Preparation, cytotoxicity and in vivo bioimaging of highly luminescent water-soluble silicon quantum dots.
TL;DR: In vitro studies in monocytes and in vivo zebrafish studies reveal that Si QDs exhibit good biocompatibility and excellent distribution throughout the cytoplasm region, along with the significant fraction translocated into the nucleus.
Abstract: Designing various inorganic nanomaterials that are cost effective, water soluble, optically photostable, highly fluorescent and biocompatible for bioimaging applications is a challenging task. Similar to semiconducting quantum dots (QDs), silicon QDs are another alternative and are highly fluorescent, but non-water soluble. Several surface modification strategies were adopted to make them water soluble. However, the photoluminescence of Si QDs was seriously quenched in the aqueous environment. In this report, highly luminescent, water-dispersible, blue- and green-emitting Si QDs were prepared with good photostability. In vitro studies in monocytes reveal that Si QDs exhibit good biocompatibility and excellent distribution throughout the cytoplasm region, along with the significant fraction translocated into the nucleus. The in vivo zebrafish studies also reveal that Si QDs can be evenly distributed in the yolk-sac region. Overall, our results demonstrate the applicability of water-soluble and highly fluorescent Si QDs as excellent in vitro and in vivo bioimaging probes.
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TL;DR: This review summarizes recent progress in the design and applications of cadmium-free quantum dots (Cd-free QDs), with an emphasis on their role in biophotonics and nanomedicine.
Abstract: This review summarizes recent progress in the design and applications of cadmium-free quantum dots (Cd-free QDs), with an emphasis on their role in biophotonics and nanomedicine. We first present the features of Cd-free QDs and describe the physics and emergent optical properties of various types of Cd-free QDs whose applications are discussed in subsequent sections. Selected specific QD systems are introduced, followed by the preparation of these Cd-free QDs in a form useful for biological applications, including recent advances in achieving high photoluminescence quantum yield (PL QY) and tunability of emission color. Next, we summarize biophotonic applications of Cd-free QDs in optical imaging, photoacoustic imaging, sensing, optical tracking, and photothermal therapy. Research advances in the use of Cd-free QDs for nanomedicine applications are discussed, including drug/gene delivery, protein/peptide delivery, image-guided surgery, diagnostics, and medical devices. The review then considers the pharma...
448 citations
TL;DR: In this article, a review of the state-of-the-art eco-friendly colloidal semiconductor quantum dots (QDs) for light-emissive solar concentrators (LSCs) is presented.
Abstract: Luminescent solar concentrators (LSCs) have attracted significant attention as promising solar energy conversion devices for building integrated photovoltaic (PV) systems due to their simple architecture and cost-effective fabrication. Conventional LSCs are generally comprised of an optical waveguide slab with embedded emissive species and coupled PV cells. Colloidal semiconductor quantum dots (QDs) have been demonstrated as efficient emissive species for high-performance LSCs because of their outstanding optical properties including tunable absorption and emission spectra covering the ultraviolet/visible to near-infrared region, high photoluminescence quantum yield, large absorption cross sections, and considerable photostability. However, current commonly used QDs for high-performance LSCs consist of highly toxic heavy metals (i.e., cadmium and lead), which are fatal to human health and the environment. In this regard, it is highly desired that heavy metal-free and environmentally friendly QD-based LSCs are comprehensively studied. Here, notable advances and developments of LSCs based on unary, binary, and ternary eco-friendly QDs are presented. The synthetic approaches, optical properties of these eco-friendly QDs, and consequent device performance of QD-based LSCs are discussed in detail. A brief outlook pointing out the existing challenges and prospective developments of eco-friendly QD-based LSCs is provided, offering guidelines for future device optimizations and commercialization.
90 citations
TL;DR: Overall, zebrafish is expected to serve as a high-throughput screening platform for nanotoxicity and drug delivery assessment, which may instruct the design of safe nanomaterials and more effective nanomedicines.
84 citations
TL;DR: A new, facile, one-pot microwave-assisted method for the synthesis SiNPs with excellent water solubility under normal pressure by employing glycerol as the solvent and featuring bright blue-green fluorescence, long lifetime, and superbly strong photostability.
Abstract: Silicon nanoparticles (SiNPs) have been reported to be synthesized by microwave-assisted methods under high pressure However, there is still a lack of knowledge about the synthesis of SiNPs via microwave-assisted methods under normal pressure Here we developed a new, facile, one-pot microwave-assisted method for the synthesis SiNPs (∼42 nm) with excellent water solubility under normal pressure by employing glycerol as the solvent Furthermore, glycerol might be responsible for the photoluminescence quantum yield (PLQY) value up to 47% for the resultant SiNPs The use of organic solvent could afford less nanoparticle surface defects compared with those prepared in aqueous solution, thus improving the fluorescent efficiency The as-prepared SiNPs simultaneously featured bright blue-green fluorescence, long lifetime (∼128 ns), obvious up-conversion luminescence originating from two-photon absorption, superbly strong photostability, and favorable low toxicity As a satisfactory probe, the as-synthesized S
76 citations
TL;DR: The review addresses the current state of progress in the use of ultra-small nanoparticles from the category of quantum dots (QDs), which presently embraces a widening range of nanomaterials of different nature, including "classical" semiconductor groups III-V and II-VI nanocrystals.
