Cantilever-Droplet-Based Sensing of Magnetic Particle Concentrations in Liquids

Sensors

Maik Bertke¹  Andi Setiono¹  WilsonOmbati Nyang’au¹  Erwin Peiner¹  Harald Bosse² 

[1] Institute of Semiconductor Technology (IHT) and Laboratory of Emerging Nanometrology (LENA), Technische Universität Braunschweig, 38106 Braunschweig, Germany;Precision Engineering Division, Physikalisch-Technische Bundesanstalt (PTB), 38116 Braunschweig, Germany;

关键词: microcantilever;    resonant frequency;    magnetic polystyrene particles;    droplet;    adsorption;    mass;    concentration;   

DOI  :  10.3390/s19214758

来源: DOAJ

【 摘 要 】

Cantilever-based sensors have attracted considerable attention in the recent past due to their enormous and endless potential and possibilities coupled with their dynamic and unprecedented sensitivity in sensing applications. In this paper, we present a technique that involves depositing and vaporizing (at ambient conditions) a particle-laden water droplet onto a defined sensing area on in-house fabricated and commercial-based silicon microcantilever sensors. This process entailed the optimization of dispensing pressure and time to generate and realize a small water droplet volume (V_d = 49.7 ± 1.9 pL). Moreover, we monitored the water evaporation trends on the sensing surface and observed total evaporation time per droplet of 39.0 ± 1.8 s against a theoretically determined value of about 37.14 s. By using monodispersed particles in water, i.e., magnetic polystyrene particles (MPS) and polymethyl methacrylate (PMMA), and adsorbing them on a dynamic cantilever sensor, the mass and number of these particles were measured and determined comparatively using resonant frequency response measurements and SEM particle count analysis, respectively. As a result, we observed and reported monolayer particles assembled on the sensor with the lowest MPS particles count of about 19 ± 2.

【 授权许可】

Unknown