(419g) Dielectrophoretic Response of Perfluorocarbon Oil-Core, Chitosan, Poly-L-Lysine, CaPO4-Shell Nanoparticles

Dielectrophoretic Response of Perfluorocarbon oil-Core, Chitosan, Poly-L-lysine, CaPO₄-Shell Nanoparticles

Chungja Yang^a, Chun-Jen Wu^b, Agnes E. Ostafin^b, Sean Kirkpatrick^c, Adrienne R. Minerick^a

^aChemical Engineering Department, Michigan Technological University

^bMaterials Science and Engineering Department, University of Utah

^cBiomedical Engineering Department, Michigan Technological University

Dielectrophoresis (DEP) is useful to assemble, discriminate, and manipulate particles based on a particle's polarizability and interactions with a surrounding medium under non-uniform electric fields. Core-shell nanoparticles are traditionally synthesized for drug delivery [1], nanoreactors [2,3], and diagnostic markers [4], and can be constructed with various liquid core and various solid shell materials. These engineered nanoparticles facilitate systematic investigation of DEP polarization mechanisms and are much simpler than biological cells. Perfluorocarbon oil in a phospholipid micellular structure were used for the core, along with three shell materials (chitosan, Poly-L-lysine, and CaPO₄) which were chosen for their dielectric properties and known synthesis procedures. We report the frequency-dependent, and medium conductivity-dependent responses of ~250nm core-shell nanoparticles. Particle-particle interactions were quantified by tracking pearl-chain assembly of the nanoparticles in two dimensions. Experiments were conducted within a 100nl chamber housing 100um wide Au quadrupole electrodes spaced 25um apart. Frequencies from 100kHz to 80MHz at 10V_pp were tested and the frequency-dependent motion was quantified via video microscopy image intensity profiles in two perpendicular planes. Experimental COF results were compared with spherical shell models of the real part of the Clausius-Mossotti factor as a function of frequency, conductivity of the shells, and medium conductivity. This work exhibited two dimensional nanoparticle patterning into pearl-chains and then bands, which were subsequently probed for coherent light scattering via spectral techniques.

[1] Schmidt, Chem. Mater, 2004, 16, 4942-4947

[2] Chen, Nanotechnology, 2010, 21, 455701

[3] Chen, Nanotechnology, 2010, 21, 215503

[4] Georganopoulou, PNAS, 2005, 102, 7, 2273-2276