76 citations
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TL;DR: The new generations of qdots have far-reaching potential for the study of intracellular processes at the single-molecule level, high-resolution cellular imaging, long-term in vivo observation of cell trafficking, tumor targeting, and diagnostics.
Abstract: Research on fluorescent semiconductor nanocrystals (also known as quantum dots or qdots) has evolved over the past two decades from electronic materials science to biological applications. We review current approaches to the synthesis, solubilization, and functionalization of qdots and their applications to cell and animal biology. Recent examples of their experimental use include the observation of diffusion of individual glycine receptors in living neurons and the identification of lymph nodes in live animals by near-infrared emission during surgery. The new generations of qdots have farreaching potential for the study of intracellular processes at the single-molecule level, high-resolution cellular imaging, long-term in vivo observation of cell trafficking, tumor targeting, and diagnostics.
7,499 citations
TL;DR: In this article, a review of the photo and electron properties of carbon nanodots is presented to provide further insight into their controversial emission origin and to stimulate further research into their potential applications, especially in photocatalysis, energy conversion, optoelectronics, and sensing.
Abstract: Carbon nanodots (C-dots) have generated enormous excitement because of their superiority in water solubility, chemical inertness, low toxicity, ease of functionalization and resistance to photobleaching. In this review, by introducing the synthesis and photo- and electron-properties of C-dots, we hope to provide further insight into their controversial emission origin (particularly the upconverted photoluminescence) and to stimulate further research into their potential applications, especially in photocatalysis, energy conversion, optoelectronics, and sensing.
2,262 citations
TL;DR: The contributions of fluorescent probes to far-field super-resolution imaging, focusing on fluorescent proteins and organic small-molecule fluorophores are described, to reach the goal of video-rate imaging of live cells with molecular resolution.
Abstract: Recent advances in fluorescent probe technology have improved spatial and temporal resolution, bringing us closer to the ideal of imaging individual cellular features in real time with molecular (1–5 nm) resolution. In parallel, the development of super-resolution imaging techniques has revolutionized fluorescence microscopy. In 1873, Ernst Abbe discovered that features closer than ∼200 nm cannot be resolved by lens-based light microscopy. In recent years, however, several new far-field super-resolution imaging techniques have broken this diffraction limit, producing, for example, video-rate movies of synaptic vesicles in living neurons with 62 nm spatial resolution. Current research is focused on further improving spatial resolution in an effort to reach the goal of video-rate imaging of live cells with molecular (1–5 nm) resolution. Here, we describe the contributions of fluorescent probes to far-field super-resolution imaging, focusing on fluorescent proteins and organic small-molecule fluorophores. We describe the features of existing super-resolution fluorophores and highlight areas of importance for future research and development.
1,284 citations
TL;DR: Near infrared (NIR) light absorbing semiconducting polymer nanoparticles (SPNs) are introduced as a new class of contrast agents for PA molecular imaging and demonstrate SPNs an ideal nanoplatform for developing PA molecular probes.
Abstract: Photoacoustic imaging holds great promise for the visualization of physiology and pathology at the molecular level with deep tissue penetration and fine spatial resolution. To fully utilize this potential, photoacoustic molecular imaging probes have to be developed. Here, we introduce near-infrared light absorbing semiconducting polymer nanoparticles as a new class of contrast agents for photoacoustic molecular imaging. These nanoparticles can produce a stronger signal than the commonly used single-walled carbon nanotubes and gold nanorods on a per mass basis, permitting whole-body lymph-node photoacoustic mapping in living mice at a low systemic injection mass. Furthermore, the semiconducting polymer nanoparticles possess high structural flexibility, narrow photoacoustic spectral profiles and strong resistance to photodegradation and oxidation, enabling the development of the first near-infrared ratiometric photoacoustic probe for in vivo real-time imaging of reactive oxygen species--vital chemical mediators of many diseases. These results demonstrate semiconducting polymer nanoparticles to be an ideal nanoplatform for developing photoacoustic molecular probes.
1,002 citations
TL;DR: Focusing on two application areas, namely communications and photovoltaics, the state of the art in each field is assessed and the challenges that need to be overcome are highlighted to make silicon a truly high-performing photonic material.
Abstract: Silicon has long been established as the material of choice for the microelectronics industry. This is not yet true in photonics, where the limited degrees of freedom in material design combined with the indirect bandgap are a major constraint. Recent developments, especially those enabled by nanoscale engineering of the electronic and photonic properties, are starting to change the picture, and some silicon nanostructures now approach or even exceed the performance of equivalent direct-bandgap materials. Focusing on two application areas, namely communications and photovoltaics, we review recent progress in silicon nanocrystals, nanowires and photonic crystals as key examples of functional nanostructures. We assess the state of the art in each field and highlight the challenges that need to be overcome to make silicon a truly high-performing photonic material.
798 citations