Membrane Permittivity Research Articles

Dielectrophoretic characterization of peroxidized retinal pigment epithelial cells as a model of age-related macular degeneration

BackgroundAge-related macular degeneration (AMD) is a prevalent ocular pathology affecting mostly the elderly population. AMD is characterized by a progressive retinal pigment epithelial (RPE) cell degeneration, mainly caused by an impaired antioxidative defense. One of the AMD therapeutic procedures involves injecting healthy RPE cells into the subretinal space, necessitating pure, healthy RPE cell suspensions. This study aims to electrically characterize RPE cells to demonstrate a possibility using simulations to separate healthy RPE cells from a mixture of healthy/oxidized cells by dielectrophoresis.MethodsBPEI-1 rat RPE cells were exposed to hydrogen peroxide to create an in-vitro AMD cellular model. Cell viability was evaluated using various methods, including microscopic imaging, impedance-based real-time cell analysis, and the MTS assay. Healthy and oxidized cells were characterized by recording their dielectrophoretic spectra, and electric cell parameters (crossover frequency, membrane conductivity and permittivity, and cytoplasm conductivity) were computed. A COMSOL simulation was performed on a theoretical microfluidic-based dielectrophoretic separation chip using these parameters.ResultsIncreasing the hydrogen peroxide concentration shifted the first crossover frequency toward lower values, and the cell membrane permittivity progressively increased. These changes were attributed to progressive membrane peroxidation, as they were diminished when measured on cells treated with the antioxidant N-acetylcysteine. The changes in the crossover frequency were sufficient for the efficient separation of healthy cells, as demonstrated by simulations.ConclusionsThe study demonstrates that dielectrophoresis can be used to separate healthy RPE cells from oxidized ones based on their electrical properties. This method could be a viable approach for obtaining pure, healthy RPE cell suspensions for AMD therapeutic procedures.

Computational Studies Using COMSOL Multiphysics on Dielectrophoretic Characterization and Separation of Mesenchymal Stem Cells Undergoing Tenogenic Differentiation

Stem cells have unique self-renewal and differentiation capacities, which are advantageous for regenerative medicine and tissue engineering applications. Stem cells can recreate cells needed to repair injured tissues and organs in the body, for example, by regenerating connective tissues, which provide support, protection, and a structural framework for various organs and other tissues. However, a significant limitation is the susceptibility of tendons to injury with long-term loss of function. Mesenchymal Stem Cell (MSC) therapies are promising for healing tendon injuries and tears but controlling stem cell differentiation and generating homogeneous tenogenic stem cell populations remains challenging. Therefore, separating differentiating and non-differentiating MSCs to collect homogenous cells is critical for further tissue repair after transplantation. To substantiate our hypothesis that differentiating and non-differentiating stem cells have unique dielectric properties, we focused on characterizing-obtaining dielectric signatures for differentiating tenogenic and non-tenogenic MSCs on the third day of differentiation using dielectrophoresis (DEP) focused on crossover frequencies [1, 2]. The estimated values for membrane capacitance, conductivity, and permittivity after 3-day treatment of undifferentiated cells differentiating into tenogenic MSCs are 2.46±0.1 pF, 0.82±0.01 S/m, and 1.97±0.05, respectively, and cytoplasm conductivity 0.82±0.02 S/m. The treated stem cells undergo differentiation, but the untreated cells don’t. The results showed a significant difference between the 3-day treatment and no-treatment group. The estimated properties from the dielectrophoretic characterization studies are crucial in designing a DEP-based enrichment microdevice to collect homogeneous differentiated stem cell populations for tendon repair. Using particle tracing, creeping flow (transport of diluted species model), and electric current physics in COMSOL Multiphysics simulation software, we designed a microdevice that achieves 100% separation of untreated and treated mesenchymal stem cells undergoing differentiation towards tendon. Applying dielectrophoresis to the microdevice architecture demonstrated high selectivity and yield, processing one million treated and untreated stem cells in 6.4 and 27.8 hours, respectively.

Early differentiation of mesenchymal stem cells is reflected in their dielectrophoretic behavior.

