Evaluation of rapid transepithelial electrical resistance (TEER) measurement as a metric of kidney toxicity in a high-throughput microfluidic culture system

Abstract

Rapid non-invasive kidney-specific readouts are essential to maximizing the potential of microfluidic tissue culture platforms for drug-induced nephrotoxicity screening. Transepithelial electrical resistance (TEER) is a well-established technique, but it has yet to be evaluated as a metric of toxicity in a kidney proximal tubule (PT) model that recapitulates the high permeability of the native tissue and is also suitable for high-throughput screening. We utilized the PREDICT96 high-throughput microfluidic platform, which has rapid TEER measurement capability and multi-flow control, to evaluate the utility of TEER sensing for detecting cisplatin-induced toxicity in a human primary PT model under both mono- and co-culture conditions as well as two levels of fluid shear stress (FSS). Changes in TEER of PT-microvascular co-cultures followed a dose-dependent trend similar to that demonstrated by lactate dehydrogenase (LDH) cytotoxicity assays and were well-correlated with tight junction coverage after cisplatin exposure. Additionally, cisplatin-induced changes in TEER were detectable prior to increases in cell death in co-cultures. PT mono-cultures had a less differentiated phenotype and were not conducive to toxicity monitoring with TEER. The results of this study demonstrate that TEER has potential as a rapid, early, and label-free indicator of toxicity in microfluidic PT-microvascular co-culture models.

Application of microfluidic chips in the simulation of the urinary system microenvironment

“…Shaughnessey et al. [ 122 ] utilized a high-throughput microfluidic platform with rapid transepithelial electrical resistance measurement capability and multi-flow control function to evaluate cisplatin-induced toxicity in human primary proximal tubule models. However, this study contained no further experiments on high-throughput drug screening.…”

Organ-on-a-Chip Platform with an Integrated Screen-Printed Electrode Array for Real-Time Monitoring Trans-Epithelial Barrier and Bubble Formation

“…16 While the community of biologists has widely used these methods, they have several drawbacks, often including time-consuming fixation and staining processes and costly materials/reagents, and do not allow continuous real-time monitoring of cells in "organ/tissue-on-a-chip" platforms. 17 An alternative approach to such optical and invasive methods is using electrical measurements to assess the barrier function of epithelial cells on porous cell culture-supported substrates. For example, electric cell-substrate impedance sensing (ECIS) is an electrical measurement technique in which a constant small alternating current (AC) is applied, and the potential drop across the electrodes is used to measure the integrity of epithelial monolayers such as cell viability and confluency.…”

“…30 Although more recent reports have shown the use of micro-engineering in preparing microelectrode arrays for on-chip TEER measurement with impedance spectroscopy assessment, most of them require costly and time-consuming photolithography and etching processes, which increases the overall cost of the device and contradicts the rationale to be used for disposable cell-culture applications. 17,31,32 Hence, for the first time, this work reports the development of a cost-effective fabrication process of a disposable microfluidics system with an integrated electrode array for real-time monitoring of TEER and air bubble formation. 33−35 The fabrication process takes advantage of additive manufacturing and scalable processing methods, including screen printing and laser cutting, for simple fabrication and integration of the electrode array with the microfluidic system.…”

“…One of the gold standard approaches in determining the tight junctions between cells, and their proper polarization, is through immunostaining for tight junction markers (e.g., Zonula occludens (ZO) and occludin) . While the community of biologists has widely used these methods, they have several drawbacks, often including time-consuming fixation and staining processes and costly materials/reagents, and do not allow continuous real-time monitoring of cells in “organ/tissue-on-a-chip” platforms . An alternative approach to such optical and invasive methods is using electrical measurements to assess the barrier function of epithelial cells on porous cell culture-supported substrates.…”

“…Due to the higher accuracy of this measurement, several automated devices have been commercialized for measuring the transendothelial impedance of various barrier-forming cells in culture. , However, such systems still have disadvantages, including discontinuous time-lapse measurements and the need to reuse the electrodes for each measurement, which requires proper reconditioning and calibration in a control buffer solution before each measurement and limits their use in long-term on-chip devices with microfluidic systems . Although more recent reports have shown the use of micro-engineering in preparing microelectrode arrays for on-chip TEER measurement with impedance spectroscopy assessment, most of them require costly and time-consuming photolithography and etching processes, which increases the overall cost of the device and contradicts the rationale to be used for disposable cell-culture applications. ,, Hence, for the first time, this work reports the development of a cost-effective fabrication process of a disposable microfluidics system with an integrated electrode array for real-time monitoring of TEER and air bubble formation. − The fabrication process takes advantage of additive manufacturing and scalable processing methods, including screen printing and laser cutting, for simple fabrication and integration of the electrode array with the microfluidic system. − The prime aim of the bubble detection system is to detect potential disturbance (>1 mm diameter air bubbles) in the culture medium, which can result in false measurements due to unwanted stress in the cells. Hence, to avoid such circumstances, a linear electrode array was positioned within the proximity of the cell culture region to detect bubbles by real-time monitoring electrical impedance throughout the microfluidic channel.…”