In an era of personalized medicine, the clinical community has become increasingly focused on understanding diseases at the cellular and molecular levels. Magnetic resonance imaging (MRI) is a ...powerful imaging modality for acquiring anatomical and functional information. However, it has limited applications in the field of molecular imaging due to its low sensitivity. To expand the capability of MRI to encompass molecular imaging applications, we introduced bioresponsive Gd(III)-based magnetic resonance contrast agents (GBCAs) in 1997. Since that time, many research groups across the globe have developed new examples of bioresponsive GBCAs. These contrast agents have shown great promise for visualizing several biochemical processes, such as gene expression, neuronal signaling, and hormone secretion. They are designed to be conditionally retained, or activated, in vivo in response to specific biochemical events of interest. As a result, an observed MR signal change can serve as a read-out for molecular events. A significant challenge for these probes is how to utilize them for noninvasive diagnostic and theranostic applications. This Perspective focuses on the design strategies that underlie bioresponsive probes, and describes the key advances made in recent years that are facilitating their application in vivo and ultimately in clinical translation. While the field of bioresponsive agents is embryonic, it is clear that many solutions to the experimental and clinical radiologic problems of today will be overcome by the probes of tomorrow.
The striking in-plane anisotropy remains one of the most intriguing properties for the newly rediscovered black phosphorus (BP) 2D crystals. However, because of its rather low-energy band gap, the ...optical anisotropy of few-layer BP has been primarily investigated in the near-infrared (NIR) regime. Moreover, the essential physics that determine the intrinsic anisotropic optical property of few-layer BP, which is of great importance for practical applications in optical and optoelectronic devices, are still in the fancy of theory. Herein, we report the direct observation of the optical anisotropy of few-layer BP in the visible regime simply by using polarized optical microscopy. On the basis of the Fresnel equation, the intrinsic anisotropic complex refractive indices (n–iκ) in the visible regime (480–650 nm) were experimentally obtained for the first time using the anisotropic optical contrast spectra. Our findings not only provide a convenient approach to measure the optical constants of 2D layered materials but also suggest a possibility to design novel BP-based photonic devices such as atom-thick light modulators, including linear polarizer, phase plate, and optical compensator in a broad spectral range extending to the visible window.
Newly born zinc‐anode‐based electrochromic devices (ZECDs), incorporating electrochromic and energy storage functions in a single transparent platform, represent the most promising technology for ...next‐generation transparent electronics. As the existing ZECDs are limited by opaque zinc anodes, the key focus should be on the development of transparent zinc anodes. Here, the first demonstration of a flexible transparent zinc‐mesh electrode is reported for a ZECD window that yields a remarkable electrochromic performance in an 80 cm2 device, including rapid switching times (3.6 and 2.5 s for the coloration and bleaching processes, respectively), a high optical contrast (67.2%), and an excellent coloration efficiency (131.5 cm2 C−1). It is also demonstrated that such ZECDs are perfectly suited for solar‐charging smart windows as they inherently address the solar intermittency issue. These windows can be colored via solar charging during the day, and they can be bleached during the night by supplying electrical energy to electronic devices. The ZECD smart window platform can be scaled to a large area while retaining its excellent electrochromic characteristics. These findings represent a new technology for solar‐charging windows and open new opportunities for the development of next‐generation transparent batteries.
The first example of flexible transparent zinc‐mesh electrodes is demonstrated for
assembly of large‐scale Zn‐anode‐based electrochromic windows, and solar‐charging smart windows with sunlight‐intermittency issues perfectly addressed are presented. These findings facilitate new opportunities for the development of next‐generation transparent electrochemical devices.
Batteries are used in every facet of human lives. Desirable battery architectures demand high capacity, rechargeability, rapid charging speed, and cycling stability, all within an environmentally ...friendly platform. Many applications are limited by opaque batteries; thus, new functionalities can be unlocked by introducing transparent battery architectures. This can be achieved by incorporating electrochromic and energy storage functions. Transparent electrochromic batteries enable new applications, including variable optical attenuators, optical switches, addressable displays, touch screen devices, and most importantly smart windows for energy‐efficient buildings. However, this technology is in the incipient state due to limited electrochromic materials having satisfactory optical contrast and capacity. As such, triggering electrochromism via Zn2+ intercalation is advantageous: Zn is abundant, safe, easily processed in aqueous electrolytes and provides two electrons during redox reactions. Here, enhanced Zn2+ intercalation is demonstrated in Ti‐substituted tungsten molybdenum oxide, yielding improved capacity and electrochromic performance. This technique is employed to engineer cathodes exhibiting an areal capacity of 260 mAh m−2 and high optical contrast (76%), utilized in the fabrication of aqueous Zn‐ion electrochromic batteries. Remarkably, these batteries can be charged by external voltages and self‐recharged by spontaneously extracting Zn2+, providing a new technology for practical electrochromic devices.
