Joule heating effects on particle immobilization in insulator‐based dielectrophoretic devices

Abstract

In this work, the temperature effects due to Joule heating obtained by application of a DC electric potential were investigated for a microchannel with cylindrical insulating posts employed for insulator based dielectrophoresis (iDEP). The conductivity of the suspending medium, the local electric field, and the gradient of the squared electric field, which directly affect the magnitude of the dielectrophoretic force exerted on particles, were computationally simulated employing COMSOL Multiphysics. It was observed that a temperature gradient is formed along the microchannel which redistributes the conductivity of the suspending medium leading to an increase of the dielectrophoretic force towards the inlet of the channel while decreasing towards the outlet. Experimental results are in good agreement with simulations on the particle trapping zones anticipated. This study demonstrates the importance of considering Joule heating effects when designing iDEP systems.

Modelling of electrokinetic phenomena for capture of PEGylated ribonuclease A in a microdevice with insulating structures

“…Moreover, previous works exhibit a trend in the values assigned to the correction factor, i.e., the smaller the particle, the higher the correction factor. [33][34][35] For example, for polystyrene beads with diameters of 1 and 4 lm, correction factors of 600 and 100 were required, respectively, to predict DEP trapping. 33 The slope of a correction factor versus particle diameter plot for that work would have a value of À166.667 Â 10 6 (1/m).…”

“…Thus, the effect of sample temperature rise via Joule Heating has a negative impact in the dielectrophoretic response of the proteins in our microfluidic device. 35 The dynamic viscosity of the suspending solution, g, is another parameter with a significant role in the dielectrophoretic streaming or trapping of particles (refer to Equations (4) and (8), where l DEP is defined). Because l DEP is inversely proportional to the suspending solution dynamic viscosity, the dielectrophoretic velocity of the particles decreases with larger values of g and increases with smaller values of g. Figure 5(b) illustrates the change in dynamic viscosity experienced by the suspending solution as a function of temperature (g ¼ 1:01 mN=m 2 s at t ¼ 0).…”

“…However, as reported by Gallo-Villanueva et al, the effective intensity of the DEP trapping slightly reduces with time. 35 Finally, the thermal conductivity, k, of the suspending solution is also a function of temperature. This property is of interest particularly as it controls the rate at which the fluid heats due to an external heat source (electricity in the present scenario).…”

Hydrodynamic and direct-current insulator-based dielectrophoresis (H-DC-iDEP) microfluidic blood plasma separation

“…Consequently, the net particle velocity along the electric field line is zero in the trapping zone. The trapping DEP flow condition is [29] Cμ DEP ∇ E:…”

Induced charge effects on electrokinetic entry flow

“…16 Its effectiveness is, however, subjected to the influence of Joule heating that may lead to a significant temperature rise in the fluid and in turn the whole microfluidic chip due to thermal diffusion. 17,18 Even worse are the resultant fluid temperature gradients at the reservoir-microchannel junction, which has been demonstrated to cause fluid circulations and hence reduce the dielectrophoretic focusing and trapping of particles. 19,20 This so-called electrothermal flow arises from the action of electric field on the inhomogeneous temperature-dependent fluid properties.…”