ABSTRACT
It is essential to precisely develop low-cost and sustainable electrocatalysts for the hydrogen evolution reaction. Herein, we explore a robust and controllable hydrothermal approach to synthesize defect-rich MoS2 nanoflakes on exfoliated MoS2 and WS2. Such well-designed hetero-structural hybrids of MoS2/exfoliated MoS2 and MoS2/exfoliated WS2 exhibit dramatically promoted electrochemical activity and high stability. The as-grown MoS2 nanoflakes hybridized on exfoliated MoS2 and WS2 generate abundant active edge sites (rich in basal defects) and unsaturated sulfur atoms, resulting in highly enhanced electrocatalytic performance. This is expected to pave the way towards a significant improvement in transition metal dichalcogenide heterostructures as electrocatalysts.
ABSTRACT
Being able to precisely control the morphologies of noble metallic nanostructures is of essential significance for promoting the surface-enhanced Raman scattering (SERS) effect. Herein, we demonstrate an overgrowth strategy for synthesizing Au @ M (M = Au, Ag, Pd, Pt) core-shell heterogeneous nanocrystals with an orientated structural evolution and highly improved properties by using Au nanorods as seeds. With the same reaction condition system applied, we obtain four well-designed heterostructures with diverse shapes, including Au concave nanocuboids (Au CNs), Au @ Ag crystalizing face central cube nanopeanuts, Au @ Pd porous nanocuboids and Au @ Pt nanotrepangs. Subsequently, the exact overgrowth mechanism of the above heterostructural building blocks is further analysed via the systematic optimiziation of a series of fabrications. Remarkably, the well-defined Au CNs and Au @ Ag nanopeanuts both exhibit highly promoted SERS activity. We expect to be able to supply a facile strategy for the fabrication of multimetallic heterogeneous nanostructures, exploring the high SERS effect and catalytic activities.
ABSTRACT
We here report smart hyaluronidase-actived theranostic nanoparticles based on hyaluronic acid (HA) coupled with chlorin e6 (Ce6) via adipic dihydrazide (ADH) forming HA-ADH-Ce6 conjugates and self-assembling into HACE NPs. The resulting nanoparticles showed stable nano-structure in aqueous condition with uniform size distribution and can be actively disassembled in the presence of hyaluronidase (over-expressed in tumor cells), exhibiting hyaluronidase-responsive "OFF/ON" behavior of fluorescence signal. The HACE NPs were rapidly taken up to human lung cancer cells A549 via CD44 (the HA receptor on the surface of tumor cells) receptor mediated endocytosis. Upon laser irradiation, the HACE NPs realized good near-infrared fluorescence imaging and photoacoustic imaging in the tumor bearing mice, which showed 5-fold higher fluorescence intensity and 3-fold higher photoacoustic (PA) intensity than free Ce6, respectively. In addition, under low dose of laser power, the HACE NPs presented more effective photodynamic therapy to suppression of tumor growth than free Ce6 in vitro and in vivo. Overall, these results suggest that the well-defined HACE NPs is a biocompatible theranostic nanoplatform for in vivo dual-modal tumor imaging and phototherapy simultaneously.
Subject(s)
Hyaluronoglucosaminidase/metabolism , Lung Neoplasms/diagnostic imaging , Lung Neoplasms/drug therapy , Nanoparticles/therapeutic use , Photochemotherapy/methods , Photosensitizing Agents/therapeutic use , Porphyrins/therapeutic use , Theranostic Nanomedicine/methods , Animals , Cell Line, Tumor , Chlorophyllides , Female , Humans , Hyaluronic Acid/metabolism , Hyaluronic Acid/therapeutic use , Lung Neoplasms/metabolism , Mice, Inbred BALB C , Mice, Nude , Micelles , Nanoparticles/metabolism , Optical Imaging/methods , Photoacoustic Techniques/methods , Photosensitizing Agents/metabolism , Porphyrins/metabolismABSTRACT
Trimetallic Au/Ag/Pt hetero-nanostructures (AAPHNs) with distinctive, designed morphology are synthesized by galvanic replacement reaction and a site-selective strategy. The three metals present on the surface are shown to act synergistically to enhance the electro-catalytic performance and durability for methanol oxidation. The described structural modification of the nanocomposites increases the range of potential applications to include both the oxygen reduction reaction in fuel cells and photocatalysis of the hydrogen evolution reaction.
