この研究は、中国国家自然科学基金会(助成金番号61974004および61931018)および中国国家重点研究開発プログラム(助成金番号2021YFB3200100)の支援を受けています。この研究は、北京大学の電子顕微鏡研究所が電子顕微鏡へのアクセスを提供したことを認めています。さらに、この研究は、ラマン測定の支援をしてくれたYing Cui氏と北京大学地球宇宙科学院にも感謝しています。

1. ナノ粒子の合成
<ol><li>硝酸銀溶液の調製<ol><li>精密天秤を使用して、0.0017 g の AR グレード硝酸銀(AgNO3、 材料表を参照)を測定し、10 mL の脱イオン(DI)水に加えます。混合物を撹拌して、10-3 mol/L AgNO3 溶液を作成します。</li>
	</ol></li>
	<li>銀 - アンモニア錯体の調製<ol><li>ARグレードのアンモニア水1mL(NH3.H2O、 材料表参照)をシリンジを用いて、撹拌しながら硝酸銀溶液に一滴ずつ加える。溶液が明確になったら、滴下を停止します。</li>
	</ol></li>
	<li>グルコース溶液の調製<ol><li>精密天秤を使用して、0.36 gのARグレードのグルコースパウダー( 材料表を参照)を測定し、10 mLの脱イオン水に加えます。混合物を完全に攪拌して、0.2 Mグルコース溶液を作成します。</li>
	</ol></li>
	<li>銀ナノ粒子(AgNP)の合成<ol><li>ピペットガンを使用して、30 μLの銀-アンモニア錯体(ステップ1.2で調製)をグルコース溶液(ステップ1.3で調製)に30分間隔で添加します。溶液が黄色に変わるまでかき混ぜながら、このプロセスを4〜6回繰り返します。</li>
	</ol></li>
</ol>2. フレキシブル基板の作製
<ol><li>PDMS基板の作製<ol><li>PDMS基質を合成するには、約5gのPDMS A溶液を採取し、B溶液(市販のキットから、 材料表を参照)を1:10の比率で添加します。</li>
		<li>PDMS A溶液とPDMS B溶液を攪拌し、完全に混合します。</li>
		<li>混合したPDMSを角い皿に移し、80°Cのオーブンで2時間焼きます。</li>
		<li>上記の工程で硬化させた後、メスを使ってペトリ皿の暗い格子に沿ってPDMSを切断し、約1cm×1cmの小さなPDMS立方体を作ります。</li>
	</ol></li>
	<li>表面改質<ol><li>前述の小さなPDMS片をプラズマ処理します。ハンドヘルドプラズマプロセッサ( 材料表を参照)を使用し、PDMS表面から約5〜10cm上を前後に動かして、表面プラズマ処理を行います。</li>
		<li>プラズマプロセッサを利用して表面を改質し、PDMS表面にヒドロキシル基の形成を誘導し、親水性にします27。</li>
	</ol></li>
	<li>APTESによる変更<ol><li>10%APTES溶液を調製します( 材料表を参照)。</li>
		<li>ステップ2.2で得られた表面改質PDMSをAPTES溶液に浸漬し、10時間放置します。これにより、APTESはPDMS表面のヒドロキシル基と結合することができます。</li>
	</ol></li>
	<li>AgNPの自己組織化<ol><li>ステップ2.3で得られたPDMS基板を、ステップ1.4で合成したAgNPs溶液に10時間浸漬する。これにより、AgNPがPDMS基板上に自己組織化され、最終的なフレキシブルSERS検出基板が作成されます。</li>
	</ol></li>
</ol>

R6GおよびThiramのSERS検出用フレキシブル基板の作製

<ol>
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著者は利益相反がないことを宣言します。

本研究では、化学修飾によりAgNPとPDMSを結合させたフレキシブルSERS基板を導入し、優れた性能を達成しました。粒子合成中、特に銀アンモニア錯体合成(ステップ1.2)では、溶液の色が重要な役割を果たします。水滴にアンモニアを添加しすぎると、AgNPの合成品質に悪影響を及ぼし、検出結果に失敗する可能性があります。合成プロセス中の基質修飾(ステップ2.2)に注意を払う必要があります?...

