The unique shape of GNBs allowed us to come up with an idea to apply them to control the formation/deformation dynamics of LLPS droplets (Figures and). The LLPS droplets are small, sphere structures that were derived from the phase separation of biomacromolecules, such as proteins, DNA, and RNA with other biomacromolecules and/or small molecules. We investigated the interference of GNBs in the formation of the LLPS droplets. As a model system, we selected the adenosine triphosphate (ATP)/poly-llysine droplets, which is a widely utilized model to study the LLPS between protein and nucleic acid . First, we prepared three types of nanomaterials with the same reagents with different concentrations, namely, GNBs, GNPs, and GNRs, to determine the local-size effect of the nanomaterials on droplet formation. Each nanoparticle was first washed with and dispersed in 100 mg/mL poly-L-lysine aqueous solution at a ca. 1 mg/mL concentration of the nanomaterial. Each dispersion and 1 M ATP solution were mixed to obtain a 1:4 molar ratio of the lysine structure and ATP molecule. Notably, this condition did not yield any droplets without the nanomaterials (Figure ).