A diverse range of remarkable boron nitride (BN) nanostructures subsuming nano-horns, nano-rods, nano-platelets, and clusters of hollow nanospheres (nano-onions, arguably of greatest applied and fundamental interest) have been produced exclusively from crystalline BN precursor powder via lamp ablation. The procedure is safe, devoid of toxic reagents, simple, rapid and scalable—generating some genres of nanoparticles that had previously proved elusive. Product structure and composition were unambiguously assessed by high-resolution transmission electron microscopy, energy-dispersive X-ray spectroscopy and electron energy loss spectroscopy.
Nanoparticles (NPs) which are innovation and research focus in drug delivery systems, still have some disadvantages limiting its application in clinical use, such as short circulation time, recognition and clearance by reticuloendothelial system (RES) and passive targeting in certain organs. However, the recent combination of natural components and nanotechnology has offered new solutions to address these problems. A novel biomimetic platform consisting of nanoparticle core and membrane shell, such as cell membrane, exosome or vesicle vastly improves properties of nanoparticles. These coated nanoparticles can replicate the unique functions of the membrane, such as prolonged blood circulation, active targeting capability and enhanced internalization. In this review, we focus on the newest development of biological-camouflaged nanoparticles and mainly introduce its application related to cancer therapy and toll-like receptor.
We propose a process of quantum-confined ion superfluid (QISF), which is enthalpy-driven confined ordered fluid, to explain the transmission of nerve signals. The ultrafast Na+ and K+ ions transportation through all sodium-potassium pump nanochannels simultaneously in the membrane is without energy loss, and leads to QISF wave along the neuronal axon, which acts as an information medium in the ultrafast nerve signal transmission. The QISF process will not only provide a new view point for a reasonable explanation of ultrafast signal transmission in the nerves and brain, but also challenge the theory of matter wave for ions, molecules and particles.
Oligo(p-phenyleneethynylene)s (OPEs) end-capped with (alkynyl)bis(diphosphine)ruthenium and thiol/thiolate groups stabilize ca. 2 nm diameter gold nanoparticles (AuNPs). The morphology, elemental composition and stability of the resultant organometallic OPE/AuNP hybrid materials have been defined using a combination of molecular- and nano-material chacterization techniques. The hybrids display long-term stability in solution (more than a month), good solubility in organic solvents, reversible ruthenium-centered oxidation, and transparency beyond 800 nm, and possess very strong nonlinear absorption activity at the first biological window, and unprecedented two-photon absorption activity in the second biological window (σ2 up to 38,000 GM at 1,050 nm).
DNA is a self-assembled, double stranded natural molecule that can chelate and align nickel ions between its base pairs. The fabrication of a DNA-guided nickel ion chain (Ni-DNA) device was successful, as indicated by the conducting currents exhibiting a Ni ion redox reaction-driven negative differential resistance effect, a property unique to mem-elements (1). The redox state of nickel ions in the Ni-DNA device is programmable by applying an external bias with different polarities and writing times (2). The multiple states of Ni-DNA-based memristive and memcapacitive systems were characterized (3). As such, the development of Ni-DNA nanowire device-based circuits in the near future is proposed.
Electronic sensors based on biomaterials can lead to novel green technologies that are low cost, renewable, and eco-friendly. Here we demonstrate bioelectronic ammonia sensors made from protein nanowires harvested from the microorganism Geobacter sulfurreducens. The nanowire sensor responds to a broad range of ammonia concentrations (10 to 106 ppb), which covers the range relevant for industrial, environmental, and biomedical applications. The sensor also demonstrates high selectivity to ammonia compared to moisture and other common gases found in human breath. These results provide a proof-of-concept demonstration for developing protein nanowire based gas sensors for applications in industry, agriculture, environmental monitoring, and healthcare.
Two-dimensional (2D) nanomaterials have attracted a great deal of attention since the discovery of graphene in 2004, due to their intriguing physicochemical properties and wide-ranging applications in catalysis, energy-related devices, electronics and optoelectronics. To maximize the potential of 2D nanomaterials for their technological applications, controlled assembly of 2D nanobulding blocks into integrated systems is critically needed. This mini review summarizes the reported strategies of 2D materials-based assembly into integrated functional nanostructures, from in-situ assembly method to post-synthesis assembly. The applications of 2D assembled integrated structures are also covered, especially in the areas of energy, electronics and sensing, and we conclude with discussion on the remaining challenges and potential directions in this emerging field.
We present a new scheme for visibly-opaque but near-infrared-transmitting filters involving 7 layers based on one-dimensional ternary photonic crystals, with capabilities in reaching nearly 100% transmission efficiency in the near-infrared region. Different decorative reflection colors can be created by adding additional three layers while maintaining the near-infrared transmission performance. In addition, our proposed structural colors show great angular insensitivity up to ±60° for both transverse electric and transverse magnetic polarizations, which are highly desired in various fields. The facile strategy described here involves a simple deposition method for the fabrication, thereby having great potential in diverse applications such as image sensors, anti-counterfeit tag, and optical measurement systems.
