Polydopamine-Enabled Approach toward Tailored Plasmonic Nanogapped Nanoparticles: From Nanogap Engineering to Multifunctionality

Abstract

We present a platform strategy that offers diverse flexibility in tailoring the structure and properties of core–shell plasmonic nanoparticles with built-in nanogaps. Our results have demonstrated that polydopamine serves multiple concerted functions as a nanoscale spacer to afford controllable nanogap sizes, a redox-active coating to promote metal shell growth, and a reactive scaffold to exclusively lock molecular probes inside the nanogap for surface-enhanced Raman scattering (SERS). More interestingly, the universal adhesion of polydopamine on diverse colloidal substrates allows for customized synthesis of multishell plasmonic nanogapped nanoparticles (NNPs) and multifunctional hybrid NNPs containing different cores (i.e., magnetic nanoparticles), which are not readily accessible by conventional methods. Internally coupled plasmonic NNPs with broadly tunable spectroscopic properties, highly active SERS, and multifunctionality hold great promise for emerging fields, such as sensing, optoelectronics, and theranostics, as demonstrated by the ultrasensitive SERS detection and efficient photothermal killing of food-borne pathogens here.

Color Engineering of Silicon Nitride Surfaces to Characterize the Polydopamine Refractive Index

“…The reported values were mainly obtained for polydopamine colloidal dispersions ,. Nowadays, accurate determination of the polydopamine refractive index is necessary since polydopamine has a central role in the development of materials for optical applications ,. Besides, the examination of skin and the diagnosis of melanomas can be based on the use of non‐invasive optical biomedical imaging techniques such as reflectance confocal microscopy, which examines tissue back‐scattering from structures with endogenous contrast such as melanin to seek for abnormal refractive index boundaries associated to melanomas .…”

Intracellular and Cellular Detection by SERS‐Active Plasmonic Nanostructures

“…The greatly amplified SERS signal of the NNPs with a 1–2 nm nanogap gave rise to ultrasensitive detection of cancer cells. Duan and co‐workers further constructed NNPs on the basis of multifunctional pdop coating . This pdop‐enabled approach made the easy preparation of barcode structures, such as multilayered NPs, possible by simply repeating the coating and metalization process.…”

“…Duan and co-workers further constructed NNPsont he basis of multifunctional pdop coating. [80] This pdop-enabled approach made the easy preparation of barcode structures, such as multilayered NPs, possible by simply repeating the coating andm etalization process. Along with the self-polymerization of dopamine molecules, aR amanr eporter carrying primary amine groups was embedded inside the pdopg ap through Michael addition and/orS chiff base reactions with the quinone groups in pdop.…”

Particle‐in‐a‐Frame Nanostructures with Interior Nanogaps

“…[11] Furthermore,u nlike solid nanostructures,a ggregating Au NFs was ineffective for the enhancement of their plasmonic function owing to the trade-off between the interior EM field and interparticle plasmon field coupling. [4,[18][19][20] However,a lmost reported nanostructures with interior nanogaps are enclosed hollow nanostructures.A ccordingly,t ofully harness the structural benefits of NFs in plasmonic applications,itishighly desirable to devise Au NFs with small interior nanogaps. [4,[18][19][20] However,a lmost reported nanostructures with interior nanogaps are enclosed hollow nanostructures.A ccordingly,t ofully harness the structural benefits of NFs in plasmonic applications,itishighly desirable to devise Au NFs with small interior nanogaps.…”