Unconventional Breathing Currents Far beyond the Quantum Tunneling Distances in Large-Gapped Nanoplasmonic Systems.

Localized surface plasmon resonance (LSPR) in plasmonic nanoparticles propels the field of plasmo-electronics, holding promise for transformative optoelectronic devices through efficient light-to-current conversion. Plasmonic excitations strongly influence the charge distribution within nanoparticles, giving rise to electromagnetic fields that can significantly impact the macroscopic charge flows within the nanoparticle housing material. In this study, we present evidence of ultralow, unconventional breathing currents resulting from dynamic irradiance interactions between widely separated nanoparticles, extending far beyond conventional electron (quantum) tunneling distances. We develop an electric analogue model and derive an empirical expression to elucidate the generation of these unconventional breathing currents in cascaded nanoplasmonic systems under irradiance modulation. This technique and theoretical model have significant potential for applications requiring a deeper understanding of current dynamics, particularly on large nanostructured surfaces relevant to photocatalysis, energy harvesting, sensing, imaging, and the development of future photonic devices.

Versatile Multi-Wavelength Light-Responsive Metal-Organic Frameworks Micromotor through Porphyrin Metalation for Water Sterilization.

Traditional metal-organic frameworks (MOFs) based micro/nanomotors (MOFtors) can achieve three-dimensional (3D) motion mainly depending on noble metal (e.g., Pt), toxic fuels (e.g., hydrogen peroxide), and surfactants, or under external magnetic fields. In this study, light-driven MOFtors are constructed based on PCN-224(H) and regulated their photothermal and photochemical properties responding to the light of different wavelengths through porphyrin metalation. The resulting PCN-224(Fe) MOFtors presented a strong 3D motion at a maximum speed of 1234.9 ± 367.5 µm s-1 under visible light due to the various gradient fields by the photothermal and photochemical effects. Such MOFtors exhibit excellent water sterilization performance. Under optimal conditions, the PCN-224(Cu) MOFtors presented the best antibacterial performance of 99.4%, which improved by 23.4% compared to its static counterpart and 43.7% compared to static PCN-224(H). The underlying mechanism demonstrates that metal doping could increase the production of reactive oxygen species (ROS) and result in a more positive surface charge under light, which are short-distance effective sterilizing ingredients. Furthermore, the motion of MOFtors appears very important to extend the short-distance effective sterilization and thus synergistically improve the antibacterial performance. This work provides a new idea for preparing and developing light-driven MOFtors with multi-responsive properties.

Light-Induced Material Motion Fingerprint - A Tool Toward Selective Interfacial Sensitive Fractioning of Microparticles via Microfluidic Methods.

In this article, a novel strategy is presented to selectively separate a mixture of equally sized microparticles but differences in material composition and surface properties. The principle relies on a photosensitive surfactant, which makes particles under light illumination phoretically active. The latter hovers microparticles from a planar interface and together with a superimposed fluid flow, particles experience a drift motion characteristic to its interfacial properties. The drift motion is investigated as a function of applied wavelength, demonstrating that particles composed of different material show a unique spectrally resolved light-induced motion profile. Differences in those motion profile allow a selective fractioning of a desired particle from a complex particle mixture made out of more than two equally sized different particle types. Besides that, the influence of applied wavelength is systematically studied, and discussed the origin of the spectrally resolved chemical activity of microparticles from measured photo-isomerization rates.

Single Atom Ag Bonding Between PF3T Nanocluster and TiO2 Leads the Ultra-Stable Visible-Light-Driven Photocatalytic H2 Production.

Atomic Ag cluster bonding is employed to reinforce the interface between PF3T nano-cluster and TiO2 nanoparticle. With an optimized Ag loading (Ag/TiO2 = 0.5 wt%), the Ag atoms will uniformly disperse on TiO2 thus generating a high density of intermediate states in the band gap to form the electron channel between the terthiophene group of PF3T and the TiO2 in the hybrid composite (denoted as T@Ag05-P). The former expands the photon absorption band width and the latter facilitates the core-hole splitting by injecting the photon excited electron (from the excitons in PF3T) into the conduction band (CB) of TiO2. These characteristics enable the high efficiency of H2 production to 16 580 µmol h-1 g-1 and photocatalysis stability without degradation under visible light exposure for 96 h. Compared to that of hybrid material without Ag bonding (TiO2@PF3T), the H2 production yield and stability are improved by 4.1 and 18.2-fold which shows the best performance among existing materials in similar component combination and interfacial reinforcement. The unique bonding method offers a new prospect to accelerate the development of photocatalytic hydrogen production technologies.

