Through innovative nanosynthesis techniques and advanced surface‐passivation methods, diversified luminescent nanocrystals, like quantum dots, metal nanoclusters, carbon dots, and upconversion ...nanoparticles, are produced successfully to exhibit greatly improved performance in various applications, due to their color tunability and resistance to photobleaching. Their further hybridization with stimuli‐responsive polymers endows the resultant nanohybrids with unique smart functions, which can reversibly respond to external stimuli or environmental changes via alternation in luminescence. Due to their multifunctional properties, these responsive luminescent nanohybrids are attracting more and more interest in foundation research and promising applications recently. Here, important developments and achievements made in this emerging field are summarized to highlight the integration concepts and fabrication methods for luminescent nanohybrids, and their special responsive functions to temperature, pH, fields, and analytes. At the same time, their smart applications are also overviewed for demonstrating novel actions of responsive nanohybrids via various intelligent operations. The aim is to understand and accelerate more advanced developments in creating varied and intelligent nanosystems, and provide perspectives to promote a further revolution of smart materials and technology.
The synergistic hybridization of diversified luminescent nanocrystals with different stimuli‐responsive polymers is summarized systematically to highlight the reversible alternation in luminescence in response to external stimuli such as temperature, pH, fields, and analytes. An overview of their smart applications is also presented to demonstrate the novel actions of responsive nanohybrids in many intelligent operation systems.
Here, we report the shell thickness-dependent Raman enhancement of silver-coated gold nanoparticles (Au@Ag NPs) for the identification and detection of pesticide residues at various fruit peels. The ...Raman enhancement of Au@Ag NPs to a large family of sulfur-containing pesticides is ∼2 orders of magnitude stronger than those of bare Au and Ag NPs, and there is a strong dependence of the Raman enhancement on the Ag shell thickness. It has been shown for the first time that the huge Raman enhancement is contributed by individual Au@Ag NPs rather than aggregated Au@Ag NPs with “hot spots” among the neighboring NPs. Therefore, the Au@Ag NPs with excellent individual-particle enhancement can be exploited as stand-alone-particle Raman amplifiers for the surface identification and detection of pesticide residues at various peels of fruits, such as apple, grape, mango, pear, and peach. By casting the particle sensors onto fruit peels, several types of pesticide residues (e.g., thiocarbamate and organophosphorous compounds) have been reliably/rapidly detected, for example, 1.5 nanograms of thiram per square centimeter at apple peel under the current unoptimized condition. The surface-lifting spectroscopic technique offers great practical potentials for the on-site assessment and identification of pesticide residues in agricultural products.
The dynamics of DNA and RNA structures in live cells are important for understanding cell behaviors, such as transcription activity, protein expression, cell apoptosis, and hereditary disease, but ...are challenging to monitor in live organisms in real time. The difficulty is largely due to the lack of photostable imaging probes that can distinguish between DNA and RNA, and more importantly, are capable of crossing multiple membrane barriers ranging from the cell/organelle to the tissue/organ level. We report the discovery of a cationic carbon quantum dot (cQD) probe that emits spectrally distinguishable fluorescence upon binding with double‐stranded DNA and single‐stranded RNA in live cells, thereby enabling real‐time monitoring of DNA and RNA localization and motion. A surprising finding is that the probe can penetrate through various types of biological barriers in vitro and in vivo. Combined with standard and super‐resolution microscopy, photostable cQDs allow time‐lapse imaging of chromatin and nucleoli during cell division and Caenorhabditis elegans (C. elegans) growth.
Connect the dots: A cationic carbon quantum dot (cQD) probe emits spectrally distinguishable fluorescence signals upon binding to DNA (green) and RNA (red) in live cells, thereby enabling real‐time imaging of DNA and RNA localization and motion. The probe can penetrate through various types of biological barriers in cells and in vivo for super‐resolution microscopy and time‐lapse imaging of chromatin and nucleoli during cell division and C. elegans growth.
Flexible electronic devices are necessary for applications involving unconventional interfaces, such as soft and curved biological systems, in which traditional silicon‐based electronics would ...confront a mechanical mismatch. Biological polymers offer new opportunities for flexible electronic devices by virtue of their biocompatibility, environmental benignity, and sustainability, as well as low cost. As an intriguing and abundant biomaterial, silk offers exquisite mechanical, optical, and electrical properties that are advantageous toward the development of next‐generation biocompatible electronic devices. The utilization of silk fibroin is emphasized as both passive and active components in flexible electronic devices. The employment of biocompatible and biosustainable silk materials revolutionizes state‐of‐the‐art electronic devices and systems that currently rely on conventional semiconductor technologies. Advances in silk‐based electronic devices would open new avenues for employing biomaterials in the design and integration of high‐performance biointegrated electronics for future applications in consumer electronics, computing technologies, and biomedical diagnosis, as well as human–machine interfaces.
