Bioinspired All-in-One Three-Dimensional Dynamic CellMatrix Improves the Manufacture of Therapeutically Qualified Cells for Cell Therapy.

Despite the great promise, cell therapy still faces practical challenges because of the scarcity of a reliable cell source. Herein, a bioinspired 3D dynamic culture system (CellMatrix) with rational structure, composite and function, was developed for improving cell supply. CellMatrix was composed of unique core-shell fibers with a core of black phosphorus-incorporated fibroin and a shell of sericin, which together formed a 3D silkworm cocoon-mimicking structure via a bottom-up fabrication technique. CellMatrix not only provided optimal engineered biomimetic niche to facilitate cell growth but exhibited good photothermal conversion to dynamically regulate cell fates. Importantly, cell-CellMatrix construct could be directly implanted into defected tissues and improved tissue remodeling. Meanwhile, CellMatrix displayed good ice resistance and thermal conductivity, which maximally maintained cell viability and proliferation after the freeze-thawing process, allowing for storing precious cells and cell-CellMatrix construct. Thus, CellMatrix represents an all-in-one biomimetic platform for the culture-production-storage of therapeutically qualified cells.

Design of robust superamphiphobic surfaces with enlarged area fractions: the considerable role of Laplace pressure in dynamics of contact lines.

Superamphiphobic surfaces have attracted widespread attention because of their great potential for applications in biotechnology, optoelectronics, water/oil separation, etc. Re-entrant curvatures are widely reported to provide a metastable Cassie state for superamphiphobicity. For high contact angles, re-entrant surfaces with a small area fraction (f) are designed according to the Cassie equation. However, this will make the surfaces take high local pressures under a mechanical force and thus suffer from frangibility. Robustness and high repellency are seemingly mutually exclusive. Herein, contrary to Cassie's equation, we show that high contact angles (>150°) with a large f (69.4%) of water and oleic acid can be achieved by utilizing a large upward Laplace pressure with narrow and parallel channel geometries. We deeply studied the effect of Laplace pressure on superamphiphobicity and suppose that the larger upward Laplace pressure stops the droplet earlier and pins the contact line at a higher position, providing a higher contact angle. The similar effect of viscous force well supports our explanation. These findings enable us to obtain robust and durable superamphiphobic surfaces with an enlarged area fraction and simple re-entrant microstructures. Our work may open up design strategies for robust superamphiphobic surfaces with practical applications.

High rate capabilities and remarkably cycle-stable flexible pseudocapacitors based on nano-coralloid arrays with sulfide vacancies enhanced Ni-Co-S nanoparticle covering.

Both poor electron conductivity and low ion diffusion of electrode materials are two main issues limiting the rate performance of pseudocapacitors. The present work reports the design and fabrication of hierarchically nano-architectured electrodes consisting of sulfide vacancies enhanced Ni-Co-S nanoparticle covering bent nickel nano-forest (BNNF). We propose new insight into vastly increased ion-accessible active sites and fast charge storage/delivery enhanced the reaction kinetics. The Ni-Co-S@BNNF electrode exhibits extremely high rate performance with 90.1% capacity retention from 1 to 20 A g-1, and even still remains 83.6% capacity at 40 A g-1, much superior to reported NiCo2S4-based electrodes. The high rate performance is attributed to the unique nano-architecture providing increased ion availability of electrochemically active sites and high conductivity for fast electron transport. Especially the electrode achieves remarkable long-term cycle stability with more than 100% initial capacity value after 5000 cycles at 5 A g-1and exhibits excellent cycle reversibility even at 20 A g-1. Goog cycle stability should be attributed to the sulfide vacancies in Ni-Co-S nano-branches and the electrode architecture sustaining structural strain during fast redox reactions. An asymmetric pseudocapacitor applying such electrode achieves a high energy density of 99.9 W h kg-1and exhibits superior cycling stability at a high current density of 20 A g-1. This study underscores the potential importance of developing nanoarrays covered with highly redox-active materials with increasing ions/charge kinetics for energy storage.

Polyvinyl alcohol: a high-resolution hydrogel resist for humidity-sensitive micro-/nanostructure.

A high-resolution nanopatterning technique is desirable with the present rapid development of hydrogel nanodevices. Here, we demonstrate that polyvinyl alcohol (PVA), a popular polymeric hydrogel, can function as the negative-tone resist for electron beam lithography (EBL) with a resolution capability as narrow as 50 nm half-pitch. Furthermore, the hydrophilic groups of PVA are stable after EBL exposure, and thus the pattern still shows rapid responsivity to humidity change. An aqueous nanopatterning process including dissolution, spin-coating and development is setup, which is friendly for organic device fabrication free of organic solvent. This high-resolution nanopatterning technique with PVA is helpful for the design and realization of hydrogel-related nanodevices in the future.

