The challenges in plasmonic charge transfer on a large‐scale and low losses are systematically investigated by optical designs using 1D‐plasmonic lattice structures. These plasmonic lattices are used ...as couplers to guide the energy in an underneath sub‐wavelength titanium dioxide layer, resulting in the photonic crystal slabs. So far, photodetection is possible at energy levels close to the semiconductor bandgap; however, with the observed hybrid plasmonic–photonic modes, other wavelengths over the broad solar spectrum can be easily accessed for energy harvesting. The photo‐enhanced current is measured locally with simple two‐point contact on the centimeter‐squared nanostructure by applying a bias voltage. As lattice couplers, interference lithographically fabricated conventional gold grating provides an advantage in fabrication; this optical concept is extended for the first time toward colloidal self‐assembled nanoparticle chains to make the charge injection accessible for large‐scale at reasonable costs with possibilities of photodetection by electric field vectors both along and perpendicular to the grating lines. To discuss the bottleneck of unavoidable isolating ligand shell of nanoparticles in contrast to the directly contacted nanobars, polarization‐dependent ultrafast characterizations are carried out to study the charge injection processes in femtosecond resolution.
Photonic crystal slabs are investigated for the realization of photonic–plasmonic hybrid modes. A colloidal photonic crystal slab with plasmonic nanoparticle chains arranged on a semiconductor waveguide exhibits similar anti‐crossing behavior under transverse electric polarization compared to transverse magnetic excitations in conventional metallic ones. Cyclic illuminations reveal photoresponse due to excitation of hybrid‐plasmonic modes, further characterized under ultrafast measurements.
Metallic nanostructures are highly attractive for refractive index sensing, as the evanescent field from the associated plasmonic resonances resides in close proximity to the adjacent analyte media. ...However, this benefit is often reduced due to broad plasmonic lineshapes producing poor quality factors. The rational design provides strategies for narrowing the plasmonic modes by incorporating photonic diffraction, which promotes surface lattice resonances . Due to the stringent parametric dependencies, these resonances in metallic lattices are not always feasible, particularly when a straightforward fabrication route with fewer process steps is desired. Herein, hybridized guided‐mode resonance in a 2D‐metallic photonic crystal slab (2D‐mPhCs) is introduced that ensures high‐quality hybrid modes while maintaining a simple fabrication methodology. In direct comparison to its constituent plasmonic and photonic modes, this concept is discussed for sensing applications. The “figure of merit (FOM)” is frequently regarded as a valid metric for measuring sensing performanceensuring high‐quality modes with an improved detection limit. The experimental results confirm enhanced FOM (three to six times) for the hybrid modes, in contrast to the constituent counterparts. For optoelectronic applications, such as photodetection and photocatalysis, these hybrid structures with high‐quality modes offer a promising platform to harvest light at the metal–semiconductor interfaces.
2D‐metallic photonic crystal slab (2D‐mPhCs) comprised of platinum nanodisc array and titania (TiO2) waveguide are explored to instigate plasmonic–photonic hybrid modes. Apart from theoretical modeling, experimental realization of the proposed structure is carried over a large area to easily implement the hybrid modes in sensing application, showing enhanced “figure of merit (FOM)” over its conventional photonic and plasmonic counterparts.
Peripartum cardiomyopathy (PPCM) is a potentially life‐threatening condition typically presenting as heart failure with reduced ejection fraction (HFrEF) in the last month of pregnancy or in the ...months following delivery in women without another known cause of heart failure. This updated position statement summarizes the knowledge about pathophysiological mechanisms, risk factors, clinical presentation, diagnosis and management of PPCM. As shortness of breath, fatigue and leg oedema are common in the peripartum period, a high index of suspicion is required to not miss the diagnosis. Measurement of natriuretic peptides, electrocardiography and echocardiography are recommended to promptly diagnose or exclude heart failure/PPCM. Important differential diagnoses include pulmonary embolism, myocardial infarction, hypertensive heart disease during pregnancy, and pre‐existing heart disease. A genetic contribution is present in up to 20% of PPCM, in particular titin truncating variant. PPCM is associated with high morbidity and mortality, but also with a high probability of partial and often full recovery. Use of guideline‐directed pharmacological therapy for HFrEF is recommended in all patients respecting contraindications during pregnancy/lactation. The oxidative stress‐mediated cleavage of the hormone prolactin into a cardiotoxic fragment has been identified as a driver of PPCM pathophysiology. Pharmacological blockade of prolactin release using bromocriptine as a disease‐specific therapy in addition to standard therapy for heart failure treatment has shown promising results in two clinical trials. Thresholds for devices (implantable cardioverter‐defibrillators, cardiac resynchronization therapy and implanted long‐term ventricular assist devices) are higher in PPCM than in other conditions because of the high rate of recovery. The important role of education and counselling around contraception and future pregnancies is emphasised.
