22 research outputs found
Quantum confined peptide assemblies with tunable visible to near-infrared spectral range
Quantum confined materials have been extensively studied for photoluminescent applications. Due to intrinsic limitations of low biocompatibility and challenging modulation, the utilization of conventional inorganic quantum confined photoluminescent materials in bio-imaging and bio-machine interface faces critical restrictions. Here, we present aromatic cyclo-dipeptides that dimerize into quantum dots, which serve as building blocks to further self-assemble into quantum confined supramolecular structures with diverse morphologies and photoluminescence properties. Especially, the emission can be tuned from the visible region to the near-infrared region (420 nm to 820 nm) by modulating the self-assembly process. Moreover, no obvious cytotoxic effect is observed for these nanostructures, and their utilization for in vivo imaging and as phosphors for light-emitting diodes is demonstrated. The data reveal that the morphologies and optical properties of the aromatic cyclo-dipeptide self-assemblies can be tuned, making them potential candidates for supramolecular quantum confined materials providing biocompatible alternatives for broad biomedical and opto-electric applications
Towards efficient photoinduced charge separation in carbon nanodots and TiO 2
In this work, photoinduced charge separation behaviors in non-long-chain-molecule-functionalized carbon nanodots (CDs) with visible intrinsic absorption (CDs-V) and TiO2 composites were investigated. Efficient photoinduced electron injection from CDs-V to TiO2 with a rate of 8.8 × 108 s−1 and efficiency of 91% was achieved in the CDs-V/TiO2 composites. The CDs-V/TiO2 composites exhibited excellent photocatalytic activity under visible light irradiation, superior to pure TiO2 and the CDs with the main absorption band in the ultraviolet region and TiO2 composites, which indicated that visible photoinduced electrons and holes in such CDs-V/TiO2 composites could be effectively separated. The incident photon-to-current conversion efficiency (IPCE) results for the CD-sensitized TiO2 solar cells also agreed with efficient photoinduced charge separation between CDs-V and the TiO2 electrode in the visible range. These results demonstrate that non-long-chain-molecule-functionlized CDs with a visible intrinsic absorption band could be appropriate candidates for photosensitizers and offer a new possibility for the development of a well performing CD-based photovoltaic system
5,5′-Bis(naphthalen-2-yl)-2,2′-bi(1,3,4-oxadiazole)
The title molecule, C24H14N4O2, lies on an inversion centre and the asymmetric unit containg one half-molecule. The naphthalene ring systems are twisted slightly with respect to the oxadiazole rings, making a dihedral angle of 1.36 (6)°. These molecules are π-stacked along the crystallographic a axis, with an interplanar distance of 3.337 (1) Å. Adjacent molecules are slipped from the `ideal' cofacial π-stack in both the long and short molecular axis (the long molecular axis is defined as the line through the naphthalene C atom in the 6-position and the molecular center, the short molecular axis is in the molecular plane perpendicular to it). The slip distance along the long molecular axis (S1) is 7.064 (1) Å, nearly a two-ring-length displacement. The side slip (S2, along the short molecular axis) is 1.159 (8) Å
The synthesis and mesomorphic behaviour of tetracatenar and hexacatenar bi‐1,3,4‐oxadiazole derivatives
Nanoparticles, Helical Fibers, and Nanoribbons of an Achiral Twin-Tapered Bi-1,3,4-oxadiazole Derivative with Strong Fluorescence
Photocatalytic Pt(IV)‐Coordinated Carbon Dots for Precision Tumor Therapy
Abstract Rapid, efficient, and precise cancer therapy is highly desired. Here, this work reports solvothermally synthesized photoactivatable Pt(IV)‐coordinated carbon dots (Pt‐CDs) and their bovine serum albumin (BSA) complex (Pt‐CDs@BSA) as a novel orange light‐triggered anti‐tumor therapeutic agent. The homogeneously distributed Pt(IV) in the Pt‐CDs (Pt: 17.2 wt%) and their carbon cores with significant visible absorption exhibit excellent photocatalytic properties, which not only efficiently releases cytotoxic Pt(II) species but also promotes hydroxy radical generation from water under orange light. When triggered with a 589 nm laser, Pt‐CDs@BSA possesses the ultrastrong cancer cell killing capacities of intracellular Pt(II) species release, hydroxyl radical generation, and acidification, which induce powerful immunogenic cell death. Activation of Pt‐CDs@BSA by a single treatment with a 589 nm laser effectively eliminated the primary tumor and inhibited distant tumor growth and lung metastasis. This study thus presents a new concept for building photoactivatable Pt(IV)‐enriched nanodrug‐based CDs for precision cancer therapy
Non‐symmetric liquid crystal dimers containing the 4‐nitrobenzohydrazide group: synthesis and mesomorphic behaviour
On–Off switching of the phosphorescence signal in a carbon dot/polyvinyl alcohol composite for multiple data encryption
Towards efficient solid-state photoluminescence based on carbon-nanodots and starch composites
A new type of environmentally friendly phosphor based on carbon nanodots (CDs) has been developed through the dispersion of CDs by integrating the CDs with starch particles. The starch particles contain large nos. of hydroxyl groups around the surfaces, which can effectively absorb the CDs, whose surfaces are functionalized by lots of carboxyl and amide groups, through hydrogen bonding. Effective dispersion of CDs on the surfaces of starch particles can suppress the non-radiative decay processes and photoluminescence (PL) quenching induced by aggregation of CDs. The starch matrix neither competes for absorbing excitation light nor absorbs the emissions of CDs, which leads to efficient PL emitting. As a result, the starch/CD phosphors with a quantum yield of ∼50% were obtained. The starch/CD phosphors show great potential in phosphor-based light emitting diodes, temp. sensors, and patterning
Photo-Cross-Linkable Polymer Dots with Stable Sensitizer Loading and Amplified Singlet Oxygen Generation for Photodynamic Therapy
Photodynamic
therapy (PDT) is a promising treatment modality for clinical cancer
therapy. However, the therapeutic effect of PDT is strongly dependent
on the property of photosensitizer. Here, we developed photo-cross-linkable
semiconductor polymer dots doped with photosensitizer Chlorin e6 (Ce6)
to construct a nanoparticle platform for photodynamic therapy. Photoreactive
oxetane groups were attached to the side chains of the semiconductor
polymer. After photo-cross-linking reaction, the Ce6-doped Pdots formed
an interpenetrated structure to prevent Ce6 leaching out from the
Pdot matrix. Spectroscopic characterizations revealed an efficient
energy transfer from the polymer to Ce6 molecules, resulting in amplified
generation of singlet oxygen. We evaluated the cellular uptake, cytotoxicity,
and photodynamic effect of the Pdots in gastric adenocarcinoma cells.
In vitro photodynamic experiments indicated that the Ce6-doped Pdots
(∼10 μg/mL) effectively killed the cancer cells under
low dose of light irradiation (∼60 J/cm<sup>2</sup>). Furthermore,
in vivo photodynamic experiments were carried out in tumor-bearing
nude mice, which indicated that the Pdot photosensitizer apparently
suppressed the growth of solid tumors. Our results demonstrate that
the photo-cross-linkable Pdots doped with photosensitizer are promising
for photodynamic cancer treatment