Novel Integrin αvß3-Specific Ligand for the Sensitive Diagnosis of Glioblastoma.

Integrin αvß3 is a cell adhesion molecule involved in the progression and invasion of glioblastoma, making it an attractive target for the diagnosis of glioblastoma. Although some integrin αvß3 specific ligands, such as RGD and its mimetic peptides (Cilengitide), have been devoted in detecting glioblastoma, their clinical practices have been limited due to low specificity and affinity. Herein, we have identified a linear peptide RWrNK, containing an unnatural d-arginine (r), as the integrin αvß3-specific ligand. RWrNK shows high binding affinity to integrin αvß3 with a Kd value of 1.6 nM, which is 2-fold higher than Cilengitide (3.2 nM), a well-established integrin αvß3 ligand. In addition, RWrNK can not only rapidly transport in human glioblastoma U87MG cells but effectively label U87MG tumor spheroids, compared to Cilengitide, indicating that it possesses an ability to sensitively detect glioblastoma. Importantly, RWrNK can pass through blood-brain tumor barrier (BBTB) and selectively accumulate in orthotopic U87MG tumor within 2 h, allowing for imaging glioblastoma in vivo with high sensitivity and specificity. Overall, RWrNK has the great potential in theranostic applications for glioblastoma, in consideration of its high specificity and affinity for integrin αvß3.

Fabrication of AlGaN nanorods with different Al compositions for emission enhancement in UV range.

Highly ordered AlxGa1-xN nanorods with varied aluminum alloy compositions (0.18 ≤ x ≤ 0.8) are fabricated with nanoimprint lithography and top-down dry etching techniques. And the structural properties and morphology are obtained by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Compared with as-grown AlGaN samples, nanorod samples reveal outstanding optical performance on account of strain releasing and light extraction enhancement. Through Raman scattering and cathodeluminescence measurements, it has been observed clear red-shifts of E2h modes and near band edge emission (NBE) peaks of AlGaN nanorods compared to the planar ones, indicating the residual strain releasing after nano-fabrication. The integrated intensities of NBE peaks of AlGaN nanorods manifest light emission enhancement up to 2.7 at deep-UV range. Finite-difference time-domain (FDTD) simulations have been adopted to investigate the light extraction and far-field distribution of such structures, it turned out that ordered nanorod array can enhance the TM polarized emission extraction 2-7 folds compared to the planar structure. The optical regulation in nanorod arrays should take the responsibility for the observed optical enhancements, which is proved by the far-field distribution of light, thus it can improve the performance of ultraviolet LEDs.

Phase Separation of Silicon-Containing Polymer/Polystyrene Blends in Spin-Coated Films.

In this Article, two readily available polymers that contain silicon and have different surface tensions, polydimethylsiloxane (PDMS) and polyphenylsilsequioxane (PPSQ), were used to produce polymer blends with polystyrene (PS). Spin-coated thin films of the polymer blends were treated by O2 reactive-ion etching (RIE). The PS constituent was selectively removed by O2 RIE, whereas the silicon-containing phase remained because of the high etching resistance of silicon. This selective removal of PS substantially enhanced the contrast of the phase separation morphologies for better scanning electron microscope (SEM) and atomic force microscope (AFM) measurements. We investigated the effects of the silicon-containing constituents, polymer blend composition, concentration of the polymer blend solution, surface tension of the substrate, and the spin-coating speed on the ultimate morphologies of phase separation. The average domain size, ranging from 100 nm to 10 µm, was tuned through an interplay of these factors. In addition, the polymer blend film was formed on a pure organic layer, through which the aspect ratio of the phase separation morphologies was further amplified by a selective etching process. The formed nanostructures are compatible with existing nanofabrication techniques for pattern transfer onto substrates.

Great enhancement in the excitonic recombination and light extraction of highly ordered InGaN/GaN elliptic nanorod arrays on a wafer scale.

A series of highly ordered c-plane InGaN/GaN elliptic nanorod (NR) arrays were fabricated by our developed soft UV-curing nanoimprint lithography on a wafer. The photoluminescence (PL) integral intensities of NR samples show a remarkable enhancement by a factor of up to two orders of magnitude compared with their corresponding as-grown samples at room temperature. The radiative recombination in NR samples is found to be greatly enhanced due to not only the suppressed non-radiative recombination but also the strain relaxation and optical waveguide effects. It is demonstrated that elliptic NR arrays improve the light extraction greatly and have polarized emission, both of which possibly result from the broken structure symmetry. Green NR light-emitting diodes have been finally realized, with good current-voltage performance and uniform luminescence.