表面増強ラマン散乱(SERS)は、ラマン散乱の一種として、高感度で穏やかな検出条件という利点があり、単一分子検出も実現できます1,2,3,4。金や銀などの金属ナノ構造は、通常、物質検出を可能にするためのSERS基板として使用されます5,6。ナノ構造表面の電磁結合強化は、SERSアプリケーションにおいて重要な役割を果たします。さまざまなサイズ、形状、粒子間距離、組成の金属ナノ構造が凝集して多数の「ホットスポット」を形成し、局所的な表面プラズモン共鳴により強い電磁場を生成する可能性があります7,8。多くの研究により、SERS基質として異なる形態の金属ナノ粒子が開発され、SERS増強の達成における有効性が実証されています9,10。
フレキシブルSERS基板は、SERS効果を生み出すことができるナノ構造をフレキシブル基板上に堆積させ、曲面での直接検出を容易にすることで、幅広い用途に使用されています。フレキシブルSERS基質は、不規則な表面、非平面的な表面、または曲面上の分析種の検出と収集に使用されます。一般的なフレキシブルSERS基板には、繊維、ポリマーフィルム、および酸化グラフェンフィルムが含まれる11,12,13,14。その中で、ポリジメチルシロキサン(PDMS)は最も広く使用されているポリマー材料の1つであり、高い透明性、高い引張強度、化学的安定性、非毒性、接着性などの利点があります15,16,17。PDMSはラマン断面積が小さいため、ラマン信号への影響はごくわずかです18。PDMSプレポリマーは液状であるため、熱や光で硬化させることができ、高い制御性と利便性を提供します。PDMSベースのSERS基質は、比較的一般的なフレキシブルSERS基質であり、例示的な性能を有する異なる生化学物質を検出するための様々な金属ナノ粒子を埋め込むために以前の研究で使用されてきた19,20。
SERS基板の作製では、ナノギャップ構造の作製が重要です。物理堆積技術には、高いスケーラビリティ、均一性、再現性などの利点がありますが、通常、良好な真空条件と特殊な機器が必要であり、その実用化には限界があります21。さらに、数ナノメートルスケールでナノ構造を作製することは、従来の堆積技術では依然として困難である22。その結果、化学的手法で合成されたナノ粒子は、様々な相互作用により柔軟な透明膜に吸着し、ナノスケールでの金属構造の自己組織化を促進することができます。吸着の成功を確実にするために、フィルム表面を物理的または化学的に修飾してその表面親水性を変化させることによって相互作用を調整することができる23。銀ナノ粒子は、金ナノ粒子と比較して、より優れたSERS性能を示すが、その不安定性、特に空気中での酸化に対する感受性は、SERS増強係数(EF)の急速な低下をもたらし、基板性能に影響を与える24。そのため、安定な粒子法の開発が不可欠です。
残留農薬の存在は大きな注目を集めており、現場で食品中のさまざまなクラスの有害化学物質を迅速に検出および特定できる堅牢な方法が緊急に必要とされています25,26。フレキシブルSERS基板は、実用化、特に食品安全の分野で独自の利点を提供します。本稿では、合成したグルコース被覆銀ナノ粒子(AgNP)をPDMS基板上に結合させることにより、フレキシブルSERS基板を調製する方法を紹介します(図1)。グルコースの存在はAgNPを保護し、空気中の銀の酸化を軽減します。この基質は優れた検出性能を発揮し、ローダミン6G(R6G)を10〜10M、農薬チラムを10〜8Mと低く検出し、均一性に優れています。さらに、フレキシブル基板は、ボンディングやサンプリングによる検出にも使用でき、多くのアプリケーションシナリオが考えられます。

<table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always">
	<tbody>
		<tr>
			<td>Ammonia (NH3.H2O, 25%)</td>
			<td>Beijing Chemical Works</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>APTES (98%)</td>
			<td>Beyotime</td>
			<td>ST1087</td>
			<td></td>
		</tr>
		<tr>
			<td>BD-20AC Laboratory Chrona Treater</td>
			<td>Electro-Technic Products Inc.</td>
			<td>12051A</td>
			<td></td>
		</tr>
		<tr>
			<td>D-glucose</td>
			<td>Beijing Chemical Works</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Environmental Scanning electron microscope (ESEM)</td>
			<td>FEI</td>
			<td>QUANTA 250</td>
			<td></td>
		</tr>
		<tr>
			<td>Raman microscope</td>
			<td>Horiba JY</td>
			<td>LabRAM HR Evolution</td>
			<td></td>
		</tr>
		<tr>
			<td>Rhodamine 6G</td>
			<td>Beijing Chemical Works</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Silicone Elastomer Base and Silicone Elastomer Curing Agent</td>
			<td>Dow Corning Corporation</td>
			<td>SYLGARD 184</td>
			<td></td>
		</tr>
		<tr>
			<td>Silver nitrate</td>
			<td>Beijing Chemical Works</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Thiram (C6H12N2S2, 99.9%)</td>
			<td>Beijing Chemical Works</td>
			<td></td>
			<td></td>
		</tr>
	</tbody>
</table>

