Design of Magnetic‐Plasmonic Nanoparticle Assemblies via Interface Engineering of Plasmonic Shells for Targeted Cancer Cell Imaging and Separation. Issue 20 (24th April 2020) - Kim, Myeong Soo
Abstract: Magnetic‐plasmonic nanoparticles have received considerable attention for widespread applications. These nanoparticles (NPs) exhibiting surface‐enhanced Raman scattering (SERS) activities are developed due to their potential in bio‐sensing applicable in non‐destructive and sensitive analysis with target‐specific separation. However, it is challenging to synthesize these NPs that simultaneously exhibit low remanence, maximized magnetic content, plasmonic coverage with abundant hotspots, and structural uniformity. Here, a method that involves the conjugation of a magnetic template with gold seeds via chemical binding and seed‐mediated growth is proposed, with the objective of obtaining plasmonic nanostructures with abundant hotspots on a magnetic template. To obtain a clean surface for directly functionalizing ligands and enhancing the Raman intensity, an additional growth step of gold (Au) and/or silver (Ag) atoms is proposed after modifying the Raman molecules on the as‐prepared magnetic‐plasmonic nanoparticles. Importantly, one‐sided silver growth occurred in an environment where gold facets are blocked by Raman molecules; otherwise, the gold growth is layer‐by‐layer. Moreover, simultaneous reduction by gold and silver ions allowed for the formation of a uniform bimetallic layer. The enhancement factor of the nanoparticles with a bimetallic layer is approximately 10 7 . The SERS probes functionalized cyclic peptides are employed for targeted cancer‐cell imaging and separation. Abstract : Magnetic‐plasmonic nanoparticle assemblies via interface engineering of plasmonic assemblies on magnetic mesocrystals are desirable in biomedical applications due to their sensitivity and stability both in magnetic and plasmonic properties. This work confirms different growth modes of gold and silver in surface‐blocked plasmonic assemblies and provides a strategy for a uniform bimetallic layer growth with a strong surface‐enhanced Raman scattering activity.