Bloch surface plasmon enhanced blue emission from InGaN/GaN light-emitting diode structures with Al-coated GaN nanorods.

InGaN/GaN light-emitting diode structures with Al-coated GaN nanorods were fabricated by using soft ultraviolet nanoimprint lithography. The intensity of light emission was found to be greatly enhanced due to the strong near-fields confined at the interface of Al/GaN and extended to the multiple quantum wells (MQWs) active region. The dynamics of carrier recombination and plasmon-enhanced Raman scattering were also investigated, providing a progressive view on the effective energy transfer between MQWs and surface plasmons.

An oxygen-insensitive degradable resist for fabricating metallic patterns on highly curved surfaces by UV-nanoimprint lithography.

In this paper, an oxygen-insensitive degradable resist for UV-nanoimprint is designed, com-prising a polycyclic degradable acrylate monomer, 2,10-diacryloyloxymethyl-1,4,9,12-tetraoxa-spiro [4.2.4.2] tetradecane (DAMTT), and a multifunctional thiol monomer pentaerythritol tetra(3-mercaptopropionate) (PETMP). The resist can be quickly UV-cured in the air atmosphere and achieve a high monomer conversion of over 98%, which greatly reduce the adhesion force between the resist and the soft mold. High conversion, in company with an adequate Young's modulus (about 1 GPa) and an extremely low shrinkage (1.34%), promises high nanoimprint resolution of sub-50 nm. The cross-linked resist is able to break into linear molecules in a hot acid solvent. As a result, metallic patterns are fabricated on highly curved surfaces via the lift off process without the assistance of a thermoplastic polymer layer.

Bioinspired Polymer Films with Surface Ordered Pyramid Arrays and 3D Hierarchical Pores for Enhanced Passive Radiative Cooling.

Passive radiative cooling (PRC) has been acknowledged to be an environmentally friendly cooling technique, and especially artificial photonic materials with manipulating light-matter interaction ability are more favorable for PRC. However, scalable production of radiative cooling materials with advanced biologically inspired structures, fascinating properties, and high throughput is still challenging. Herein, we reported a bioinspired design combining surface ordered pyramid arrays and internal three-dimensional hierarchical pores for highly efficient PRC based on mimicking natural photonic structures of the white beetle Cyphochilus' wings. The biological photonic film consisting of surface ordered pyramid arrays with a bottom side length of 4 µm together with amounts of internal nano- and micropores was fabricated by using scalable phase separation and a quick hot-pressing process. Optimization of pore structures and surface-enhanced photonic arrays enables the bioinspired film to possess an average solar reflectance of ∼98% and a high infrared emissivity of ∼96%. A temperature drop of ∼8.8 °C below the ambient temperature is recorded in the daytime. Besides the notable PRC capability, the bioinspired film exhibits excellent flexibility, strong mechanical strength, and hydrophobicity; therefore, it can be applied in many complex outdoor scenarios. This work provides a highly efficient and mold replication-like route to develop highly efficient passive cooling devices.

Room-Temperature Growth of Square-Millimeter Single-Crystalline Two-Dimensional Metal Halides on Silicon.

Silicon is the cornerstone of electronics and photonics. In this context, almost all integrated devices derived from two-dimensional (2D) materials stay rooted in silicon technology. However, as the growth substrate, silicon has long been thought to be a hindrance for growing 2D materials through bottom-up methods that require high growth temperatures, and thus, indirect routes are usually considered instead. Although promising growth of large-area 2D materials on silicon has been demonstrated, the direct growth of single-crystalline materials using low-thermal-budget synthesis methods remains challenging. Here, we report the room-temperature growth of millimeter-scale single-crystal 2D metal halides on silicon substrates with a hydroxyl-terminated surface. Theoretical calculations reveal that the activation energy for surface diffusion can be reduced by an order of magnitude by terminating the surface with hydroxyl groups, from which on-silicon growth is greatly facilitated at room temperature and enables a 4-order-of-magnitude increase in area. The high quality and uniformity of the resulting single crystals are further evidenced. The optoelectronic devices employing the as-grown materials show an ultralow dark current of 10-13 A and a high detectivity of 1013 Jones, thereby corroborating a weak-light detection ability. These results would point to a rich space of surface modulation that can be used to surmount current limitations and demonstrate a promising strategy for growing 2D materials directly on silicon at room temperature to produce large single crystals.

Large-scale fabrication and luminescence properties of GaN nanostructures by a soft UV-curing nanoimprint lithography.