The therapeutic use of mesenchymal stem cells (MSCs) becomes more and more important due to their potential for cell replacement procedures as well as due to their immunomodulatory properties. However, protocols for MSCs differentiation can be lengthy and may result in incomplete or asynchronous differentiation. To ensure homogeneous populations for therapeutic purposes, it is crucial to develop protocols for separation of the different cell types after differentiation. In this article we show that, when MSCs start to differentiate towards adipogenic or osteogenic progenies, their dielectrophoretic behavior changes. The values of cell electric parameters which can be obtained by dielectrophoretic measurements (membrane permittivity, conductivity, and cytoplasm conductivity) change before the morphological features of differentiation become microscopically visible. We further demonstrate, by simulation, that these electric modifications make possible to separate cells in their early stages of differentiation by using the dielectrophoretic separation technique. A label free method which allows obtaining cultures of homogenously differentiated cells is thus offered.

Light-Induced Dielectrophoresis for Characterizing the Electrical Behavior of Human Mesenchymal Stem Cells

Human mesenchymal stem cells (hMSCs) offer a patient-derived cell source for conducting mechanistic studies of diseases or for several therapeutic applications. Understanding hMSC properties, such as their electrical behavior at various maturation stages, has become more important in recent years. Dielectrophoresis (DEP) is a method that can manipulate cells in a nonuniform electric field, through which information can be obtained about the electrical properties of the cells, such as the cell membrane capacitance and permittivity. Traditional modes of DEP use metal electrodes, such as three-dimensional electrodes, to characterize the response of cells to DEP. In this paper, we present a microfluidic device built with a photoconductive layer capable of manipulating cells through light projections that act as in situ virtual electrodes with readily conformable geometries. A protocol is presented here that demonstrates this phenomenon, called light-induced DEP (LiDEP), for characterizing hMSCs. We show that LiDEP-induced cell responses, measured as cell velocities, can be optimized by varying parameters such as the input voltage, the wavelength ranges of the light projections, and the intensity of the light source. In the future, we envision that this platform could pave the way for technologies that are label-free and perform real-time characterization of heterogeneous populations of hMSCs or other stem cell lines.

Analysis of electromagnetic response of cells and lipid membranes using a model-free method

Electromagnetic radiation (EMR) is omnipresent on earth and may interact with the biological systems in diverse manners. But the scope and nature of such interactions remain poorly understood. In this study, we have measured the permittivity of cells and lipid membranes over the EMR frequency range of 20 Hz to 4.35 × 1010 Hz. To identify EMR frequencies that display physically intuitive permittivity features, we have developed a model-free method that relies on a potassium chloride reference solution of direct-current (DC) conductivity equal to that of the target sample. The dielectric constant, which reflects the capacity to store energy, displays a characteristic peak at 105–106 Hz. The dielectric loss factor, which represents EMR absorption, is markedly enhanced at 107–109 Hz. The fine characteristic features are influenced by the size and composition of these membraned structures. Mechanical disruption results in abrogation of these characteristic features. Enhanced energy storage at 105–106 Hz and energy absorption at 107–109 Hz may affect certain membrane activity relevant to cellular function.

Erythrocyte Membrane Biophysical Changes Mediated by Pooled Immunoglobulin G and Hematin: Electrokinetic and Lipid Peroxidation Studies.

Pooled Immunoglobulin G (IgG), hematin and the membrane-disruptive amphipathic peptide melittin have received attention as powerful biomacromolecules for biomedical and pharmacology applications. Their action on surface properties, oxidation status and epifluorescence properties measured in vitro provide useful information about the functional activity of upper biomacromolecules in erythrocytes in vivo. The hemolysis of erythrocyte membranes, as well as changes in hematocrit and the morphology of erythrocytes, was investigated here via fluorescence microscopy using FITC-concanavalin A binding to cells. The effect of melittin on the membrane capacitance and resistance of model lipid bilayers was probed via electrochemical impedance spectroscopy. Lipid bilayer capacitance was higher in the presence of 0.10 g/L melittin compared to that in the control, which is likely related to bilayer thinning and alterations of the dielectric permittivity of melittin-treated membranes. The biomolecule interactions with red blood cells were probed in physiological media in which the surface of erythrocyte membranes was negatively charged. Surface parameters of erythrocytes are reported upon IgG/hematin and IgG/melittin treatment. Pooled IgG in the presence of melittin, preincubated IgG/hematin preparations promoted a significant decrease in the electrokinetic potential of erythrocytes (Rh-positive). A malondialdehyde (MDA) assay revealed a high rate of lipid peroxidation in erythrocytes treated with IgG/hematin or IgG/melittin preparations. This finding might be a result of pooled IgG interactions with the hematin molecule and the subsequent conformational changes in the protein molecule altering the electrokinetic properties of the erythrocyte membrane related to the Rh group type of erythrocytes. The pooled IgG and hematin are reported to have important consequences for the biophysical understanding of the immunopathological mechanisms of inflammatory, autoimmune and antibody-mediated pathological processes.