Tailorable chiral plasmonic nanostructures have attracted great interest due to their potential applications in photonics and sensing. However, there are limited straightforward fabrication routes to ...modulate the morphology of chiral materials with an external stimulus. Here, a helical assembly of gold nanospheres (AuNSs) is successfully obtained via self‐assembly using glycopeptide helical nanofibers as templates based on electrostatic interactions. The assembly morphology can be readily tailored from short debris to single‐/double‐ and multiple helical threads by changing pHs, resulting in well‐controlled modulation of circular dichroism (CD) in the visible range. Further, this tunable assembly and corresponding chiroptical properties are fully reversible in the pH range from 6 to 10. The electromagnetic simulation revealed how the structural geometries of AuNS helices changed the electromagnetic field propagation pattern to facilitate corresponding chiral optical properties. This approach is a unique and facilely obtained example of chiral nanomaterials with in situ tailoring morphology and chiral properties through external stimulus, demonstrating a potential application for biosensing.
Chiral plasmonic structure based on helical assembled gold nanoparticles is realized through colloidal self‐assembly with glycopeptide‐based chiral nanofibers as templates via electrostatic interactions. The chiral assembly demonstrates dynamically tunable of morphology and chiroptical performance under external pH stimulus, which is fully reversible.
Controlled formation and breaking of weak chemical bonds is a versatile method for modifying the properties of materials. Anthracene 4+4 cycloadducts are a prime example that can be formed by light ...and opened by external forces. We address the theoretical description of mechanochemistry of these cycloadducts, where the standard constraint geometry simulates forces approach fails due to the lack of consideration of temperature. Explicit inclusion of external forces reveals the corresponding transition barriers that are clearly dominated by rupture of the 4+4 inter-anthracene bonds. Other bonds come into play at extremely large forces only, which cannot be expected to be reached under ambient conditions. The theoretical results are in line with the experimental rheology of 4+4-linked anthracene polymers, which indicates reversible re-formation of 4+4 cycloaddition bonds with ultraviolet light after mechanochemical bond breaking due to applied shear stress.
Purpose
The chemokine receptor CXCR4 is a promising target for molecular imaging of CXCR4
+
cell types, e.g. inflammatory cells, in cardiovascular diseases. We speculated that a specific CXCR4 ...ligand,
68
Gapentixafor, along with novel techniques for motion correction, would facilitate the in vivo characterization of CXCR4 expression in small culprit and nonculprit coronary atherosclerotic lesions after acute myocardial infarction by motion-corrected targeted PET/CT.
Methods
CXCR4 expression was analysed ex vivo in separately obtained arterial wall specimens.
68
GaPentixafor PET/CT was performed in 37 patients after stent-based reperfusion for a first acute ST-segment elevation myocardial infarction. List-mode PET data were reconstructed to five different datasets using cardiac and/or respiratory gating. Guided by CT for localization, the PET signals of culprit and various groups of nonculprit coronary lesions were analysed and compared.
Results
Ex vivo, CXCR4 was upregulated in atherosclerotic lesions, and mainly colocalized with CD68
+
inflammatory cells. In vivo, elevated CXCR4 expression was detected in culprit and nonculprit lesions, and the strongest CXCR4 PET signal (median SUV
max
1.96; interquartile range, IQR, 1.55–2.31) was observed in culprit coronary artery lesions. Stented nonculprit lesions (median SUV
max
1.45, IQR 1.23–1.88;
P
= 0.048) and hot spots in naive remote coronary segments (median SUV
max
1.34, IQR 1.23–1.74;
P
= 0.0005) showed significantly lower levels of CXCR4 expression. Dual cardiac/respiratory gating provided the strongest CXCR4 PET signal and the highest lesion detectability.
Conclusion
We demonstrated the basic feasibility of motion-corrected targeted PET/CT imaging of CXCR4 expression in coronary artery lesions, which was triggered by vessel wall inflammation but also by stent-induced injury. This novel methodology may serve as a platform for future diagnostic and therapeutic clinical studies targeting the biology of coronary atherosclerotic plaque.