fabrication of polydimethylsiloxane (pdms)-based flexible surface-enhanced raman scattering (sers) substrate for ultrasensitive detection

本稿では、表面増強ラマン散乱(SERS)用に設計されたフレキシブル基板の作製方法を紹介します。銀ナノ粒子(AgNP)は、硝酸銀(AgNO3)とアンモニアとの錯体化反応を経て合成され、その後グルコースで還元されました。得られたAgNPは、20nmから50nmの範囲で均一な粒度分布を示しました。続いて、3-アミノプロピルトリエトキシシラン(APTES)を用いて、酸素プラズマで表面処理したPDMS基板を改質しました。このプロセスにより、基板上へのAgNPの自己組織化が容易になりました。様々な実験条件が基板性能に及ぼす影響を系統的に評価した結果、優れた性能とエンハンスドファクター(EF)を持つSERS基板が開発されました。この基質を利用して、R6G(ローダミン6G)で10-10 M、チラムで10-8 Mという優れた検出限界を達成しました。この基質は、リンゴの残留農薬の検出に使用され、非常に満足のいく結果が得られました。フレキシブルなSERS基板は、複雑なシナリオでの検出など、実際のアプリケーションに大きな可能性を秘めています。

本研究では、合成AgNPをグルコースで包み、APTESを用いてPDMS上で自己組織化させた柔軟なSERS基質を開発し、実用的な農薬検出アプリケーションにおいて優れた検出性能を実現しました。R6G と Thiram の検出限界は、それぞれ 10-10 M と 10-8 M で到達し、エンハンスメント係数 (EF) は 1 x 10 5 でした。さらに、基板は均一性を示した。
グルコースに包まれ...

Watch this Scientific Journal Video about Development and Application of SERS Flexible Substrates Using Synthesized AgNPs at JoVE.com

著者スポットライト:合成AgNPを用いたSERSフレキシブル基板の開発と応用 

このプロトコルでは、表面増強ラマン散乱用のフレキシブル基板の製造方法について説明します。この分析法は、低濃度の R6G と Thiram の検出に使用されています。

超高感度検出のためのポリジメチルシロキサン(PDMS)ベースのフレキシブル表面増強ラマン散乱(SERS)基板の作製

This article presents a fabrication method for a flexible substrate designed for Surface-Enhanced Raman Scattering (SERS). Silver nanoparticles (AgNPs) ...

このプロトコルでは、SERSフレキシブル基板を調製し、実際の検出シナリオに適用する方法について説明します。このプロトコルが提供するSERSフレキシブル基板は、環境に優しく、優れた検出性能を実現します。銀ナノ粒子は、単純な容器で容易に合成でき、複雑な実験条件や環境を必要としません。当研究室では、本研究で用いた容器を通して合成された銀ナノ粒子の研究に注力していく予定です。SERS検出機能を強化し、その独自の特性と特性を活用して、より高性能なSERS検出基板を設計する方法を探ります。

fabrication-polydimethylsiloxane-pdms-based-flexible-surface-enhanced

Research

JoVE Journal

Engineering

Fabrication of polydimethylsiloxane (PDMS)-Based Flexible Surface-Enhanced Raman Scattering (SERS) Substrate for Ultrasensitive Detection

2.0K ビュー.  Peking University. このプロトコルでは、SERSフレキシブル基板を調製し、実際の検出シナリオに適用する方法について説明します。このプロトコルが提供するSERSフレキシブル基板は、環境に優しく、優れた検出性能を実現します。銀ナノ粒子は、単純な容器で容易に合成でき、複雑な実験条件や環境を必要としません。当研究室では、本研究で用いた容器を通して合成された銀ナノ?...

