Modeling of dielectrophoretic transport of myoglobin molecules in microchannels

Abstract

Myoglobin is one of the premature identifying cardiac markers, whose concentration increases from 90 pg/ml or less to over 250 ng/ml in the blood serum of human beings after minor heart attack. Separation, detection, and quantification of myoglobin play a vital role in revealing the cardiac arrest in advance, which is the challenging part of ongoing research. In the present work, one of the electrokinetic approaches, i.e., dielectrophoresis ͑DEP͒, is chosen to separate the myoglobin. A mathematical model is developed for simulating dielectrophoretic behavior of a myoglobin molecule in a microchannel to provide a theoretical basis for the above application. This model is based on the introduction of a dielectrophoretic force and a dielectric myoglobin model. A dielectric myoglobin model is developed by approximating the shape of the myoglobin molecule as sphere, oblate, and prolate spheroids. A generalized theoretical expression for the dielectrophoretic force acting on respective shapes of the molecule is derived. The microchannel considered for analysis has an array of parallel rectangular electrodes at the bottom surface. The potential and electric field distributions are calculated using Green's theorem method and finite element method. These results also compared to the Fourier series method, closed form solutions by Morgan et al. ͓J. Phys. D: Appl. Phys. 34, 1553 ͑2001͔͒ and Chang et al. ͓J. Phys. D: Appl. Phys. 36, 3073 ͑2003͔͒. It is observed that both Green's theorem based analytical solution and finite element based numerical solution for proposed model are closely matched for electric field and square electric field gradients. The crossover frequency is obtained as 40 MHz for given properties of myoglobin and for all approximated shapes of myoglobin molecule. The effect of conductivity of medium and myoglobin on the crossover frequency is also demonstrated. Further, the effect of hydration layer on the crossover frequency of myoglobin molecules is also presented. Both positive and negative DEP effects on myoglobin molecules are obtained by switching the frequency of applied electric field. The effect of different shapes of myoglobin on DEP force is studied and no significant effect on DEP force is observed. Finally, repulsion of myoglobin molecules from the electrode plane at 1 KHz frequency and 10 V applied voltage is observed. These results provide the ability of applying DEP force for manipulating nanosized biomolecules such as myoglobin.

Tuning direct current streaming dielectrophoresis of proteins

“…As motivated in the Introduction, a generic model describing protein polarization is still lacking, so that we relate our theoretical considerations on well-established classical theories for solid particles. Although this approach surely does not take into account all subtleties of protein polarization, it allowed others 40 and us 25 to study transport phenomena based on DEP in microfluidic environments. Because this approach is the basis for our numerical simulations, it is briefly reviewed here.…”

“…Moreover, a generic theoretical model predicting protein polarizability and accounting for the large protein variety has not been developed yet. DEP based transport phenomena have been studied following Maxwell Wagner O'Konski theory 39 while assuming a globular protein shape 40 and on the basis of experimentally reported protein conductivity. 25 For nanocolloids, corrections to the classical Maxwell Wagner O'Konski approach were suggested due to the apparent size dependent crossover frequencies.…”

Dielectrophoresis for Manipulation of Bioparticles

“…Maximum concentration distribution of the myoglobin was found at 240 nm, the channel height from the bottom wall under 10 Vpp, and 1 kHz AC voltage and frequency respectively. Both, positive and negative DEP effects were observed at 50 MHz and 1 kHz AC frequency respectively 2010b).…”

“…The particles are levitated to certain height due to repulsive DEP forces. This analysis is applied to myoglobin 2010b) to study the behavior of myoglobin in microchannel. In their study, a channel of 400 nm length and 300 nm height with 100 nm width electrodes and 100 nm gap is utilized to create nonuniformities in the electric field gradients.…”

Myoglobin-biomimetic electroactive materials made by surface molecular imprinting on silica beads and their use as ionophores in polymeric membranes for potentiometric transduction

“…Human Mb has 153 amino acid residues in a highly folded and compact structure with eight separate and distinct alpha helical secondary structures and molecular weight 16.7 kDa. The dimension of Myoglobin is (3 nm × 4 nm × 5 nm) and the molar volume is 1.87 × 104 cm 3 mol −1 (Singh-Zocchi et al, 2002;Gunda and Mitra, 2010).…”