Electrokinetic transport properties of deoxynucleotide monophosphates (dNMPs) through α-phase phosphorene carbide nanochannel for electrophoretic detection

Abstract

Electrokinetic identification of biomolecules is an effective analytical method in which an electric field drives the nucleic acids, peptides, and other species through a nanoscale channel and the time of flight (TOF) is recorded. The mobilities of the molecules are determined by the water/nanochannel interface, including the electrostatic interactions, surface roughness, van der Waals interactions, and hydrogen bonding. The recently reported α-phase phosphorus carbide (α-PC) has an intrinsically wrinkled structure that can efficiently regulate the migrations of biomacromolecules on it, making it a highly promising candidate for the fabrication of nanofluidic devices for electrophoretic detection. Herein, we studied the theoretical electrokinetic transport process of dNMPs in α-PC nanochannel. Our results clearly show that the α-PC nanochannel can efficiently separate dNMPs in a wide range of electric field strengths from 0.5 to 0.8 V nm⁻¹. The electrokinetic speed order is deoxy thymidylate monophosphates (dTMP) > deoxy cytidylate monophosphates (dCMP) > deoxy adenylate monophosphates (dAMP) > deoxy guanylate monophosphates (dGMP) and is almost independent of the electric field strength. For a nanochannel with a typical height of 3.0 nm and an optimized electric field of 0.7–0.8 V nm⁻¹, the difference in TOF is large enough to guarantee accurate identification. We find that dGMP is the weakest link among the four dNMPs for sensitive detection in the experiment because its velocity always shows large fluctuations. This is because of its significantly different velocities when dGMP is bound to α-PC in different orientations. In contrast, for the other three nucleotides, the velocities are independent of the binding orientations. The high performance of the α-PC nanochannel is attributed to its wrinkled structure in which the nanoscale grooves can form nucleotide-specific interactions that greatly regulate the transport velocities of the dNMPs. This study illustrates the high potential of α-PC for electrophoretic nanodevices. This could also provide new insights for the detection of other types of biochemical or chemical molecules.