이 작품은 화학의 부서 및 연구의 사무실 (RCAP 13-8032)에서 내부 지원을 포함하여 과학 및 공학, 웨스턴 켄터키 대학의 오그 덴 대학에서 지원하고있다. WKU 현미경 시설에서 닥터 존 Andersland (SEM 이미지) 및 연소 공학 (BET 분석)에 대한 WKU 연구소의 부교수 연의 카오의 지원은이 작업을 수행의 중심이되고있다.

에멀젼 1. 준비 <ol><li> 에멀젼 내용 <ol><li> 질량 소금 적당량 0.03 M 용액 10 ㎖를 제조한다. 백금 (IV) 클로라이드 측정 0.101 g, 아연 (II) 클로라이드 (ZnCl 2) 측정 값 0.032 g 및 염화나트륨 0.018 g위한 계수. </li><li> 각각의 시험관에, DI 물 10 ㎖로 각각의 염을 용해. 나중에 사용하기 위해 따로 설정합니다. </li><li> 이 절차를 통해 내용에 대한 20 ml의 밀봉 유리 병을 사용합니다. 유리 병에 균형을 용기. </li><li> 천천히 교반로드 이상과 제로화 규모에 휴식 유리 병으로 그것을 부어 비닐 말단 폴리 디메틸 실록산의 무게. (1.080 ml의에 해당) 1.02 g을 달아. 참고 :이 폴리머의 높은 점도 피펫 비현실적 있습니다. </li><li> 피펫 유리 병에 n- 헵탄 1.02 ml의. 유리 병에 비 이온 계면 활성제 (소르 비탄 모노 올레 에이트) 2 방울을 추가합니다. 피펫 염 용액 0.3 ㎖의 유리 병에 DI-물 0.45 ml의. </li><li> 단단히에서 뚜껑을 돌려서 유리 병을 밀봉합니다. 초음파 처리를 시작하기 전에 유제를 개시하기 위해 60 초 동안 격렬하게 흔들어. </li></ol></li><li> 물 목욕 초음파 처리 장치의 건설 <ol><li> 최소 적재 선에 물 위로 초음파기를 입력합니다. 400 mL의 비커에 수돗물의 250 ML을 추가합니다. 수위가 단지 림이되도록 얼음과 400 mL의 비커를 입력합니다. </li><li> 물 목욕 초음파 처리기 내부에이 비커를 놓습니다. 초음파기에 필 온라인, 필요한 경우 조정을 확인합니다. 링이 물에 목욕 초음파기 바로 옆에 서 놓습니다. </li><li> 팔이 밖으로 확장 될 수 있도록 두 개의 링, 클램프 스탠드를 배치하여, 링에 수직 스탠드하고 얼음 물이 가득 비커에 아래쪽을 가리 키도록 다른 하나는 물 목욕으로 확장됩니다. 온도가 초음파 통하여 모니터 할 수 있도록 또 다른 클램프 링 다운 400 ㎖의 비이커에 온도계를 부착 스탠드. </li></ol></li><li> Emulsif확인해 주시죠 절차 <ol><li> 완전히 비커에 아래로 돌출 클램프로 고정하여 400 mL의 비커에 빠져​​들도록 에멀젼 함유 병을 놓습니다. </li><li> PDMS를 함유하는 혼합물을 유리 바이알은 마찰로 인한 열을 제거하기 위해 비이커의 측면을 건드리지되지 않는다는 것을 보장한다. </li><li> 초음파기를 켜고 7 분간 초음파 시간을 설정합니다. 에멀젼은 매우 열 민감하기 때문에, 비커 내의 온도가 0 ° C에서 5 사이에 걸쳐 초음파인지 확인. 비커 내의 온도가 바람직하다 일단 초음파를 시작한다. </li><li> 초음파의 7 분 후, 에멀젼에 형성 수있는 덩어리를 제거하기 위해 유리 병의 상단을 잡고, 1 분 / 소용돌이를 흔들 부드럽게 병을 제거하고. </li><li> 비커의 내용을 폐기하십시오. 물 250 ㎖로 채우고 내에서 1cm로 채우기에 비커의 상단을 얼음을 추가합니다. </li><li> 다시 클램프의 병을 놓습니다. resum하기 위해 얼음 물 아래 잠수함7 분 동안 전자 초음파. </li><li> 반복 여덟, 7 분간 초음파 처리 기간의 총 1.3.6 1.3.3하는 단계, 또는 초음파 균질 것으로 나타나고 더 덩어리가 존재하지 않을 때까지. 실온에서 보관하십시오. 주 : 유화 며칠 동안 안정해야하지만 균일 나타날 때까지 7 분 간격으로 상기와 같이 초음파에 의해 회수 될 수있다. 실온에서 보관하십시오. </li></ol></li></ol> 2. 교차 결합 <ol><li> 트리에 톡시 실란 / 계면 활성제 용액을 첨가 설치 프로그램 <ol><li> 피펫 5.4 ml를 시험관에 톡시 실란. 나중에 사용하기 위해 후드 테스트 튜브 랙에 놓는다. </li><li> 얼음 물 400 mL의 비커를 입력하고 후드 아래에 배치합니다. 다음 링이 부착 된 클램프 스탠드 400 mL의 비커 장소에, 비커의 입구에 직접 확장. 이 트리에 톡시 실란의 추가를위한 얼음 욕조됩니다. </li><li> 링 스탠드의 반대편에 핫 플레이트를 놓습니다. 약 700 ml의 800 비이커를 채우수돗물. 핫 플레이트에 놓습니다. </li><li> 핫 플레이트의 전원을 켜고 800 mL의 비커 내부에 85 ° C 75의 온도를 유지한다. 800 ㎖의 비이커 안에 물의 온도가 모니터링 될 수 있도록 링 스탠드에 온도계를 부착 클램프. </li><li> 물 375 ㎖ (4.62 mM)을로 도데 실 황산나트륨 0.5 g을 용해시킴으로써 계면 활성제 용액을 생성한다. 