Electrochromic batteries provide new applications, including optical switches, addressable displays, touch‐screen devices, and most importantly self‐powered smart windows for energy‐efficient buildings. The first example of an aqueous zinc‐ion electrochromic battery is presented, which exhibits excellent performance within a platform compatible with a large‐scale solution process. These findings facilitate new opportunities for the development of next‐generation electrochromic devices.
Amaç: Bu in vitro çalışmanın amacı, farklı kimyasal kompozisyona sahip çeşitli kalınlıklardaki üç farklı CAD-CAM materyalinin opalaseans parametresi (OP) ve kontrast oranının (CR) ...karşılaştırılmasıdır.
Gereç ve Yöntem: Doksan adet A2 renkte örnek; lösitle güçlendirilmiş feldspatik seramik (LS, G-Ceram), lityum disilikat seramik (LD, IPS e.max CAD) ve rezin nano seramik (RN, Lava Ultimate) CAD-CAM bloklardan 0,5 mm, 0,7 mm ve 1 mm kalınlığında olacak şekilde hazırlandı (n=10). Renk ölçümleri siyah ve beyaz arka planlar üzerinde bir spektrofotometre ile gerçekleştirilerek CIE L*a*b* verileri kaydedildi. Örneklerin OP ve CR değerleri hesaplandı. İstatistiksel analiz iki yönlü ANOVA ve Bonferroni testleri ile yapıldı (α=0,05).
Bulgular: Materyal ve kalınlık temel etkisi ile materyal ve kalınlık etkileşimi OP ve CR için önemli bulundu (P
High-resolution, multiplexed experiments are a staple in cellular imaging. Analogous experiments in animals are challenging, however, due to substantial scattering and autofluorescence in tissue at ...visible (350-700 nm) and near-infrared (700-1,000 nm) wavelengths. Here, we enable real-time, non-invasive multicolour imaging experiments in animals through the design of optical contrast agents for the shortwave infrared (SWIR, 1,000-2,000 nm) region and complementary advances in imaging technologies. We developed tunable, SWIR-emissive flavylium polymethine dyes and established relationships between structure and photophysical properties for this class of bright SWIR contrast agents. In parallel, we designed an imaging system with variable near-infrared/SWIR excitation and single-channel detection, facilitating video-rate multicolour SWIR imaging for optically guided surgery and imaging of awake and moving mice with multiplexed detection. Optimized dyes matched to 980 nm and 1,064 nm lasers, combined with the clinically approved indocyanine green, enabled real-time, three-colour imaging with high temporal and spatial resolutions.
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•WO3/PEDOT core-shell hybrid nanorod arrays are synthesized by wet chemical methods.•The hybrid nanorods exhibit modulated electrochromic properties.•Interfacial synergistic effect ...may play a vital role in the property enhancement.
Designed growth of tungsten oxide (WO3)/poly(3,4-ethylenedioxythiophene) (PEDOT) core/shell hybrid nanorod arrays has been obtained by combining solvothermal and in situ electropolymerization techniques. High-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM) and Raman characterization results indicate that the hybrid nanorods are composed of single crystalline WO3 nanocores wrapped by thin amorphous PEDOT nanoshells. The hybrid nanorods exhibit promising electrochromic performance of much shorter response time (3.8 s for coloring and 3.6 s for bleaching) than the bare WO3 nanorods (12.4 s for coloring and 7.6 s for bleaching), while the optical contrast of the hybrid nanorods increases from 26% of PEDOT to 72% in 633 nm. And the coloring efficiency and stability of the core/shell hybrid nanorods are also enhanced compared to the individual components. Dynamic analysis suggests a synergistic effect between the WO3 nanocore and the PEDOT nanoshell. In addition, color depth and optical contrast of the hybrid nanorods can be modulated by adjusting the applied voltage and the deposition of the PEDOT nanoshell. The hybrid nanorod films obtained by the cost-effective wet chemical methods may find promising applications in energy-saving windows, smart displays as well as other energy efficient technologies.