ビデオ: 著者スポットライト:合成AgNPを用いたSERSフレキシブル基板の開発と応用 

Coherent anti-Stokes Raman Scattering (CARS) Microscopy Visualizes Pharmaceutical Tablets During Dissolution

Traditional pharmaceutical dissolution tests determine the amount of drug dissolved over time by measuring drug content in the dissolution medium. This method provides little direct information about what is happening on the surface of the dissolving tablet. As the tablet surface composition and structure can change during dissolution, it is essential to monitor it during dissolution testing. In this work coherent anti-Stokes Raman scattering microscopy is used to image the surface of tablets during dissolution while UV absorption spectroscopy is simultaneously providing inline analysis of dissolved drug concentration for tablets containing a 50% mixture of theophylline anhydrate and ethyl cellulose. The measurements showed that in situ CARS microscopy is capable of imaging selectively theophylline in the presence of ethyl cellulose. Additionally, the theophylline anhydrate converted to theophylline monohydrate during dissolution, with needle-shaped crystals growing on the tablet surface during dissolution. The conversion of theophylline anhydrate to monohydrate, combined with reduced exposure of the drug to the flowing dissolution medium resulted in decreased dissolution rates. Our results show that in situ CARS microscopy combined with inline UV absorption spectroscopy is capable of monitoring pharmaceutical tablet dissolution and correlating surface changes with changes in dissolution rate.

Coherent anti-Stokes Raman Scattering CARS Microscopy Visualizes Pharmaceutical Tablets During Dissolution

Coherent anti-Stokes Raman scattering (CARS) microscopy is combined with an intrinsic flow-through dissolution setup to allow in situ and real-time visualization of the surface of pharmaceutical tablets undergoing dissolution. Using this custom-built setup, it is possible to correlate CARS videos with drug dissolution profiles recorded using inline UV absorption spectroscopy.

溶解中にコヒーレント反ストークスラマン散乱（CARS）顕微鏡可視化薬錠

Traditional pharmaceutical dissolution tests determine the amount of drug dissolved over time by measuring drug content in the dissolution medium. This ...

工学

Surface Enhanced Raman Spectroscopy Detection of Biomolecules Using EBL Fabricated Nanostructured Substrates

Fabrication and characterization of conjugate nano-biological systems interfacing metallic nanostructures on solid supports with immobilized biomolecules is reported. The entire sequence of relevant experimental steps is described, involving the fabrication of nanostructured substrates using electron beam lithography, immobilization of biomolecules on the substrates, and their characterization utilizing surface-enhanced Raman spectroscopy (SERS). Three different designs of nano-biological systems are employed, including protein A, glucose binding protein, and a dopamine binding DNA aptamer. In the latter two cases, the binding of respective ligands, D-glucose and dopamine, is also included. The three kinds of biomolecules are immobilized on nanostructured substrates by different methods, and the results of SERS imaging are reported. The capabilities of SERS to detect vibrational modes from surface-immobilized proteins, as well as to capture the protein-ligand and aptamer-ligand binding are demonstrated. The results also illustrate the influence of the surface nanostructure geometry, biomolecules immobilization strategy, Raman activity of the molecules and presence or absence of the ligand binding on the SERS spectra acquired.

We describe the fabrication and characterization of nano-biological systems interfacing nanostructured substrates with immobilized proteins and aptamers. The relevant experimental steps involving lithographic fabrication of nanostructured substrates, bio-functionalization, and surface-enhanced Raman spectroscopy (SERS) characterization, are reported. SERS detection of surface-immobilized proteins, and probing of protein-ligand and aptamer-ligand binding is demonstrated.

表面EBL作製したナノ構造基板を用いた生体分子のラマン分光検出の強化

Fabrication and characterization of conjugate nano-biological systems interfacing metallic nanostructures on solid supports with immobilized biomolecules ...