Electrochemo-poromechanics of Ionic Polymer Metal Composites: Towards the Accurate Finite Element Modelling of Actuation and Sensing

Ionic polymer metal composites (IPMCs) consist of an electroactive polymeric membrane, which is plated with metal electrodes and includes a fluid phase of ions in a solvent, whose diffusion allows for actuation and sensing applications. We build on a previous finite-deformation theory of our group that accounts for the cross-diffusion of ions and solvent and couples the mass balances of these species with the stress balance and the Gauss law. Here, we abandon the assumption that the fluid phase is a dilute solution, with benefits on both modelling and computation. A reliable finite element (FE) implementation of electrochemomechanical theories for IPMCs is challenging because the IPMC behaviour is governed by boundary layers (BLs) occurring in tiny membrane regions adjacent to the electrodes, where steep gradients of species concentrations occur. We address this issue by adopting the generalized FE method to discretise the BLs. This allows unprecedented analyses of the IPMC behaviour since it becomes possible to explore it under external actions consistent with applications, beside obtaining accurate predictions with a reasonable computational cost. Hence, we provide novel results concerning the influence of the membrane permittivity on the species profiles at the BLs. Additionally, by leveraging on the mobility matrix, we establish that the initial peak deflection in actuation strongly depends on the constitutive equations for the species transport and discuss the predictions of some experimental results from the literature. Overall, we demonstrate the potential of the proposed model to be an effective tool for the thorough analysis and design of IPMCs.

Microflow cytometer chip with multiple electro-rotation units for measuring electrical properties of single yeast cells

At present, many single-cell electrical parameter measurement techniques have exhibit broad application prospects, but there are still some limitations such as complex single-cell operation and time-consuming measurement. This paper proposed a microflow cytometer chip with multiple electro-rotation units for measuring the electrical properties of single cells. The microdevice leverages three serial electro-rotation units to rapidly obtain rotation speeds under different signal frequencies. According to the rotation results, the electrical parameters (membrane permittivity and cytoplasmic conductivity) are estimated by using Maxwell's mixture equation fitting and neural network fitting methods respectively. We demonstrated the measurement advantages of combining microflow and electro-rotation techniques. Experimental results show that the cytometer measurement method greatly improves the throughput of single-cell characterization with a guaranteed error of less than 0.8%. The microdevice provides a microfluidic platform capable of characterizing the electrical properties of cells and the possibility of combining with neural networks.

Continuous-flow electrorotation (cROT): improved throughput characterization for dielectric properties of cancer cells.

This paper presents the concept of a newly developed high-throughput measurement device for determining the dielectric properties of cancer cells. The proposed continuous-flow electrorotation (cROT) device can induce electrorotation (ROT) with vertical rotation using two sets of interdigitated electrodes on the top and bottom substrates to torque the cells. In the developed device, multiple rotating cells flowing in a microchannel are aligned between electrodes using dielectrophoresis. This allows for the measurement of the rotational behavior of the cells with continuous flow, resulting in a significant improvement in throughput compared to the conventional ROT devices reported previously. The dielectric properties, permittivity of the cell membrane and conductivity of the cell cytoplasm, of HeLa cells obtained by simultaneous measurements using the developed cROT device were 9.13 ± 1.02 and 0.93 ± 0.10 S m-1, respectively. Moreover, the measurement throughput was successfully increased to 2700 cells per h using the cROT technique.

Influence of Membrane Permittivity on Charge Regulation of Weak Polyelectrolytes End-Tethered in Nanopores

Influence of Membrane Permittivity on Charge Regulation of Weak Polyelectrolytes End-Tethered in Nanopores

The murburn precepts for cellular ionic homeostasis and electrophysiology.

Starting from the basic molecular structure and redox properties of its components, we build a macroscopic cellular electrophysiological model. We first present a murburn purview that could explain ion distribution in bulk-milieu/membrane-interface and support the origin of trans-membrane potential (TMP) in cells. In particular, the discussion focuses on how cells achieve disparity in the distribution of monovalent and divalent cations within (K+ > Na+ > Mg2+ > Ca2+ ) and outside (Na+ > K+ > Ca2+ > Mg2+ ). We explore how TMP could vary for resting/graded/action potentials generation and project a model for impulse conduction in neurons. Outcomes based on murburn bioenergetic equilibriums leading to solubilization of ion-pairs, membrane's permittivity, protein channels' fluxes, and proteins' innate ability to bind/adsorb ions selectively are projected as the integral rationale. We also provide experimental modalities to ratify the projections.

