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Solid-state lithium batteries (SSLBs) are promising energy-storage devices.

Rational design of efficient lanthanide-doped down-shifting nanoparticles (DSNPs) has attracted tremendous attention. However, energy loss was inevitable in the multiple Ln3+ doping systems owing to complex energy migration processes. Here, an efficient NaErF4@NaYF4@NaYF4:10%Nd@NaYF4 DSNP was tactfully designed, in which a buffer layer of NaYF4 was modulated to restrict the interionic energy migration between Er3+ and Nd3+; meanwhile, the surface defects were passivated by an outermost layer of NaYF4. Therefore, the as-prepared DSNPs exhibited two intensive near-infrared-II fluorescence emissions of 1525 nm from Er3+ and 1060 nm from doped Nd3+ under 808 nm excitation. Further, a novel ratiometric nanoprobe NaErF4@NaYF4@NaYF4:10%Nd@NaYF4@A1094 was fabricated by coupling an organic dye of A1094 onto the DSNP surface to quench the 1060 nm emission by the efficient Forster resonance energy transfer, while emission at 1525 nm retained. Thereafter, these activatable ratiometric nanoprobes were used for rapid and sensitive detection of peroxynitrite (ONOO-) in vivo.

Professor Nicholas A. Kotov, Professor Luis M. Liz-Marzán and Professor Qiangbin Wang introduce a themed collection in Materials Advances on chiral nanomaterials.

Early monitoring of gastrointestinal diseases via orally delivered NIR-II ratiometric fluorescent probes represents a promising noninvasive diagnostic modality, but is challenging due to the limitation of harsh digestive environment. Here, we report a single-component NIR-II ratiometric molecular nanoprobe (LC-1250 NP) to monitor gastrointestinal disease with high specificity to its biomarker H

Semiconductor quantum dots (QDs) with photoluminescence (PL) emission at 900-1700 nm (denoted as the second near-infrared window, NIR-II) exhibit much-depressed photon absorption and scattering, which has stimulated extensive researches in biomedical imaging and NIR devices. However, it is very challenging to develop NIR-II QDs with a high photoluminescence quantum yield (PLQY) and excellent biocompatibility. Herein, we designed and synthesized an alloyed silver gold selenide (AgAuSe) QD with a bright emission from 820 to 1170 nm and achieved a record absolute PLQY of 65.3% at 978 nm emission among NIR-II QDs without a toxic element and a long lifetime of 4.58 μs. It is proved that the high PLQY and long lifetime are mainly attributed to the prevented nonradiative transition of excitons, probably resulted from suppressing cation vacancies and crystal defects from the high mobility of Ag ions by alloying Au atoms. These high-PLQY QDs with nontoxic heavy metal exhibit great application potential in bioimaging, light emitting diodes (LEDs), and photovoltaic devices.

Accurate intraoperative tissue identification is critical to tumor surgery. However, conventional methods are labor- and time-intensive, which greatly delay the intraoperative decision-making. Herein, a matrix metalloproteinase (MMP)14-activated NIR-II nanoprobe (AM meanwhile, the exposure of the membrane penetrating peptide R9 (TAT-peptide) results in efficient internalization of nanoprobes in the cancer cells, providing superior tumor-to-normal (T/N) tissue ratio. Instant illumination of the lesion and well-defined tumor margins make the nanoprobes a suitable rapid diagnostic reagent for cancer surgical or tissue biopsy procedures.

We present a strategy of interfacially bridging covalent network within tobacco mosaic virus (TMV) virus-like particles (VLPs). We arranged T103C cysteine to laterally conjugate adjacent subunits. In the axis direction, we set A74C mutation and systematically investigated candidate from E50C to P54C as the other thiol function site, for forming longitudinal disulfide bond chains. Significantly, the T103C-TMV-E50C-A74C shows the highest robustness in assembly capability and structural stability with the largest length, for TMV VLP to date. The fibers with lengths from several to a dozen of micrometers even survive under pH 13. The robust nature of this TMV VLP allows for reducer-free synthesis of excellent electrocatalysts for application in harshly alkaline hydrogen evolution.

