DNA Base Detection Using 2D Materials Beyond Graphene

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PROJECT SUMMARY/ABSTRACT Two-dimensional (2D) materials have emerged as revolutionary materials for fast, single-nucleotide direct-read DNA sequencing with a minimum amount of consumables. Due to its commercial availability, graphene remains the most widely explored 2D material for DNA sequencing applications. The major hindrance of graphene is the hydrophobic nature of its surface which causes DNA bases to stick to its surface, slowing down translocation speed, and making single-base discrimination difficult as multiple bases interact with graphene at any given time. Furthermore, the lack of a band gap in pristine graphene makes it undesirable for use in electronic detection modalities. With all the disadvantages of graphene, we strongly believe that graphene will not be the ultimate material for DNA sequencing. More promising in our view are approaches that explore the conductive properties of various 2D materials beyond graphene. The primary goal of this research is to perform large-scale, first- principles computational studies to evaluate various 2D materials beyond graphene for faster and affordable DNA sequencing using electronic methods. A secondary goal is to train undergraduate and graduate students in computational materials modeling. To accomplish our goals, we will focus on three independent, but interrelated specific aims as outlined below: (1) DNA base detection using elemental 2D materials. In Aim 1, we will expand on existing studies involving graphene for DNA base detection to include other elemental 2D materials such as silicene, germanene, and phosphorene. One of the major goals of Aim 1 is the research training of undergraduate students. (2) DNA base detection using 2D transition metal dichalcogenides (TMDs). We will perform a comprehensive study of DNA sequencing using six of the most popular TMDs (MoS2, WS2, MoSe2, WSe2, MoTe2, and WTe2). These materials have desirable properties such as tunable direct band gap, excellent mobility, and they are easy to fabricate. Moreover, due to their hydrophilic nature, we anticipate strong couplings with bases on the DNA that can enhance the tunneling currents leading to improved signal-to- noise ratios. (3) DNA base detection using van der Waals (vdW) materials. This activity will shift the current paradigm in DNA sequencing, because we will evaluate, for the first time, the potential of vdW heterostructures for DNA sequencing. vdW systems formed by combining two or more single-layer 2D materials allow for a greater number of potential sensing materials. Also, the synergetic effects produced when different materials are combined could lead to advanced detection principles that are superior to those of the individual materials. The impact of our research will be deeper insights that will help guide the integration of 2D materials as active components of electronic devices for direct-read, affordable DNA sequencing. This award will strengthen the research environment at the University of Central Oklahoma and engage students in computational research. Our research plan has specifically been designed to optimize the utilization of students with diverse background and interests.