Dielectric Spectroscopy Based Detection of Specific and Nonspecific Cellular Mechanisms.

Using radiofrequency dielectric spectroscopy, we have investigated the impact of the interaction between a G protein-coupled receptor (GPCR), the sterile2 α-factor receptor protein (Ste2), and its cognate agonist ligand, the α-factor pheromone, on the dielectric properties of the plasma membrane in living yeast cells (Saccharomyces cerevisiae). The dielectric properties of a cell suspension containing a saturating concentration of α-factor were measured over the frequency range 40Hz–110 MHz and compared to the behavior of a similarly prepared suspension of cells in the absence of α-factor. A spherical three-shell model was used to determine the electrical phase parameters for the yeast cells in both types of suspensions. The relative permittivity of the plasma membrane showed a significant increase after exposure to α-factor (by 0.06 0.05). The equivalent experiment performed on yeast cells lacking the ability to express Ste2 showed no change in plasma membrane permittivity. Interestingly, a large change also occurred to the electrical properties of the cellular interior after the addition of α-factor to the cell suspending medium, whether or not the cells were expressing Ste2. We present a number of different complementary experiments performed on the yeast to support these dielectric data and interpret the results in terms of specific cellular reactions to the presence of α-factor.

Dielectrophoretic Characterization of Tenogenically Differentiating Mesenchymal Stem Cells.

Tendons are collagenous musculoskeletal tissues that connect muscles to bones and transfer the forces necessary for movement. Tendons are susceptible to injury and heal poorly, with long-term loss of function. Mesenchymal stem cell (MSC)-based therapies are a promising approach for treating tendon injuries but are challenged by the difficulties of controlling stem cell fate and of generating homogenous populations of stem cells optimized for tenogenesis (differentiation toward tendon). To address this issue, we aim to explore methods that can be used to identify and ultimately separate tenogenically differentiated MSCs from non-tenogenically differentiated MSCs. In this study, baseline and tenogenically differentiating murine MSCs were characterized for dielectric properties (conductivity and permittivity) of their outer membrane and cytoplasm using a dielectrophoretic (DEP) crossover technique. Experimental results showed that unique dielectric properties distinguished tenogenically differentiating MSCs from controls after three days of tenogenic induction. A single shell model was used to quantify the dielectric properties and determine membrane and cytoplasm conductivity and permittivity. Together, cell responses at the crossover frequency, cell morphology, and shell models showed that changes potentially indicative of early tenogenesis could be detected in the dielectric properties of MSCs as early as three days into differentiation. Differences in dielectric properties with tenogenesis indicate that the DEP-based label-free separation of tenogenically differentiating cells is possible and avoids the complications of current label-dependent flow cytometry-based separation techniques. Overall, this work illustrates the potential of DEP to generate homogeneous populations of differentiated stem cells for applications in tissue engineering and regenerative medicine.

Electrical properties characterization of single yeast cells by dielectrophoretic motion and electro-rotation.

The electrical parameters of single cells are label-free and intrinsic properties that can reflect the physiological characteristics. In recent years, many measurement methods based on impedance spectroscopy and rotation spectrum analysis have been developed. However, most of these works need to measure the response at whole frequency range to obtain DEP spectra and estimate the electrical parameters by fitting method, which are time-consuming and limit the measurement throughput. Therefore, improving the measurement throughput for single cells is an essential problem to be solved addressed. In this paper we present a microfluidic chip that combines dielectrophoretic motion and electro-rotation technology for single-cell electrical properties characterization. Since the movement and rotation speed of single cell in mediums are related to the electrical parameters of itself, electric signals and medium, the electrical properties can be obtained by measuring and analyzing the movement trajectory and rotation speed of the cell. Numerical simulations were performed to analyze the electric field distribution of the chip under different signal configurations, which predict the movement trajectory and rotation state, and determine the values of electric field on the cells. Based on the simulation results, cell focusing, dielectrophoretic motion and electro-rotation were successfully realized. By analyzing the movement trajectory and rotation speed, the conductivity of wall and the permittivity of membrane of yeast cells were characterized. The measurement method avoids the time-consuming of the traditional rotational spectra method, and can realize rapid and efficiency and single-cell electrical characterization.

