Biosensors & Bioelectronics

Effect of Cell Density on Reproducibility in a Cell-Based Biosensor Using a Microwell Array

Abstract

Satoshi Migita, Kazuyoshi Itoga, Jun Kobayashi, Teruo Okano and Akiyoshi Taniguchi

Combinations of living cell-based biosensors and microdevices are attractive tools for real-time monitoring of gene expression profiling in a small population of cells involving small amount of analytes. However, due to the heterogeneous responsiveness of cells, cell-based biosensors have poor reproducibility and a low signal-to-noise (S/N) ratio. Previously, we constructed a “sensor cell”, a GFP reporter cell line containing an engineered Heart Shock Protein 70B’ promoter generated by stably transfecting mouse NIH/3T3 cells. In this study, we manipulated the cell density to overcome the lower signal and poor reproducibility using the sensor cells. We found that a cell density of 2 x 105 cells/cm2 provides good responsiveness of sensor cells that appears to be related to the G0/G1 phase of cell cycle. However, higher cell densities had a negative effect for on sensor performance. We also designed microdomains to regulate cell density. The GFP-positive rate of cells grown on domains at 2 x 105 cells/cm2 density was approximately 1.5 times higher than that of control cells. Our results suggest that cell density is an important factor for the design of cell-based biosensors with microdevices.