Next Article in Journal
Pick-and-Place Operation of Single Cell Using Optical and Electrical Measurements for Robust Manipulation
Next Article in Special Issue
Integrated Lateral Flow Device for Flow Control with Blood Separation and Biosensing
Previous Article in Journal
Swimming Characteristics of Bioinspired Helical Microswimmers Based on Soft Lotus-Root Fibers
Previous Article in Special Issue
An Electromagnetically Actuated Double-Sided Cell-Stretching Device for Mechanobiology Research
Article Menu
Issue 12 (December) cover image

Export Article

Open AccessArticle
Micromachines 2017, 8(12), 353; https://doi.org/10.3390/mi8120353

Electrical Tweezer for Droplet Transportation, Extraction, Merging and DNA Analysis

1
Department of Mechanical Engineering, McMaster University, 1280 Main St. W., Hamilton, ON L8S 4L7, Canada
2
Regional Virology Laboratory, St. Joseph’s Healthcare Hamilton, Hamilton, ON L8N 4A6, Canada
3
Department of Pathology and Molecular Medicine, McMaster University, Hamilton, ON L8S 4L8 Canada
4
Department of Electrical and Computer Engineering, McMaster University, Hamilton, ON L8S 4L7, Canada
*
Author to whom correspondence should be addressed.
Received: 1 November 2017 / Revised: 21 November 2017 / Accepted: 28 November 2017 / Published: 30 November 2017
(This article belongs to the Special Issue Biomedical Microdevices: Design, Fabrication and Application)
View Full-Text   |   Download PDF [3491 KB, uploaded 30 November 2017]   |  

Abstract

Droplets of aqueous solutions distributed in an immiscible oil phase are increasingly used and investigated as a means to handle and assay small volumes of samples. The primary attraction of this method is that surface interactions are kept to a minimum, and changes in sample concentration, especially due to adsorption to the walls, are avoided. Microfluidic methods to generate, transport, merge, split and perform reactions in droplets were developed recently. These methods depend on the continuous flow of the two phases involved inside closed microfluidic channels. Alternatively, an electrowetting phenomenon was also exploited to control the movement of droplets between two solid substrates. However, there are some situations where small volume sample transport and assaying are required in open systems. Here, we demonstrate a simple electromechanical probe (tweezers) that is capable of manipulating a small aqueous droplet in a bi-layer oil phase. The tweezer consists of two needles positioned close to each other and uses polarization of the aqueous droplet in an applied electrical field to confine the droplet between the needles with minimal solid contact. Mechanical motion of the tweezer can be used to transport the droplet to various positions. Operations such as aliquoting, merging and transport are demonstrated. Finally, this method was used to perform a DNA amplification assay where droplets of the sample and the amplification mixture are aliquoted separately, mixed and amplified using an in-situ heater. This electromechanical tweezer is of interest in low-throughput, small-volume biological and chemical assays where the investigator requires direct and open access to the samples. View Full-Text
Keywords: droplets; electrical tweezer; microfluidics; amplification; nanoliter; droplet extraction; droplet merging; droplet transportation droplets; electrical tweezer; microfluidics; amplification; nanoliter; droplet extraction; droplet merging; droplet transportation
Figures

Figure 1

This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. (CC BY 4.0).
SciFeed

Share & Cite This Article

MDPI and ACS Style

Shahid, A.; Chong, S.; Mahony, J.; Deen, M.J.; Selvaganapathy, P.R. Electrical Tweezer for Droplet Transportation, Extraction, Merging and DNA Analysis. Micromachines 2017, 8, 353.

Show more citation formats Show less citations formats

Note that from the first issue of 2016, MDPI journals use article numbers instead of page numbers. See further details here.

Related Articles

Article Metrics

Article Access Statistics

1

Comments

[Return to top]
Micromachines EISSN 2072-666X Published by MDPI AG, Basel, Switzerland RSS E-Mail Table of Contents Alert
Back to Top