One example of frequency dependent sample response is demonstrated with agarose gels of varying stiffness. PeakForce QNM measurements were performed on three different agarose gels – 1.25%, 2.5% and 5% - at three different frequencies – 1kHz, 500Hz, and 250Hz. As expected, the resulting modulus values increased with the agarose gel percentage. Modulus values also increased in each of the gel types measured as PeakForce QNM frequency increased. The data demonstrates frequency dependent behavior of the gels which could suggest a viscoelastic effect.
There is relatively small standard deviation associated with each of the modulus values despite being taken by multiple users, using multiple probes, and multiple samples. The data shows that there is very good consistency in the measurements, and that PeakForce QNM can be used to quantitatively measure sample behavior within a wide frequency spectrum.