깨끗하고 빈 시험관에 계면 활성제 용액의 약 10 ML을 추가합니다. </li><li> 다른 링 클램프 활성제 시험관과 후드 아래 스탠드 부착은 액체 레벨이 800 ㎖의 비커 안에서 수면 아래가되도록 고정. 열 평형 10 분을 허용합니다. </li><li> 여과지를 적시고 작은 깔때기의 상단에 배치. 250 ㎖의 삼각 플라스크 내부의 깔때기의 줄기를 놓고 후드 아래에 플라스크를 배치합니다. </li></ol></li><li> 트리에 톡시 실란의 추가 <ol><li> 빙수 부리 위에 클램프 에멀젼 바이알을 놓고후드 안쪽 어. 바이알 내용물이 물의 표면 아래에 있도록 클램프 PDMS 혼합물을 위치. 트리에 톡시 실란의 첨가는 발열 반응을 초래하므로 에멀젼은 구조를 유지하기 위하여 저온 유지되어야한다. </li><li> 가스 축적을 방지하는 데 유리 바이알에서 뚜껑을 제거한다. </li><li> 천천히 약 10 초 (약 0.5 ㎖ / 초)에 걸쳐 연속적인 스트림으로 유리 바이알에 시험관 함유 트리에 톡시 실란을 붓는다. 주의 : 트리에 톡시 실란의 첨가는 발열 반응과 부식성 염화수소 가스의 방출을 개시한다. 유리 병은 매우 뜨거워 질 것이고, 독성 가스 혼합물로부터 진화 할 것이다. 트리에 톡시 실란을 추가하는 동안 내용을 저어하지 마십시오. </li><li> 열 보호 장갑을 착용 한 채 완전히 트리에 톡시 실란을 추가 한 후, 부드럽게 유리 교반 막대와 내용을 저어. 2 분 동안 또는 유리 병에서 진화 가스 멈출 때까지 기다립니다. </li><li> FOLL가교 때문에, 시료에서 볼 상분리 없다. 덩어리가 존재하는 경우, 바이알을 밀봉하고 뚜껑으로 병 채 20 초 동안 흔들어 엄격. </li></ol></li><li> 구슬 생산 <ol><li> 유리 병에서 가교 유화를 그릴 청소, 유리 파스퇴르 피펫을 사용합니다. 적가 시험관 방울 사이에 가능한 한 적은 시간이 소요로 (75 및 85 ° C 사이에서 유지되어야한다), 계면 활성제 용액에 가교 된 에멀젼을 추가한다. </li><li> 30 초 에멀젼의 첨가 후 1 분 고체 시험관 내부에 형성되기 시작으로, 계면 활성제 용액을 천천히 가스를 포한한다. </li><li> 열 보호 장갑을 착용하고있는 동안, 클램프에서 테스트 튜브를 타고 후드 아래 여과 장치에 전체 내용을 붓는다. 5 분 동안 필터. 필터에서 필터 용지를 제거합니다. </li><li> H 하에서 O / N의 건조 시계 유리 비드 상에 분리 된 고체를 여과를 전송할짐 우드. 구슬의 청소는 무기한 연기 될 수있다. 상점은 필요할 때까지 밀폐 된 유리 병에 실온에서 구슬을 건조하고 깨끗한 즉시 사용하기 전에. </li></ol></li><li> 구슬 청소 <ol><li> 후드 아래 다른 여과 장치를 만들고 필터 종이 위에 깔때기 내부의 건조 구슬을 배치합니다. </li><li> 모든 구슬이 세척되어 있는지 확인하기 위해 주위에 약간을 이동, 부드럽게 구슬을 씻어 DI-물이 가득 플라스틱 세척 병을 사용합니다. </li><li> 구슬은 후드 아래에 시계 접시에 그들을 배치하여 1 시간 동안 건조 시키십시오. 물 세척에 대해 동일한 방법을 사용하여 구슬을 씻어 헥산 가득 세척 병을 사용합니다. </li><li> 시계 유리 구슬을 놓습니다. 시계 접시를 놓고 후드 아래 구슬은 건조. </li><li> 구슬이 완전히 건조 된 후 나중에 사용하기 위해 실온에서 작은 밀폐 유리 병 및 저장에 배치합니다. </li></ol></li><li> SEM 분석 및 SEM 설정의 구슬을 장착 <ol><li> DO의 스트립을 배치구슬이 장착 될에 그루터기 위에 uble 양면 탄소 전도성 테이프. 가위를 사용하여, 가장자리 아무런 테이프 중단 없도록 그루터기 주위 트림. </li><li> 평평한 표면에 스텁에서 필터 종이를 놓습니다. 접착제 밑면이 노출되도록 테이프로부터 상부층을 제거한다. </li><li> 조심스럽게 그루터기 위에 구슬을 붓는다. 일부 구슬 테이프에 충실하지만, 대부분은 필터 종이에 반사되어 토지 것입니다. 그들은 필터 종이에 머물 경우 유리 병에이 다시 부어. 필요한 경우 오염 될 (2.4.5 2.4.2에 따라) 어떤 구슬을 세척, 반복합니다. </li><li> 구슬이 스텁에 안전하게 보장하기 위해, 전구 주사기를 사용하여 가볍게 스텁 표면에 매우 밀접하게 날려. 일부만 테이프에 부착하는 경우 스텁 위에 더 구슬 붓는다. 모든 구슬은 SEM 챔버에 그루터기를 배치하고 대피하기 전에 안전한지 확인합니다. </li><li> 샘플이 제대로 장착되고 나면 그들은 지금 SEM의 항문을받을 준비가되어이 Analysis (15). 비드의 표면 형상의 분해능을 최적화하기 위해 15 keV의 VAC에서 LOW 모드에서 이미지를 수집한다. </li></ol></li></ol>