Abstract The chemical binding between metal nanoparticles and (semi-)conductive polymer layers is essential to control the (opto-)electronic properties of such hybrid materials. Current approaches ...that achieve a conjugated binding of organic (semi-)conductive ligands to metal nanoparticles demonstrated promising functional properties, but are based on tedious multi-step organic synthesis to incorporate the required binding moieties at the chain ends of targeted macromolecular species. Herein, we explore the pre-functionalization of gold nanoparticles with p -aminothiophenol and subsequent surfactant-assisted formation of a poly(aniline) (PANI) shell as a means to access gold/PANI core–shell-type nanoparticles with enhanced conductive properties. Controlled surface deposition of these hybrid nanoparticles is achieved via template-assisted self-assembly. For these surface-deposited nanoparticles, charge transport properties are characterized at the nanoscale by conductive atomic force microscopy measurements and show a significant conductivity increase of our core–shell particles as compared to reference particles formed by conventional surfactant-assisted PANI-shell formation. Graphical Abstract
Here, for the first time, the high‐yield (87.6%) robust and facile synthesis of water‐processable donor–acceptor Janus nanoparticles (JNP) that are of high potential for optoelectronic applications ...is reported. The water‐processable JNPs have easily controlled Janus ratios and are of excellent quality, which is shown by energy‐filtered transmission electron microscopy. The JNPs exhibit improved charge separation and transfer properties compared to the conventional donor–acceptor nanoparticles which is characterized via both steady‐state and transient photoluminescence spectroscopy. The Janus character of particles allows the combination of two materials into one composite and programs morphology of structures, which can be formed on the basis of the particles. Finally, outstanding performance of JNP‐based photovoltaic cells with 53% improvement of efficiency is shown.
The internal structure of donor:acceptor (D:A) nanoparticles can be well controlled through a facile route. This strategy is successfully applied to synthesize high‐yield and high‐quality environmentally friendly D:A Janus nanoparticles with tuned internal morphology. These obtained Janus nanoparticles exhibit efficient charge separation and effective charge transfer properties, manifesting a significant enhancement compared to traditional core–shell structures in photovoltaics devices.
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The present paper reports the fabrication of novel types of hybrid fibrous photocatalysts by combining block copolymer (BCP) templating, sol–gel processing, and coaxial ...electrospinning techniques. Coaxial electrospinning produces core–shell nanofibers (NFs), which are converted into hollow porous TiO2 NFs using an oxidative calcination step. Hybrid BCP micelles comprising a single plasmonic nanoparticle (NP) in their core and thereof derived silica-coated core–shell particles are utilized as precursors to generate yolk-shell type particulate inclusions in photocatalytically active NFs. The catalytic and photocatalytic activity of calcined NFs comprising different types of yolk-shell particles is systematically investigated and compared. Interestingly, calcined NFs comprising silica-coated yolk-shells demonstrate enhanced catalytic and photocatalytic performance despite the presence of silica shell separating plasmonic NP from the TiO2 matrix. Electromagnetic simulations indicate that this enhancement is caused by a localized surface plasmon resonance and a confinement effect in silica-coated yolk-shells embedded in porous TiO2 NFs. Utilization of the coaxially electrospun TiO2 NFs in combination with yolk-shells comprising plasmonic NPs reveals to be a potent method for the photocatalytic decomposition of numerous pollutants. It is worth noting that this study stands as the first occurrence of combining yolk-shells (Au@void@SiO2) with porous electrospun NFs (TiO2) for photocatalytic purposes and gaining an understanding of plasmon and confinement effects for photocatalytic performance. This approach represents a promising route for fabricating highly active and up-scalable fibrous photocatalytic systems.
Truly spherical silver nanoparticles are of great importance for fundamental studies including plasmonic applications, but their direct synthesis in aqueous media is not feasible. Using the commonly ...employed copper-based etching processes, an isotropic plasmonic response can be achieved by etching well-defined silver nanocubes. Whilst spherical-like shape is typically prevailing in such processes, we established that there is a preferential growth toward silver rhombicuboctahedra, which is the thermodynamically most stable product of this synthesis. The rhombicuboctahedral morphology is further evidenced by comprehensive characterization with small-angle X-ray scattering in combination with transmission electron microscopy (TEM) tomography and high-resolution TEM. We also elucidate the complete reaction mechanism based on UV–vis kinetic studies, and the postulated mechanism can also be extended to all copper-based etching processes.
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