Enlighting Electron Routes In Oxyfunctionalizing Synechocystis sp. PCC 6803.

Phototrophic microorganisms, like cyanobacteria, are gaining attention as host organisms for biocatalytic processes with light as energy source and water as electron source. Redox enzymes, especially oxygenases, can profit from in-situ supply of co-substrates, i. e., reduction equivalents and O2 , by the photosynthetic light reaction. The electron transfer downstream of PS I to heterologous electron consuming enzymes in principle can involve NADPH, NADH, and/or ferredoxin, whereas most direct and efficient transfer is desirable. Here, we use the model organism Synechocystis sp. PCC 6803 to investigate, to what extent host and/or heterologous constituents are involved in electron transfer to a heterologous cytochrome P450 monooxygenase from Acidovorax sp. CHX100. Interestingly, in this highly active light-fueled cycloalkane hydroxylating biocatalyst, host-intrinsic enzymes were found capable of completely substituting the function of the Acidovorax ferredoxin reductase. To a certain extent (20 %), this also was true for the Acidovorax ferredoxin. These results indicate the presence of a versatile set of electron carriers in cyanobacteria, enabling efficient and direct coupling of electron consuming reactions to photosynthetic water oxidation. This will both simplify and promote the use of phototrophic microorganisms for sustainable production processes.

Poly(dehydroalanine)-Based Hydrogels as Efficient Soft Matter Matrices for Light-Driven Catalysis.

Soft matter integration of photosensitizers and catalysts provides promising solutions to developing sustainable materials for energy conversion. Particularly, hydrogels bring unique benefits, such as spatial control and 3D-accessibility of molecular units, as well as recyclability. Herein, the preparation of polyampholyte hydrogels based on poly(dehydroalanine) (PDha) is reported. Chemically crosslinked PDha with bis-epoxy poly(ethylene glycol) leads to a transparent, self-supporting hydrogel. Due to the ionizable groups on PDha, this 3D polymeric matrix can be anionic, cationic, or zwitterionic depending on the pH value, and its high density of dynamic charges has a potential for electrostatic attachment of charged molecules. The integration of the cationic molecular photosensitizer [Ru(bpy)3 ]2+ (bpy = 2,2'-bipyridine) is realized, which is a reversible process controlled by pH, leading to light harvesting hydrogels. They are further combined with either a thiomolybdate catalyst ([Mo3 S13 ]2- ) for hydrogen evolution reaction (HER) or a cobalt polyoxometalate catalyst (Co4 POM = [Co4 (H2 O)2 (PW9 O34 )2 ]10- ) for oxygen evolution reaction (OER). Under the optimized condition, the resulting hydrogels show catalytic activity in both cases upon visible light irradiation. In the case of OER, higher photosensitizer stability is observed compared to homogeneous systems, as the polymer environment seems to influence decomposition pathways.

Synergistic regulation of nonbinary molecular switches by protonation and light.

We report a molecular switching ensemble whose states may be regulated in synergistic fashion by both protonation and photoirradiation. This allows hierarchical control in both a kinetic and thermodynamic sense. These pseudorotaxane-based molecular devices exploit the so-called Texas-sized molecular box (cyclo[2]-(2,6-di(1H-imidazol-1-yl)pyridine)[2](1,4-dimethylenebenzene); 14+, studied as its tetrakis-PF6- salt) as the wheel component. Anions of azobenzene-4,4'-dicarboxylic acid (2H+•2) or 4,4'-stilbenedicarboxylic acid (2H+•3) serve as the threading rod elements. The various forms of 2 and 3 (neutral, monoprotonated, and diprotonated) interact differently with 14+, as do the photoinduced cis or trans forms of these classic photoactive guests. The net result is a multimodal molecular switch that can be regulated in synergistic fashion through protonation/deprotonation and photoirradiation. The degree of guest protonation is the dominating control factor, with light acting as a secondary regulatory stimulus. The present dual input strategy provides a complement to more traditional orthogonal stimulus-based approaches to molecular switching and allows for the creation of nonbinary stimulus-responsive functional materials.

