title: Encapsulation of particle ensembles in graphene nanosacks as a new route to multifunctional materials.
abstract: Hybrid nanoparticles with multiple functions are of great interest in biomedical diagnostics, therapies, and theranostics but typically require complex multistep chemical synthesis. Here we demonstrate a general physical method to create multifunctional hybrid materials through aerosol-phase graphene encapsulation of ensembles of simple unifunctional nanoparticles. We first develop a general theory of the aerosol encapsulation process based on colloidal interactions within drying microdroplets. We demonstrate that a wide range of cargo particle types can be encapsulated, and that high pH is a favorable operating regime that promotes colloidal stability and limits nanoparticle dissolution. The cargo-filled graphene nanosacks are then shown to be open structures that rapidly release soluble salt cargoes when reintroduced into water, but can be partially sealed by addition of a polymeric filler to achieve slow release profiles of interest in controlled release or theranostic applications. Finally, we demonstrate an example of multifunctional material by fabricating graphene/Au/Fe3O4 hybrids that are magnetically responsive and show excellent contrast enhancement as multimodal bioimaging probes in both magnetic resonance imaging and X-ray computed tomography in full-scale clinical instruments.
authors.affiliation: Department of Chemistry, Brown University, Providence, Rhode Island 02912, United States.
authors.forename: Yantao
authors.initials: Y
authors.lastname: Chen
authors.forename: Fei
authors.initials: F
authors.lastname: Guo
authors.forename: Yang
authors.initials: Y
authors.lastname: Qiu
authors.forename: Hiroe
authors.initials: H
authors.lastname: Hu
authors.forename: Indrek
authors.initials: I
authors.lastname: Kulaots
authors.forename: Edward
authors.initials: E
authors.lastname: Walsh
authors.forename: Robert H
authors.initials: RH
authors.lastname: Hurt
mesh_terms: D002214:Capsules; D003287:Contrast Media / Q000737:chemistry; D052203:Ferrosoferric Oxide / Q000737:chemistry; D006046:Gold / Q000737:chemistry; D006108:Graphite / Q000737:chemistry*; D008279:Magnetic Resonance Imaging; D049329:Nanostructures / Q000737:chemistry*; D012995:Solubility; D014057:Tomography, X-Ray Computed
chemical_list: D002214:Capsules; D003287:Contrast Media; D006046:Gold; D006108:Graphite; D052203:Ferrosoferric Oxide