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Synthesis, characterization, and fluorescence study of tryptone-self-assembled and Zn(II)-coordinated nanoparticles
摘要： Peptides/amino acids are biodegradable and biocompatible and have been used as suitable biomaterials for many bioengineering and medical applications in the last few decades. However, sometimes they show very limited intrinsic optical properties when used as optical imaging probes for biological diagnostics and target-based drug monitoring applications. Here we synthesized novel tryptone-self-assembled and Zn(II)-coordinated nanoparticles (TZFNPs), which shifted the intrinsic fluorescence emission peak from ultraviolet (270 nm) of tryptone to the visible wavelength (470 nm). Furthermore, when coordinated with 4-chloro-7-nitrobenzofurazan (NBD-Cl), a fluorogenic reagent, the fluorescence signals of our TZFNPs were further enhanced directly and in the cellular environment as well. We also studied the fluorescent signals of these TZFNPs after transferring them into the intracellular space of U2OS and HeLa cell lines. These fluorescent nanoparticles are intrinsically fluorescent and suitable for bioimaging. We hope they will pave the new way for further applications in medical sciences from diagnostics to clinical trials.
关键词： Tryptophan,Nanoparticle,Tryptone,Fluorescence,Self-assembly,Optical imaging
更新于2025-09-23 15:19:57
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Cu Nanoparticle Array-Mediated III-V/Si Integration: Application in Series-Connected Tandem Solar Cells
摘要： The integration of III-V materials with crystalline Si (c-Si) is a promising pathway to design high-performance optoelectronic devices, including solar cells. We have previously reported high-efficiency III-V/Si tandem cells using our unique semiconductor bonding technique, termed smart stack. In the conventional smart stack cells, Pd nanoparticle (NP) arrays have been commonly employed as bonding mediators between III-V and c-Si; however, from an economical point of view, the use of other low-cost metals would be preferable. Therefore, this study focused on the possibility of Cu. A polystyrene-block-poly-2-vinylpyridine (PS-b-P2VP)-based block copolymer was utilized to prepare Cu NP arrays. Desired Cu NP arrays were achieved by starting with self-assembled PS-b-P2VP micelles preloaded with Cu2+ ions. Satisfying bonding properties (low-resistance interfaces) were confirmed when GaAs subcells were stacked on the Cu NP arrays formed on native oxide-removed c-Si subcells. Conversion efficiencies up to 25.9% have been demonstrated with triple-junction structures consisting of InGaP/GaAs top and c-Si bottom subcells. The long-term reliability of Cu NP array-mediated smart stack cells were also verified by the thermal cycle and damp heat tests. Hence, we have successfully confirmed that not only Pd but also Cu is available to realize high-efficiency smart stack cells.
关键词： III-V,Copper,block copolymer,solar cell,tandem,nanoparticle,silicon,self-assembly
更新于2025-09-23 15:19:57
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Au@Ag nanorod horizontal arrays: Self-assembly preparation and in situ monitoring SERS of plasmonic catalytic reaction
摘要： Here, we successfully synthesized silver-coated gold nanorods (Au@Ag NRs) via a facile wet chemical method. The catalytic property of Au@Ag NRs in water solution was much better than that of Au NRs in water solution. To obtain high catalytic properties, we self-assembled a single-layer Au@Ag NR array by evaporation on a silicon wafer. The catalytic activity of the Au@Ag NR array was probed using the reduction of 4-nitrothiophenol. The reaction processes were monitored and identified through in situ surface-enhanced Raman spectroscopy based on the confocal Raman microscope system. This study provides a simple and fast method to improve the catalytic property of the noble nanoparticles.
