Seeded Growth of Plasmonic Core-Shell NU-1000 NanoMOFs With Intracellular Optical Readout.

Abstract

Plasmonic gold bipyramids (AuBipy) encapsulated within a NU-1000 metal-organic framework (MOF) create robust core-shell nanocomposites. These porous nanoassemblies combine the near-infrared (NIR) plasmonic resonance of the metallic core with the intrinsic photoluminescence of the pyrene-based organic linkers. Comprehensive optical characterization reveals efficient photothermal heating under NIR irradiation and robust surface-enhanced Raman scattering (SERS) capabilities in colloidal dispersions. For biological applications, AuBipy@NU-1000 nanocomposites exhibit good colloidal stability and maintain high cell viability in A549 cells up to a 200 pM particle concentration (equivalent to 152 µM of Au and 302 µM of Zr). Wide-field hyperspectral microscopy enables label-free intracellular mapping of the distinct optical signatures of both components after cellular internalization. Spatial analysis of these signals supports preservation of the core-shell architecture inside cells. Consequently, these nanomaterials provide a versatile platform for intracellular optical readout, with additional potential for chemical sensing and photothermal applications.