An alternative quantitative acoustical and electrical method for detection of cell adhesion process in real‐time

Abstract

Sauerbrey [(1956), Z Phys 55:206-222] showed that the shift in resonance frequency of thickness shear mode (TSM) of a quartz crystal sensor is proportional to the mass, which is deposited on it. However, new powerful electrical circuits were developed that are capable of operating TSM quartz crystal sensors in fluids which enabled this method to be introduced into electrochemical and biological applications. These applications include the detection of virus capsids, bacteria, mammalian cells, the interaction of DNA and RNA with complementary strands, specific recognition of protein ligands by immobilized receptors, and last but not least the study of complete immunosensors. Piezoelectric quartz transducers allow a label-free identification of molecules; they are more than mass sensors since the biosensor response is also influenced by the surface charge of adsorbed proteins, interfacial phenomena, surface roughness and viscoelastic properties of the adhered biomaterial. These new characteristics have recently been used to investigate cell, liposome, and protein adhesion onto surfaces, thus permitting the rapid determination of morphological cell changes as a response to pharmacological substances, and changes in the water content of biopolymers avoiding of time-consuming methods. We validated an alternative quantitative acoustical engineering for cell adhesion process monitored by the TSM. Shear acoustical results (motional resistance) are further correlated to cell counting procedures and are sensitive of adhesion processes in real-time.

Characterization of mechanical behavior of an epithelial monolayer in response to epidermal growth factor stimulation

“…The changes in dissipation factor (Δ D ) for the third overtone were recorded at 37°C for a period of 3 hours. The sensing depth of this overtone is approximately 100 nm from the surface of the oscillating sensor crystal [14]. Because of the variations that are often associated with cell assays, each experiment described here was conducted on three replicate cell samples to ensure the reliability and reproducibility of the results.…”

“…Δ D is defined as the ratio of the loss of mechanical energy per oscillation period of the sensor crystal to the total mechanical energy stored in the system. Because the acoustic signal diminishes exponentially with distance above the surface of the quartz crystal oscillator on which the cells are deposited, it probes primarily the basal area of the cell monolayer [12, 14], and Δ D for adherent cells can be expected to be related to changes in contact area of the cells, strength or quality of adhesion between the cell and matrix [15, 16]. …”

Acoustic detection of cell adhesion on a quartz crystal microbalance

“…The sensor's resonance frequency and motional resistance were measured during cell growth under serum‐free and serum‐supplemented media to obtain the physical parameters associated with the cell adhesion, Δ f , and Δ R . These parameters are expected to physically signal and characterize the cell adhesion process as cell deposition is translated by a decrease of the sensor resonance frequency and viscoelastic alterations are translated by an increase of the motional resistance ,,.…”

Dynamic Mechanical Response of Epithelial Cells to Epidermal Growth Factor

“…When the instrument used has the capability for monitoring the change in dissipation factor as well as frequency, the technique is termed QCM-D (QCM with dissipation monitoring). Because the acoustic signal diminishes exponentially with distance above the surface of the quartz crystal oscillator on which the cells are deposited, the QCM probes primarily the basal area of the cell monolayer Le Guillou-Buffello et al, 2011). The test configuration is shown in Figure 2.…”