Fig. 4: Dynamics of fibre disassembly monitored via liquid-phase AFM.
From: De novo design of pH-responsive self-assembling helical protein filaments
a–c, Time-lapse of AFM images of DpHF19_9his fibres when the pH is reduced from 8 to 4.1 (a), 4.4 (b) and 4.5 (c). 0 min is defined as the time when the acidic solution is introduced into the flow cell. d, Comparison of linear-fit fibre disassembly rates at pH 4.1, 4.4 and 4.5. Fibre length is a measurement of the longest remaining fibre fragment. e, External stimulus-driven fibre disassembly. As illustrated in the diagram on the left, local (405 nm laser) and global (364 nm lamp) activation of photoacids lowers the solution pH for the disassembly of fibres on a surface. The location, pattern and area can be precisely controlled by the spot size of the UV light source. The image with a green outline shows a higher magnification of the area in the green dashed rectangle. White dashed lines delineate areas where fibres were exposed and disassembled.
