Xcelligence real time cell analyzer

xCELLigence Real-Time Cell Analyzer (ACEA Biosciences, USA) was employed to investigate the cell index (a dimensionless parameter which indicates the adhesive properties of cells and proliferation rate by measuring the electrical impedance) in cell cultures studied. Cells were treated with DX-HNTs and then plated in 12-well plate (E-plate) with gold electrodes on bottom at a density 7 × 10³ cells per well. The plates were installed in xCELLigence analyser, which was placed in humidified atmosphere with 5% CO² at 37 °C for 24 h. The cell index was monitored in real time using the xCELLigence software.

An xCELLigence real-time cell analyzer (ACEA Biosciences, Inc., Hangzhou, China) was placed in an incubator in advance. Afterward, 1 × 10⁵/mL cells were seeded in a test E-Plate and placed in an analyzer, which can automatically record the cell growth curve.

MCF-7 cells were seeded in 96-well plates and treated for 72 h with 5, 10, 20, 50, and 100 μM atorvastatin to evaluate the effect of the treatment on cell proliferation using the xCELLigence Real-Time Cell Analyzer (ACEA Bioscience, Inc.).

The time course for effects of Atlantic stingray venom was measured on HDFa cells maintained in culture for 5 days using an impedance-based biosensor system (xCELLigence Real-Time Cell Analyzer, ACEA Biosciences) [14 (link)]. Time-dependent changes in impedance values reflect changes in cell growth and adherence to the well surface over time [14 (link)]. HDFa cells were seeded in 96-well polyethylene terephthalate E-plates (ACEA Biosciences, San Diego, CA, USA) and maintained in culture for up to 5 days at 37 °C, 5% CO₂. After 3 days in culture, cells were treated with SRV at varying concentrations (0, 1, 3, 10, 30, and 100 μg/mL) in triplicate wells. TritonX-100 at 0.1% was used as a positive control for detaching cells from the well surface. Impedance values for each individual well were recorded every 15 min over the 5-day experimental period. Analysis of the recorded impedance values, quantified as Cell Index (CI) values, was then performed using the system software and data exported to an Excel-compatible file format. The SRV concentration producing a 50% reduction in the normalized CI value (IC50) was also calculated for different exposure periods by non-linear least squares regression using the Hill equation (Equation (1)) and the online Quest Graph™ IC50 Calculator [20 ].

Continuous cell proliferation of NCI-H460 and NCI-H460/R cancer cells untreated or treated with 500 nM DOX was analyzed using the xCELLigence Real Time Cell Analyzer (ACEA Biosciences Inc., Santa Clara, CA, USA) which facilitates label free real-time cell analysis by measuring impedance-based signals across a series of gold electrodes. Using E-plates, 50 µL of complete medium RPMI 1640 was added to each well and the electrodes were allowed to stabilize for 30 min. The plates were then moved into the xCELLigence Real Time Cell Analyzer to set a base line without cells. The cells were then seeded on E-plate at a following density—4000 cells per well. Cells on the electrodes were monitored by reading and recording the cell impedance every 30 min through 165 h.