Anionic polymers amplify electrokinetic perfusion through extracellular matrices.

Electrical stimulation (ES) promotes healing of chronic epidermal wounds and delays degeneration of articular cartilage. Despite electrotherapeutic treatment of these non-excitable tissues, the mechanisms by which ES promotes repair are unknown. We hypothesize that a beneficial role of ES is dependent on electrokinetic perfusion in the extracellular space and that it mimics the effects of interstitial flow.

Electrokinetic Perfusion Through Three-Dimensional Culture Reduces Cell Mortality.

Cell proliferation and survival are dependent on mass transfer. , fluid flow promotes mass transfer through the vasculature and interstitial space, providing a continuous supply of nutrients and removal of cellular waste products. In the absence of sufficient flow, mass transfer is limited by diffusion and poses significant challenges to cell survival during tissue engineering, tissue transplantation, and treatment of degenerative diseases.

Electromigration of cell surface macromolecules in DC electric fields during cell polarization and galvanotaxis.

DC electric fields (EFs) can often induce cellular polarity, and direct migration of cells toward one of the electrical poles. The mechanism(s) by which cells sense weak EFs is not established. We present here a molecular flux model to describe electromigration of plasma membrane macromolecules and compare its predictions to electromigration of a lipid-anchored surface protein, tdTomato-GPI, under different experimental conditions.

Advances in Electrochemistry for Monitoring Cellular Chemical Flux.

The transport of molecules and inorganic ions across the plasma membrane results in chemical fluxes that reflect cellular function in healthy and diseased states. Measurement of these chemical fluxes enables the characterization of protein function and transporter stoichiometry, characterization of the viability of single cells and embryos prior to implantation, and screening of pharmaceutical agents. Electrochemical sensors are sensitive and noninvasive tools for measuring chemical fluxes immediately outside the cells in the boundary layer, that are capable of monitoring a diverse range of transported analytes including inorganic ions, gases, neurotransmitters, hormones, and pharmaceutical agents.

Reversing the direction of galvanotaxis with controlled increases in boundary layer viscosity.

Weak external electric fields (EFs) polarize cellular structure and direct most migrating cells (galvanotaxis) toward the cathode, making it a useful tool during tissue engineering and for healing epidermal wounds. However, the biophysical mechanisms for sensing weak EFs remain elusive. We have reinvestigated the mechanism of cathode-directed water flow (electro-osmosis) in the boundary layer of cells, by reducing it with neutral, viscous polymers.