Bioinspired micro/nanomotor with visible light energy-dependent forward, reverse, reciprocating, and spinning schooling motion.

In nature, microorganisms could sense the intensity of the incident visible light and exhibit bidirectional (positive or negative) phototaxis. However, it is still challenging to achieve the similar biomimetic phototaxis for the artificial micro/nanomotor (MNM) counterparts with the size from a few nanometers to a few micrometers. In this work, we report a fuel-free carbon nitride (C3N4)/polypyrrole nanoparticle (PPyNP)-based smart MNM operating in water, whose behavior resembles that of the phototactic microorganism. The MNM moves toward the visible light source under low illumination and away from it under high irradiation, which relies on the competitive interplay between the light-induced self-diffusiophoresis and self-thermophoresis mechanisms concurrently integrated into the MNM. Interestingly, the competition between these two mechanisms leads to a collective bidirectional phototaxis of an ensemble of MNMs under uniform illuminations and a spinning schooling behavior under a nonuniform light, both of which can be finely controllable by visible light energy. Our results provide important insights into the design of the artificial counterpart of the phototactic microorganism with sophisticated motion behaviors for diverse applications.

Early-stage dynamics of chloride ion-pumping rhodopsin revealed by a femtosecond X-ray laser.

Chloride ion-pumping rhodopsin (ClR) in some marine bacteria utilizes light energy to actively transport Cl- into cells. How the ClR initiates the transport is elusive. Here, we show the dynamics of ion transport observed with time-resolved serial femtosecond (fs) crystallography using the Linac Coherent Light Source. X-ray pulses captured structural changes in ClR upon flash illumination with a 550 nm fs-pumping laser. High-resolution structures for five time points (dark to 100 ps after flashing) reveal complex and coordinated dynamics comprising retinal isomerization, water molecule rearrangement, and conformational changes of various residues. Combining data from time-resolved spectroscopy experiments and molecular dynamics simulations, this study reveals that the chloride ion close to the Schiff base undergoes a dissociation-diffusion process upon light-triggered retinal isomerization.

Light-driven rGO/Cu2 + 1O tubular nanomotor with active targeted drug delivery for combination treatment of cancer cells.

The unprecedented navigation ability in micro/nanoscale and tailored functionality tunes micro/nanomotors as new target drug delivery systems, open up new horizons for biomedical applications. Herein, we designed a light-driven rGO/Cu2 + 1O tubular nanomotor for active targeting of cancer cells as a drug delivery system. The propulsion performance is greatly enhanced in real cell media (5% glucose cells isotonic solution), attributing to the introduction of oxygen vacancy and reduced graphene oxide (rGO) layer for separating photo-induced electron-hole pairs. The motion speed and direction can be readily modulated. Meanwhile, doxorubicin (DOX) can be loaded quickly on the rGO layer because of π-π bonding effect. The Cu2 + 1O matrix in the tiny robots not only serves as a photocatalyst to generate a chemical concentration gradient as the driving force but also acts as a nanomedicine to kill cancer cells as well. The strong propulsion of light-driven rGO/Cu2 + 1O nanomotors coupled with tiny size endow them with active transmembrane transport, assisting DOX and Cu2 + 1O breaking through the barrier of the cell membrane. Compared with non-powered nanocarrier and free DOX, light-propelled rGO/Cu2 + 1O nanomotors exhibit greater transmembrane transport efficiency and significant therapeutic efficacy. This proof-of-concept nanomotor design presents an innovative approach against tumor, enlarging the list of biomedical applications of light-driven micro/nanomotors to the superficial tissue treatment.

