Photoreversible Color-Switching Cu-Doped TiO Nanoparticles for High-Contrast Rewritable Printing.

Light-printable rewritable paper that can be used multiple times has attracted extensive attention because of its potential benefits in reducing environmental pollution and energy consumption. Developing rewritable paper with high black-to-colorless contrast, lasting legibility, and a fast response is fascinating but challenging. Here, we integrate the redox chemistry of Cu ions into photoreductive TiO nanoparticles to produce Cu-doped TiO nanoparticles capable of highly photoreversible switching between colorless and black with excellent contrast and color stability.

Near-infrared light-induced homogeneous photoelectrochemical biosensor based on 3D walking nanomotor-assisted CRISPR/Cas12a for ultrasensitive microRNA-155 detection.

The dysregulation of microRNA (miRNA) expression levels is intricately linked to a myriad of human diseases, and the precise and delicate detection thereof holds paramount significance in the realm of clinical diagnosis and therapy. Herein, a near-infrared (NIR) light-mediated homogeneous photoelectrochemical (PEC) biosensor was constructed for miRNA-155 detection based on NaYF: Yb, Tm@ZnInS (NYF@ ZIS) coupled with a three-dimensional (3D) walking nanomotor-assisted CRISPR/Cas12a strategy. The upconverted light emitted by the NYF in the visible and UV region upon NIR light excitation could be utilized to excite ZIS to produce a photocurrent response.

Visible-Light-Responsive Photoreversible Multi-Color Switching for Rewritable Light-Printing and Information Display.

Photoreversible color switching systems (PCSSs) exhibiting multi-color responses to visible light are favored for sustainable societal development over those relying on ultraviolet light due to safer operation and better penetration depth. Here, a PCSS capable of multi-color switching responsive to visible light based on highly photoreductive rutile-phase Sn-doped TiO nanoparticles is reported. The Sn-doping significantly red-shifts the absorption band of the nanoparticles to the visible region, improving charge separation and transfer efficiencies and introducing Ti species and oxygen vacancies as internal sacrificial electron donors for scavenging photogenerated holes.

Decomposition of SO on Ni(111) Surface and the Effect of Metal Doping: A First-Principles Study.

Sulfides poisoning of metallic Ni is an important issue in catalyst deactivation. SO, similar to HS and other sulfides, is an impurity presented in reactants or during the regeneration steps. Herein, spin-polarized density functional theory calculations were used to study the adsorption and decomposition of SO on a pristine and metal-doped Ni(111) surface.

Self-Powered Flexible Multicolor Electrochromic Devices for Information Displays.

The development of self-powered flexible multicolor electrochromic (EC) systems that could switch different color without an external power supply has remained extremely challenging. Here, a new trilayer film structure for achieving self-powered flexible multicolor EC displays based on self-charging/discharging mechanism is proposed, which is simply assembled by sandwiching an ionic gel film between 2 cathodic nickel hexacyanoferrate (NiHCF) and Prussian blue (PB) nanoparticle films on indium tin oxide substrates. The display exhibits independent self-powered color switching of NiHCF and PB films with fast responsive time and high reversibility by selectively connecting the Al wire as anodes with the 2 EC films.

Near-infrared light-induced photoelectrochemical biosensor based on plasmon-enhanced upconversion nanocomposites for microRNA-155 detection with cascade amplifications.

Herein, a novel near-infrared (NIR) light-driven photoelectrochemical (PEC) biosensor based on NaYF:Yb, Er@BiMoO@Bi (NYF@BMO@Bi) nanocomposites was elaborately developed to achieve highly sensitive detection of microRNA-155 (miRNA-155). To realize signal enhancement, the coupled plasmonic bismuth (Bi) nanoparticles were constructed as an energy relay to facilitate the transfer of energy from NaYF:Yb, Er to BiMoO, ultimately enabling the efficient separation of electron-hole pairs of BiMoO under the irradiation of a 980 nm laser. For constructing biosensing system, the initial signal was firstly amplified after the addition of alkaline phosphatase (ALP) in conjunction with the biofunctionalized NYF@BMO@Bi nanocomposites, which could catalyze the conversion of ascorbic acid 2-phosphate into ascorbic acid, and then consumed the photoacoustic holes created on the surface of BiMoO for the enlarging photocurrent production.

