Formation of Gold Nanostar-Coated Hollow Mesoporous Silica for Tumor Multimodality Imaging and Photothermal Therapy

Abstract

Development of multifunctional nanoplatforms for tumor multimode imaging and therapy is of great necessity. Herein, we report a new type of Au nanostar (NS)-coated, perfluorohexane (PFH)-encapsulated hollow mesoporous silica nanocapsule (HMS) modified with poly(ethylene glycol) (PEG) for tumor multimode ultrasonic (US)/computed tomography (CT)/photoacoustic (PA)/thermal imaging, and photothermal therapy (PTT). HMSs were first synthesized, silanized to have thiol surface groups, and coated with gold nanoparticles via a Au-S bond. Followed by growth of Au NSs on the surface of the HMSs, encapsulation of PFH in the interior of the HMSs, and surface conjugation of thiolated PEG, multifunctional HMSs@Au-PFH-mPEG NSs (for short, HAPP) were formed and well-characterized. We show that the HAPP are stable in a colloidal manner and noncytotoxic in the studied range of concentrations, possess multimode US/CT/PA/thermal imaging ability, and can be applied for multimode US/CT/PA/thermal imaging of tumors in vivo after intravenous or intratumoral injection. Additionally, the near-infrared absorption property of the HAPP enables the use of the HAPP for photothermal ablation of cancer cells in vitro and a tumor model in vivo after intratumoral injection. The developed multifunctional HAPP may be used as a novel multifunctional theranostic nanoplatform for tumor multimode imaging and PTT.

A Multifunctional Biodegradable Nanocomposite for Cancer Theranostics

“…To develop US or PA imaging systems, nanoscale platforms can be used to encapsulate stable species (e.g., CaCO 3 , [24] perfluoropentane (PFP), [25] or perfluorohexane (PFH) [26] ).…”

“…The nanobubbles will subsequently grow to micrometer-size, providing enhanced US contrast. [26] Despite recent progress, there is still much work to do in the development of biodegradable nanoscale theranostic platforms. [27,28] Mild hyperthermia induced by photothermal conversion agents under near-infrared (NIR) irradiation is one route that can be used to vaporize the liquid.…”

Gold Nanorattles with Intense Raman In Silica Nanoparticles (Nano‐IRIS) as Multimodal System for Imaging and Therapy

“…Coating gold with silica offers (i) colloidal, chemical and thermal stabilization of the inner core (ii) insulating the cores from the surrounding medium and (iii) controlling the molecular transport through pores in case of mesoporous structure . A thick silica shell not only efficiently prevents aggregation of the metal nanoparticles, but also inhibits the leaching of metal ions from the core.…”

“…[1][2][3] In this regard, hybrid colloids consisting of plasmonic metal cores and silica shells are being investigated for different sensing, imaging and therapeutic applications. [2,[4][5][6][7][8][9][10][11][12][13][14][15][16][17] Gold is the most preferred and widely used plasmonic material for biomedical applications because of its inertness and compatibility to biological system. Further, different anisotropic nanostructures of gold can be prepared having strong plasmonic field leading to strong extinction and highly tunable optical properties including SERS.…”

“…[18][19][20][21] Coating gold with silica offers (i) colloidal, chemical and thermal stabilization of the inner core (ii) insulating the cores from the surrounding medium and (iii) controlling the molecular transport through pores in case of mesoporous structure. [6] A thick silica shell not only efficiently prevents aggregation of the metal nanoparticles, but also inhibits the leaching of metal ions from the core. Further, if a porous metal core is loaded with a fluorescent or Raman active probes, a dense silica shell around it protects it from getting released and interact with the environment.…”