable, monodisperse, W/O microdroplets using a capillary-based centrifugal microfluidic device. W/O microdroplets have recently been used in powerful methods that enable miniaturized chemical experiments. Therefore, developing a versatile method to yield monodisperse W/O microdroplets is needed. We have developed a method for generating monodisperse W/O microdroplets based on a capillary-based centrifugal axisymmetric co-flowing microfluidic device. We succeeded in controlling the size of microdroplets by adjusting the capillary orifice. Our method requires equipment that is easier-to-use than with other microfluidic techniques, requires only a small volume (0.1-1 &#181;l) of sample solution for encapsulation, and enables the production of hundreds of thousands number of W/O microdroplets per second. We expect this method will assist biological studies that require precious biological samples by conserving the volume of the samples for rapid quantitative analysis biochemical and biological studies.

Here, we demonstrate a simple production method for size-controllable, monodisperse, water-in-oil (W/O) microdroplets using a capillary-based centrifugal microfluidic device. This method requires only a small sample volume and enables high-yield production. We expect this method will be useful for rapid biochemical and cellular analyses.

단 분산 미세 방울의 크기가 제어 형성을위한 모세관 기반 원심 미세 유체 장치

Here, we demonstrate a simple method for the rapid production of size-controllable, monodisperse, W/O microdroplets using a capillary-based centrifugal ...

Fabrication and Operation of Acoustofluidic Devices Supporting Bulk Acoustic Standing Waves for Sheathless Focusing of Particles

Acoustophoresis refers to the displacement of suspended objects in response to directional forces from sound energy. Given that the suspended objects must be smaller than the incident wavelength of sound and the width of the fluidic channels are typically tens to hundreds of micrometers across, acoustofluidic devices typically use ultrasonic waves generated from a piezoelectric transducer pulsating at high frequencies (in the megahertz range). At characteristic frequencies that depend on the geometry of the device, it is possible to induce the formation of standing waves that can focus particles along desired fluidic streamlines within a bulk flow. Here, we describe a method for the fabrication of acoustophoretic devices from common materials and clean room equipment. We show representative results for the focusing of particles with positive or negative acoustic contrast factors, which move towards the pressure nodes or antinodes of the standing waves, respectively. These devices offer enormous practical utility for precisely positioning large numbers of microscopic entities (e.g., cells) in stationary or flowing fluids for applications ranging from cytometry to assembly.

Acoustofluidic devices use ultrasonic waves within microfluidic channels to manipulate, concentrate and isolate suspended micro and nanoscopic entities. This protocol describes the fabrication and operation of such a device supporting bulk acoustic standing waves to focus particles in a central streamline without the aid of sheath fluids.

제조 및 Acoustofluidic 장치의 작동은 입자의 초점 쉬스에 대한 대량 음향 서 파도 지원

Acoustophoresis refers to the displacement of suspended objects in response to directional forces from sound energy. Given that the suspended objects must ...

Measuring Spray Droplet Size from Agricultural Nozzles Using Laser Diffraction

When making an application of any crop protection material such as an herbicide or pesticide, the applicator uses a variety of skills and information to make an application so that the material reaches the target site (i.e., plant). Information critical in this process is the droplet size that a particular spray nozzle, spray pressure, and spray solution combination generates, as droplet size greatly influences product efficacy and how the spray moves through the environment. Researchers and product manufacturers commonly use laser diffraction equipment to measure the spray droplet size in laboratory wind tunnels. The work presented here describes methods used in making spray droplet size measurements with laser diffraction equipment for both ground and aerial application scenarios that can be used to ensure inter- and intra-laboratory precision while minimizing sampling bias associated with laser diffraction systems. Maintaining critical measurement distances and concurrent airflow throughout the testing process is key to this precision. Real time data quality analysis is also critical to preventing excess variation in the data or extraneous inclusion of erroneous data. Some limitations of this method include atypical spray nozzles, spray solutions or application conditions that result in spray streams that do not fully atomize within the measurement distances discussed. Successful adaption of this method can provide a highly efficient method for evaluation of the performance of agrochemical spray application nozzles under a variety of operational settings. Also discussed are potential experimental design considerations that can be included to enhance functionality of the data collected.

We present protocols to be used in the measurement of spray droplet size from agricultural nozzles used in both aerial and ground based agrochemical applications. These methods presented were developed to provide consistent and repeatable droplet size data both inter- and intra-laboratory, when using laser diffraction systems.

레이저 회절을 사용하여 농업 노즐에서 측정 스프레이 물방울 크기

When making an application of any crop protection material such as an herbicide or pesticide, the applicator uses a variety of skills and information to ...

A Pipette-Tip Based Method for Seeding Cells to Droplet Microfluidic Platforms

Amongst various microfluidic platform designs frequently used for cellular analysis, droplet-microfluidics provides a robust tool for isolating and analyzing cells at the single-cell level by eliminating the influence of external factors on the cellular microenvironment. Encapsulation of cells in droplets is dictated by the Poisson distribution as a function of the number of cells present in each droplet and the average number of cells per volume of droplet. Primary cells, especially immune cells, or clinical specimens can be scarce and loss-less encapsulation of cells remains challenging. In this paper, we present a new methodology that uses pipette-tips to load cells to droplet-based microfluidic devices without the significant loss of cells. With various cell types , we demonstrate efficient cell encapsulation in droplets that closely corresponds to the encapsulation efficiency predicted by the Poisson distribution. Our method ensures loss-less loading of cells to microfluidic platforms and can be easily adapted for downstream single cell analysis, e.g., to decode cellular interactions between different cell types.

This article presents a protocol for seeding scarce population of cells using pipette-tips to droplet microfluidic devices in order to provide higher encapsulation efficiency of cells in droplets.

피 펫 팁 드롭릿 미세 플랫폼 시드 셀에 대 한 메서드를 기반으로

Amongst various microfluidic platform designs frequently used for cellular analysis, droplet-microfluidics provides a robust tool for isolating and ...