Fabrication of bio/nano interfaces between biological cells and carbon nanotubes using dielectrophoresis

Abstract

The authors have previously demonstrated the manipulation of bacteria and carbon nanotubes (CNTs) using dielectrophoresis (DEP) and its application for various types of biological and chemical sensors. This paper demonstrates simultaneous DEP handling of bacteria and CNTs, which are mixed and suspended in water. The CNTs were solubilized in water using microplasma-based treatment. When a microelectrode was energized with an ac voltage in the suspension of Escherichia coli (E. coli) cells and multi-walled CNTs (MWCNTs), both of them were simultaneously trapped in the microelectrode gap. Scanning electron microscopy (SEM) images revealed that E. coli cells were trapped on the surface or the tip of MWCNTs, where the electric field strength was intensified due to high aspect ratio of MWCNTs. As a result, bio/nano interfaces between bacteria and MWCNTs were automatically formed in a self-assembly manner. A potential application of the DEP-fabricated bio/nano interfaces is a drug delivery system (DDS), which is realized by transporting drug molecules from CNTs to cells across the cell membrane, which can be electroporated by the local high electric field formed on the CNT surface.

DNA Hybridization Sensors Based on Electrochemical Impedance Spectroscopy as a Detection Tool

“…The magnetic nanoparticles modified with HBV probe DNA was attached to the gold surface, and the hybridization with the target HBV sequence was detected by an increase in resistance using non-faradaic EIS, which led to the detection limit of 50 pmol for a 20 μL sample [ 77 ]. Another example of the nanoparticle platform as a sensing material is praseodymium oxide nanoparticles with a high dielectric constant, a large band gap, and a high electron affinity [ 78 ]. Thiol modified probe DNA attached to the amine-modified praseodymium oxide nanoparticles was allowed to hybridize with its target DNA, which was detected by the decrease in capacitance without a redox indicator present.…”

Carbon nanotube dielectrophoresis: Theory and applications

“…This section discusses the use of MWNTs in DEP‐based microfluidic applications involving alignment, self‐assembly, sensing, and separations following a similar layout as for SWNTs above. Additionally, Table 3 [38, 143, 144, 146, 205, 215‐234] enlists the various applications for MWNTs discussed in Section 6.…”

“…Owing to its versatile surface properties, MWNTs have also been used for their surface functionalization properties as a bio/nanointerface to capture and trap bacterial cells using DEP [234]. A mixture of MWNTs and E. coli were used for pDEP trapping using interdigitated microelectrodes formed by a chrome film patterned on a glass substrate.…”

Scanning Techniques for Nanobioconjugates of Carbon Nanotubes

“…One of the important applications is CNT-mediated drug delivery [ 155 , 161 , 168 – 189 ]. The fabrication of bio/nanointerfaces of Escherichia coli and MWNTs has been described Suehiro et al [ 157 ]. In the unique approach, a mixture of E. coli and solubilized MWNTs was deposited between two microelectrodes.…”

“…(c) Trapped cells and MWNTs. (d) Cells trapped at the tip of MWNTs (reprinted from Suehiro et al [ 157 ] with permission).…”