Deriving an electric circuit equivalent model of cell membrane pores in electroporation

Electroporation is the formation of reversible pores in cell membranes under a brief pulse of high electric field. Dynamics of pore formation during electroporation suggests that the transmembrane potential would settle approximately at the threshold transmembrane potential and the transmembrane resistance would decrease significantly from the state of relaxation. The current electric circuit equivalent models for electroporation containing time-invariant, static and passive components are unable to capture the pore dynamics. A biophysically-inspired electric circuit equivalent model containing dynamic components for membrane pores has been derived using biological parameters. The model contains a voltage-controlled resistor driven by a two-stage cascaded integrator that is activated through a voltage-gated switch. Simulation results with the derived model showed higher accuracy compared to a commonly used model, where the transmembrane resistance decreased million-fold at the onset of electroporation and the transmembrane potential settled at 99.5% of the critical transmembrane potential, thus enabling improved dynamic behavior modeling ability of the pores in electroporation. The derived model allows fast and reliable analysis of this biophysical phenomenon and potentially aids in optimization of various parameters involved in electroporation

Effects of thrombus simulants on acoustic characteristics of artificial heart-valves

Thrombus simulants were attached to the inflow valve housing and in-vitro sound recordings were made of mechanical aortic valves in a mock circulatory loop driven by a pulsatile ar

Design and analysis of a class-E frequency-controlled transcutaneous energy transfer system

This article introduces a frequency-controlled transcutaneous energy transfer system as well as a particular circuit structure for it. The analysis method, design and realization of this system are studied and its performance evaluation based on the simulations and experimental results of a prototype circuit is carried out. The simplicity of the required hardware as well as the high performance and reliability are among the attractive features of the proposed system

Electrical lysis: Dynamics revisited and advances in on-chip operation

Electrical lysis (EL) is the process of breaking the cell membrane to expose the internal contents under an applied high electric field. Lysis is an important phenomenon for cellular analysis, medical treatment, and biofouling control. This paper aims to review, summarize, and analyze recent advancements on EL. Major databases including PubMed, Ei Engineering Village, IEEE Xplore, and Scholars Portal were searched using relevant keywords. More than 50 articles published in English since 1997 are cited in this article. EL has several key advantages compared to other lysis techniques such as chemical, mechanical, sonication, or laser, including rapid speed of operation, ability to control, miniaturization, low cost, and low power requirement. A variety of cell types have been investigated for including protoplasts, E. coli, yeasts, blood cells, and cancer cells. EL has been developed and applied for decontamination, cytology, genetics, single-cell analysis, cancer treatment, and other applications. On-chip EL is a promising technology for multiplexed automated implementation of cell-sample preparation and processing with micro- or nanoliter reagents

Identifying severity of electroporation through quantitative image analysis

Electroporation is the formation of reversible hydrophilic pores in the cell membrane under electric fields. Severity of electroporation is challenging to measure and quantify. An image analysis method is developed, and the initial results with a fabricated microfluidic device are reported. The microfluidic device contains integrated microchannels and coplanar interdigitated electrodes allowing low-voltage operation and low-power consumption. Noninvasive human buccal cell samples were specifically stained, and electroporation was induced. Captured image sequences were analyzed for pixel color ranges to quantify the severity of electroporation. The method can detect even a minor occurrence of electroporation and can perform comparative studies

Overview of photo-induced therapy for ATP production

The purpose of this report is to provide a review of the effects of low-power photo-induced therapy using lasers of different device parameters such as intensity, wavelength, lasing mechanism (i.e., pulsed or continuous) on the production of Adenosine triphosphate (ATP) in mammalian cells. This is a very important research topic as it is suggested in literature that there might be a relationship between the ATP levels and specific diseases. It has been shown that the ATP production was enhanced at wavelengths ranging between 600 nm and 1000 nm (also known as the optical window), in particular at 600nm, 632.8nm, 635nm, 650nm, and 904nm. However, certain experiments showed that the effectiveness of the photo-induced therapy was also dependent on the dosage and the duration of the supplied light. We present the research conclusions drawn from the experiments reported within the last decade, and provide a list of potential medical treatment(s) for patients using visible and near infrared (NIR) light