Anisotropic two-dimensional (2D) materials exhibit lattice-orientation dependent optical and electrical properties. Carriers doping of such materials has been used to modulate their energy band structures for opto-electronic applications. Herein, we show that by stacking monolayer rhenium disulfide (ReS2) on a flat gold film, the electrons doping in ReS2 can affect the in-plane anisotropic Raman enhancement of molecules adsorbed on ReS2. The change of enhancement factor and the degree of anisotropy in enhancement with layer number are sensitively dependent on the doping level of ReS2 by gold, which is further confirmed by Kelvin probe force microscopy (KPFM) measurements. These findings could open an avenue for probing anisotropic electronic interactions between molecules and 2D materials with low symmetry using Raman enhancement effect.
The development of high-efficiency peroxidase mimetics is highly desirable in view of high cost and low stability of natural enzymes. From the perspective of mimicking active site microenvironment at low cost, we herein report a novel histidine-functionalized graphene quantum dot (His-GQD)/hemin complex, which exhibits the highest catalytic rate for the peroxidase-based chromogenic reaction among the hemin-containing mimetics reported so far. Also, our peroxidase mimetic shows excellent tolerance to strongly acidic conditions and can function in a wide temperature range. Lineweaver-Burk plots and comprehensive electron paramagnetic resonance analysis reveal a ping-pong type catalytic mechanism for this mimetic. In addition, His-GQD/hemin demonstrates high efficiency and accuracy in detecting H2O2 and blood glucose. Our work provides an effective design of artificial enzymes for practical applications.
The rapid development of solar cells based on lead halide perovskites (LHPs) has prompted very active research activities in other closely-related fields. Colloidal nanostructures of such materials display superior optoelectronic properties. Especially, one-dimensional (1D) LHPs nanowires show anisotropic optical properties when they are highly oriented. However, the ionic nature makes them very sensitive to external environment, limiting their large scale practical applications. Here, we introduce an amphiphilic block copolymer, polystyrene-block-poly(4-vinylpyridine) (PS-P4VP), to chemically modify the surface of colloidal CsPbBr3 nanowires. The resulting core-shell nanowires show enhanced photoluminescent emission and good colloidal stability against water. Taking advantage of the stability enhancement, we further applied a modified Langmuir-Blodgett technique to assemble monolayers of highly aligned nanowires, and studied their anisotropic optical properties.
The remarkable ability of biological systems to sense and adapt to complex environmental conditions has inspired the design of next-generation electronics with advanced functionalities. This review focuses on emerging bio-inspired strategies for the development of flexible and stretchable electronics that can accommodate mechanical deformations and integrate seamlessly with biological systems. We will provide an overview of the practical considerations in the materials and structure designs of flexible and stretchable electronics. Recent progress in bio-inspired pressure/strain sensors, stretchable electrodes, mesh electronics, and flexible energy devices are then discussed, with an emphasis on their unconventional micro/nanostructure designs and advanced functionalities. Finally, current challenges and future perspectives are identified and discussed.
Ocular drug delivery remains a significant challenge that is limited by poor corneal retention and permeation, resulting in low ocular bioavailability (< 5%). Worse still, the most convenient and safe route of ocular drug administration, topical administration results in a drug bioavailability of less than 1%. iRGD modified drug delivery strategies have been developed for cancer therapy, however active targeting iRGD platforms for ocular drug delivery have yet to be explored. Herein, an iRGD modified liposomes was developed for ocular drug delivery via topical administration. The results indicated that iRGD modified liposomes could prolong the corneal retention time and enhance corneal permeability in an iRGD receptor mediated manner. These findings provided a novel strategy for topical ocular drug delivery for the treatment of posterior ocular diseases.
Small-sized bimetallic nanoparticles that possess numerous accessible metal sites and optimal geometric/electronic structures show great promise for advanced synergetic catalysis but remain synthetic challenge so far. Here, an universial synthetic method is developed for building a library of bimetallic nanoparticles on mesoporous sulfur-doped carbon supports, consisting of 24 combinations of 3 noble metals (that is, Pt, Rh, Ir) and 7 other metals, with average particle sizes ranging from 0.7 to 1.4 nm. The synthetic strategy is based on the strong metal-support interaction arising from the metal-sulfur bonding, which suppresses the metal aggregation during the H2-reduction at 700 °C and ensure the formation of small-sized and alloyed bimetallic nanoparticles. The enhanced catalytic properties of the ultrasmall bimetallic nanoparticles are demonstrated in the dehydrogenation of propane at high temperature and oxidative dehydrogenations of N-heterocycles.
