Encapsulation of Single Plasmonic Nanoparticles within ZIF‐8 and SERS Analysis of the MOF Flexibility

Abstract

Hybrid nanostructures composed of metal nanoparticles and metal-organic frameworks (MOFs) have recently received increasing attention toward various applications due to the combination of optical and catalytic properties of nanometals with the large internal surface area, tunable crystal porosity and unique chemical properties of MOFs. Encapsulation of metal nanoparticles of well-defined shapes into porous MOFs in a core-shell type configuration can thus lead to enhanced stability and selectivity in applications such as sensing or catalysis. In this study, the encapsulation of single noble metal nanoparticles with arbitrary shapes within zeolitic imidazolate-based metal organic frameworks (ZIF-8) is demonstrated. The synthetic strategy is based on the enhanced interaction between ZIF-8 nanocrystals and metal nanoparticle surfaces covered by quaternary ammonium surfactants. High resolution electron microscopy and tomography confirm a complete core-shell morphology. Such a well-defined morphology allowed us to study the transport of guest molecules through the ZIF-8 porous shell by means of surface-enhanced Raman scattering by the metal cores. The results demonstrate that even molecules larger than the ZIF-8 aperture and pore size may be able to diffuse through the framework and reach the metal core.

Aqueous Stable Gold Nanostar/ZIF‐8 Nanocomposites for Light‐Triggered Release of Active Cargo Inside Living Cells

“…[10] These types of nanocomposites have been recently explored for optical sensing, [11] therapeutics, [12] theranostics, [13] and heterogeneous catalysis with encouraging results. [10] These types of nanocomposites have been recently explored for optical sensing, [11] therapeutics, [12] theranostics, [13] and heterogeneous catalysis with encouraging results.…”

“…In this context, nanocomposites based on MOFs and inorganic nanoparticles (NPs) seem like ag ood strategy to promote drug delivery under ag iven stimulus (for example, light, magnetic fields,u ltrasounds), as already demonstrated for other materials. [10] These types of nanocomposites have been recently explored for optical sensing, [11] therapeutics, [12] theranostics, [13] and heterogeneous catalysis with encouraging results. [14] Nevertheless,t he precise (temporal and spatial) controlled delivery of the cargo inside cells upon stimuli has not been achieved, since the challenging inherent aqueous instability of MOFs has not yet been addressed.…”

“…[16] These NSs were used as seeds to grow the ZIF-8 shell. [11,17] Then umber of ZIF-8 seeds was optimized to minimize byproducts such as non-coated NSs and/or pristine ZIF-8 NPs.T he resulting NCs showed ap olyhedral morphology with an average size of 218 AE 24 nm ( Figure 1A-C and Figure S2). As the bioactive cargo/ reporter we choose the bisbenzimide compound Hoechst H33258 (HOE), ab lue fluorescent dye typically used for DNAstaining in molecular biology.…”

Metal‐Organic Framework as a Protective Coating for Biodiagnostic Chips

“…We hypothesize that MOFs can be a powerful class of materials for preserving the biorecognition capability of antibodies immobilized on biosensor surfaces, considering that the MOFs can be adapted to grow on different substrates (films, particles, and gels). [16,17]…”

Construction of Large‐Area Ultrathin Conductive Metal–Organic Framework Films through Vapor‐Induced Conversion

“…After 1000 buckling cycles, the conductance showed no obvious decrease (Figure S19, Supporting Information). We hope that these efforts can provide new strategies to light the way toward the flexible integrated circuits, spin valve, supercapacitors, catalysis, surface‐enhanced Raman scattering (SERS), and so on …”