Dielectrophoretic force characteristics toward Lactobacillus casei on an oblique-patterned electrode
Khazanna (a), Sri Fitriyani (b), Rini Safitri (a), Kurnia Lahna (a), Elin Yusibani (a), Irwansyah (c), Edwar Iswardy (a*)

(a) Department of Physics, Faculty of Mathematics and Natural Sciences, Universitas Syiah Kuala, Banda Aceh 23111, Indonesia
(b) Department of Dental Materials, Faculty of Dentistry, Universitas Syiah Kuala, Banda Aceh 23111, Indonesia
(c) Department of Mechanical Engineering, Faculty of Engineering, Universitas Syiah Kuala, Banda Aceh 23111, Indonesia
* edwariswardy[at]usk.ac.id

Abstract

Dielectrophoresis-based biochips with various microelectrode configurations have been extensively studied within the last five decades. However, wide-field application is still challenging. This study aims to fabricate an oblique-configuration microelectrode and then utilizes to determine the dielectrophoretic (DEP) characteristics of Lactobacillus casei based on the generated non-uniform electric field. The analysis of electric field distribution on microelectrodes was simulated with Quickfield 6.6 student version software. The oblique microelectrodes were fabricated using a copper film on a glass substrate. Meanwhile, testing the DEP characteristics of Lactobacillus casei was carried out by applying a sinusoidal AC signal to the microelectrode. The medium solution was prepared with an electrical conductivity of 0.05 S/m. The results on electric field simulation showed that the strongest electric field was generated on the electrode spacing region, and the weakest electric field was generated on the electrode tip spacing. The testing on the fabricated oblique-patterned microelectrode toward Lactobacillus casei showed that the negative DEP force was observed at the frequency of 60-130 kHz, while the positive DEP force was observed at the frequency of 380-700 kHz at a voltage of 2-6 Vpp. The negative DEP force caused Lactobacillus casei to be pushed toward the weak electric field on the electrode tip space area, and the positive DEP force induced Lactobacillus casei to be attracted toward the strong field on the electrode spacing. In general, the presence of negative and positive DEP phenomena provides a promising opportunity for bioparticle separation applications on the fabricated oblique-patterned microelectrode.

Keywords: Dielectrophoresis- Oblique microelectrode- Non-uniform electric field- AC signal- Lactobacillus casei

Topic: Biophysics and Medical Physics