Research

PAPER: Can particles move and deposit, from 25 to 40 deg-C surface? ~40℃表面に微粒子を集積させた流体の制御技術

閉ループ式エアロゾル流によるサブミクロン蛍光粒子の集積 Deposition of Submicron Fluorescent Particles by a Closed-Loop Aerosol Flow

This study considered the deposition of submicron particles on living-cell or “human-body”-modelled surface.本研究では,「細胞」システム・モデル表面上へのサブミクロン粒子の堆積を背景とした。

Why a fluorescence microscope? Because other analytical tools such as SEM, need low pressure or vacuum condition, which is not “good” for living-system. なぜ蛍光顕微鏡? SEMのような他の分析ツールは低圧または真空条件を必要とするが,これは生体系に対して「良い」ではない。

空気・液体界面への粒子の輸送を模倣するために、エアロゾル・フロー・システムが構築された。An aerosol flow system has been constructed to mimic the delivery of particles to the air-liquid interface. A colloidal suspension of submicron fluorescent core-shell silica-based particles was sprayed by an ultrasonic nebulizer. The dynamics of the aerosol settling was investigated by numerical simulation to determine the carrier gas flow rate, which was further verified through experimentation.

Fluorescent microscopy was used to observe the particles deposited on the substrate. It was found that the apparent (fluorescent) size distribution was shifted from 2.9 ± 6.0 μm to 1.7 ± 2.2 μm, which is correlated to the changes of aggregate size from 0.70 μm to 0.24 μm due to the changes in the colloidal suspension concentration. In addition, the uniformity of the particles dispersed on the substrate was not significantly affected by the suspension’s concentration, as confirmed by the inter-particle distance analysis.

It is therefore suggested that the method presented here may potentially be applied for the deposition and analysis of submicron particles on various types of substrate (i.e. air-liquid interface) without the need for vacuum imaging analysis (e.g. electron microscopy).

Comsol

閉ループ式のエアロゾル流システムを構築した。サブミクロンの蛍光コアシェル型シリカ系粒子のコロイド懸濁液を(室温で)噴霧し、温度が40℃の基板に集積させることが目的とした。エアロゾル粒子の沈降の流動状態を数値シミュレーションにより調べた。常圧型可視化法である蛍光顕微鏡法(光学顕微鏡)を用いて、基板上に堆積したサブミクロンの粒子を観察した。基板上に集積粒子の「均一性」は、懸濁液の濃度によって有意な影響を受けなかった。

出発原料のコロイド懸濁液濃度の変化による凝集体サイズの0.70μmから0.24μmへの変化は、見かけの(蛍光)サイズ分布が2.9±6.0μmから1.7±2.2μmに変化する相関が見出された。提案した方法は、真空イメージング分析(電子顕微鏡法SEMなど)を使わないで、基板上のサブミクロン粒子の沈着とその分析に適用できる。

particlesizedistribution

Open/Free Accessdoi.org/10.11203/jar.33.102

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