Molecular docking assisted exploration on solubilization of poorly soluble drug remdesivir in sulfobutyl ether-tycyclodextrin.

Objective: To study structure-specific solubilization effect of Sulfobutyl ether-β-cyclodextrin (SBE-β-CD) on Remdesivir (RDV) and to understand the experimental clathration with the aid of quantum mechanics (QM), molecular docking and molecular dynamics (MD) calculations.

Methods: The experiment was carried out by phase solubility method at various pH and temperatures, while the concentration of Remdesivir in the solution was determined by HPLC. The complexation mechanism and the pH dependence of drug loading were investigated following a novel procedure combining QM, MD and molecular docking, based on accurate pKa predictions.

Dual pH-/Photo-Responsive Color Switching Systems for Dynamic Rewritable Paper.

Smart color switching materials that can change color with a fast response and a high reversibility have attracted increasing attention in color-on-demand applications. However, most of them can only respond to a single stimulus from their external environment, which dramatically limits their broad applications. To address this problem, we report a new strategy in developing a dual pH-/photo-responsive color switching system by coupling the pH-dependent and redox-driven color switchable neutral red (NR) with photoreductive TiO nanoparticles.

Polymer-Based Dual-Responsive Self-Emulsifying Nanodroplets as Potential Carriers for Poorly Soluble Drugs.

A biodegradable amphiphilic liquid polymer was designed to form self-emulsifying nanodroplets in water for delivering poorly soluble drugs. The polymer was composed of multiple short blocks of poly(ethylene glycol) (PEG) and poly(caprolactone) (PCL) connected through acid-labile acetal linkages. With an overall average molecular weight of over 18 kDa, the polymer remained as a viscous liquid under room and physiological temperatures.

On-Demand Regulation of Photoreversible Color Switching for Rewritable Paper and Transient Information Encryption.

The achievement of photoreversible color switching systems (PCSS) has offered great opportunities for fundamental studies and practical applications. However, the development of PCSS that possessing highly reversible cyclability and on-demand regulation of recoloration process remains a grand challenge. Herein, we report a hydrazine-mediated self-doping strategy for the synthesis of alkaline Ti self-doped TiO nanoparticles, enabling the TiO nanoparticles/methylene blue based PCSS with long photoreversible cyclability and rapid color switching rate.

Near-Infrared Light-Initiated Photoelectrochemical Biosensor Based on Upconversion Nanorods for Immobilization-Free miRNA Detection with Double Signal Amplification.

Photoelectrochemical (PEC) sensors are relatively new sensing platforms with high detection sensitivity and low cost. However, the current PEC biosensors dependent on ultraviolet or visible light as the exciting resource cause injuries to biological samples and systems, which restrains the applications in complicated matrixes. Herein, a near-infrared light (NIR)-initiated PEC biosensor based on NaYF:Yb,Tm@NaYF@TiO@CdS (csUCNRs@TiO@CdS) was constructed for sensitive detection of acute myocardial infarction (AMI)-related miRNA-133a in an immobilization-free format coupled with a hybridization chain reaction and a redox circle signal amplification strategy.

Balancing Dielectric Loss and Magnetic Loss in Fe-NiS/NiS/PVDF Composites toward Strong Microwave Reflection Loss.

Lightweight, broad-band, and highly efficient microwave-absorbing materials (MAMs) with tunable electromagnetic properties are in high demand. However, the absorption properties are limited by the simple loss mechanism in commonly used absorbing materials. Here, we tested the microwave-absorbing properties of Fe-NiS/NiS/poly(vinylidene fluoride) (PVDF) in the frequency range of 2-18 GHz.