Stimulated Stokes and Antistokes Raman Scattering in Microspherical Whispering Gallery Mode Resonators

Dielectric microspheres can confine light and sound for a length of time through high quality factor whispering gallery modes (WGM). Glass microspheres can be thought as a store of energy with a huge variety of applications: compact laser sources, highly sensitive biochemical sensors and nonlinear phenomena. A protocol for the fabrication of both the microspheres and coupling system is given. The couplers described here are tapered fibers. Efficient generation of nonlinear phenomena related to third order optical non-linear susceptibility &#935;(3) interactions in triply resonant silica microspheres is presented in this paper. The interactions here reported are: Stimulated Raman Scattering (SRS), and four wave mixing processes comprising Stimulated Anti-stokes Raman Scattering (SARS). A proof of the cavity-enhanced phenomenon is given by the lack of correlation among the pump, signal and idler: a resonant mode has to exist in order to obtain the pair of signal and idler. In the case of hyperparametric oscillations (four wave mixing and stimulated anti-stokes Raman scattering), the modes must fulfill the energy and momentum conservation and, last but not least, have a good spatial overlap.

Efficient generation of nonlinear phenomena related to third order optical non-linear susceptibility &#935;(3) interactions in triply resonant silica microspheres is presented in this paper. The interactions here reported are: Stimulated Raman Scattering (SRS), and four wave mixing processes comprising Stimulated Anti-stokes Raman Scattering (SARS).

微小球ウィスパリングギャラリーモード共振器で刺激ストークスとAntistokesラマン散乱

Dielectric microspheres can confine light and sound for a length of time through high quality factor whispering gallery modes (WGM). Glass microspheres ...

Scanning Light Scattering Profiler (SLPS) Based Methodology to Quantitatively Evaluate Forward and Backward Light Scattering from Intraocular Lenses

The scanning light scattering profiler (SLSP) methodology has been developed for the full-angle quantitative evaluation of forward and backward light scattering from intraocular lenses (IOLs) using goniophotometer principles. This protocol describes the SLSP platform and how it employs a 360&#176; rotational photodetector sensor that is scanned around an IOL sample while recording the intensity and location of scattered light as it passes through the IOL medium. The SLSP platform can be used to predict, non-clinically, the propensity for current and novel IOL designs and materials to induce light scatter. Non-clinical evaluation of light scattering properties of IOLs can significantly reduce the number of patient complaints related to unwanted glare, glistening, optical defects, poor image quality, and other phenomena associated with the unintended light scattering. Future studies should be conducted to correlate SLSP data with clinical results to help identify which measured light scatter is most problematic for patients that have undergone cataract surgery subsequent to IOL implantation.

Scanning Light Scattering Profiler SLPS Based Methodology to Quantitatively Evaluate Forward and Backward Light Scattering from Intraocular Lenses

This protocol describes the scanning light scattering profiler (SLSP) that enables the full-angle quantitative evaluation of forward and backward scattering of light from intraocular lenses (IOLs) using goniophotometer principles.

眼内レンズからの前方散乱光および後方散乱光を定量的に評価するための走査型光散乱プロファイラ（SLPS）に基づく方法論

The scanning light scattering profiler (SLSP) methodology has been developed for the full-angle quantitative evaluation of forward and backward light ...

Scalable Solution-processed Fabrication Strategy for High-performance, Flexible, Transparent Electrodes with Embedded Metal Mesh

Here, the authors report the embedded metal-mesh transparent electrode (EMTE), a new transparent electrode (TE) with a metal mesh completely embedded in a polymer film. This paper also presents a low-cost, vacuum-free fabrication method for this novel TE; the approach combines lithography, electroplating, and imprint transfer (LEIT) processing. The embedded nature of the EMTEs offers many advantages, such as high surface smoothness, which is essential for organic electronic device production; superior mechanical stability during bending; favorable resistance to chemicals and moisture; and strong adhesion with plastic film. LEIT fabrication features an electroplating process for vacuum-free metal deposition and is favorable for industrial mass production. Furthermore, LEIT allows for the fabrication of metal mesh with a high aspect ratio (i.e., thickness to linewidth), significantly enhancing its electrical conductance without adversely losing optical transmittance. We demonstrate several prototypes of flexible EMTEs, with sheet resistances lower than 1 &#937;/sq and transmittances greater than 90%, resulting in very high figures of merit (FoM) &#8211; up to 1.5 x 104 &#8211; which are amongst the best values in the published literature.

This protocol describes a solution-based fabrication strategy for high-performance, flexible, transparent electrodes with fully-embedded, thick metal mesh. Flexible transparent electrodes fabricated by this process demonstrate among the highest reported performances, including ultra-low sheet resistance, high optical transmittance, mechanical stability under bending, strong substrate adhesion, surface smoothness, and environmental stability.