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Chem. 46 (1), 21-32 (2007).</li><li>Sun, W., Yan, X., Zhu, X. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Synthesis,+porous+structure,+and+underwater+acoustic+properties+of+macroporous+cross-linked+copolymer+beads.">Synthesis, porous structure, and underwater acoustic properties of macroporous cross-linked copolymer beads.</a> Colloid Polym. Sci. 290 (1), 73-80 (2012).</li><li>Dufaud, O., Favre, E., Sadtler, V. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Porous+elastomeric+beads+from+crosslinked+emulsions.">Porous elastomeric beads from crosslinked emulsions.</a> J. Appl. Polym. Sci. 83 (5), 967-971 (2002).</li><li>Farmer, B. C., Mason, M., Nee, M. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Concave+porosity+non-polar+beads+by+a+modified+microbubble+fabrication.">Concave porosity non-polar beads by a modified microbubble fabrication.</a> Mater. Lett. 98, 105-107 (2013).</li><li>Flegler, S. L., Heckman, J. W., Klomparens, K. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Scanning and Transmission Electron Microscopy: An Introduction. , 151-155 (1995).</li><li>Brunauer, S., Emmett, P. H., Teller, E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Adsorption+of+Gases+in+Multimolecular+Layers.">Adsorption of Gases in Multimolecular Layers.</a> J. Am. Chem. Soc. 60 (2), 309-319 (1938).</li><li>Sing, K. S. W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Characterization+of+porous+materials:+past,+present+and+future.">Characterization of porous materials: past, present and future.</a> Colloids Surf. A. 241 (1), 3-7 (2004).</li></ol>

The authors have nothing to disclose.

