Adaptive Nanoplasmonics Controlled by Soft Polymers

Plasmonic nanoparticles are important building blocks in contemporary nanoscience and nanotechnology and have demonstrated promising applications in biosensing, biodiagnostics, and drug delivery. However, nanoplasmonic structures are mainly based on inorganic materials that are typically rigid and lack adaptiveness. A viable solution is to attach soft ligands─including molecules, polymers, and biospecies─to plasmonic nanoparticles to offer adaptive and stimuli-responsive functionalities at biointerfaces. Among these, polymeric ligands offer several advantages, such as highly tunable ligand lengths, diverse functionalities, and modularity in the architectural design. This perspective focuses on the dynamic control of both individual plasmonic nanoparticles and their aggregates or assemblies at biological interfaces through the use of smart polymer ligands. We begin by outlining various polymer grafting strategies onto plasmonic nanoparticles, followed by a classification of representative examples of stimuli-responsive polymers that guide adaptive nanoplasmonics, organized by the type of external stimulus. We also discuss the underlying molecular mechanisms driving these responses. Finally, we provide a summary of the field and offer perspectives on future directions for soft, stimuli-responsive nanoplasmonics at biointerfaces.