The effects of magnetite (Fe3O4) nanoparticles on electroporation-induced inward currents in pituitary tumor (GH3) cells and in RAW 264.7 macrophages

Abstract

Aims: Fe 3 O 4 nanoparticles (NPs) have been known to provide a distinct image contrast effect for magnetic resonance imaging owing to their super paramagnetic properties on local magnetic fields. However, the possible effects of these NPs on membrane ion currents that concurrently induce local magnetic field perturbation remain unclear. Methods: We evaluated whether amine surface-modified Fe 3 O 4 NPs have any effect on ion currents in pituitary tumor (GH 3 ) cells via voltage clamp methods. Results: The addition of Fe 3 O 4 NPs decreases the amplitude of membrane electroporationinduced currents (I MEP ) with a half-maximal inhibitory concentration at 45 µg/mL. Fe 3 O 4 NPs at a concentration of 3 mg/mL produced a biphasic response in the amplitude of I MEP , ie, an initial decrease followed by a sustained increase. A similar effect was also noted in RAW 264.7 macrophages. Conclusion:The modulation of magnetic electroporation-induced currents by Fe 3 O 4 NPs constitutes an important approach for cell tracking under various imaging modalities or facilitated drug delivery.

Identification of Minuscule Inward Currents as Precursors to Membrane Electroporation-Induced Currents: Real-Time Prediction of Pore Appearance

“…Figure 1 depicts a typical example of one of these experiments showing effects of large hyperpolarization on membrane current measured from a pituitary GH 3 cell. Consistent with previous observations [10,11,12,26], a population of irregular and transient inward currents occurring in a periodical fashion were clearly elicited. These inward currents occurring asynchronously were increased with greater hyperpolarizations and have been previously identified as I MEP .…”

“…Consistent with previous studies [10,11,26], the externally applied electrical field directs ion movement and influences the kinetics of I MEP . PCA presented herein is capable of detecting high principal eigenvalues in the series of current traces elicited by membrane hyperpolarization.…”

“…Additionally, owing to high conductance of MEP-induced channels, even at low probability of opening, significant currents tend to flow, thereby altering the electrical behavior of cells [1,2,6,7,8]. Recent work in our laboratory has characterized the electrical properties of MEP-induced currents ( I MEP ) in different types of cells [9,10,11,12]. Besides that, despite numerous experimental and theoretical studies, many aspects of MEP-induced currents ( I MEP ) remain elusive.…”

The Inhibition of Inwardly Rectifying K+Channels by Memantine in Macrophages and Microglial Cells

“…The clonal strain BV2 cell line was kindly provided from Professor Dr. Jau-Shyong Hong (National Institute of Environmental Health Sciences, National Institute of Health, Research Triangle Park, NC) [19]. Both of cells were maintained in phenol red-free Dulbecco's modified Eagle medium supplemented with 10% heat-inactivated FBS, 100 U/ml penicillin and 10 µg/ml streptomycin [6,19,24]. …”

Silencing effect of lentiviral vectors encod­ing shRNA of Herp on endoplasmic reticulum stress and inflammatory responses in RAW 264.7 macrophages

“…difficult. Although the RAW 264.7 macrophages can be efficiently transfected by plasmid DNA via electroporation, electroporation can induce macrophage cell death (Krysko et al, 2006;Liu et al, 2012). Recombinant vectors based on adenoviruses and lentiviruses have been used to deliver modified genes into macrophages much more efficiently (Stein and Falck-Pedersen, 2012;Tong et al, 2014).…”