도 1의 다른 SEM 이미지로도 1a의 비교에 의해 볼 수 있듯이,이 프로토콜을 이용하여 (전해질 농도 및 아이덴티티를 조정함으로써) 생성 된 비드., 낮은 이온 강도 에멀젼 제조 것과는 근본적으로 다르다 당초 보고서 사용 상기 수성 지방족 인터페이스 14 중합 가교 결합 반응을 촉매 의도 PTCL 4. 이 보고서에서, 큰 오목 들여 쓰기는 볼 수 있었다. 해당 보고서...

Polydimethylsiloxane (PDMS) is one of the most widely used silicone compounds. Its biocompatibility has led to widespread use in implant and other biomedical engineering structures1,2. It is trivially cross-linked into elastic structures using an organosilyl compound (such as triethoxysilane), a simple and reliable procedure which has made it useful for cast polymer applications where some flexibility is required3. Once cross-linked, PDMS is largely inert, particularly in biological conditions, and is therefore useful for a variety of food and medical applications4,5. Ease of casting, chemical inertness, and hydrophobicity have made it a natural choice for microfluidic devices6,7. Its affinity for non-halogenated, non-polar organic compounds has made it a popular stationary phase in separations chemistry8-10. 
Recently, microbubble fabrications have been used to generate porous beads for use as catalyst structural substrates or in chemical separations11,12. In both applications, ideal materials will have a maximized surface-area-to-volume (SAV) ratio for best efficiency. In a microbubble fabrication process, microstructuring of materials is typically accomplished by isolating the polymer in aliphatic &#8220;microbubbles&#8221; by emulsification in an aqueous continuous phase. The initial report of microporous PDMS beads produced them by mechanical emulsification of two phases (aliphatic and aqueous)13. The stock PDMS liquid (and its cross-linking agent) is dissolved into the aliphatic phase, which is structured into microscopic beads by being forced to cavitate within the (continuous) aqueous phase. The emulsification is stabilized by the addition of a non-ionic surfactant. When the emulsion is added dropwise to a heated bath, solid beads form by agglomeration of the microbubbles into clusters of tiny spheres of cross-linked PDMS. Our goal in this protocol is to modify this procedure to develop beads with an inverted porosity to improve the SAV ratio of the material.
As reported previously, control of the beads can be directed to some extent by the aliphatic:aqueous ratios in the emulsion. However, we have reported recently that addition of platinum(IV) chloride (PtCl4) inverts the porosity: materials are formed in which the PDMS is riddled with concave pores14. This indicates that the aqueous layer cavitates inside the aliphatic one, despite having similar aliphatic:aqueous ratios to those published in the original work13. The primary advantage of our method is that this concave porosity should naturally result in an increased SAV ratio, and thus, improved efficiency for analytical chemistry applications. While we are continuing to explore the specific effects of the addition of the platinum compound, we show here that the same effect can be accomplished using any aqueously soluble ionic compound, though perhaps to a reduced extent. Because our techniques also differ in some key aspects from what has been previously reported, we present our protocols here as a video to encourage others to extend our methods. Most notably, we use a common bath sonicator of the type used to clean glassware or other equipment, rather than the (considerably more expensive) probe sonicator often used in microbubble fabrication. This adjusted approach to the microbubble fabrication procedure could potentially be extended for the production of large quantities of bulk materials as well, creating porous sheets or slabs which could have applications for biomedical devices, aerospace and automotive industry, or substrates for chemical catalysis. Users seeking to generate high-SAV-ratio, microstructured materials using other similar polymers for such analyses may find that our protocols can be extended to any polymer for which the microbubble emulsion technique can be applied.

<table border="0">
	<tbody>
		<tr>
			<td>Poly(dimethylsiloxane), vinyl terminated</td>
			<td>Sigma-Aldrich</td>
			<td>68083-19-2</td>
			<td></td>
		</tr>
		<tr>
			<td>n-Heptane</td>
			<td>Sigma-Aldrich</td>
			<td>142-82-5</td>
			<td>Flammable</td>
		</tr>
		<tr>
			<td>Triethoxysilane</td>
			<td>Sigma-Aldrich</td>
			<td>998-30-1</td>
			<td>Flammable, Accutely Toxic</td>
		</tr>
		<tr>
			<td>Sorbitan Monoleate (Span-80)</td>
			<td>Fluker</td>
			<td>1338-43-8</td>
			<td></td>
		</tr>
		<tr>
			<td>Platinum (IV) Chloride</td>
			<td>Sigma-Aldrich</td>
			<td>13454-96-1</td>
			<td>Accutely Toxic</td>
		</tr>
		<tr>
			<td>Zinc (II) Chloride</td>
			<td>Sigma-Aldrich</td>
			<td>7646-85-7</td>
			<td></td>
		</tr>
		<tr>
			<td>Sodium Chloride</td>
			<td>Sigma-Aldrich</td>
			<td>7647-14-5</td>
			<td></td>
		</tr>
		<tr>
			<td>2.8L Water Bath Sonicator</td>
			<td>VWR</td>
			<td>97043-964</td>
			<td></td>
		</tr>
	</tbody>
</table>

