We also attempted the on-demand control of the reverse droplet deformation process with the photothermal effects of the gold nanomaterial . We previously reported a goldnanomaterial-driven system for facilitating the photothermal control of structure formation . We adopted a similar photothermal system to manipulate droplet deformation (Figure ). We dropped 50 uL of the GNB condensate dispersant in 96-well plates and irradiated them with a 660nm laser. After cooling down, the irradiated dispersant was dropped on a silicon chamber and kept for 1 h or 4 h to allowthe droplets settled onto the bottom of each chamber(Figure6D). NIR-laser irradiation for 1 min kept the droplets; however, ≥2 min irradiation significantly dispersed the droplet structures. After 4 h of incubation in the chamber, the 1 min-and 2 min-irradiated samples appeared In the first step (left), the cation-π interaction between Ag + or Au + and BDAC determine the anisotropic one-direction growth. Inhibition of cation-π interaction caused an excessive increase in the aspect ratio. In the second step (right), the Au + ions accumulated on the typical facet of the nanoparticles via the cation-π interaction between BDAC and Au + . The location of BDAC was affected by the hydrophobic interaction between the surfactants as shown in figure , as well as the effect on the crystal growth of the nanoparticles into GNB to recover their condensate structures to some extent. This result indicated two things. First, the condensate exhibited a droplet tendency. The slow movement of the macromolecule at a high concentration induced LLPS after the incubation. Second, the required laser power for driving droplet deformation would be lower than the power for decomposition of poly-L-lysine, which would occur in the 3 min-irradiated samples. Although the local heating of phase-separated structures was performed using the photothermal effect derived from the usual surface plasmon of gold nanomaterial , this study is the first demonstration of photocontrol of the LLPS formation. Recently, LLPS droplets as well as other phase separated structures were considered as a target of drug discovery (ref), however, their targeting and modulation have been still challenging. Thus, GNBs are the first nanomaterial capable of them.