Exploring the Limits of Cell Adhesion under Shear Stress within Physiological Conditions and beyond on a Chip

Abstract

Cell adhesion processes are of ubiquitous importance for biomedical applications such as optimization of implant materials. Here, not only physiological conditions such as temperature or pH, but also topographical structures play crucial roles, as inflammatory reactions after surgery can diminish osseointegration. In this study, we systematically investigate cell adhesion under static, dynamic and physiologically relevant conditions employing a lab-on-a-chip system. We screen adhesion of the bone osteosarcoma cell line SaOs-2 on a titanium implant material for pH and temperature values in the physiological range and beyond, to explore the limits of cell adhesion, e.g., for feverish and acidic conditions. A detailed study of different surface roughness Rq gives insight into the correlation between the cells’ abilities to adhere and withstand shear flow and the topography of the substrates, finding a local optimum at Rq = 22 nm. We use shear stress induced by acoustic streaming to determine a measure for the ability of cell adhesion under an external force for various conditions. We find an optimum of cell adhesion for T = 37 °C and pH = 7.4 with decreasing cell adhesion outside the physiological range, especially for high T and low pH. We find constant detachment rates in the physiological regime, but this behavior tends to collapse at the limits of 41 °C and pH 4.

Surface acoustic wave devices for chemical sensing and microfluidics: a review and perspective

“…, a temperature of 37°C and pH of 74) where was adhesion was favorable or detachment promoted. 192 Bussonnière et al 193 and Sivanantha et al 194 both applied this concept to use SAW-initiated cell de-adhesion as a method for cell separation and identification, with Bussonnière et al separating human embryonic kidney (HEK 293) cells from, smooth muscle cells (A7r5) in a droplet and Sivanantha et al applying the technique to healthy, treated, and malaria-infected red blood cells. The advantage with the SAW approach is that the method is inherently label-free and highly selective, without adversely affecting cell viability (Bussonnière et al measured apoptosis rates less than 5%).…”

Chitosan-Graphene Oxide-Based Ultra-Thin and Flexible Sensor for Diabetic Wound Monitoring

“…2d). The HDF cell firmly adhered to RGD functionalized CS-GO substrate showed well spreading morphology and overcame dissociation with several washing steps during the fixation process prior to the SEM imaging [16,30]. In the absence of RGD, the cells did not withstand such washing force and were dissociated from the electrode, as evident from SEM images shown in Fig.…”

Correlation of in vitro cell adhesion, local shear flow and cell density

“…On a piezoelectric LiNbO 3 substrate a radio frequency (rf) signal (frequency $160 MHz, power P ¼ 28 dBm) is applied to an interdigital transducer (IDT) with a periodicity of p ¼ 25 mm resulting in a streaming towards the top cover as described earlier. 16 The ow velocities as function of lateral and vertical position and the resulting distribution of the shear velocities were analyzed employing scanning particle image velocimetry (sPIV) based on Thielicke's time-resolved particle image velocimetry (PIV) soware. Here, latex beads (Polysciences, Inc., Polybead® polystyrene, size 3 mm) were added to the uid in the chamber, which follow the streamlines and are recorded using the high speed camera FASTCAM 1024PCI, Photron.…”

“…12,13 Within the last years, miniaturized setups to study cell adhesion phenomena using Surface Acoustic Wave (SAW) induced ow have been established. [14][15][16] Basically there exist two options to generate the ow. On the one hand, the cells, e.g.…”

“…Within a single measurement studying one ensemble of cells the complete shear force range of interest is covered. Here, we used a setup as described earlier 16 to investigate the adhesion behavior of SaOs-2 cells on medical implants under micro-uidic shear ow. The analysis capability of the setup was tremendously enhanced by the implementation of custom soware entitled 'Particle Image Velocimetry De-Adhesion Correlation' (PIVDAC) that correlates the detachment of the cells with the local shear velocity of the streaming uid.…”