A Collagen Thin Film-Based Bioimpedance Sensor for Cell Proliferation Rate Assessment

Collagen is the main structural protein in the human body and plays an important role in different cellular behaviors like proliferation, migration, and differentiation. It is important to study different cellular characteristics on a natural substrate similar to the extracellular matrix (ECM) in the body. In this paper, a bioimpedance sensor was used to measure the impedance behavior of biological cells cultured on a scaffold of collagen thin films. The collagen thin films with different concentrations were created on a 1-hexadecanethiol modified surface of the interdigitated electrodes (IDEs). The mesenchymal stem cells (MSCs) and human umbilical vein endothelial cells (HUVECs) were cultured on the collagen thin films. The interaction and the proliferation rate of these cells were investigated by the microscopic, and bioimpedance approaches. Impedance measurements of the cells cultured on the collagen thin film were performed by an impedance analyzer at the frequency band of 10 kHz to 1MHz at 10 mV. Differential impedances (
${Z}$
) were used as a quantitative criterion to evaluate cellular proliferation on collagen thin films. Results showed that collagen thin films with lower concentration lead to higher proliferation rate and vice versa.