埋め込み金属メッシュを用いた高性能で柔軟で透明な電極のための拡張可能なソリューション処理製作戦略

Here, the authors report the embedded metal-mesh transparent electrode (EMTE), a new transparent electrode (TE) with a metal mesh completely embedded in a ...

A Fabrication and Measurement Method for a Flexible Ferroelectric Element Based on Van Der Waals Heteroepitaxy

Flexible non-volatile memories have received much attention as they are applicable for portable smart electronic device in the future, relying on high-density data storage and low-power consumption capabilities. However, the high-quality oxide based nonvolatile memory on flexible substrates is often constrained by the material characteristics and the inevitable high-temperature fabrication process. In this paper, a protocol is proposed to directly grow an epitaxial yet flexible lead zirconium titanate memory element on muscovite mica. The versatile deposition technique and measurement method enable the fabrication of flexible yet single-crystalline non-volatile memory elements necessary for the next generation of smart devices.

In this paper, we present a protocol to directly grow an epitaxial yet flexible lead zirconium titanate memory element on muscovite mica.

作製と Van Der waals 力ヘテロエピタキシーに基づくフレキシブル強誘電性要素の測定法

Flexible non-volatile memories have received much attention as they are applicable for portable smart electronic device in the future, relying on ...

Fabrication of Flexible Image Sensor Based on Lateral NIPIN Phototransistors

Flexible photodetectors have been intensely studied for the use of curved image sensors, which are a crucial component in bio-inspired imaging systems, but several challenging points remain, such as a low absorption efficiency due to a thin active layer and low flexibility. We present an advanced method to fabricate a flexible phototransistor array with an improved electrical performance. The outstanding electrical performance is driven by a low dark current owing to deep impurity doping. Stretchable and flexible metal interconnectors simultaneously offer electrical and mechanical stabilities in a highly deformed state. The protocol explicitly describes the fabrication process of the phototransistor using a thin silicon membrane. By measuring I-V characteristics of the completed device in deformed states, we demonstrate that this approach improves the mechanical and electrical stabilities of the phototransistor array. We expect that this approach to a flexible phototransistor can be widely used for the applications of not only next-generation imaging systems/optoelectronics but also wearable devices such as tactile/pressure/temperature sensors and health monitors.

We present a detailed method to fabricate a deformable lateral NIPIN phototransistor array for curved image sensors. The phototransistor array with an open mesh form, which is composed of thin silicon islands and stretchable metal interconnectors, provides flexibility and stretchability. The parameter analyzer characterizes the electrical property of the fabricated phototransistor.

横 NIPIN フォト トランジスタを用いた柔軟な画像センサーの作製

Flexible photodetectors have been intensely studied for the use of curved image sensors, which are a crucial component in bio-inspired imaging systems, ...

One-Step Approach to Fabricating Polydimethylsiloxane Microfluidic Channels of Different Geometric Sections by Sequential Wet Etching Processes

Polydimethylsiloxane (PDMS) materials are substantially exploited to fabricate microfluidic devices by using soft lithography replica molding techniques. Customized channel layout designs are necessary for specific functions and integrated performance of microfluidic devices in numerous biomedical and chemical applications (e.g., cell culture, biosensing, chemical synthesis, and liquid handling). Owing to the nature of molding approaches using silicon wafers with photoresist layers patterned by photolithography as master molds, the microfluidic channels commonly have regular cross sections of rectangular shapes with identical heights. Typically, channels with multiple heights or different geometric sections are designed to possess particular functions and to perform in various microfluidic applications (e.g., hydrophoresis is used for sorting particles and in continuous flows for separating blood cells6,7,8,9). Therefore, a great deal of effort has been made in constructing channels with various sections through multiple-step approaches like photolithography using several photoresist layers and assembly of different PDMS thin sheets. Nevertheless, such multiple-step approaches usually involve tedious procedures and extensive instrumentation. Furthermore, the fabricated devices may not perform consistently and the resulted experimental data may be unpredictable. Here, a one-step approach is developed for the straightforward fabrication of microfluidic channels with different geometric cross sections through PDMS sequential wet etching processes, that introduces etchant into channels of planned single-layer layouts embedded in PDMS materials. Compared to the existing methods for manufacturing PDMS microfluidic channels with different geometries, the developed one-step approach can significantly simplify the process to fabricate channels with non-rectangular sections or various heights. Consequently, the technique is a way of constructing complex microfluidic channels, which provides a fabrication solution for the advancement of innovative microfluidic systems.

