Figure 14. MAMs for single molecule force spectroscopy.

a) (top middle) Schematic of the polymer force clamp (PFC), a composite MAM nanoparticle capable of delivering pN-scale forces to attached biomolecules through NIR illumination. Much like stretching a spring, (bottom) the actuation of PFC MAMs unfolds fluorescently labeled DNA molecules, resulting in increased fluorescence. b) Actuation of PFCs was evidenced through fluorescent labeling of the MAM, with increased fluorescence density under NIR illumination indicating particle shrinkage. c) PFCs provide robust and repeatable unfolding of attached biomolecules, shown by cyclic increases in fluorescence from unfolded DNA structures across multiple NIR laser exposures. Reproduced with permission.^[140] Copyright 2018, American Chemical Society.