Denting Nanospheres with a Short Peptide

Dented nanospheres show promising potential in drug delivery, nanomotors, etc . However, it is still challenging to prepare them by homopolymer self-assembly because of the strict structural requirements of the homopolymer. Herein, we propose a strategy for preparing dented nanospheres from homopolymers by co-assembly with a short peptide. They were co-assembled from poly(2-hydroxy-3-((4-(ethoxycarbonyl)phenyl)amino)propyl methacrylate) (PHBzoMA 59 ) and ( S )-2-(( S )-2-((((9 H -fluoren-9-yl)methoxy)carbonyl)amino)-3-phenylpropanamido)-3-phenylpropanoic acid (Fmoc-FF-OH). PHBzoMA homopolymers can only self-assemble into nanospheres without dent, and the addition of a short peptide introduced hydrogen bonding and complementary π-π stacking interactions led to the final dented nanosphere morphology. The weight fractions of the short peptide can be adjusted to regulate the final morphology. It was confirmed that the radius of curvature of the dent on the surface was related to the organic bubble inside the protospheres prepared at critical aggregation concentration (CAC). The organic bubble can be adjusted by altering the kind of organic solvent and solution pH, which allowed control over the dented nanosphere dimension. The use of different organic solvents with various polarities allows adjustment of the interfacial tension, and hence the denting degree. This degree can also be controlled by manipulating the solution pH to (de)protonate the short peptide and homopolymer. Furthermore, the versatility of this method was highlighted by using a different homopolymer and the applicability of the resulting dented nanospheres was demonstrated by decoration with gold nanoparticles. Overall, this study provided important insights and a new simple strategy to prepare dented nanospheres in a controlled fashion.