GaN nanorods with a period of 400 nm and diameter of 200 nm, and nano-gratings with a period of 400 nm and gap width of 100 nm are fabricated on wafers by a soft UV-curing nanoimprint lithography. These nanostructures show high periodicity and good morphology. The photoluminescence (PL) spectra exhibit that the integral PL intensity of GaN nanorods is enhanced as much as 2.5 times, compared to that of as-grown GaN films. According to finite-difference time-domain simulations and cathodoluminescence mappings, it is concluded that the enhancement for nanorods is due to the improvements of both spontaneous emission rate and light extraction efficiency caused by periodic GaN structures on the surface. By identifying the Raman shift of E1(TO) and E2(H) modes of GaN films with nano-gratings and nanorods, the normal-plane strain ε(zz) is determined. The PL emission energy is found to be proportional to the ε(zz), whose linear proportionality factor is calculated to be -27 meV GPa(-1).

Double transfer UV-curing nanoimprint lithography.

A challenge in the fabrication of nanostructures into non-planar substrates is to form a thin, uniform resist film on non-planar surfaces. This is critical to the fabrication of nanostructures via a lithographic technique due to the subsequent pattern transfer process. Here we report a new double transfer UV-curing nanoimprint technique that can create a nanopatterned thin film with a uniform residual layer not only on flat substrates but also on highly curved surfaces. Surface relief gratings with pitches down to 200 nm are successfully imprinted on the cylindrical surface of optical fibers, and further transferred into a SiO2 matrix using reactive ion etching (RIE), demonstrating that our technique is applicable for fabricating high-resolution nanostructures on non-planar substrates.

Open-Microcolumn Array: A Novel Approach for Enhanced Electrocatalytic Bubble Desorption in Microreactors.

High-efficiency electrocatalytic water splitting requires high intrinsic activity of catalysts and even more importantly favorable mass transfer. However, gas bubbles adhering to the surface of catalysts limit the re-expose of catalytic active sites to the electrolyte and reduce the catalytic activities. The efficient desorption of bubbles can be facilitated by a hierarchical multiscale structure of the electrode surface. Herein, we report an opened periodic three-dimensional electrode composed of iron (Fe)-cobalt (Co)-nickel (Ni) (oxy)hydroxide nanorods (NRs) grown in situ on a high aspect ratio nickel microcolumn array (NCA) for electrocatalytic water splitting. Compared with the flat nickel plate, the NCA not only increases the surface area for catalyst loading but also improves the wettability of the electrolyte on the electrode surface, exhibiting superhydrophilicity/superaerophobicity (the electrolyte and the bubble contact angles were about ∼0 and 163°, respectively), which accelerates the bubble evolution and desorption process. The X-ray photoelectron spectroscopy indicates that the synergy of Fe-Co-Ni could enhance the ratio of Co3+/Co2+ and Ni3+/Ni2+ and promote the electrocatalytic activity. Benefiting from the microstructure design and synergistic effects, the Co4Fe0.5Ni0.5OOH-NR@NCA electrode achieves a superior OER performance with an overpotential of 199 mV at 10 mA·cm-2.

Tube-Sponge-Inspired Hierarchical Electrocatalysts with Boosted Mass and Electron Transfer for Efficient Oxygen Evolution.

Hindered gas bubble release and limited electron conducting process represent the major bottlenecks for large-scale electrochemical water splitting. Both the desorption of bubbles and continuous electron transport are achievable on the surfaces of biomimetic catalytic materials by designing multiscale structural hierarchy. Inspired by the tubular structures of the deep-sea sponges, an exceptionally active and binder-free porous nickel tube arrays (PNTA) decorated with NiFe-Zn2+ -pore nanosheets (NiFe-PZn ) are fabricated. The PNTA facilitate removal of bubbles and electron transfer in the oxygen evolution reaction by reproducing trunks of the sponges, and simultaneously, the NiFe-PZn increase the number of catalytic active sites by simulating the sponge epidermis. With improved external mass transfer and interior electron transfer, the hierarchical NiFe-PZn @PNTA electrode exhibits superior oxygen evolution reaction performance with an overpotential of 172 mV at 10 mA cm-2 (with a Tafel slope of 50 mV dec-1 ). Furthermore, this electrocatalytic system recorded excellent reaction stability over 360 h with a constant current density of 100 mA cm-2 at the potential of 1.52 V (versus RHE). This work provides a new strategy of designing hierarchical electrocatalysts for highly efficient water splitting.

Orthogonal Chemical Reporter Strategy Enables Sensitive and Specific SERS Detection of Hydrazine Derivatives.