Study and Classification of Cell Bio-Impedance Signature for Identification of Malignancy Using Artificial Neural Network

This article presents development of a microcapacitive sensor-based bio-impedance classification system for identification of malignant cells in a known volume (400 $\mu \text{L}$ ) of biological tissue sample. Malignancy induces various physical changes in an affected cell, among which increased intracellular water and sodium ion content are a couple of prominent ones. In this work, the change in electrical properties of a cell [here white blood cell (WBC)] that is membrane and cytoplasm permittivity due to afore-mentioned reasons is used for distinguishing malignant from normal cells based on their deviation in bio-impedance signature. This change in bio-impedance signature of the WBC is measured by exciting the mentioned microcapacitive sensor by a 2 V p-p signal. The developed system consists of an on-board impedance analyzer to carry out bio-impedance spectroscopy over a frequency range of 1–100 kHz. The bio-impedance data are then obtained from the sensor for different concentrations of cultured human malignant and normal white blood cells. The difference in impedance values between concentrations is then used as a discerning factor for identification the degree of malignancy, for which an artificial neural network (ANN) is employed. A detailed study considering detection efficiency for this ANN revealed classification accuracy up to 95.0%, upon which this ANN model is transferred to a portable single board computer (SBC) along with other associated circuitry that could carry out the same classification at a nominal power consumption of 516.45 mW.

Dielectric properties of nucleated erythrocytes as simulated by the double spherical-shell model* *Project supported by the National Natural Science Foundation of China (Grant Nos. 51277099 and 52007087), the Natural Science Foundation of Zhejiang Province, China (Grant Nos. LY20C110001 and LSY19A010002), the Natural Science Foundation of Ningbo City, China (Grant Nos. 2019A610349 and 202003N4116), the Fund from the Educational Commission of

The dielectric properties of nucleated erythrocytes from bullfrogs were measured in a frequency range of 10 kHz–110 MHz. The complex permittivity (ε *), complex conductivity (κ *), and complex resistivity (ρ *) were analyzed and compared in the 10.63% to 37.58% haematocrit (Hct) range. The relaxation behavior, the passive electrical properties, and the cellular structure parameters, including the cell membrane, the cytoplasm, the nuclear membrane, and the nucleoplasm of the nucleated erythrocyte suspensions were investigated. The method used is based on the binomial Cole–Cole equation and the double spherical-shell physical models. Upon the elimination of the electrode polarization effect, two definite relaxations related to the interfacial polarization are observed on low- and high-frequency dispersions. The permittivity values and the characteristic frequency values differ by one order of magnitude: the low-frequency relaxation increments [Δ ε 1 = (5.63 ± 1.43)× 103] and the characteristic frequency [f c1 = (297.06 ± 14.48) kHz] derived from the cell membrane, the high-frequency relaxation increments [Δ ε 2 = (5.21 ± 1.20) × 102] and the characteristic frequency [f c2 = (3.73 ± 0.06) MHz] derived from the dielectric response to the external electric field of the nuclear membrane, respectively. Moreover, the other core dielectric parameters, such as the relative permittivity of the cell membrane [ε m = (7.57 ± 0.38)] and the nuclear envelope [ε ne = (23.59 ± 4.39)], the conductivity of the cytoplasm (hemoglobin, κ Hb = (0.50 ± 0.13) S/m] and the nuclear endoplasm [κ np = (2.56 ± 0.75) S/m], and the capacitance of the bilayer membranes [C m: (0.84 ± 0.04) μF/cm2], and C ne: (0.52 ± 0.10) μF/cm2] were also accurately and reliably measured. This work presents a feasible method to evaluate the dielectric parameters and the cellular structure of the erythrocytes of bullfrogs. Moreover, it paves the way for new studies on the haematology of frogs and the detection of nucleated cells via dielectric impedance spectroscopy.

Interfacial effects on ferroelectric and dielectric properties of GO reinforced free-standing and flexible PVDF/ZnO composite membranes: Bias dependent impedance spectroscopy