Silk fibroin is an ancient biomaterial with exquisite mechanical, optical, and electrical properties. Its intriguing properties and environmental benignity render silk fibroin compelling for the advancement of next‐generation biocompatible and biodegradable flexible electronic devices.
The discovery of graphene and subsequent verification of its unique properties have aroused great research interest to exploit diversified graphene‐analogous 2D nanomaterials with fascinating ...physicochemical properties. Through either physical or chemical doping, linkage, adsorption, and hybridization with other functional species into or onto them, more novel/improved properties are readily created to extend/expand their functionalities and further achieve great performance. Here, various functionalized hybridizations by using different types of 2D nanomaterials are overviewed systematically with emphasis on their interaction formats (e.g., in‐plane or inter plane), synergistic properties, and enhanced applications. As the most intensely investigated 2D materials in the post‐graphene era, transition metal dichalcogenide nanosheets are comprehensively investigated through their element doping, physical/chemical functionalization, and nanohybridization. Meanwhile, representative hybrids with more types of nanosheets are also presented to understand their unique surface structures and address the special requirements for better applications. More excitingly, the van der Waals heterostructures of diverse 2D materials are specifically summarized to add more functionality or flexibility into 2D material systems. Finally, the current research status and faced challenges are discussed properly and several perspectives are elaborately given to accelerate the rational fabrication of varied and talented 2D hybrids.
Through physical or chemical hybridization with other functional species into or onto 2D nanomaterials, more novel/improved properties are readily created to extend/expand their functionalities and further achieve great performances. Here, various functionalized hybridizations using different types of 2D nanomaterials are overviewed systematically with emphasis on their interaction formats (e.g., in‐plane or inter‐plane), synergistic properties, and enhanced applications.
The collective oscillation of free electrons at the nanoscale surface of gold nanostructures is closely modulated by tuning the size, shape/morphology, phase, composition, hybridization, assembly, ...and nanopatterning, along with the surroundings of the plasmonic surface located at a dielectric interface with air, liquid, and solid. This review first introduces the physical origin of the intrinsic optical properties of gold nanostructures and further summarizes stimuli‐responsive changes in optical properties, metal‐field‐enhanced optical signals, luminescence spectral shaping, chiroptical response, and photogenerated hot carriers. The current success in the landscape of nanoscience and nanotechnology mainly originates from the abundant optical properties of gold nanostructures in the thermodynamically stable face‐centered cubic (fcc) phase. It has been further extended by crystal phase engineering to prepare thermodynamically unfavorable phases (e.g., kinetically stable) and heterophases to modulate their intriguing phase‐dependent optical properties. A broad range of promising applications, including but not limited to full‐color displays, solar energy harvesting, photochemical reactions, optical sensing, and microscopic/biomedical imaging, have fostered parallel research on the multitude of physical effects occurring in gold nanostructures.
State‐of‐the‐art advances in nanoscience and technology have been promoted to reveal the physical origin of the intrinsic optical properties of gold nanostructures with consideration of size, shape, phase, composition, hybridization, assembly, and nanopatterning. The perspectives on the future developments, challenges, and opportunities of gold nanostructures are discussed to provide insights for improving their optical properties and performance in various applications.
Silica-coated metal nanoparticles Liu, Shuhua; Han, Ming-Yong
Chemistry - an Asian journal,
January 4, 2010, Letnik:
5, Številka:
1
Journal Article
Recenzirano
Odprti dostop
The advanced high-quality synthesis of dense and porous silica-coated nanostructures is enjoying ever-increasing research interests for their important properties and diverse applications, especially ...for catalytic, controlled release, colorimetric diagnostics, photothermal therapy, surface enhanced Raman scattering (SERS) detection, and so forth. In this timely Focus Review, we summarize the up-to-date synthesis strategies, improved properties, and emerging applications of silica-coated metal nanoparticles. In particular, the large scale synthesis of silica-coated metal nanoparticles and the recent development of hollowed-out silica-coated metal nanoparticles by silica dissolution are emphasized for new and practical applications.