Effective cancer therapy largely depends on inducing apoptosis in cancer cells via chemotherapy and/or radiation. Monitoring apoptosis in real-time provides invaluable information for evaluating ...cancer therapy response and screening preclinical anticancer drugs. In this work, we describe the design, synthesis, characterization, and in vitro evaluation of caspase probe 1 (CP1), a bimodal fluorescence-magnetic resonance (FL-MR) probe that exhibits simultaneous FL-MR turn-on response to caspase-3/7. Both caspases exist as inactive zymogens in normal cells but are activated during apoptosis and are unique biomarkers for this process. CP1 has three distinct components: a DOTA-Gd(III) chelate that provides the MR signal enhancement, tetraphenylethylene as the aggregation induced emission luminogen (AIEgen), and DEVD peptide which is a substrate for caspase-3/7. In response to caspase-3/7, the water-soluble peptide DEVD is cleaved and the remaining Gd(III)-AIEgen (Gad-AIE) conjugate aggregates leading to increased FL-MR signals. CP1 exhibited sensitive and selective dual FL-MR turn-on response to caspase-3/7 in vitro and was successfully tested by fluorescence imaging of apoptotic cells. Remarkably, we were able to use the FL response of CP1 to quantify the exact concentrations of inactive and active agents and accurately predict the MR signal in vitro. We have demonstrated that the aggregation-driven FL-MR probe design is a unique method for MR signal quantification. This probe design platform can be adapted for a variety of different imaging targets, opening new and exciting avenues for multimodal molecular imaging.
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In this paper, we report an electrochromic device (ECD) using novel porous TiO2@prussian blue core-shell nanostructures as electrodes. The core-shell nanostructures were formed by ...coating prussion blue (PB) on TiO2 nanorod templates through two-step soft chemical methods. The surface area of PB is remarkably enlarged and the diffusion length of ions is notably shortened due to the distinct porous morphology of the nanostructures, resulting in highly increased storage capacity of K+ ions in electrochromic process. Compared with the ECD based on dense PB film, higher optical contrast (48%) and faster response speed (tc=6.2s, tb=2.2s) are realized in the TiO2@PB core-shell structures. In particular, the coloration efficiency of the ECD based on the core-shell nanostructures is significantly improved to 131.5cm2C−1 at 700nm. Moreover, a model of insertion/extraction of K+ ions was proposed to interpret the enhanced electrochromic performance of core-shell nanostructures.
DNAzymes hold promise for gene‐silencing therapy, but the lack of sufficient cofactors in the cell cytoplasm, poor membrane permeability, and poor biostability have limited the use of DNAzymes in ...therapeutics. We report a DNAzyme–MnO2 nanosystem for gene‐silencing therapy. MnO2 nanosheets adsorb chlorin e6‐labelled DNAzymes (Ce6), protect them from enzymatic digestion, and efficiently deliver them into cells. The nanosystem can also inhibit 1O2 generation by Ce6 in the circulatory system. In the presence of intracellular glutathione (GSH), MnO2 is reduced to Mn2+ ions, which serve as cofactors of 10–23 DNAzyme for gene silencing. The release of Ce6 generates 1O2 for more efficient photodynamic therapy. The Mn2+ ions also enhance magnetic resonance contrast, providing GSH‐activated magnetic resonance imaging (MRI) of tumor cells. The integration of fluorescence recovery and MRI activation provides fluorescence/MRI bimodality for monitoring the delivery of DNAzymes.
Multitasking: A smart carrier for DNAzymes has been developed in which MnO2 nanosheets are able to enhance cellular uptake of DNAzymes, protect them from endogenous nuclease digestion, and self‐generate in situ cofactors (Mn2+ ions) in the cell cytoplasm to maintain the catalytic activity of 10–23 DNAzyme for RNA cleavage and gene silencing. Ce6–DNAzyme=chlorin e6‐labelled DNAzyme.
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