microbubble fabrication of concave-porosity pdms beads

Microbubble fabrication (by use of a fine emulsion) provides a means of increasing the surface-area-to-volume (SAV) ratio of polymer materials, which is particularly useful for separations applications. Porous polydimethylsiloxane (PDMS) beads can be produced by heat-curing such an emulsion, allowing the interface between the aqueous and aliphatic phases to mold the morphology of the polymer. In the procedures described here, both polymer and crosslinker (triethoxysilane) are sonicated together in a cold-bath sonicator. Following a period of cross-linking, emulsions are added dropwise to a hot surfactant solution, allowing the aqueous phase of the emulsion to separate, and forming porous polymer beads. We demonstrate that this method can be tuned, and the SAV ratio optimized, by adjusting the electrolyte content of the aqueous phase in the emulsion. Beads produced in this way are imaged with scanning electron microscopy, and representative SAV ratios are determined using Brunauer&#8211;Emmett&#8211;Teller (BET) analysis. Considerable variability with the electrolyte identity is observed, but the general trend is consistent: there is a maximum in SAV obtained at a specific concentration, after which porosity decreases markedly.

다른 전해질 조건 에멀젼으로부터 발생 비드의 대표적인 SEM 이미지가도 1에 도시된다.도 1a는 DuFaud하여 얻은, 등. (13)과 유사한 비드를 도시 모든 전해질의 첨가없이, 우리의 방법을 사용하여 제조. 구슬은 각각의 금속 이온에 대해 서로 다른 형태 학적 결과, 그림 1B-D에 표시. 도시 된 모든 이미지에 대해, 0.03 - M 전해질 용액 300 μL 그 위상 0.012 M의 전해질 농...

Watch this Scientific Journal Video about Microbubble Fabrication of Concave-porosity PDMS Beads at JoVE.com

Microbubble Fabrication of Concave-porosity PDMS Beads

Procedures used to generate microstructured concave-porosity polydimethylsiloxane beads are presented. Effects of electrolyte concentration and identity within the aqueous phase are particularly emphasized.

오목 다공성 PDMS 비즈의 마이크로 버블 제작

Microbubble fabrication (by use of a fine emulsion) provides a means of increasing the surface-area-to-volume (SAV) ratio of polymer materials, which is ...

microbubble-fabrication-of-concave-porosity-pdms-beads

Research

JoVE Journal

Chemistry

8.2K 조회수.  Western Kentucky University. Procedures used to generate microstructured concave-porosity polydimethylsiloxane beads are presented. Effects of electrolyte concentration and identity within the aqueous phase are particularly emphasized. 

비디오: Microbubble Fabrication of Concave-porosity PDMS Beads

Fabrication of Large-area Free-standing Ultrathin Polymer Films

This procedure describes a method for the fabrication of large-area and ultrathin free-standing polymer films. Typically, ultrathin films are prepared using either sacrificial layers, which may damage the film or affect its mechanical properties, or they are made on freshly cleaved mica, a substrate that is difficult to scale. Further, the size of ultrathin film is typically limited to a few square millimeters. In this method, we modify a surface with a polyelectrolyte that alters the strength of adhesion between polymer and deposition substrate. The polyelectrolyte can be shown to remain on the wafer using spectroscopy, and a treated wafer can be used to produce multiple films, indicating that at best minimal amounts of the polyelectrolyte are added to the film. The process has thus far been shown to be limited in scalability only by the size of the coating equipment, and is expected to be readily scalable to industrial processes. In this study, the protocol for making the solutions, preparing the deposition surface, and producing the films is described.

We describe a method for the fabrication of large-area (up to 13 cm diameter) and ultrathin (as thin as 8 nm) polymer films. Instead of using a sacrificial interlayer to delaminate the film from its substrate, we use a self-limiting surface treatment suitable for arbitrarily large areas.