Flexible membranes with attractive ferroelectric and dielectric properties are promising for numerous technological devices, such as, energy storage and harvesting devices, sensors etc. Here we report the development of conducting nanofiller containing inorganic semiconductor and organic polymer based tri-phase composite membranes and demonstrate their ferroelectric and frequency dependent dielectric characteristics. The graphene oxide (GO) nanosheet reinforced free-standing, flexible and β-phase abundant PVDF/ZnO composite membranes are fabricated by simple, low-cost and scalable chemical method. The ferroelectric properties of the PVDF polymer based composite membranes are modified through incorporation of small amount of GO and ZnO without sacrificing the mechanical flexibility as evidenced by electrical polarization characteristics. The ferroelectric polarization for PVDF/ZnO and PVDF/ZnO/GO membranes are respectively 15.98 and 14.14 μC/cm2 at only 15 kV/cm electric field which are distinctly superior than PVDF-copolymer and PVDF-perovskite based composites as reported recently. Furthermore, as per our knowledge for the first time we have studied the effects of external electric field on dielectric relaxation times originating from the electrical responses from core grains and grain-boundary or interfaces by using dc bias dependent impedance spectroscopy. The modulation in dielectric permittivity of the composite membranes is attributed to the formation of complete β-crystalline phase in PVDF/ZnO/GO membranes and introduction of active interfaces facilitating induced electrical polarization. These studies provide significant insight into the interfacial effects on the electrical transport, ferroelectric and dielectric properties of tri-phase PVDF/ZnO/GO polymer membrane, an emerging energy material.

Thermal Shock Response of Yeast Cells Characterised by Dielectrophoresis Force Measurement.

Dielectrophoresis is an electric force experienced by particles subjected to non-uniform electric fields. Recently, several technologies have been developed focused on the use of dielectrophoretic force (DEP) to manipulate and detect cells. On the other hand, there is no such great development in the field of DEP-based cell discrimination methods. Despite the demand for methods to differentiate biological cell states, most DEP developed methods have been focused on differentiation through geometric parameters. The novelty of the present work relies upon the point that a DEP force cell measurement is used as a discrimination method, capable of detecting heat killed yeast cells from the alive ones. Thermal treatment is used as an example of different biological state of cells. It comes from the fact that biological properties have their reflection in the electric properties of the particle, in this case a yeast cell. To demonstrate such capability of the method, 279 heat-killed cells were measured and compared with alive cells data from the literature. For each cell, six speeds were taken at different points in its trajectory inside a variable non-uniform electric field. The electric parameters in cell wall conductivity, cell membrane conductivity, cell membrane permittivity of the yeast cell from bibliography explains the DEP experimental force measured. Finally, alive and heat-treated cells were distinguished based on that measure. Our results can be explained through the well-known damage of cell structure characteristics of heat-killed cells.

Calculation of specific absorption rate (SAR) in human brain neurons using complex permittivity

The effect of the external electromagnetic radiation on the human brain has been investigated by the numerical calculation of the frequency-dependent complex permittivity. Using the Hodgkin–Huxley neuron model, an analytical method for the calculation of the electromagnetic power absorption in the brain neurons is proposed based on the complex permittivity of neuron membranes. The effect of the human head is considered through the calculation of forward and backward travelling electromagnetic waves. The modified time-dependent Hodgkin–Huxley equations have been used to obtain the reflectivity and transmissivity of the external stimulus at the membrane of the cell. The amount of absorbed energy by the human head is presented in the form of the electromagnetic absorption rate.

Impacts of low concentration surfactant on red blood cell dielectrophoretic responses

Cell dielectrophoretic responses have been extensively studied for biomarker expression, blood typing, sepsis, circulating tumor cell separations, and others. Surfactants are often added to the analytical buffer in electrokinetic cellular microfluidic systems to lower surface/interfacial tensions. In nonelectrokinetic systems, surfactants influence cell size, shape, and agglomeration; this has not been systematically documented in electrokinetic systems. In the present work, the impacts of the Triton X-100 surfactant on human red blood cells (RBCs) were explored via ultraviolet-visible spectroscopy (UV-Vis) and dielectrophoresis (DEP) to compare nonelectrokinetic and electrokinetic responses, respectively. The UV-Vis spectra of Triton X-100 treated RBCs were dramatically different from that of native RBCs. DEP responses of RBCs were compared to RBCs treated with low concentrations of Triton X-100 (0.07-0.17 mM) to ascertain surfactant effects on dielectric properties. A star-shaped electrode design was used to quantify RBC dielectric properties by fitting a single-shell oblate cell model to experimentally-derived DEP spectra. The presence of 0.07 and 0.11 mM of Triton X-100 shifted the RBC's DEP spectra yielding lower crossover frequencies . The single-shell oblate model revealed that cell radius and membrane permittivity are the dominant influencers of DEP spectral shifts. The trends observed were similar for 0.11 mM and 0.07 mM Triton X-100 treated cells. However, a further increase of Triton X-100 to 0.17 mM caused cells to only exhibit negative DEP. The magnitude of the DEP force increased with Triton X-100 concentration. This work indicates that dynamic surfactant interactions with cell membranes alter cell dielectric responses and properties.