Electrokinetic Enrichment and Label-Free Electrochemical Detection of Nucleic Acids by Conduction of Ions Along the Surface of Bioconjugated Beads for Point-of-Care Testing

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Berzina, Beatrise
Peramune, Umesha
Claus, Echo L.
Kim, Sungu
Saurabh, Kumar
Strait, Madison E.
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Anand, Robbyn
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The Department of Chemistry seeks to provide students with a foundation in the fundamentals and application of chemical theories and processes of the lab. Thus prepared they me pursue careers as teachers, industry supervisors, or research chemists in a variety of domains (governmental, academic, etc).

The Department of Chemistry was founded in 1880.

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Mechanical Engineering
The Department of Mechanical Engineering at Iowa State University is where innovation thrives and the impossible is made possible. This is where your passion for problem-solving and hands-on learning can make a real difference in our world. Whether you’re helping improve the environment, creating safer automobiles, or advancing medical technologies, and athletic performance, the Department of Mechanical Engineering gives you the tools and talent to blaze your own trail to an amazing career.
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The Department of Electrical and Computer Engineering (ECpE) contains two focuses. The focus on Electrical Engineering teaches students in the fields of control systems, electromagnetics and non-destructive evaluation, microelectronics, electric power & energy systems, and the like. The Computer Engineering focus teaches in the fields of software systems, embedded systems, networking, information security, computer architecture, etc.

The Department of Electrical Engineering was formed in 1909 from the division of the Department of Physics and Electrical Engineering. In 1985 its name changed to Department of Electrical Engineering and Computer Engineering. In 1995 it became the Department of Electrical and Computer Engineering.

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  • Department of Electrical Engineering and Computer Engineering (1985-1995)

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Plant Sciences Institute
The Plant Sciences Institute is dedicated to enhancing Iowa State University's international prominence in the plant sciences. Our research focus is to understand the effects of genotype and environment on phenotypes (traits) sufficiently well that we will be able to predict phenotype of a given genotype in a given environment (i.e., predictive phenomics)
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In this paper, we report a method to integrate electrokinetic pre-enrichment of nucleic acids within a bed of probe-modified microbeads with their label-free electrochemical detection. In this detection scheme, hybridization of locally enriched target nucleic acids to the beads modulates the conduction of ions along the bead surfaces. This is a fundamental advancement in that this mechanism is similar to that observed in nanopore sensors, yet occurs in a bed of microbeads with microscale interstices. In application, this approach has several distinct advantages. First, electrokinetic enrichment requires only a simple DC power supply, and in combination with non-optical detection, makes this method amenable to point-of-care application. Second, the sensor is easy to fabricate, comprised of a packed bed of commercially-available microbeads, which can be readily modified with a wide range of probe types, thereby making this a versatile platform. Finally, the sensor is highly sensitive (picomolar) despite the modest 100-fold pre-enrichment we employ here by faradaic ion concentration polarization (fICP). Further gains are anticipated under conditions for fICP focusing that are known to yield higher enrichment factors (up to 100,000-fold enrichment). Here, we demonstrate detection of 3.7 pM single-stranded DNA complementary to the bead-bound oligoprobe, following a 30-min single step of enrichment and hybridization. Our results indicate that a shift in the slope of a current-voltage curve (CVC) occurs upon hybridization, and that this shift is proportional to the logarithm of the concentration of target DNA. Finally, we investigate the proposed mechanism of sensing by developing a numerical simulation that shows an increase in ion flux through the bed of insulating beads given changes in surface charge and zeta potential consistent with our experimental conditions.
This article is published as Berzina, Beatrise, Umesha Peramune, Echo Claus, Sungu Kim, Kumar Saurabh, Madison Strait, Baskar Ganapathysubramanian, and Robbyn Anand. "Electrokinetic Enrichment and Label-Free Electrochemical Detection of Nucleic Acids by Conduction of Ions Along the Surface of Bioconjugated Beads for Point-of-Care Testing." (2022). DOI: 10.26434/chemrxiv-2022-n3qsl. Copyright 2022 The Authors. The content is available under CC BY NC 4.0 License. Posted with permission.