대 면적의 제작은 초박막 고분자 필름을 무료 서

This procedure describes a method for the fabrication of large-area and ultrathin free-standing polymer films.  Typically, ultrathin films are prepared ...

연구

화학

Flow-pattern Guided Fabrication of High-density Barcode Antibody Microarray

Antibody microarray as a well-developed technology is currently challenged by a few other established or emerging high-throughput technologies. In this report, we renovate the antibody microarray technology by using a novel approach for manufacturing and by introducing new features. The fabrication of our high-density antibody microarray is accomplished through perpendicularly oriented flow-patterning of single stranded DNAs and subsequent conversion mediated by DNA-antibody conjugates. This protocol outlines the critical steps in flow-patterning DNA, producing and purifying DNA-antibody conjugates, and assessing the quality of the fabricated microarray. The uniformity and sensitivity are comparable with conventional microarrays, while our microarray fabrication does not require the assistance of an array printer and can be performed in most research laboratories. The other major advantage is that the size of our microarray units is 10 times smaller than that of printed arrays, offering the unique capability of analyzing functional proteins from single cells when interfacing with generic microchip designs. This barcode technology can be widely employed in biomarker detection, cell signaling studies, tissue engineering, and a variety of clinical applications.

This protocol outlines the fabrication of a large-scale, multiplexed two-dimensional DNA or antibody array, with potential applications in cell signaling studies and biomarker detection.

고밀도 바코드 항체 마이크로 어레이의 흐름 패턴 가이드 제작

Antibody microarray as a well-developed technology is currently challenged by a few other established or emerging high-throughput technologies. In this ...

Immobilization of Multi-biocatalysts in Alginate Beads for Cofactor Regeneration and Improved Reusability

We have recently developed a simple, reusable and coupled whole-cell biocatalytic system with the capability of cofactor regeneration and biocatalyst immobilization for improved production yield and sustained synthesis. Described herewith is the experimental procedure for the development of such a system consisting of two E. coli strains that express functionally complementary enzymes. Together, these two enzymes can function co-operatively to mediate the regeneration of expensive cofactors for improving the product yield of the bioreaction. In addition, the method of synthesizing an immobilized form of the coupled biocatalytic system by encapsulation of whole cells in calcium alginate beads is reported. As an example, we present the improved biosynthesis of L-xylulose from L-arabinitol by coupling E. coli cells expressing the enzymes L-arabinitol dehydrogenase or NADH oxidase. Under optimal conditions and using an initial concentration of 150 mM L-arabinitol, the maximal L-xylulose yield reached 96%, which is higher than those reported in the literature. The immobilized form of the coupled whole-cell biocatalysts demonstrated good operational stability, maintaining 65% of the yield obtained in the first cycle after 7 cycles of successive re-use, while the free cell system almost completely lost the catalytic activity. Therefore, the methods reported here provides two strategies that could help improve the industrial production of L-xylulose, as well as other value-added compounds requiring the use of cofactors in general.

Presented is the protocol for co-immobilizing whole-cell biocatalysts for cofactor regeneration and improved reusability, using the production of L-xylulose as an example. The cofactor regeneration is achieved by coupling two Escherichia coli strains expressing functionally complementary enzymes; the whole-cell biocatalyst immobilization is achieved by cell encapsulation in calcium alginate beads.

공동 인자 재생 및 개선 재사용에 대한 알긴산 구슬의 다중 생체 촉매의 고정화

We have recently developed a simple, reusable and coupled whole-cell biocatalytic system with the capability of cofactor regeneration and biocatalyst ...

Influence of Hybrid Perovskite Fabrication Methods on Film Formation, Electronic Structure, and Solar Cell Performance

Hybrid organic/inorganic halide perovskites have lately been a topic of great interest in the field of solar cell applications, with the potential to achieve device efficiencies exceeding other thin film device technologies. Yet, large variations in device efficiency and basic physical properties are reported. This is due to unintentional variations during film processing, which have not been sufficiently investigated so far. We therefore conducted an extensive study of the morphology and electronic structure of a large number of CH3NH3PbI3 perovskite where we show how the preparation method as well as the mixing ratio of educts methylammonium iodide and lead(II) iodide impact properties like film formation, crystal structure, density of states, energy levels, and ultimately the solar cell performance.

We present an extensive study on the effects of different fabrication methods for organic/inorganic perovskite thin films by comparing crystal structures, density of states, energy levels, and ultimately the solar cell performance.