We describe a route to the preparation of (metal yolk)/(porous ceria shell) nanostructures through the heterogeneous growth of ceria on porous metal nanoparticles followed by the calcination-induced shrinkage of the nanoparticles. The approach allows for the control of the ceria shell thickness, the metal yolk composition and size, which is difficult to realize through common templating approaches. The yolk/shell nanostructures with monometallic Pt and bimetallic PtAg yolks featuring plasmon-induced broadband light absorption in the visible region are rationally designed and constructed. The superior photocatalytic activities of the obtained nanostructures are demonstrated by the selective oxidation of benzyl alcohol under visible light. The excellent activities are ascribed to the synergistic effects of the metal yolk and the ceria shell on the light absorption, electron-hole separation and efficient mass transfer. Our synthesis of the (metal yolk)/(porous ceria shell) nanostructures points out a way to the creation of sophisticated heteronanostructures for high-performance photocatalysis.
Electrochemical N2 reduction offers a promising alternative to the Haber-Bosch process for sustainable NH3 synthesis at ambient conditions, but it needs efficient catalysts for the N2 reduction reaction (NRR). Here, we report that FeOOH quantum dots decorated graphene sheet acts as a superior catalyst toward enhanced electrocatalytic N2 reduction to NH3 under ambient conditions. In 0.1 M LiClO4, this hybrid attains a large NH3 yield rate and a high Faradaic efficiency of 27.3 µg·h−1·mg−1cat. and 14.6% at −0.4 V vs. reversible hydrogen electrode, respectively, rivalling the current efficiency of all Fe-based NRR electrocatalysts in aqueous media. It also shows strong durability during the electrolytic process.
A comprehensive understanding of excited-state dynamics of semiconductor quantum dots or nanomaterials at the atomic or molecular level is of scientific importance. Pure inorganic (or non-covalently protected) seimiconductor molecular nanoclusters with atomically precise structure are contributive to establish accurate correlation of excited-state dynamics with their composition/structure, however, the related studies are almost blank because of unresolved solvent dispersion issue. Herein, we designedly created the largest discrete chalcogenide seimiconductor molecular nanoclusters (denoted P2-CuMSnS, M = In or/and Ga) with great dispersibility, and revealed an interesting intracluster “core-shell” charge transfer relaxation dynamics. A systematic red shift in absorption spectra with the gradual substitution of In by Ga was experimentally and computationally investigated, and femtosecond transient absorption measurements further manifested there were three ultrafast processes in excited-state dynamics of P2 nanoclusters with the corresponding amplitudes directed by composition variation. Current results hold the great promise of the solution-processible applications of semiconductor-NC-based quantum dots and facilitate the development of atomically precise nano-chemistry.
Over the past decade, numerous studies have attempted to enhance the effectiveness of radiotherapy (external beam radiotherapy and internal radioisotope therapy) for cancer treatment. However, the low radiation absorption coefficient and radiation resistance of tumors remain major critical challenges for radiotherapy in the clinic. With the development of nanomedicine, nanomaterials in combination with radiotherapy offer the possibility to improve the efficiency of radiotherapy in tumors. Nanomaterials act not only as radiosensitizers to enhance radiation energy, but also as nanocarriers to deliver therapeutic units in combating radiation resistance. In this review, we discuss opportunities for a synergistic cancer therapy by combining radiotherapy based on nanomaterials designed for chemotherapy, photodynamic therapy, photothermal therapy, gas therapy, genetic therapy, and immunotherapy. We highlight how nanomaterials can be utilized to amplify antitumor radiation responses and describe cooperative enhancement interactions among these synergistic therapies. Moreover, the potential challenges and future prospects of radio-based nanomedicine to maximize their synergistic efficiency for cancer treatment are identified.
Printable elastic conductors promote the wide application of consumable electronic textiles (e-textiles) for pervasive healthcare monitoring and wearable computation. To assure a clean appearance, the e-textiles require a washing process to clean up the dirt after daily use. Thus, it is crucial to develop low-cost printable elastic conductors with strong adhesion to the textiles. Here, we report a composite elastic conductor based on Ag nanowires (NWs) and polyurethane elastomer. The composite could be dispersed into ink and easily printed onto textiles. One-step print could form robust conductive coatings without sealing on the textiles. Interestingly, the regional concentration of Ag NWs within the polyurethane matrix was observed during phase inversion, endowing the elastic conductor with a low percolation threshold of 0.12 vol.% and high conductivity of 3,668 S·cm−1. Thanks to the high adhesion of the elastic conductors, the resulted e-textiles could withstand repeated stretching, folding, and machine washing (20 times) without obvious performance decay, which reveals its potential application in consumable e-textiles.