3D microgroove electrical impedance sensing to examine 3D cell cultures for antineoplastic drug assessment

Abstract

In recent decades, three-dimensional (3D) cancer cell models have attracted increasing interest in the field of drug screening due to their significant advantages in more accurate simulations of heterogeneous tumor behavior in vivo compared to two-dimensional models. Furthermore, drug sensitivity testing based on 3D cancer cell models can provide more reliable in vivo efficacy prediction. The gold standard fluorescence staining is hard to achieve real-time and label-free viability monitoring in 3D cancer cell models. In this study, a microgroove impedance sensor (MGIS) was specially developed for the dynamic and noninvasive monitoring of 3D cell viability. 3D cancer cells were trapped in microgrooves with gold electrodes on opposite walls for in situ impedance measurement. The change in the number of live cells caused inversely proportional changes to the impedance magnitude of the entire cell/Matrigel construct and reflected the proliferation and apoptosis of the 3D cells. It was confirmed that the 3D cell viability detected by the MGIS was highly consistent with the standard live/dead staining by confocal microscope characterization. Furthermore, the accuracy of the MGIS was validated quantitatively using a 3D lung cancer model and sophisticated drug sensitivity testing. In addition, the parameters of the MGIS in the measurement experiments were optimized in detail using simulations and experimental validation. The results demonstrated that the MGIS coupled with 3D cell culture would be a promising platform to improve the efficiency and accuracy of cell-based anticancer drug screening in vitro.

Extending In-Plane Impedance Measurements from 2D to 3D Cultures: Design Considerations

“…To the best of our knowledge there have been no impedance studies of fibroblast cells immerse in a collagen gel before. Pan et al [ 17 , 18 ] and Lei et al [ 16 ] were able to monitor cell proliferation of 3D spheroids using parallel and interdigitated electrodes, respectively. However, their 3D cell culture model was fundamentally different as it consisted of multiple spheroids with each spheroid consisting of a cluster of cells connected via tight junctions.…”

“…In their study Pan et al used an absolute value of the CI to determine the difference between their controls and the samples containing cells, ascribing growth with CI value differences no larger than 0.6 [ 17 , 18 ]. Here we obtained a CI of 0.3 that can be attributed to protein adsorption.…”

“…Researchers have started applying this technique with 3D cultures [ 12 , 13 , 14 , 15 , 16 , 17 , 18 , 19 ]. Lei et al and Pan et al successfully detected cell proliferation and death of cells within 3D spheroids [ 15 , 16 , 17 , 18 ]. Further, Lee et al were able to monitor single cells embedded in a hydrogel using vertical parallel electrodes positioned on either side of the culture [ 14 ].…”

“…The cell index (CI) has been introduced by scientists to normalise the impedance values for data analysis. This allows for better analysis of the cell data as the background from control measurements is subtracted [ 18 , 20 ]. Further, it gives biologists an easier readout from their 2D systems that they can then correlate with cell proliferation and death.…”

Electrochemical Sensing in 3D Cell Culture Models: New Tools for Developing Better Cancer Diagnostics and Treatments

“…Drug efficiency was tested using antitumour drug cisplatin in the following concentrations: 10, 100, and 1000 μM, and the drug synergy effect was also explored in the drug assays adding concentrations of gemcitabine/pemetrexed along with cisplatin. For further analysis, the investigators decided to establish a comparison between results obtained using the MGIS chip and a 2D biosensor, detecting significant differences in the drug responses between an in vivo like environment and 2D cells assays [ 76 ].…”