Photoreductive BiOCl Ultrathin Nanosheets for Highly Efficient Photocatalytic Color Switching.

The reversible photocatalytic color switching systems (PCSSs) driven by semiconductor nanoparticles have attracted considerable attention because of their wide applications. However, the developed semiconductor nanoparticles with photoreductive activity are mainly limited to TiO-based photocatalysts, which greatly hinder their broad applications. Here we report a cocapping ligand-assisted strategy for the development of photoreductive BiOCl ultrathin nanosheets with abundant oxygen vacancies.

Fast Dual-Stimuli-Responsive Dynamic Surface Wrinkles with High Bistability for Smart Windows and Rewritable Optical Displays.

The dynamic dual-stimuli-responsive surface wrinkles on a bilayer film with high bistability are unattainable and attractive for the applications of smart windows and optical displays. Here, we report a new strategy in developing moisture and temperature dual-responsive surface wrinkles on the polyvinyl alcohol/polydimethylsiloxane (PVA/PDMS) bilayer film by rationally designing the modulus changes of the PVA skin layer upon moisture and temperature. By optimizing the thickness of the PVA layer to 4.

Surface-bound sacrificial electron donors in promoting photocatalytic reduction on titania nanocrystals.

Titania nanocrystals have been investigated for fast color switching through photocatalytic reduction of dyes and hexacyanometalate pigments. Here we reveal that direct binding of sacrificial electron donors (SEDs) to the surface of titania nanocrystals can significantly promote the charge transfer rate by more efficiently scavenging photogenerated holes and releasing more photogenerated electrons for reduction reactions. Using diethylene glycol (DEG) as an example, we show that its binding to the nanoparticle surface, which can be achieved either during or after the nanoparticle formation, greatly enhances the photocatalytic reduction in comparison with the case where free DEG molecules are simply added as external SEDs.

Dynamic Color-Switching of Plasmonic Nanoparticle Films.

The fast and reversible switching of plasmonic color holds great promise for many applications, while its realization has been mainly limited to solution phases, achieving solid-state plasmonic color-switching has remained a significant challenge owing to the lack of strategies in dynamically controlling the nanoparticle separation and their plasmonic coupling. Herein, we report a novel strategy to fabricate plasmonic color-switchable silver nanoparticle (AgNP) films. Using poly(acrylic acid) (PAA) as the capping ligand and sodium borate as the salt, the borate hydrolyzes rapidly in response to moisture and produces OH ions, which subsequently deprotonate the PAA on AgNPs, change the surface charge, and enable reversible tuning of the plasmonic coupling among adjacent AgNPs to exhibit plasmonic color-switching.

Fast-Response Flexible Photochromic Gels for Self-Erasing Rewritable Media and Colorimetric Oxygen Indicator Applications.

Photoreversible color switching that can change colors with fast response and high stability is urgently desired in color-on-demand applications. Yet, developing such materials has long been a significant challenge. In this work, a strategy based on the integration of TiO nanoparticle (NP) photocatalytic color switching of redox dyes and poly(vinyl alcohol) gel matrix could produce robust and flexible photochromic gels (FPGs) that exhibit fast light-responsive time and high photoreversible stability.

Reversible Assembly and Dynamic Plasmonic Tuning of Ag Nanoparticles Enabled by Limited Ligand Protection.

Dynamic manipulation of optical properties through the reversible assembly of plasmonic nanoparticles offers great opportunities for practical applications in many fields. The previous success, however, has been limited to Au nanoparticles. Reversible assembly and plasmonic tuning of Ag nanoparticles (AgNPs) have remained a significant challenge due to difficulty in finding an appropriate surface agent that can effectively stabilize the particle surface and control their interactions.

Coassembly of Mixed Weakley-Type Polyoxometalates to Novel Nanoflowers with Tunable Fluorescence for the Detection of Toluene.