Bi2WO6/TiO2-based visible light-driven photoelectrochemical enzyme biosensor for glucose measurement.

Nowadays, the frequent occurrence of food adulteration makes glucose detection particularly important in food safety and quality management. The quality and taste of honey are closely related to the glucose content. However, due to the drawbacks of expensive equipment, complex operating procedures, and time-consuming processes, the application scope of traditional glucose detection methods is limited. Hence, this study developed a photoelectric chemical (PEC) sensor, which is composed of a photoactive material of bismuth tungstate (Bi2WO6) with titanium dioxide (TiO2) and glucose oxidase (GOD), for simple and rapid detection of glucose. Notably, the composites' absorption prominently increased in the visible light region, and the photo-generated electron-hole pairs were efficiently separated by virtue of the unique nanostructure system, thus playing a crucial role in facilitating PEC activity. In the presence of dissolved oxygen, the photocurrent intensity was enhanced by H2O2 generated from glucose under electro-oxidation specifically catalyzed by GOD fixed on the modified electrode. When the working potential was 0.3 V, the changes of photocurrent response indicated that the PEC enzyme biosensor provides a low detection limit (3.8 µM), and a wide linear range (0.008-8 mM). This method has better selectivity in honey samples and broad application prospects in clinical diagnosis for future.

Recent Advances in Light-Driven Semiconductor-Based Micro/Nanomotors: Optimization Strategies and Emerging Applications.

Micro/nanomotors represent a burgeoning field of research featuring small devices capable of autonomous movement in liquid environments through catalytic reactions and/or external stimuli. This review delves into recent advancements in light-driven semiconductor-based micro/nanomotors (LDSM), focusing on optimized syntheses, enhanced motion mechanisms, and emerging applications in the environmental and biomedical domains. The survey commences with a theoretical introduction to micromotors and their propulsion mechanisms, followed by an exploration of commonly studied LDSM, emphasizing their advantages. Critical properties affecting propulsion, such as surface features, morphology, and size, are presented alongside discussions on external conditions related to light sources and intensity, which are crucial for optimizing the propulsion speed. Each property is accompanied by a theoretical background and conclusions drawn up to 2018. The review further investigates recent adaptations of LDSM, uncovering underlying mechanisms and associated benefits. A brief discussion is included on potential synergistic effects between different external conditions, aiming to enhance efficiency-a relatively underexplored topic. In conclusion, the review outlines emerging applications in biomedicine and environmental monitoring/remediation resulting from recent LDSM research, highlighting the growing significance of this field. The comprehensive exploration of LDSM advancements provides valuable insights for researchers and practitioners seeking to leverage these innovative micro/nanomotors in diverse applications.

Zn-Doped MnCO3/CS Composite Photocatalyst for Visible-Light-Driven Decomposition of Organic Pollutants.

Zn-doped MnCO3/carbon sphere (Zn-doped MnCO3/CS) composites were synthesized using a simple hydrothermal procedure. Among various samples (ZM-50, ZM-05, and ZMC-0), the ternary Zn-doped MnCO3/CS (ZMC-2) catalyst demonstrated excellent visible light-induced photocatalytic activity. This improvement comes from the Zn addition and the conductive CS, which facilitate electron movement and charge transport. The catalyst exhibited efficient degradation of methylene blue (MB) over a wide pH range, achieving a removal efficiency of 99.6% under visible light. Radical trapping experiments suggested that •OH and •O2- played essential roles in the mechanism of organic pollutant degradation. Moreover, the catalyst maintained good degradation performance after five cycles. This study offers valuable perspectives into the fabrication of carbon-based composites with promising photocatalytic activity.

Functionalized Linear Conjugated Polymer/TiO2 Heterojunctions for Significantly Enhancing Photocatalytic H2 Evolution.