필름 형성에 하이브리드 페 로브 스카이 트 제조 방법, 전자 구조 및 태양 전지 성능의 영향

Hybrid organic/inorganic halide perovskites have lately been a topic of great interest in the field of solar cell applications, with the potential to ...

Fabrication and Testing of Photonic Thermometers

In recent years, a push for developing novel silicon photonic devices for telecommunications has generated a vast knowledge base that is now being leveraged for developing sophisticated photonic sensors. Silicon photonic sensors seek to exploit the strong confinement of light in nano-waveguides to transduce changes in physical state to changes in resonance frequency. In the case of thermometry, the thermo-optic coefficient, i.e., changes in refractive index due to temperature, causes the resonant frequency of the photonic device such as a Bragg grating to drift with temperature. We are developing a suite of photonic devices that leverage recent advances in telecom compatible light sources to fabricate cost-effective photonic temperature sensors, which can be deployed in a wide variety of settings ranging from controlled laboratory conditions, to the noisy environment of a factory floor or a residence. In this manuscript, we detail our protocol for the fabrication and testing of photonic thermometers.

We describe the process of fabrication and testing of photonic thermometers.

제조 및 광 온도계의 테스트

In recent years, a push for developing novel silicon photonic devices for telecommunications has generated a vast knowledge base that is now being ...

Fabrication and Testing of Catalytic Aerogels Prepared Via Rapid Supercritical Extraction

Protocols for preparing and testing catalytic aerogels by incorporating metal species into silica and alumina aerogel platforms are presented. Three preparation methods are described: (a) the incorporation of metal salts into silica or alumina wet gels using an impregnation method; (b) the incorporation of metal salts into alumina wet gels using a co-precursor method; and (c) the addition of metal nanoparticles directly into a silica aerogel precursor mixture. The methods utilize a hydraulic hot press, which allows for rapid (&#60;6 h) supercritical extraction and results in aerogels of low density (0.10 g/mL) and high surface area (200-800 m2/g). While the work presented here focuses on the use of copper salts and copper nanoparticles, the approach can be implemented using other metal salts and nanoparticles. A protocol for testing the three-way catalytic ability of these aerogels for automotive pollution mitigation is also presented. This technique uses custom-built equipment, the Union Catalytic Testbed (UCAT), in which a simulated exhaust mixture is passed over an aerogel sample at a controlled temperature and flow rate. The system is capable of measuring the ability of the catalytic aerogels, under both oxidizing and reducing conditions, to convert CO, NO and unburned hydrocarbons (HCs) to less harmful species (CO2, H2O and N2). Example catalytic results are presented for the aerogels described.

Here we present protocols for preparing and testing catalytic aerogels by incorporating metal species into silica and alumina aerogel platforms. Methods for preparing materials using copper salts and copper-containing nanoparticles are featured. Catalytic testing protocols demonstrate the effectiveness of these aerogels for three-way catalysis applications.

제조 및 급속 한 초 임계 추출 통해 준비 촉매 Aerogels의 테스트

Protocols for preparing and testing catalytic aerogels by incorporating metal species into silica and alumina aerogel platforms are presented. Three ...

Preparation of Poly(pentafluorophenyl acrylate) Functionalized SiO2 Beads for Protein Purification

We demonstrate a simple method to prepare poly(pentafluorophenyl acrylate) (poly(PFPA)) grafted silica beads for antibody immobilization and subsequent immunoprecipitation (IP) application. The poly(PFPA) grafted surface is prepared via a simple two-step process. In the first step, 3-aminopropyltrimethoxysilane (APTMS) is deposited as a linker molecule onto the silica surface. In the second step, poly(PFPA) homopolymer, synthesized via the reversible addition and fragmentation chain transfer (RAFT) polymerization, is grafted to the linker molecule through the exchange reaction between the pentafluorophenyl (PFP) units on the polymer and the amine groups on APTMS. The deposition of APTMS and poly(PFPA) on the silica particles are confirmed by X-ray photoelectron spectroscopy (XPS), as well as monitored by the particle size change measured via dynamic light scattering (DLS). To improve the surface hydrophilicity of the beads, partial substitution of poly(PFPA) with amine-functionalized poly(ethylene glycol) (amino-PEG) is also performed. The PEG-substituted poly(PFPA) grafted silica beads are then immobilized with antibodies for IP application. For demonstration, an antibody against protein kinase RNA-activated (PKR) is employed, and IP efficiency is determined by Western blotting. The analysis results show that the antibody immobilized beads can indeed be used to enrich PKR while non-specific protein interactions are minimal.