Fluorescence imaging has become a fundamental tool for biomedical applications; nevertheless, its intravital imaging capacity in the conventional wavelength range (400-950 nm) has been restricted by its extremely limited tissue penetration. To tackle this challenge, a novel imaging approach using the fluorescence in the second near-infrared window (NIR-II, 1000-1700 nm) has been developed in the past decade to achieve deep penetration and high-fidelity imaging, and thus significant biomedical applications have begun to emerge. In this Perspective, we first examine recent discoveries and challenges in the development of novel NIR-II fluorophores and compatible imaging apparatuses. Subsequently, the recent advances in bioimaging, biosensing, and therapy using such a cutting-edge imaging technique are highlighted. Finally, based on the achievement in the representative studies, we elucidate the main concerns regarding this imaging technique and give some advice and prospects for the development of NIR-II imaging for future biomedical applications.

Biomolecular assembly in biological systems is typically a complex dynamic process regulated by the exchange of molecular information between biomolecules such as proteins and nucleic acids. Here, we demonstrate a nucleic-acid-based system that can program the dynamic assembly process of viral proteins. Tobacco mosaic virus (TMV) genome-mimicking RNA is anchored on DNA origami nanostructures via hybridization with a series of DNA strands which also function as locks that prevent the packaging of RNA by the TMV proteins. The selective, sequential releasing of the RNA via toehold-mediated strand displacement allows us to program the availability of RNA and subsequently the TMV growth in situ. Furthermore, the programmable dynamic assembly of TMV on DNA templates also enables the production of new DNA-protein hybrid nanostructures, which are not attainable by using previous assembly methods.

Activatable theranostic systems show potential for improved tumor diagnosis and therapy owing to high detection specificities, effective ablation, and minimal side-effects. Herein, a tumor microenvironment (TME)-activated NIR-II nanotheranostic system (FEAD1) for precise diagnosis and treatment of peritoneal metastases is presented. FEAD1 was fabricated by self-assembling the peptide Fmoc-His, mercaptopropionic-functionalized Ag2 S quantum dots (MPA-Ag2 S QDs), the chemodrug doxorubicin (DOX), and NIR absorber A1094 into nanoparticles. We show that in healthy tissue, FEAD1 exists in an NIR-II fluorescence "off" state, because of Ag2 S QDs-A1094 interactions, while DOX remains in stealth mode. Upon delivery of FEAD1 to the tumor, the acidic TME triggers its disassembly through breakage of the Fmoc-His metal coordination and DOX hydrophobic interactions. Release of A1094 switches on Ag2 S fluorescence, illuminating the tumor, accompanied by burst release of DOX within the tumor tissue, thereby achieving precise tumor theranostics. This TME-activated theranostic strategy holds great promise for future clinical applications.

The science of protein self-assembly has experienced significant development, from discrete building blocks of self-assembled nanoarchitectures to advanced nanostructures with adaptive functionalities. Despite the prominent achievements in the field, the desire of designing de novo protein-nanoparticle (NP) complexes and constructing dynamic NP systems remains highly challenging. In previous works, l-rhamnulose-1-phosphate aldolase (C98RhuA) tetramers were self-assembled into two-dimensional (2D) lattices via disulfide bond interactions. These interactions provided 2D lattices with high structural quality and a sophisticated assembly mode. In this study, we devised a rational design for RhuA building blocks to fabricate 2D functionalized protein lattices. More importantly, the lattices were used to direct the precise assembly of NPs into highly ordered and diverse nanoarchitectures. These structures can be employed as an excellent tool to adequately verify the self-assembly mode and structural quality of the designed RhuA crystals. The subsequent redesign of RhuA building blocks enabled us to predictably produce a novel protein lattice whose conformational dynamics can be controllably regulated. Thus, a dynamic system of AuNP lattices was achieved. Transmission electron microscopy and small-angle X-ray scattering indicated the presence of these diverse NP lattices. This contribution enables the fabrication of future NP structures in a more programmable manner with more expected properties for potential applications in nanoelectronics and other fields.

Reliable orthogonal bonding with precise and flexible orientation control would be ideal for building finite complex nanostructures via self-assembly. Employing a three-dimensional (3D) DNA origami, hexagonal prism DNA origami (HDO), as building block, we demonstrate it is practical to construct finite hierarchical nanoarchitectures with complicated conformations through orthogonal and directional bonding. The as-designed HDO building block has twelve prescribed directional valences in 3D space and each of them supports two opposite orientations, yielding the capability to generate abundant directional bonding. Meanwhile, we minimize the thorny non-specific interactions among HDOs and enable the orthogonal bonding between any two valences based on self-similar designing. Consequently, various hierarchical nanostructures are prepared at will simply by the combination of HDOs with appropriate valences. We believe this route towards hierarchically assembly is inspiring and hope it will facilitate the fabrication of functional superstructures.