Hydrazine and its derivatives are well-known environmental hazards and biological carcinogens; therefore, there is a great need for a powerful workflow solution for protecting the public from unexpected exposure to toxic contaminants. Recently, functional surface-enhanced Raman scattering (SERS) exhibits enormous benefits in sensing trace biochemical substances due to its fingerprint-like identification of individual molecules, making it an ideal method for detecting and quantifying hydrazine. Herein, for the first time, we integrated the orthogonal chemical reporter strategy with SERS to build an intelligent hydrazine detection platform (orthogonal chemical SERS, ocSERS), in which 4-mercaptobenzaldehyde was incorporated on a nanoimprinted gold nanopillar array, which acted as an orthogonal coupling partner of hydrazine to form Raman active benzaldehyde hydrazone, allowing for sensitively detecting hydrazine with a detection limit of 10-13 M in complex circumstances. Particularly, ocSERS could effectively identify the carcinogen N-nitrosodimethylamine (NDMA) after its reduction to dimethylhydrazine (UDMH), enabling ultrasensitive detection of UDMH (10-13 M). Importantly, ocSERS could not only monitor elevated levels of NDMA in ranitidine due to improper storage but also quantify NDMA in urine and blood after oral administration of NDMA-containing drugs, thereby preventing NDMA overexposure. Therefore, ocSERS represents the first click SERS sensor and may open up a new analytical field.

A Smart "Energy NanoLock" Selectively Blocks Oral Cancer Energy Metabolism through Synergistic Inhibition of Exogenous Nutrient Supply and Endogenous Energy Production.

The major challenge in oral cancer is the lack of state-of-the-art treatment modality that effectively cures cancer while preserving oral functions. Recent insights into tumor metabolic dependency provide a therapeutic opportunity for exploring optimal treatment approaches. Herein, a smart responsive "Energy NanoLock" is developed to improve cancer metabolic intervention by simultaneously inhibiting nutrient supply and energy production. NanoLock is a pomegranate-like nanocomplex of cyclicRGD-modified carboxymethyl chitosan (CyclicRC, pI = 6.7) encapsulating indocyanine green and apoptotic peptides functionalized gold nanoparticles (IK-AuNPs), which together form a dual pH- and photoresponsive therapeutic platform. NanoLock exhibits good stability under physiological conditions, but releases small-size CyclicRC and IK-AuNPs in response to the tumor acidic microenvironment, leading to deep tumor penetration. CyclicRC targets integrins to inhibit tumor angiogenesis, and consequently blocks tumor nutrient supply. Meanwhile, IK-AuNPs specifically induce apoptotic peptides and photothermally mediated mitochondrial collapse, and consequently inhibits endogenous energy production, thereby facilitating cell death. Importantly, in both xenograft and orthotopic oral cancer models, NanoLock selectively eliminates tumors with little cross-reactivity with normal tissues, especially oral functions, resulting in prolonged survival of mice. Therefore, NanoLock provides a novel metabolic therapy to exploit synergistic inhibition of exogenous nutrient supply and endogenous energy production, which potentially advances oral cancer treatment.

Photoactive "Bionic Virus" Robustly Elicits the Synergy Anticancer Activity of Immunophotodynamic Therapy.

Coronavirus represents an inspiring model for designing drug delivery systems due to its unique infection machinery mechanism. Herein, we have developed a biomimetic viruslike nanocomplex, termed SDN, for improving cancer theranostics. SDN has a unique core-shell structure consisting of photosensitizer chlorin e6 (Ce6)-loaded nanostructured lipid carrier (CeNLC) (virus core)@poly(allylamine hydrochloride)-functionalized MnO2 nanoparticles (virus spike), generating a virus-mimicking nanocomplex. SDN not only prompted cellular uptake through rough-surface-mediated endocytosis but also achieved mitochondrial accumulation by the interaction of cationic spikes and the anionic mitochondrial surface, leading to mitochondria-specific photodynamic therapy. Meanwhile, SDN could even mediate oxygen generation to relieve tumor hypoxia and, consequently, improve macrophage-associated anticancer immune response. Importantly, SDN served as a robust magnetic resonance imaging (MRI) contrast agent due to the fast release of Mn2+ in the presence of intracellular redox components. We identified that SDN selectively accumulated in tumors and released Mn2+ to generate a 5.71-fold higher T1-MRI signal, allowing for effectively detecting suspected tumors. Particularly, SDN induced synergistic immunophotodynamic effects to eliminate malignant tumors with minimal adverse effects. Therefore, we present a novel biomimetic strategy for improving targeted theranostics, which has a wide range of potential biomedical applications.