The white backlight in displays is generated by optimizing the proportions of individual emitters with different wavelengths by variations in materials composition, phase, and structure. Color pixels ...usually result from the separation of white light or the excitation with multiwavelength or multipulse sources. However, it is a challenge to develop a material that comprises a single structure and emits over the full visible spectrum, but where the emission wavelengths can be controlled by a simple excitation source. Herein, we report an upconversion nanostructure that incorporates several lanthanide ions in the same core@shell@shell structure. The combination of multiple narrow spectral bands results in the emission of white light. The emission colors can be tuned by changing the excitation power density, which manipulates the photon transfer pathways. Applications such as flat‐panel displays and imaging have been demonstrated.
Seeing the light: An upconversion nanostructure comprises several lanthanide ions integrated in a single system. The balance of numerous narrow emission bands covering the full visible spectrum results in white‐light emission. The emission colors can be determined by changing the excitation power density (see picture), which manipulates the photon transfer pathways to bring potential applications such as multicolor displays or imaging.
Semiconductor nanostructures that can effectively serve as light-responsive photocatalysts have been of considerable interest over the past decade. This is because their use in light-induced ...photocatalysis can potentially address some of the most serious environmental and energy-related concerns facing the world today. One important application is photocatalytic hydrogen production from water under solar radiation. It is regarded as a clean and sustainable approach to hydrogen fuel generation because it makes use of renewable resources (i.e., sunlight and water), does not involve fossil fuel consumption, and does not result in environmental pollution or greenhouse gas emission. Another notable application is the photocatalytic degradation of nonbiodegradable dyes, which offers an effective way of ridding industrial wastewater of toxic organic pollutants prior to its release into the environment. Metal oxide semiconductors (e.g., TiO2) are the most widely studied class of semiconductor photocatalysts. Their nanostructured forms have been reported to efficiently generate hydrogen from water and effectively degrade organic dyes under ultraviolet-light irradiation. However, the wide band gap characteristic of most metal oxides precludes absorption of light in the visible region, which makes up a considerable portion of the solar radiation spectrum. Meanwhile, nanostructures of cadmium chalcogenide semiconductors (e.g., CdS), with their relatively narrow band gap that can be easily adjusted through size control and alloying, have displayed immense potential as visible-light-responsive photocatalysts, but the intrinsic toxicity of cadmium poses potential risks to human health and the environment. In developing new nanostructured semiconductors for light-driven photocatalysis, it is important to choose a semiconducting material that has a high absorption coefficient over a wide spectral range and is safe for use in real-world settings. Among the most promising candidates are the multinary chalcogenide semiconductors (MCSs), which include the ternary I-III-VI2 semiconductors (e.g., AgGaS2, CuInS2, and CuInSe2) and the quaternary I2-II-IV-VI4 semiconductors (e.g., Cu2ZnGeS4, Cu2ZnSnS4, and Ag2ZnSnS4). These inorganic compounds consist of environmentally benign elemental components, exhibit excellent light-harvesting properties, and possess band gap energies that are well-suited for solar photon absorption. Moreover, the band structures of these materials can be conveniently modified through alloying to boost their ability to harvest visible photons. In this Account, we provide a summary of recent research on the use of ternary I-III-VI2 and quaternary I2-II-IV-VI4 semiconductor nanostructures for light-induced photocatalytic applications, with focus on hydrogen production and organic dye degradation. We include a review of the solution-based methods that have been employed to prepare multinary chalcogenide semiconductor nanostructures of varying compositions, sizes, shapes, and crystal structures, which are factors that are known to have significant influence on the photocatalytic activity of semiconductor photocatalysts. The enhancement of photocatalytic performance through creation of hybrid nanoscale architectures is also presented. Lastly, views on the current challenges and future directions are discussed in the concluding section.
Biomaterials is an exciting and dynamic field, which uses a collection of diverse materials to achieve desired biological responses. While there is constant evolution and innovation in materials with ...time, biomaterials research has been hampered by the relatively long development period required. In recent years, driven by the need to accelerate materials development, the applications of machine learning in materials science has progressed in leaps and bounds. The combination of machine learning with high‐throughput theoretical predictions and high‐throughput experiments (HTE) has shifted the traditional Edisonian (trial and error) paradigm to a data‐driven paradigm. In this review, each type of biomaterial and their key properties and use cases are systematically discussed, followed by how machine learning can be applied in the development and design process. The discussions are classified according to various types of materials used including polymers, metals, ceramics, and nanomaterials, and implants using additive manufacturing. Last, the current gaps and potential of machine learning to further aid biomaterials discovery and application are also discussed.
The advancement of machine learning (ML) in materials science has progressed in leaps and bounds and has made a big impact into biomaterials research, ranging from discovery of bioactive chemical moieties, screening and optimization of material properties, to developing materials that interface better with biological systems. There is still untapped potential to integrate with ML for the next frontier in biomaterials.
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