Herein, we report the assembly of gold nanobipyramids (AuNBPs) into static and dynamic chiral plasmonic nanostructures via DNA origami. Compared with conventional chiral dimers of gold nanorods (AuNRs), AuNBP dimers exhibit more intriguing chiroptical responses, suggesting that they could be a superior alternative for constructing chiral plasmonic nanostructures for biosensing.

Real-time tracking drug release behavior is fundamentally important for avoiding adverse effects or unsuccessful treatment in personalize medical treatment. However, the development of a non-invasive drug reporting platform still remains challenging. Herein the design of a novel synthetic magnetic resonance imaging (MRI) agent for drug release tracking (SMART) is reported, which integrates photothermal core and paramagnetic ion/drug loading shell with a thermal valve in a hybrid structure. Through near-infrared (NIR)-II photothermal effect originating from inner Au-Cu9S5 nanohybrid core, burst release of drugs loaded in the mesoporous silica shell is achieved. The concomitant use of a phase change material not only prevents premature drug release, but also regulates heating effect, keeping local temperature below 45 °C, enabling synergistic chemotherapy and mild hyperthermia in vitro and in vivo. Furthermore, the drug release from SMART facilitates proton accessibility to the paramagnetic ions anchored inside mesopores channels, enhancing longitudinal T1 relaxation rate and displaying positive signal correlation to the amount of released drug, thus allowing non-invasive real-time monitoring of drug release event. The current study highlights the potential of designed MRI nanophores such as SMART for real-time and in-situ monitoring of drug delivery for precision theranostic applications.

The plasma membrane of cells is a crucial biological membrane that involved in a variety of cellular processes including cell signaling transduction through membrane electrical activity. Recently, monitoring membrane electrical activity using fluorescence imaging has attracted numerous attentions for its potential applications in evaluating how the nervous system works. However, the development of ideal fluorescent voltage-sensitive probes with both high membrane labeling efficiency and voltage sensitivity is still retain a big challenge. Herein, glutathione-capped CdSe@ZnS quantum dots (CdSe@ZnS-GSH QDs) with a size of 2.5 nm and an emission peak at 520 nm are synthesized using a facile ligand exchange method for plasma membrane labeling and membrane potential imaging. The as-synthesized CdSe@ZnS-GSH QDs can effectively label cell membrane at neutral pH within 30 min and exhibit excellent optical stability in continuous imaging for up to 60 min. With the test concentration up to 200 nM, CdSe@ZnS-GSH QDs show high biocompatibility to cells and do not affect cell proliferation, disturb cell membrane integrity or cause apoptosis and necrosis of cells. Then, a two-component voltage sensor strategy based on fluorescence resonance energy transfer (FRET) between CdSe@ZnS-GSH QDs and the dipicrylamine (DPA) is successfully developed to monitor the membrane potential by the fluorescence of CdSe@ZnS-GSH QDs. This study offers a facile strategy for labeling plasma membrane and monitoring the membrane potential of cells and will hold great potential in the research of signaling within intact neuronal circuits.

Tuning the crystal phase of metal alloy nanomaterials has been proved a significant way to alter their catalytic properties based on crystal structure and electronic property. Herein, we successfully developed a simple strategy to controllably synthesize a rare crystal structure of hexagonal close-packed (hcp) NiFe nanoparticle (NP) encapsulated in a N-doped carbon (NC) shell (hcp-NiFe@NC). Then, we systemically investigated the oxygen evolution reaction (OER) performance of the samples under alkaline conditions, in which the hcp-NiFe@NC exhibits superior OER activity compared to the conventional face-centered cubic (fcc) NiFe encapsulated in a N-doped carbon shell (fcc-NiFe@NC). At the current densities of 10 and 100 mA cm-2 , the hcp-NiFe@NC with Fe/Ni ratio of ≈5.4 % only needs ultralow overpotentials of 226 mV and 263 mV versus reversible hydrogen electrode in 1.0 m KOH electrolyte, respectively, which were extremely lower than those of fcc-NiFe@NC and most of other reported NiFe-based electrocatalysts. We proposed that hcp-NiFe possesses favorable electronic property to expedite the reaction on the NC surface, resulting higher catalytic activity for OER. This research provides a new insight to design more efficient electrocatalysts by considering the crystal phase correlated electronic property.