Conjugated polymers (CPs) have attracted much attention in recent years due to their structural abundance and tunable energy bands. Compared with CP-based materials, the inorganic semiconductor TiO2 has the advantages of low cost, non-toxicity and high photocatalytic hydrogen production (PHP) performance. However, studies on polymeric-inorganic heterojunctions, composed of D-A type CPs and TiO2, for boosting the PHP efficiency are still rare. Herein, an elucidation that the photocatalytic hydrogen evolution activity can actually be improved by forming polymeric-inorganic heterojunctions TFl@TiO2, TS@TiO2 and TSO2@TiO2, facilely synthesized through efficient in situ direct C-H arylation polymerization, is given. The compatible energy levels between virgin TiO2 and polymeric semiconductors enable the resulting functionalized CP@TiO2 heterojunctions to exhibit a considerable photocatalytic hydrogen evolution rate (HER). Especially, the HER of TSO2@TiO2 heterojunction reaches up to 11,220 µmol g-1 h-1, approximately 5.47 and 1260 times higher than that of pristine TSO2 and TiO2 photocatalysts. The intrinsic merits of a donor-acceptor conjugated polymer and the interfacial interaction between CP and TiO2 account for the excellent PHP activity, facilitating the separation of photo-generated excitons. Considering the outstanding PHP behavior, our work discloses that the coupling of inorganic semiconductors and suitable D-A conjugated CPs would play significant roles in the photocatalysis community.

Bidirectional Regulation of Intracellular Enzyme Activity Using Light-Driven Nano-Inhibitors.

Photochemical regulation provides precise control over enzyme activities with high spatiotemporal resolution. A promising approach involves anchoring "photoswitches" at enzyme active sites to modulate substrate recognition. However, current methods often require genetic mutations and irreversible enzyme modifications for the site-specific anchoring of "photoswitches", potentially compromising the enzyme activities. Herein, we present a pioneering reversible nano-inhibitor based on molecular imprinting technique for bidirectional regulation of intracellular enzyme activity. The nano-inhibitor employs a molecularly imprinted polymer nanoparticle as its body and azobenzene-modified inhibitors ("photoswitches") as the arms. By using a target enzyme as the molecular template, the nano-inhibitor acquires oriented binding sites on its surface, resulting in a high affinity for the target enzyme and non-covalently firm anchoring of the azobenzene-modified inhibitor to the enzyme active site. Harnessing the reversible isomerization of azobenzene units upon exposure to ultraviolet and visible light, the nano-inhibitor achieves bidirectional enzyme activity regulation by precisely docking and undocking inhibitor at the active site. Notably, this innovative approach enables the facile in situ regulation of intracellular endogenous enzymes, such as carbonic anhydrase. Our results represent a practical and versatile tool for precise enzyme activity regulation in complex intracellular environments.

The circadian clock is required for rhythmic lipid transport in Drosophila in interaction with diet and photic condition.

Modern lifestyle is often at odds with endogenously driven rhythmicity, which can lead to circadian disruption and metabolic syndrome. One signature for circadian disruption is a reduced or altered metabolite cycling in the circulating tissue reflecting the current metabolic status. Drosophila is a well-established model in chronobiology, but day-time dependent variations of transport metabolites in the fly circulation are poorly characterized. Here, we sampled fly hemolymph throughout the day and analyzed diacylglycerols (DGs), phosphoethanolamines (PEs) and phosphocholines (PCs) using LC-MS. In wild-type flies kept on sugar-only medium under a light-dark cycle, all transport lipid species showed a synchronized bimodal oscillation pattern with maxima at the beginning and end of the light phase which were impaired in period01 clock mutants. In wild-type flies under constant dark conditions, the oscillation became monophasic with a maximum in the middle of the subjective day. In strong support of clock-driven oscillations, levels of the targeted lipids peaked once in the middle of the light phase under time-restricted feeding independent of the time of food intake. When wild-type flies were reared on full standard medium, the rhythmic alterations of hemolymph lipid levels were greatly attenuated. Our data suggest that the circadian clock aligns daily oscillations of DGs, PEs, and PCs in the hemolymph to the anabolic siesta phase, with a strong influence of light on phase and modality.

Light-Driven Spatiotemporal Pickering Emulsion Droplet Manipulation Enabled by Plasmonic Hybrid Microgels.

