Membrane Conductance Through Voltage-Gated Ion Channels in the Presence of Carbon Nanomaterials and Dielectrophoretic Force

Jakubek, Lorin Mari

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Year:: 2011
Contributor:: Jakubek, Lorin Mari (creator); Hurt, Robert (Director); Lipscombe, Diane (Reader); Palmore, G. Tayhas (Reader); Tripathi, Anubhav (Reader); Bellamkonda, Ravi (Reader); Brown University. Biomedical Engineering (sponsor)
Genre:: theses
Subject:: Nanomaterials; Neuroengineering Nanotoxicology; Carbon nanotubes; Ion channels; Calcium; Dielectrophoresis; Nanostructured materials; Yttrium
Extent:: xii, 127 p.
DOI: https://doi.org/10.7301/Z0H1308S

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Abstract:: In order to explore the interactions of technological interfaces with the electrical properties of cells, two independent studies evaluate membrane conductivity in the presence of carbon nanomaterials and dielectrophoretic force.The first study investigates the effect of carbon nanotubes (CNTs) on voltage-gated calcium ion channels. CNTs are used with increasing frequency in neuro-engineering. CNT scaffolds are used to stimulate cultured neurons and to control outgrowth and branching patterns of neurites. CNTs have been reported to disrupt normal neuronal function including alterations in endocytotic capability and inhibition of ion channels. Calcium ion channels regulate numerous neuronal and cellular functions including endo and exocytosis, neurite outgrowth, and gene expression. CNT interactions with these channels would have significant biological implications. The techniques of inductively-coupled plasma atomic emission spectroscopy and calcium ion channel electrophysiology are used to assess this interaction. The results show that physiological solutions containing CNTs inhibit neuronal voltage-gated calcium ion channels in a dose-dependent and sample-dependent manner with IC50 as low as 1.2 μg/ml. Importantly, the inhibitory activity does not involve the tubular graphene structure, but rather very low concentrations of soluble yttrium released from the nanotube growth catalyst. Cationic yttrium inhibits calcium ion channel function with an inhibitory efficacy, IC50, of 0.07 ppm w/w. Because of this inhibitory potency, unpurified and even some reportedly "purified" CNT samples contain sufficient bioavailable yttrium to inhibit channel function at low nanotube doses. The results have important implications for emerging nano-neurotechnologies and highlight the critical role that trace components can play in the biological response to complex nanomaterials. The secondary study evaluates the use of dielectrophoresis to direct the movement of insulin-secreting cells. Primary beta cells and INS-1 cells (Insulinoma cell line) were placed in a dielectrophoretic chamber. The osmolarity of the media was altered and through the methods of dielectrophoresis and electrorotation, cell membrane capacitance and membrane conductance values were reported. These values fall within the range expected for mammalian cells and demonstrate that dielectrophoresis can be used to direct the movement of insulin-secreting cells.
Notes:: Thesis (Ph.D. -- Brown University (2011)

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Jakubek, Lorin Mari, "Membrane Conductance Through Voltage-Gated Ion Channels in the Presence of Carbon Nanomaterials and Dielectrophoretic Force" (2011). Biomedical Engineering Theses and Dissertations. Brown Digital Repository. Brown University Library. https://doi.org/10.7301/Z0H1308S

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Biomedical Engineering Theses and Dissertations

Theses and Dissertations for the Biomedical Engineering department.
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