Image-guided photothermal therapy (PTT) is an attractive strategy to improve the diagnosis accuracy and treatment outcomes by monitoring the accumulation of photothermal agents in tumors in real-time and determining the best treatment window. Taking advantage of the superior imaging quality of NIR-II fluorescence imaging and remote-controllable phototherapy modality of PTT, we developed a facile macromolecular fluorophore (PF) by conjugating a small-molecule NIR-II fluorophore (Flav7) with an amphiphilic polypeptide. The PF can form uniform micelles in aqueous solution, which exhibit a slight negative charge. In vitro experimental results showed that the PF nanoparticles showed satisfactory photophysical properties, prominent photothermal conversion efficiency (42.3%), excellent photothermal stability, negligible cytotoxicity, and photothermal toxicity. Meanwhile, the PF can visualize and feature the tumors by NIR-II fluorescence imaging owing to prolonged blood circulation time and enhanced accumulation in tumors. Moreover, in vivo studies revealed that the PF nanoparticles achieved an excellent photothermal ablation effect on tumors with a low dose of NIR-II dye and light irradiation, and the process can be traced by NIR fluorescence imaging.

Axonal transport plays a significant role in the establishment of neuronal polarity, axon growth, and synapse formation during neuronal development. The axon of a naturally growing neuron is a highly complex and multifurcated structure with a large number of bends and branches. Nowadays, the study of dynamic axonal transport in morphologically complex neurons is greatly limited by the technological barrier. Here, a sparse gene transfection strategy was developed to locate fluorescent mCherry in the lysosome of primary neurons, thus enabling us to track the lysosome-based axonal transport with a single-particle resolution. Thereby, several axonal transport models were observed, including forward or backward transport model, stop-and-go model, repeated back-and-forth transport model, and cross-branch transport model. Then, the accurate single-particle velocity quantification by TrackMate revealed a highly heterogeneous and discontinuous transportation process of lysosome-based axonal transport in freely orientated axons. And, multiple physical factors, such as the axonal structure and the size of particles, were disclosed to affect the velocity of particle transporting in freely orientated axons. The combined single-particle fluorescence tracking and TrackMate assay can be served as a facile tool for evaluating axonal transport in neuronal development and axonal transport-related diseases.

Controlling molecular chirality is of great importance in nanotechnology. Many biologically active molecules are chiral, including the naturally occurring amino acids, nuclear acids and sugars. In biological systems, most of these compounds are of the same chirality and the circular dichroism (CD) response of natural molecules is very weak. On the other hand, when metallic nanostructures, especially noble metal, illuminated by light with proper energy and momentum, surface plasmons can be excited, which have been used to enhance the electric field and excite higher electric and magnetic modes, leading to a series of fantastic optical phenomena and applications. Chirality of natural molecules can be manipulated by reconfiguring molecular structures through light, electric field, and thermal stimuli. While, the fabrication of complex metal structures is limited by the condition of current technology, especially for the precise fabrication and manipulation molecules at the nanoscale. Moreover, how to achieve chiroptical response in the visible range needs more efforts. In recent years, DNA nanotechnology, using DNA as building blocks of self-assembly, could be finely engineered into desired nanoarchitectures with high complexity and precision. It provides an effective way to easily control and tailor the arrangement of nanoparticles, and to form chiral metamolecules with complicated geometry. Among a variety of functionalized particles, metal nanoparticles such as gold nanoparticles feature an important pathway to endow DNA origami assembled nanostructures with tailored optical functionalities. Such DNA nanostructures were used for building versatile chiral plasmonic nanostructures from static to dynamic. Taking advantages of the spherical metal nanomaterials own isotropy and the programable of DNA nanostructures, the chiral configuration of self-assembled plasmonic nanostructures mainly consider the overall geometry of chiral space, which is easy to expand to more chiral and complex structure. Researchers can arrange achiral metal nanoparticles including gold nanoparticles, silver nanoparticles and quantum dots to fabricate chiral plasmonic nanostructures by analyzing and simulating the optically active molecular analogs. In addition, the interest in self-assembly of chiral plasmonic nanostructures, such as gold nanorods, as anisotropic building blocks is growing quickly. Researchers have developed a variety of complex superstructures such as chiral tetrahedral nanoparticles, pyramid nanoparticles, helical structures and three-dimensional plasmonic nanostructures. DNA nanotechnology provides one of the few ways to form designed, complex structures with precise control over nanoscale features. As a result, plasmonic chiral nanostructures assembled by DNA allow for dynamic manipulation of chirality and reversible switching of strong CD responses, hold great promise for applications in adaptable nanophotonic circuitry, artificial nanomachinery, as well as optical sensing of molecular binding and interaction activities. This article briefly reviews the developments and achievements of chiral plasmonic nanostructures enabled by DNA nanotechnology. Firstly, we show chiral plasmonic nanostructures based on spherical AuNPs, including plasmonic helices, tetramers, and chiral geometric conformations. Then, to challenge the complex configurations and enhance the CD responses, anisotropic gold nanorods with larger extinction coefficients are utilized to fabricate chiral plasmonic nanostructures including dimers, tripod and superhelix. Finally, we introduce dynamic manipulation based on DNA nanostructures with the fast development of this interdisciplinary field. We envision that the combination of DNA nanotechnology and plasmonics will open an avenue toward a new generation of functional plasmonic systems with tailored optical properties and useful applications, including polarization conversion devices, biomolecular sensing, surface-enhanced Raman and fluorescence spectroscopy, and diffraction-limited optics.