关键词： In situ monitoring,Self-assembly,Au@Ag nanorods,Plasmonic catalytic reaction,SERS
更新于2025-09-23 15:19:57
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Robustness of Optical Response for Selfa??Assembled Plasmonic Metamaterials with Morphological Disorder and Surface Roughness
摘要： Bottom-up fabrication of metallized biotemplated nanostructures to form specific plasmonic nanoresonators holds promise as a means of achieving large-scale optical metamaterials. However, in contrast to top-down methods, the stochastic growth of self-assembled nanoresonators is prone to significant disorder and surface roughness, which naturally raise an important question about the robustness of their resonant properties in terms of structural imperfections. An aggregated-random-sphere model is developed to mimic the nucleated growth of metallized DNA origami assembly, leading to meta-atoms with realistic, experimentally observed morphological disorder and surface roughness. Using the well-known split-ring-resonator (SRR) motif as an example, the resonant properties of meta-atoms under different levels of roughness are investigated and a strong tolerance of optical response against morphological disorder is revealed. It is found that in SRRs, even with dramatic roughness introduced, the expected resonances are still observed, despite broadening line shapes compared to ideal smooth structure. Only for extreme disorder, which causes drastic segmentation of SRRs, does the resonant response disappear. The demonstrations are very encouraging for the prospects of bottom-up fabrication toward versatile functional metamaterials and metadevices.
关键词： self-assembly,DNA origami,metamaterials,metasurfaces,surface roughness,morphological disorder
更新于2025-09-23 15:19:57
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Manipulating and probing the distribution of excess electrons in an electrically-isolated self-assembled molecular structure
摘要： Exploiting single electrical charges and their mutual interactions for computation has been proposed as a concept for future nanoelectronics. Controlling and probing charge transfer in electrically isolated atomic-scale structures are fundamental to push its experimental realization. Here, we controllably inject individual excess electrons and study their distribution in a self-assembled structure supported on a non-conductive substrate. The self-assembly ensures structural order down to the atomic scale. Depending on the charge state of the molecular assembly, intermolecular electron hopping and specific electron distributions have been resolved by atomic force microscopy, clarifying the charge-transfer pathways in the tunnel-coupled structure. Exploiting the mutual charge interactions, control over specific charge distributions in the self-assembled structure has been achieved with single-molecule precision, paving the way towards the design of data processing platforms based on molecular nanostructures.
关键词： self-assembly,atomic force microscopy,dissipation,single electron charging
更新于2025-09-23 15:19:57
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Superspreading and Drying of Trisiloxane-Laden Quantum Dot Nanofluids on Hydrophobic Surfaces
摘要： Nano?uids hold promise for a wide range of areas of industry. However, understanding the wetting behavior and deposition formation in the course of drying and spreading of nano?uids, particularly containing surfactants, is still poor. In this paper, the evaporation dynamics of quantum dot-based nano?uids and evaporation-driven self-assembly in nanocolloidal suspensions on hexamethyldisilazane-, polystyrene-, and polypropylene-coated hydrophobic surfaces have been studied experimentally. Moreover, for the very ?rst time, we make a step toward understanding the wetting dynamics of superspreader surfactant-laden nano?uids. It was revealed that drying of surfactant-free quantum dot nano?uids in contrast to pure liquids undergoes not three but four evaporation modes including last additional pinning mode when the contact angle decreases while the triple contact line is pinned by the nanocrystals. In contrast to previous studies, it was found out that addition of nanoparticles to aqueous surfactant solutions leads to deterioration of the spreading rate and to formation of a double co?ee ring. For all surfaces examined, superspreading in the presence and absence of quantum dot nanoparticles takes place. Despite the formation of co?ee rings on all substrates, they have di?erent morphologies. In particular, the knot-like structures are incorporated into the ring on hexamethyldisilazane- and polystyrene-coated surfaces.
关键词： Self-assembly,Superspreading,Quantum dots,Wetting dynamics,Evaporation,Nano?uids
更新于2025-09-23 15:19:57
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Long Range Energy Transfer in Self-Assembled Stacks of Semiconducting Nanoplatelets
摘要： Fluorescent emitters like ions, dye molecules or semiconductor nanoparticles are widely used in opto-electronic devices, usually within densely-packed layers. Their luminescence properties can then be very different from when they are isolated, because of short-range interparticle interactions such as F?rster resonant energy transfer (FRET). Understanding these interactions is crucial to mitigate FRET-related losses and could also lead to new energy transfer strategies. Exciton migration by FRET hopping between consecutive neighbor fluorophores has been evidenced in various systems but was generally limited to distances of tens of nanometers and involved only a few emitters. Here we image self-assembled linear chains of CdSe nanoplatelets (colloidal quantum wells) and demonstrate exciton migration over 500-nm distances, corresponding to FRET hopping over 90 platelets. By comparing a diffusion-equation model to our experimental data, we measure a (1.5 ps)-1 FRET rate, much faster than all decay mechanisms, so that strong FRET-mediated collective photophysical effects can be expected.
