Ultrafast Dense Immobilization of Noble Metal Nanoparticles on Customizable Multifunctional Polymer Microspheres for...

Constructing colloidal particles into designated hierarchies with integrated functionalities offers insights into bottom-up material fabrication. However, the arbitrary and controllable assembly of individual nanoscale and microscale particles remains highly challenging due to their diverse structural properties. Here, a general paradigm for the robust co-assembly of plasmonic noble metal nanoparticles and multifunctional polymer microspheres through thermodynamically driven heterocoagulation and coordination interactions is developed. Monodisperse poly(styrene-co-maleic anhydride) microspheres (PSMA MSs) are facilely synthesized using a one-step emulsification method with optional simultaneous encapsulation of magnetic and fluorescent nanoparticles. Upon surfactant removal, the purified PSMA MSs become metastable and trigger ultrafast co-assembly of silver nanocubes (AgNCs) onto MSs within 5 min with the maximum coverage rate reaching nearly 50%. The densely immobilized AgNCs outside magnetic MSs exhibit excellent catalytic efficiency (>89% conversion across 15 cycles) and enable enzyme integration for cascade reactions. Moreover, the largest reported plasmonic-fluorescent encoded array (124 codes) is realized, achieving a significantly improved detection limit of 10 copies/reaction for respiratory viruses. This work addresses the long-standing challenge of achieving uniform distribution and dense immobilization of plasmonic noble metal nanoparticles and offers a general approach to fabricating designated hierarchies based on noble metal nanoparticles, with integrated functionalities for high-performance practical applications.