Influence of scale on electrostatic forces and torques in AC particulate electrokinetics.

Dielectrophoretic forces and torques move and manipulate biological cells, typically of the order of 10 mum ( approximately 10(-5) m) in diameter and ordinarily suspended in aqueous liquids, using electrodes with dimensions around 100 mum ( approximately 10(-4) m). The ability to exploit these same electromechanical effects for particles below 1 mum, that is, <10(-6) m, creates opportunities for remote manipulation and handling of subcellular components, biological macromolecules, and DNA. In this paper, Trimmer's bracket notation is adapted for systematic examination of the scaling laws governing electrokinetic behaviour. The purpose is to shed light on how critical performance measures relevant to the laboratory on a chip are affected by reducing particle sizes and electrode dimensions into the nanometre range. The scaling methodology facilitates consideration of the effect of electrode structure and particle size reduction on voltage, electric field, heating, and response time. Particles with induced moments, dipolar and quadrupolar, as well as permanent dipoles are examined. Separate consideration is given to electrical torque and its application in electrorotation and particle alignment. An eventual goal of these scaling studies is to identify the lower limit on the size of particles that can be manipulated effectively using electrokinetic phenomena.

[1]  O. Velev,et al.  Dielectrophoretic assembly of oriented and switchable two-dimensional photonic crystals , 2003 .

[2]  J. Landes.  Application of a J-Q Model for Fracture in the Ductile-Brittle Transition , 1997 .

[3]  Hywel Morgan,et al.  Rapid rotation of micron and submicron dielectric particles measured using optical tweezers , 2003 .

[4]  Masao Washizu,et al.  Applications of electrostatic stretch-and-positioning of DNA , 1993, Conference Record of the 1993 IEEE Industry Applications Conference Twenty-Eighth IAS Annual Meeting.

[5]  J. Voldman,et al.  Holding forces of single-particle dielectrophoretic traps. , 2001, Biophysical journal.

[6]  William S. N. Trimmer,et al.  Microrobots and micromechanical systems , 1989 .

[7]  Masao Washizu,et al.  Molecular dielectrophoresis of bio-polymers , 1992, Conference Record of the 1992 IEEE Industry Applications Society Annual Meeting.

[8]  O. Velev,et al.  Dielectrophoretic Assembly of Electrically Functional Microwires from Nanoparticle Suspensions , 2001, Science.

[9]  M. Washizu,et al.  Electrostatic manipulation of DNA in microfabricated structures , 1989, Conference Record of the IEEE Industry Applications Society Annual Meeting,.

[10]  Thomas B. Jones,et al.  Multipolar dielectrophoretic and electrorotation theory , 1996 .

[11]  Karan V. I. S. Kaler,et al.  Quadrupole levitation of microscopic dielectric particles , 1999 .

[12]  Thomas B. Jones,et al.  Multipolar dielectrophoretic force calculation , 1994 .

[13]  Thomas B. Jones,et al.  Electromechanics of Particles , 1995 .

[14]  Michael P. Hughes,et al.  Nanoelectromechanics in Engineering and Biology , 2002 .

[15]  G. Temple.  Static and Dynamic Electricity , 1940, Nature.

[16]  Limitations on the scale of an electrode array for trapping particles in microfluidics by positive dielectrophoresis , 2003 .

[17]  K. Kaler,et al.  Dielectrophoretic spectra of single cells determined by feedback-controlled levitation. , 1990, Biophysical journal.

[18]  Hywel Morgan,et al.  Dielectrophoretic trapping of single sub-micrometre scale bioparticles , 1998 .

[19]  R. Feynman.  The Character of Physical Law , 1965 .

[20]  O. Kurosawa,et al.  Quantitative analysis of DNA orientation in stationary AC electric field using fluorescence anisotropy , 1995, IAS '95. Conference Record of the 1995 IEEE Industry Applications Conference Thirtieth IAS Annual Meeting.

[21]  H. Morgan,et al.  Electrohydrodynamics and dielectrophoresis in microsystems: scaling laws , 2003 .

[22]  Hywel Morgan,et al.  AC ELECTROKINETICS: COLLOIDS AND NANOPARTICLES. , 2002 .