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Characterization of the binding of functionalized microparticles to surfaces with a specific chemistry sheds light on molecular scale interactions. Polymer or protein adsorption are often monitored by colloid particle deposition. Force measurements on microbeads by atomic force microscopy (AFM) or optical tweezers are standard methods in molecular biophysics, but typically have low throughput. Washing and centrifuge assays with (bio)chemically decorated microbeads provide better statistics, but only qualitative results without a calibrated binding force or energy value. In the present work we demonstrate that a computer controlled micropipette (CCMP) is a straightforward and high-throughput alternative to quantify the surface adhesion of functionalized microparticles. However, being an indirect force measurement technique, its in-depth comparison with a direct force measurement is a prerequisite of applications requiring calibrated adhesion force values. To this end, we attached polystyrene microbeads to a solid support by the avidin-biotin linkage. We measured the adhesion strength of the microbeads with both a specialized robotic fluid force microscope (FluidFM BOT) and CCMP. Furthermore, the bead-support contact zone was directly characterized on an optical waveguide biosensor to determine the density of avidin molecules. Distribution of the detachment force recorded on ∼50 individual beads by FluidFM BOT was compared to the adhesion distribution obtained from CCMP measurements on hundreds of individual beads. We found that both methods provide unimodal histograms. We conclude that FluidFM BOT can directly measure the detachment force curve of 50 microbeads in 150 min. CCMP can provide calibrated binding/adhesion force values of 120 microbeads in an hour.

Cell-cell and cell-matrix adhesions are fundamental in all multicellular organisms. They play a key role in cellular growth, differentiation, pattern formation and migration. Cell-cell adhesion is substantial in the immune response, pathogen-host interactions, and tumor development. The success of tissue engineering and stem cell implantations strongly depends on the fine control of live cell adhesion on the surface of natural or biomimetic scaffolds. Therefore, the quantitative and precise measurement of the adhesion strength of living cells is critical, not only in basic research but in modern technologies, too. Several techniques have been developed or are under development to quantify cell adhesion. All of them have their pros and cons, which has to be carefully considered before the experiments and interpretation of the recorded data. Current review provides a guide to choose the appropriate technique to answer a specific biological question or to complete a biomedical test by measuring cell adhesion.