Fluorescence imaging is one of the most widely used in vivo imaging methods for both fundamental research and clinical practice. Due to the reduced photon scattering, absorption, and autofluorescence in tissues, the emerging near-infrared (NIR) imaging (650-1700 nm) can afford deep tissue imaging with high spatiotemporal resolution and in vivo report the anatomical structures as well as the physiological activities in a whole-body level. Here, we give a brief introduction to fluorescence imaging in the first NIR (NIR-I, 650-950 nm) and second NIR (NIR-II, 1000-1700 nm) windows, summarize the recently developed NIR fluorophores and their applications in whole-body vascular system imaging, precision cancer theranostics, and regenerative medicine. Finally, the clinical applications and future prospects of in vivo NIR fluorescence imaging are also discussed.

Fluorescence located in 1500-1700 nm (denoted as the near-infrared IIb window, NIR-IIb) has drawn great interest for bioimaging, owing to its ultrahigh tissue penetration depth and spatiotemporal resolution. Therefore, NIR-IIb fluorescent probes with high photoluminescence quantum yield (PLQY) and stability along with high biocompatibility are urgently pursued. Herein, a novel NIR-IIb fluorescent probe of Au-doped Ag

Engineering noncovalent interactions for assembling nonspherical proteins into supramolecular architectures with tunable morphologies and dynamics is challenging due to the structural heterogeneity and complexity of protein surfaces. Herein, we employed an anisotropic building block l-rhamnulose-1-phosphate aldolase (RhuA) to control supramolecular polymorphism in highly ordered protein assemblies by introducing histidine residues. Histidine-based π-π stacking interactions enabled thermodynamically controlled self-organization of RhuA to form three-dimensional (3D) nanoribbons and crystals. Self-assembly of different 3D crystal phases was kinetically modulated by the strong metal ion-histidine chelation, and double-helical protein superstructures were formed by engineering increased histidine interactions at the RhuA binding surface. Their structural properties and dynamics were determined via fluorescence microscopy, transmission electron microscopy, atomic force microscopy, and small-angle X-ray scattering. This work is aimed at expanding the toolbox for the programming of tunable, highly ordered, protein superstructures and increasing the understanding of the mechanisms of protein interfacial interactions.

Fluorescence imaging is one of the most widely used in vivo imaging methods for both fundamental research and clinical practice. Due to the reduced photon scattering, absorption, and autofluorescence in tissues, the emerging near-infrared (NIR) imaging (650–1700 nm) can afford deep tissue imaging with high spatiotemporal resolution and in vivo report the anatomical structures as well as the physiological activities in a whole-body level. Here, we give a brief introduction to fluorescence imaging in the first NIR (NIR-I, 650–950 nm) and second NIR (NIR-II, 1000–1700 nm) windows, summarize the recently developed NIR fluorophores and their applications in whole-body vascular system imaging, precision cancer theranostics, and regenerative medicine. Finally, the clinical applications and future prospects of in vivo NIR fluorescence imaging are also discussed.