The past decades have witnessed the development of various stimuli-responsive materials with tailored functionalities, enabling droplet manipulation through external force fields. Among different strategies, light exhibits excellent flexibility for contactless control of droplets, particularly in three-dimensional space. Here, we present a facile synthesis of plasmonic hybrid microgels based on the electrostatic heterocoagulation between cationic microgels and anionic Au nanoparticles. The hybrid microgels are effective stabilizers of oil-in-water Pickering emulsions. In addition, the laser irradiation on Au nanoparticles creats a "cascade effect" to thermally responsive microgels, which triggers a change in microgel wettability, resulting in microgel desorption and emulsion destabilization. More importantly, the localized heating generated by a focused laser induces the generation of a vapor bubble inside oil droplets, leading to the formation of a novel air-in-oil-in-water (A/O/W) emulsion. These A/O/W droplets are able to mimic natural microswimmers in an aqueous environment by tracking the motion of a laser spot, thus achieving on-demand droplet merging and chemical communication between isolated droplets. Such proposed systems are expected to extend the applications of microgel-stabilized Pickering emulsions for substance transport, programmed release and controlled catalytic reactions.

Unique Visualization Growth Process of Long-Lived Room Temperature Phosphorescence in Polymer System.

Recently, embedding organic phosphors into the polyvinyl alcohol (PVA) matrix has emerged as a convenient strategy to obtain efficient long-lived room temperature phosphorescence (RTP) via forming strong intermolecular hydrogen bonds with organic phosphors to minimize nonradiative relaxations. Regrettably, it is discovered that PVA is unable to trigger RTP emission when a novel functional phosphor THBE containing six extended biphenyl formaldehyde arms is doped into PVA matrix. Surprisingly, the excellent long-lived RTP emission can be easily obtained by doping THBE into PVA analogs, poly(vinyl alcohol-co-ethylene) (PVA-co-PE). The unique visualization growth process (i.e., white streak generation) of long-lived RTP is observed by UV light-driven aggregation of functional molecules THBE in PVA-co-PE matrix. The phosphorescent intensity of the luminescent film is enhanced by 55 times, from 729 to 40,785 a.u., and its phosphorescence lifetime is increased by 38 times, from 37.08 to 1415.41 ms. Due to the dynamically reversible RTP performance, as well as the permeability, flexibility, and wrinkle-free properties of the luminescent film, it can be utilized to create cutting-edge information storage devices.

Electron Injection via Interfacial Atomic Au Clusters Substantially Enhance the Visible-Light-Driven Photocatalytic H2 Production of the PF3T Enclosed TiO2 Nanocomposite.

A hybrid composite of organic-inorganic semiconductor nanomaterials with atomic Au clusters at the interface decoration (denoted as PF3T@Au-TiO2 ) is developed for visible-light-driven H2 production via direct water splitting. With a strong electron coupling between the terthiophene groups, Au atoms and the oxygen atoms at the heterogeneous interface, significant electron injection from the PF3T to TiO2 occurs leading to a quantum leap in the H2 production yield (18 578 µmol g-1 h-1 ) by ≈39% as compared to that of the composite without Au decoration (PF3T@TiO2 , 11 321 µmol g-1 h-1 ). Compared to the pure PF3T, such a result is 43-fold improved and is the best performance among all the existing hybrid materials in similar configurations. With robust process control via industrially applicable methods, it is anticipated that the findings and proposed methodologies can accelerate the development of high-performance eco-friendly photocatalytic hydrogen production technologies.

Synthetic Light-Driven Consortia for Carbon-Negative Biosynthesis.

Synthetic light-driven consortia composed of phototrophs and heterotrophs have attracted increasing attention owing to their potential to be used in sustainable biotechnology. In recent years, synthetic phototrophic consortia have been used to produce bulk chemicals, biofuels, and other valuable bioproducts. In addition, autotrophic-heterotrophic symbiosis systems have potential applications in wastewater treatment, bioremediation, and as a method for phytoplankton bloom control. Here, we discuss progress made on the biosynthesis of phototrophic microbial consortia. In addition, strategies for optimizing the synthetic light-driven consortia are summarized. Moreover, we highlight current challenges and future research directions for the development of robust and controllable synthetic light-driven consortia.