Preparation of Polypentafluorophenyl acrylate Functionalized SiO2 Beads for Protein Purification

A protocol for the preparation of poly(pentafluorophenyl acrylate) (poly(PFPA)) grafted silica beads is presented. The poly(PFPA) functionalized surface is then immobilized with antibodies and used successfully for the protein separation through immunoprecipitation.

단백질 정화에 대 한 Poly(pentafluorophenyl acrylate) 기능성 SiO2 구슬의 준비

We demonstrate a simple method to prepare poly(pentafluorophenyl acrylate) (poly(PFPA)) grafted silica beads for antibody immobilization and subsequent ...

Fabrication of Thin Film Silver/Silver Chloride Electrodes with Finely Controlled Single Layer Silver Chloride

This paper aims to present a protocol to form smooth and well-controlled films of silver/silver chloride (Ag/AgCl) with designated coverage on top of thin film silver electrodes. Thin film silver electrodes sized 80 &#181;m x 80 &#181;m and 160 &#181;m x 160 &#181;m were sputtered on quartz wafers with a chromium/gold (Cr/Au) layer for adhesion. After passivation, polishing and cathodic cleaning processes, the electrodes underwent galvanostatic oxidation with consideration of Faraday&#39;s Law of Electrolysis to form smooth layers of AgCl with a designated degree of coverage on top of the silver electrode. This protocol is validated by inspection of scanning electron microscope (SEM) images of the surface of the fabricated Ag/AgCl thin film electrodes, which highlights the functionality and performance of the protocol. Sub-optimally fabricated electrodes are fabricated as well for comparison. This protocol can be widely used to fabricate Ag/AgCl electrodes with specific impedance requirements (e.g., probing electrodes for impedance sensing applications like impedance flow cytometry and interdigitated electrode arrays).

This paper aims to present a method to form smooth and well-controlled films of silver chloride (AgCl) with designated coverage on top of thin film silver electrodes.

정밀하게 제어된 단일 층 실버 염화물필름 의 박막 실버/실버 염화물 전극 제조

This paper aims to present a protocol to form smooth and well-controlled films of silver/silver chloride (Ag/AgCl) with designated coverage on top of thin ...

유세포 분석에서의 Porphyrin-modified beads

Porphyrin-Modified Beads for Use as Compensation Controls in Flow Cytometry

Flow cytometry can rapidly characterize and quantify diverse cell populations based on fluorescence measurements. The cells are first stained with one or more fluorescent reagents, each functionalized with a different fluorescent molecule (fluorophore) that binds to cells selectively based on their phenotypic characteristics, such as cell surface antigen expression. The intensity of fluorescence from each reagent bound to cells can be measured on the flow cytometer using channels that detect a specified range of wavelengths. When multiple fluorophores are used, the light from individual fluorophores often spills over into undesired detection channels, which requires a correction to the fluorescence intensity data in a process called compensation. 
Compensation control particles, typically polymer beads bound to a single fluorophore, are needed for each fluorophore used in a cell labeling experiment. Data from compensation particles from the flow cytometer are used to apply a correction to the fluorescence intensity measurements. This protocol describes the preparation and purification of polystyrene compensation beads covalently functionalized with the fluorescent reagent meso-tetra(4-carboxyphenyl) porphine (TCPP) and their application in flow cytometry compensation. In this work, amine-functionalized polystyrene beads were treated with TCPP and the amide coupling reagent EDC (N-(3-dimethylaminopropyl)-N&#8242;-ethylcarbodiimide hydrochloride) at pH 6 and at room temperature for 16 h with agitation. The TCPP beads were isolated by centrifugation and resuspended in a pH 7 buffer for storage. TCPP-related particulates were observed as a byproduct. The number of these particulates could be reduced using an optional filtration protocol. The resultant TCPP beads were successfully used on a flow cytometer for compensation in experiments with human sputum cells labeled with multiple fluorophores. The TCPP beads proved stable following storage in a refrigerator for 300 days.

저자 스포트라이트: Porphyrin-Modified Beads for Use as Compensation Control in Flow Cytometry  

The protocol describes how porphyrin-based compensation beads for flow cytometry are prepared by the reaction of amine-functionalized polystyrene beads with the porphyrin TCPP and the amide coupling reagent EDC. A filtration procedure is used to reduce the particulate byproducts.

유세포 분석에서 보상 대조군으로 사용하기 위한 포르피린 변형 비드

Flow cytometry can rapidly characterize and quantify diverse cell populations based on fluorescence measurements. The cells are first stained with one or ...