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Joseph D Hickey

Publications and source records attributed to Joseph D Hickey.

3 recordsLinked to original sources

Electric field mediated DNA motion model.

Understanding the motion and the governing equations of a molecule's path in tissue is an ultimate requirement for the repeatable, site specific delivery of molecules [Joseph D. Hickey. Modelling the Motion of Ions and Molecules in Electroporation and Electrophoresis Field Conditions. University of South Florida, College of Arts and Sciences, Department of Physics, Tampa, Florida, 2003., Joseph D. Hickey and Richard Gilbert. Modeling the electromobility of ions in a target tissue. DNA and Cell Biology, 22 (12) (2003) 823-828.]. This paper describes a computationally efficient mathematical model and simulation technique for the examination of DNA fragments in a 1% agarose gel. The speed of the individual DNA fragments through the agarose gel was described through two parts. The maximum velocity was calculated using the Coulombic force divided by Stoke's law and that value was retarded by an exponential rate equation. The simulation utilizes previously published techniques modified for this specific application [Joseph D. Hickey and Richard Gilbert. Fluid flow electrophoresis model. Bioelectrochemistry, 63 (2) (2004) 365-367., Joseph D. Hickey and Richard Gilbert. Modeling the electromobility of ions in a target tissue. DNA and Cell Biology, 22 (12) (2003) 823-828.]. Five representative DNA fragment sizes that span the resolution of a 1% agarose gel were chosen for this analysis. The speeds corresponding to these five DNA fragment sizes were converted into discrete values and used in a 50 step simulation. The resultant error comparing the simulation with experimental distance was 7.76%. Through a 1-D optimization procedure, this error was reduced to 3.02% for a 52 step simulation.

Algorithms↗

Fluid flow electrophoresis model.

Molecular delivery via electroporation is typically done via molecular diffusion and tissue perfusion. The inherent variability in those distribution methods limits the efficacy of this medical and laboratory technique. Electrophoresis has been shown to improve the distribution and placement of the molecule [Gene Therapy 9 (2002) 1286]. This paper presents a fluid flow model for electrophoresis in tissues. Parallel plate and four-needle needle array electrodes are the electrodes modeled as the delivery devices. The parallel plate electrode produces a homogeneous distribution of the analyte but the needle array electrode creates a peak where the electric field effects diminish.

Animals↗

Modeling the electromobility of ions in a target tissue.

Electroporation is a clinical and laboratory technique for the delivery of molecules to cells. This method imposes electric fields onto cells or tissues through the use of electrodes and a set of electrical parameters to ultimately incorporate molecules into the cells. Clinical applications may include using directional fields to bring therapeutics to the target tissues before triggering an electroporation event. The choice of applicator may also have a significant influence on this molecular flow. Modeling ionic flow in tissues will yield insight into selecting the appropriate parameters or electroporation signature for a desired target application. In this paper, the motion of tissue injected ions was modeled for two common electroporation applicator configurations-the parallel plate, and the four needle electrodes. This electric field induced fluid flow model predicts that the parallel plate applicator ultimately directs the movement of an ionic therapeutic in a forward manner with side motion due only to obstruction, while the four-needle applicator directs anisotropic flow within the field ultimately forcing the therapeutic into a mound at the fringes of the induced electric field.

Cell Physiological Phenomena↗