Images were acquired using a Bruker Multimode 8 operated in peak-force tapping with PEAKFORCE-HIRS-F-B probes (Bruker, CA). Peak-tapping is operated by rapidly modulating the z-piezo in order to acquire a force curve for each pixel in the image, resulting in intermittent contact of the probe with the sample and largely eliminating lateral forces. As such, the maximum applied force to the sample can be controlled and minimized (on the order of 100 pN), allowing for high-resolution imaging of soft, aqueous structures. PEAKFORCE-HIRS-F-B probes, with a nominal spring constant of 0.12 N m -1 and tip radius of 1 nm, facilitated high-resolution imaging.