Selective Manipulation of Biomolecules with Insulator-Based Dielectrophoretic Tweezers

Abstract

Insulator-based dielectrophoretic (iDEP) trapping, separating, and concentrating nanoscale objects is carried out using a non-metal, unbiased, mobile tip acing as a tweezers. The spatial control and manipulation of fluorescently-labeled polystyrene particles and DNA were performed to demonstrate the feasibility of the iDEP tweezers. Frequency-dependent iDEP tweezers' strength and polarity were quantitatively determined using two theoretical approaches to DNA, which resulted in a factor of 2 ~ 40 differences between them. In either approach, the strength of iDEP was at least 4-order of magnitude stronger than the thermal force, indicating iDEP was a dominant force for trapping, holding, and separating DNA. The trapping strength and volume of the iDEP tweezers were also determined, which further supports direct capture and manipulation of DNA at the tip end.

Insulator Based Dielectrophoresis: Micro, Nano, and Molecular Scale Biological Applications

“…In early 2020, Oh et al [ 123 ] reported an iDEP tweezers platform to manipulate and selectively separate DNA and polystyrene particles. The strength and polarity of the tweezers were determined numerically and experimentally.…”

“…External AC voltage was applied on the electrodes and with the help of a fluorescence microscope, DNA manipulation was captured, as shown in Figure 10 b. The low-frequency AC voltage seems to attract DNA to the electrode (at 9 V, 80 kHz) generating a strong pDEP effect, whereas DNA was found to experience slightly reduced pDEP at the increased frequency of 120 kHz, which triggers the confined DNA to slightly move away from the electrode [ 123 ]. At 200 kHz and the same voltage of 9 V, the DNA was entirely stretched, suggesting a considerable dependence of the DEP frequency of the applied AC voltage.…”

“…The results indicated that the strength of iDEP dominant over thermal force for DNA manipulation. The technique effectively separated DNA in a fluid microfluidic environment without fouling, electrolysis, and joule heating [ 123 ].…”

“… iDEP manipulation with optical tweezer [ 123 ]. ( a ) Graphic diagram of the device showing an insulating tip with xyz manipulator control.…”

“…An AC voltage (7 V, 200 kHz) applied to manipulate DNA. All scale bars are 5 μm [ 123 ]. © Figure 10 Reprinted (adapted) with permission from [ 123 ].…”