关键词： nanoplatelets,exciton transfer,self-assembly,fluorescence microscopy,FRET
更新于2025-09-23 15:19:57
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Self-Assembled Nanophotosensitizing Systems with Zinc(II) Phthalocyanine-Peptide Conjugates as Building Blocks for Targeted Chemo-Photodynamic Therapy
摘要： Two zinc(II) phthalocyanines (ZnPcs) substituted with a short peptide (Gly-Gly-Lys) with either a carboxyl or a carbamoyl group at the C-terminus and an appended biotin moiety were prepared and characterized. They could self-assemble into spherical nanoparticles, namely ZnPc-GGK(B)-COOH NP and ZnPc-GGK(B)-CONH2 NP, through noncovalent interactions, which encapsulated the hydrophobic ZnPc units in the core and exposed the biotin moieties on the surface. The zeta potential of ZnPc-GGK(B)-COOH NP in water was found to be ?28 mV, whereas that of ZnPc-GGK(B)-CONH2 NP was in opposite sign (+15 mV), reflecting the different functionality at the C-terminus, which also greatly affected the stability of the self-assembled nanoparticles. The targeting effect of ZnPc-GGK(B)-COOH NP was examined against human hepatocellular carcinoma HepG2 cells, which overexpress biotin receptor, and Chinese Hamster Ovary CHO-K1 cells, which have a low expression of biotin receptor. This nanosystem was also coassembled with the chemotherapeutic doxorubicin (DOX) to form ZnPc-GGK(B)-COOH/DOX NP. Both ZnPc-GGK(B)-COOH NP and ZnPc-GGK(B)-COOH/DOX NP could induce photocytotoxicity and apoptosis on HepG2 cells with an IC50 value of 1.48 and 0.49 μM ZnPc, respectively. For the latter nanosystem, the ZnPc and DOX components induced cytotoxicity in a synergistic manner. The photodynamic and chemotherapeutic effects of these two nanosystems were also examined on nude mice bearing a human colorectal adenocarcinoma HT29 tumor. The ZnPc-GGK(B)-COOH/DOX NP exhibited a stronger tumor inhibition effect upon irradiation, demonstrating the presence of dual chemo-photodynamic therapeutic actions.
关键词： photodynamic therapy,phthalocyanine,peptide,nanomedicine,self-assembly
更新于2025-09-23 15:19:57
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Helical Magnetic Field-Induced Real-Time Plasmonic Chirality Modulation
摘要： Astrophysical phenomenon mimetic helical magnetic field (hB)-assisted self-assembly is herein introduced to build helical superstructures that display chiroptical properties. As a building block, magnetoplasmonic (MagPlas) Ag@Fe3O4 core-shell nanoparticles are used to guide plasmonic Ag nanoparticles onto a helical magnetic flux. The chirality of the assembled helical structures and tailored circular dichroism are successfully tuned in real-time, and the handedness of the assembled structures is dynamically switched by the hB at the millisecond level, which is at least 6,000-fold faster than other template-assisted methods. The peak position of circular dichroism can be reconfigured by altering the plasmonic resonance or coupling by controlling the size of the Ag core and magnetic flux density. The hB-induced chirality modulation represents a method to control the polarization state of light at the nexus of plasmonics, magnetic self-assembly, colloidal science, liquid crystals, and chirality. It presents active and dynamic chiral assemblies of magnetoplasmonic nanomaterials, enabling further practical applications in optical devices.
关键词： magnetoplasmonic nanoparticles,helical magnetic field (hB),self-assembly,dynamic chirality,real-time modulation
更新于2025-09-23 15:19:57
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Mechanically Robust and Broadband Blackbody Composite Films Based on Self-Assembled Layered Structures
摘要： Inspired by nacre that is mechanically strong and versatile in light manipulation, large-scale black films with a nacre-like microstructure and carbon nanotubes inclusion were prepared using a facile self-assembly technique. Layered structure promoted blackness and toughness were simultaneously realized, affording robust films with solar–absorptivity as high as 96.9%. Our design strategy and fabrication process will be beneficial for the facile access to various advanced blackbody coatings.
关键词： vacuum-assisted self-assembly,layered structure,mechanical property,blackbody,polymer nanocomposite
更新于2025-09-23 15:19:57