Polymers on Metal Nanoparticles: Emerging Chemistry, Self-Assembly, and Their Biomedical Applications.

Advances in ligand design and nanoscale surface engineering have transformed metal nanoparticles (NPs) into highly programmable platforms with tunable optical, plasmonic, and therapeutic properties. This review provides a perspective on polymer-ligand functionalization, charting how macromolecular-level binding chemistry translates into multiscale structure-property relationships and ultimately governs material function. We first examine strategies for incorporating diverse ligand chemistries, through both covalent and noncovalent interactions, into polymer architectures with controlled multivalency and spatial organization to generate robust and stable surface coatings. We then discuss how facet-selective binding and polymer-solvent interactions give rise to asymmetric surface functionalization and directional interparticle interactions, providing a basis for programmable NP self-assembly. Next, we review chiral ligand- and biomolecule-directed assembly as a powerful strategy for organizing these NPs into plasmonic architectures with amplified chiroptical responses. We then illustrate how these precise surfaces and assembly concepts dictate biomedical performance, specifically by defining biological identity, minimizing nonspecific interactions, and enabling multifunctional platforms for imaging, sensing, and therapy. Ultimately, this review bridges the gap between synthetic polymer chemistry and nanoscale self-assembly to offer design rules for the next generation of programmable metal nanomaterials.