5/30/2023 0 Comments Evo 9 ac turns off evom![]() ![]() A whole region circuit model considering the impedance of the non-cell covered region was also established, which enables TEER measurements to be independent of the changes in the cell covered region. Here, we proposed a new whole-region model of the TEER and developed a real-time TEER measurement system that contains an organ chip with a plate electrode. However, due to the limitation of the electrical equivalent model for organ chips, the existing TEER measurements usually neglect the changes of the TEER during cell proliferation, resulting in the low accuracy of the measurements. The measurement of the TEER in organ-on-chips (organ chips) plays a significant role in medical and pharmacological research. ![]() The trans-epithelial electrical resistance (TEER) is widely used to quantitatively evaluate cellular barrier function at the organ level in vitro. This platform could be regarded as a stepping stone for the fabrication of disposable and low-cost organ and tissue-on-a-chip models with integrated sensors to facilitate studying the dynamic response of epithelial tissues to different substances in more physiologically relevant conditions. As a proof of concept, the fully integrated platform was tested with HMT3522 S1 epithelial cells to evaluate the tight barrier junction formation through TEER measurement and validated with standard immunostaining procedures for Zonula occludens-1 protein. The integrated printed electrode array exhibited excellent stability (with less than ∼0.02 Ω change in resistance) even after long-term exposure to a complex culture medium. To address this need, we have developed a low-cost microfluidic platform with an integrated electrode array that allows continuous real-time monitoring of TEER and the risk of bubble formation in the microfluidic system by using scalable manufacturing technologies such as screen printing and laser processing. However, most of these platforms require the use of high-cost and time-consuming photolithography processes, which limits their scalability and practical implementation in clinical research. Over the past decade, significant efforts have been conducted to develop more clinically relevant "organ-on-a-chip" models with integrated trans-epithelial electrical resistance (TEER) monitoring systems to help better understand the fundamental underpinnings of epithelial tissue physiology upon exposure to different substances. Although we demonstrated the use of our add-on device on EVOM® instrument only, the concept (multiplexing using digitally controlled relays) and hardware (custom data logger) presented here can be applied to more advanced TEER instruments to improve the performance of those devices.Ĭellular tight junctions play a key role in establishing a barrier between different compartments of the body by regulating the selective passage of different solutes across epithelial and endothelial tissues. Furthermore, by monitoring temperature of the cell culture medium, we were able to detect fluctuations in TEER due to temperature change after the medium change process, and were able to correct the data offset. To demonstrate the functionality of the device prototype, we monitored TEER in 4 transwell samples containing retinal cells (ARPE-19) for 67 h. Thus, to solve the current limitation of the EVOM® instrument, we built an add-on device using a custom designed electronic board and a 3D printed electrode holder that allowed automated TEER measurements in multiple transwell samples. ![]() The inconsistency in electrode placement, temperature variation, and a typically large (12–24 h) time interval between measurements result in large data variabilities. The original EVOM® instrument is designed for measuring TEER in transwell samples manually using a pair of Ag/AgCl electrodes. This study provides design of a low-cost and open source add-on device that enhances the functionality of the popular EVOM® instrument for transepithelial/endothelial electrical resistance (TEER) measurement. ![]()
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