Confined Construction of Ultrasmall Molybdenum Disulfide-Loaded Porous Silica Particles for Efficient Tumor Therapy.

Recently, molybdenum sulfide (MoS2) has shown great application potential in tumor treatment because of its good photothermal properties. Unfortunately, most of the current molybdenum disulfide-based nanotherapeutic agents suffer from complex preparation processes, low photothermal conversion efficiencies, and poor structural/compositional regulation. To address these issues, in this paper, a facile "confined solvothermal" method is proposed to construct an MoS2-loaded porous silica nanosystem (designated as MoS2@P-hSiO2). The maximum photothermal efficiency of 79.5% of molybdenum-based materials reported in the literature at present was obtained due to the ultrasmall MoS2 nanoclusters and the rich porous channels. Furthermore, both in vitro and in vivo experiments showed that the cascade hybrid system (MoS2/GOD@P-hSiO2) after efficient loading of glucose oxidase (GOD) displayed a significant tumor-suppressive effect and good biosafety through the combined effects of photothermal and enzyme-mediated cascade catalytic therapy. Consequently, this hybrid porous network system combining the in situ solvothermal strategy of inorganic functional components and the efficient encapsulation of organic enzyme macromolecules can provide a new pathway to construct synergistic agents for the efficient and safe treatment of tumors.

Magnetic/Gold Core-Shell Hybrid Particles for Targeting and Imaging-Guided Photothermal Cancer Therapy.

The development of hybrid particles for tumor diagnosis and therapy has received considerable attention because they are capable of combining tumor diagnosis and treatment concurrently. So far hybrid particles for efficient and safe tumor theranostics are still very limited. Herein we have designed a new type of hybrid particles and evaluated its potential to be used in image-guided cancer diagnosis and therapy without the need of any toxic anticancer or contrast agents. The hybrid particles, consist of magnetic nanoparticles which are embedded in the poly(methyl methacrylate) (PMMA) cores and gold shells on chitosan (CTS) (γ-Fe2O3 @PMMA/CTS@Au). The hybrid particles were synthesized through initial formation of the core-shell structured γ-Fe2O3 @PMMA/CTS particles containing approximately 20% loading of magnetic nanoparticles. A gold layer was then built on top of the core-shell magnetic particles via a reduction of gold salt by amines from the chitosan assisted with the reducing agent NaBH4, followed by growing to complete gold shells in the presence of ascorbic acid (42.6% Au content). The properties of the composite particles including their chemical composition, morphology, particle size, size distribution, surface charge, magnetic responsiveness and photothermal ability were systematically characterized. The potential application of the γ-Fe2O3 @PMMA/CTS@Au hybrid particles in tumor diagnosis and therapy was assessed in vitro and in vivo using 4T1 tumor cells and 4T1 tumor-bearing mice through combining magnetic targeting, photoacoustic (PA)/computed tomography (CT) imaging and photothermal therapy. Results suggest that the γ-Fe2O3 @PMMA/CTS@Au particles can serve as a multifunctional tumor theranostic nanoplatform for magnetically targeted photothermal therapy. Breast cancer has been effectively eliminated without the use of any anticancer drugs or contrast agents. Therefore, this type of core-shell hybrid particles represents a new composite particle design for effective and safe tumor theranostics.

Confined growth of multiple gold nanorices in dual-mesoporous silica nanospheres for improved computed tomography imaging and photothermal therapy.

INTRODUCTION: In this work, we have developed a novel "confined-growth" strategy to synthesize PEGylated multiple gold nanorices-encapsulated dual-mesoporous silica nanospheres (designated as PEGylated MGNRs@DMSSs) containing both small mesopores (2.5 nm) in the shell and large mesopores (21.7 nm) in the core based on a well-established, seed-mediated growth method. The photothermal effect and CT imaging ability were also studied. METHODS: The nanoparticles were characterized by Fourier transform infrared (FT-IR) spectra, N2 absorption isotherms, Field-emission scanning electron microscopy (FE-SEM), Transmission electron microscopy (TEM), Inductively coupled plasma atomic emission spectroscopy (ICP-AES) and Confocal microscopy. RESULTS: The longitudinally-localized surface (LSPR) absorption properties of MGNRs@DMSSs can be easily tuned by altering the amount of HAuCl4 in the gold growth solution. Additionally, the resultant PEGylated MGNRs@DMSSs have monodispersed, spherical morphology and good colloidal stability in an aqueous solution. More importantly, when exposed to NIR irradiation, the PEGylated MGNRs@DMSSs exhibit both higher temperature increments and better photothermal effects than that of single PEGylated gold nanorods at nearly an equivalent LSPR absorption. In addition, as CT contrast agents, the PEGylated MGNRs@DMSSs display a better CT imaging performance, in comparison with single PEGylated gold nanorods at the same Au concentration. CONCLUSION: Taken together, results indicate the potential for MGNRs@DMSSs used in CT imaging-guided photothermal therapy. Such a simple "confined-growth" strategy within a porous matrix offers a promising platform to design and prepare novel metal(s) oxide@silica nanocomposites for use in further cancer bio-imaging and therapy.

Multifunctional gold nanostar-based nanocomposite: Synthesis and application for noninvasive MR-SERS imaging-guided photothermal ablation.

We report here the design and facile synthesis of multifunctional gold nanostars based nanocomposites (MGSNs) through direct organosilica coating onto anisotropic gold nanostars followed by the conjugation of Gd chelates. The as-synthesized MGSNs possess strong NIR absorbance, SERS signal and enhanced T1-MR imaging capability with excellent dispersivity and uniform size, as well as great photothermal stability and Raman stability under photothermal conditions. Importantly, MGSNs present excellent performance in vivo after their intravenous injection for both MR and SERS imaging and the high efficiency for killing tumor cells through photothermal ablation with NIR irradiation. A combination of the high spatial resolution of MR and the exciting sub-cell-level sensitivity and resolution of SERS can provide comprehensive information about the tumor to achieve the optimized therapeutic outcome. Therefore, MGSNs are of great potential as a multifunctional nanoplatform for MR-SERS bimodal imaging-guided, focused photothermal tumor therapy.