Several methods are available for the fabrication of channels of non-rectangular sections embedded in polydimethylsiloxane microfluidic devices. Most of them involve multistep manufacturing and extensive alignment. In this paper, a one-step approach is reported for fabricating microfluidic channels of different geometric cross sections by polydimethylsiloxane sequential wet etching.

ワンステップ連続湿式エッチング法によって異なる幾何学的なセクションのポリジメチルシロキサン マイクロ流路の加工方法

Polydimethylsiloxane (PDMS) materials are substantially exploited to fabricate microfluidic devices by using soft lithography replica molding techniques. ...

Drawing and Hydrophobicity-patterning Long Polydimethylsiloxane Silicone Filaments

Polydimethylsiloxane (PDMS) silicone is a versatile polymer that cannot readily be formed into long filaments. Traditional spinning methods fail because PDMS does not exhibit long-range fluidity at melting. We introduce an improved method to produce filaments of PDMS by a stepped temperature profile of the polymer as it cross-links from a fluid to an elastomer. By monitoring its warm-temperature viscosity, we estimate a window of time when its material properties are amendable to drawing into long filaments. The filaments pass through a high-temperature tube oven, curing them sufficiently to be harvested. These filaments are on the order of hundreds of micrometers in diameter and tens of centimeters in length, and even longer and thinner filaments are possible. These filaments retain many of the material properties of bulk PDMS, including switchable hydrophobicity. We demonstrate this capability with an automated corona-discharge patterning method. These patternable PDMS silicone filaments have applications in silicone weavings, gas-permeable sensor components, and model microscale foldamers.

Here, we present a protocol to produce long filaments of polydimethylsiloxane (PDMS) silicone by gravity-drawing through a furnace. Filaments are on the order of hundreds of micrometers in diameter and tens of centimeters in length and are hydrophobically patternable via an Arduino-controlled corona discharge system.

図面と疎水性パターン形成の長いポリジメチルシロキサン シリコーン フィラメント

Polydimethylsiloxane (PDMS) silicone is a versatile polymer that cannot readily be formed into long filaments. Traditional spinning methods fail because ...

Scattering And Absorption of Light in Planetary Regoliths

Theoretical, numerical, and experimental methods are presented for multiple scattering of light in macroscopic discrete random media of densely-packed microscopic particles. The theoretical and numerical methods constitute a framework of Radiative Transfer with Reciprocal Transactions (R2T2). The R2T2 framework entails Monte Carlo order-of-scattering tracing of interactions in the frequency space, assuming that the fundamental scatterers and absorbers are wavelength-scale volume elements composed of large numbers of randomly distributed particles. The discrete random media are fully packed with the volume elements. For spherical and nonspherical particles, the interactions within the volume elements are computed exactly using the Superposition T-Matrix Method (STMM) and the Volume Integral Equation Method (VIEM), respectively. For both particle types, the interactions between different volume elements are computed exactly using the STMM. As the tracing takes place within the discrete random media, incoherent electromagnetic fields are utilized, that is, the coherent field of the volume elements is removed from the interactions. The experimental methods are based on acoustic levitation of the samples for non-contact, non-destructive scattering measurements. The levitation entails full ultrasonic control of the sample position and orientation, that is, six degrees of freedom. The light source is a laser-driven white-light source with a monochromator and polarizer. The detector is a mini-photomultiplier tube on a rotating wheel, equipped with polarizers. The R2T2 is validated using measurements for a mm-scale spherical sample of densely-packed spherical silica particles. After validation, the methods are applied to interpret astronomical observations for asteroid (4) Vesta and comet 67P/Churyumov-Gerasimenko (Figure 1) recently visited by the NASA Dawn mission and the ESA Rosetta mission, respectively.

Numerical and experimental methods are presented for multiple scattering of light in discrete random media of densely-packed particles. The methods are utilized to interpret the observations of asteroid (4) Vesta and comet 67P/Churyumov-Gerasimenko.

惑星レゴリスにおける光の散乱と吸収

Theoretical, numerical, and experimental methods are presented for multiple scattering of light in macroscopic discrete random media of densely-packed ...