In this work, three-dimensional nanoflowers with tunable fluorescent properties constructed with mixed Weakley-type polyoxometalates (POMs, Na[LnWO]·32HO, Ln = Eu, Tb, abbreviated to LnW) and tetraethylenepentamine (TEPA) have been successfully prepared through a facile ionic self-assembly (ISA) method. The shape and petal size of the nanoflower as well as its fluorescent behaviors can be tuned through varying the ratio of EuW/TbW. The varied-temperature emission behaviors at 80-260 K show that the fluorescent intensity of both Tb and Eu decreased with the increase in temperature, which makes them potential luminescent ratiometric thermometers.

Photocatalytic Self-Doped SnO Nanocrystals Drive Visible-Light-Responsive Color Switching.

Visible-light-responsive reversible color-switching systems are attractive to many applications because visible light has superior penetration and causes far less damage to organic molecules than UV. Herein, we report that self-doping of SnO nanocrystals with Sn red-shifts their absorption to the visible region and simultaneously produces oxygen vacancies, which can effectively scavenge photogenerated holes and thus enable the color switching of redox dyes using visible light. Wavelength-selective switching can also be achieved by coupling the photocatalytic activity of the SnO NCs with the color-switching kinetics of different redox dyes.

Design, Fabrication and Characterization of Pressure-Responsive Films Based on The Orientation Dependence of Plasmonic Properties of Ag@Au Nanoplates.

A novel pressure-responsive polymer composite film was developed based on Ag@Au composite nanoplates (NPLs) and polyvinylpyrrolidone (PVP) by using Au nanoparticles as concentration reference. The orientation change of Ag@Au NPLs is impelled by the deformation of polymer matrix under pressure, resulting in its localized surface plasmon resonance (LSPR) intensity change of in-plane dipolar peak. The intensity ratio between plasmon peak of Au nanoparticles and in-plane dipolar peak of Ag@Au NPLs relies on the intensity and duration of pressure.

Photocatalytic Color Switching of Transition Metal Hexacyanometalate Nanoparticles for High-Performance Light-Printable Rewritable Paper.

Developing efficient photoreversible color switching systems for constructing rewritable paper is of significant practical interest owing to the potential environmental benefits including forest conservation, pollution reduction, and resource sustainability. Here we report that the color change associated with the redox chemistry of nanoparticles of Prussian blue and its analogues could be integrated with the photocatalytic activity of TiO nanoparticles to construct a class of new photoreversible color switching systems, which can be conveniently utilized for fabricating ink-free, light printable rewritable paper with various working colors. The current system also addresses the phase separation issue of the previous organic dye-based color switching system so that it can be conveniently applied to the surface of conventional paper to produce an ink-free light printable rewritable paper that has the same feel and appearance as the conventional paper.

Photocatalytic removal of hexavalent chromium by newly designed and highly reductive TiO nanocrystals.

Hexavalent chromium Cr(VI), a highly toxic oxyanion, widely occurs in drinking water supplies. This study designed and synthesized a new type of highly reductive TiO nanocrystals for photochemical Cr(VI) removal, via the thermal hydrolysis of TiCl in the presence of diethylene glycol (DEG). Surface analyses and hydroxyl radical measurements suggested that DEG was chemically bonded on TiO surface that resulted in an internal hole-scavenging effect and a high electron-releasing capacity, making it advantageous to conventional TiO materials.

Nanocomposite Polymers with "Slimy" Surfaces that Refresh Following Abrasion.

Creating polymeric biomaterials with antifouling surface properties that persist after mechanical abrasion is a significant challenge. We report a simple but effective approach based on nanocomposites consisting of a bulk biocompatible polymer, polycaprolactone (PCL), admixed with a minute fraction (1-3 wt %) of nanoparticles consisting of a hyaluronic acid (HA)-PCL graft copolymer (HA--PCL). In a nonaqueous solvent such as chloroform, the HA-PCL graft copolymer adopts a reverse-micelle-like structure with a shell dominated by PCL chains, allowing it to be mixed well with high-molecular-weight PCL in the same solvent and cast into a nanocomposite film.