Defect-Mediated Energy Transfer Mechanism by Modulating Lattice Occupancy of Alkali Ions for the Optimization of Upconversion Luminescence.

The performance optimization of photoluminescent (PL) materials is a hot topic in the field of applied materials research. There are many different crystal defects in photoluminescent materials, which can have a significant impact on their optical properties. The luminescent properties and chemical stability of materials can be effectively improved by adjusting lattice defects in crystals.

Combined effect of polystyrene nanoparticles and chlorpyrifos to Daphnia magna.

Microplastics and nanoplastics (MPs/NPs) are emerging contaminants ubiquitous in the environment. These particles can act as carriers of hydrophobic organic compounds (HOCs), such as chlorpyrifos (CPF), an organophosphorus insecticide. This study investigates the acute toxicity of CPF combined with model polystyrene nanoplastics (PS-NPs) using Daphnia magna as a model organism.

Cyclometalated -Difluoromethylbenzimidazolylidene Platinum(II) Complexes with Built-in Secondary Coordination Spheres: Photophysical Properties and Bioimaging.

Bidentate Pt(II) complexes with cyclometalated -heteroarene or -heterocyclic carbene (NHC) ligands have been extensively studied as phosphorescent emitters over the past two decades. Herein, we introduce a difluoromethyl group (CFH) into the wingtip of NHCs, where CFH acts as a lipophilic hydrogen bond (HB) donor. Their cyclometalated Pt(II) complexes show excellent PLQYs (up to 93%) and phosphorescence lifetimes mainly due to the rigid structure with hydrogen bonding between the CFH group and the adjacent O atom at the β-diketonate ligand.

Light-Quality-Adapted Carotenoid Photoprotection in the Photosystem of .

The photosystem of filamentous anoxygenic phototroph (.) comprises a light-harvesting (LH) complex encircling a reaction center (RC), which intensely absorbs blue-green light by carotenoid (Car) and near-infrared light by bacteriochlorophyll (BChl). To explore the influence of light quality (color) on the photosynthetic activity, we compared the pigment compositions and triplet excitation dynamics of the LH-RCs from .

Stimulus-Responsive Hydrogels as Drug Delivery Systems for Inflammation Targeted Therapy.

Deregulated inflammations induced by various factors are one of the most common diseases in people's daily life, while severe inflammation can even lead to death. Thus, the efficient treatment of inflammation has always been the hot topic in the research of medicine. In the past decades, as a potential biomaterial, stimuli-responsive hydrogels have been a focus of attention for the inflammation treatment due to their excellent biocompatibility and design flexibility.

Daphnia magna uptake and excretion of luminescence-labelled polystyrene nanoparticle as visualized by high sensitivity real-time optical imaging.

The environmental and ecological consequences of nanoplastics (NPs) draw increasing research interests and social concerns. However, the in situ and real-time detection of NPs from living organisms and transferring media remains as a major technical obstacle for scientific investigation. Herein we report a novel time-gated imaging (TGI) strategy capable of real-time visualizing the intake of NPs by an individual living organism, which is based on the polystyrene NPs labelled with lanthanide up-conversion luminescence.

as a model to study the ecotoxicity of 1-alkyl-3-methylimidazolium bromide.

The purple non-sulfur bacterium was selected as a biological model to investigate its response to the toxicity of 1-alkyl-3-methylimidazolium bromide ([Cmim]Br), a type of ionic liquid (IL), with different alkyl chain lengths ( describes the number of carbon atoms in the alkyl chain). The inhibition of bacterial growth by [Cmim]Br was positively correlated with . Morphological characterization revealed that [Cmim]Br caused cell membrane perforation.

Photoinduced chlorophyll charge transfer state identified in the light-harvesting complex II from a marine green alga .

The light-harvesting complex II of (-LHCII), a green alga, differs from that of spinach (-LHCII) in chlorophyll (Chl) and carotenoid (Car) compositions. We investigated ultrafast excitation dynamics of -LHCII with visible-to-near infrared time-resolved absorption spectroscopy. Absolute fluorescence quantum yield ( ) of LHCII and spectroelectrochemical (SEC) spectra of Chl and were measured to assist the spectral analysis.

A Possible Mechanism for Aggregation-Induced Chlorophyll Fluorescence Quenching in Light-Harvesting Complex II from the Marine Green Alga .

The light-harvesting complex II of a green alga (-LHCII) is peculiar in that it contains siphonein and siphonaxathin as carotenoid (Car). Since the S state of siphonein and siphonaxathin lies substantially higher than the Q state of chlorophyll (Chl ), the Chl (Q)-to-Car(S) excitation energy transfer is unfeasible. To understand the photoprotective mechanism of algal photosynthesis, we investigated the influence of temperature on the excitation dynamics of -LHCII in trimeric and aggregated forms.

Promotion effects of flavonoids on browning induced by enzymatic oxidation of tyrosinase: structure-activity relationship.

Tyrosinase, widely distributed in nature, is a copper-containing polyphenol oxidase involved in the formation of melanin. Flavonoids are most often considered as tyrosinase inhibitors but have also been confirmed to be tyrosinase substrates. Four structure-related flavonoids including flavones (apigenin and luteolin) and flavonols (kaempferol and quercetin) are found to promote not inhibit browning induced by tyrosinase catalyzed oxidation both in model systems and in mushrooms under aerobic conditions.

Inflammation-Triggered Supramolecular Nanoplatform for Local Dynamic Dependent Imaging-Guided Therapy of Rheumatoid Arthritis.

The aging of population has resulted in a significant increase in the prevalence of rheumatoid arthritis (RA), which is a persistent and recurrent synovial inflammation caused by abnormal immune activation. Herein, the authors designed an inflammation-triggered disassembly (ITD) nanoplatform by a supramolecular assembly method, which controls the decomposition and drug release through changes in cytokine concentrations and redox potentials during the onset of arthritis, and its dual-targeted synergistic effect on collagen-induced arthritis (CIA) rats resulted in higher cell death rate and immunosuppressive rate. Meanwhile, they propose the local dynamic dependent imaging (LDDI) technology to diagnose the disease status, which may produce corresponding changes with the fluctuation of inflammatory activity and improve the accuracy of dual-target therapy by monitoring the synovial changes through in situ photoactivation of the second near infrared light (NIR-II).

Spatial effects of photosensitization on morphology of giant unilamellar vesicles.

Singlet oxygen (O) formed through photosensitization may initiate oxidative destruction of biomembranes, however, the influence from the spatial organization of photosensitizers (PS) relative to membranes remains unclear. To clarify this issue, we loaded riboflavin 5'-(dihydrogen phosphate) monosodium (FMN-Na) as a hydrophilic PS into the lumen of halloysite nanotubes (HNTs), and attached the nanoassemblies (FMN-Na@HNTs), via Pickering effects, to the outer surfaces of giant unilamellar vesicles (GUVs) of phospholipids. We also prepared GUVs dopped with lumiflavin (LF) as a lipophilic PS having a O quantum yield comparable to FMN-Na.

Electrochemiluminescence Based on a Dual Carbon Ultramicroelectrode with Confined Steady-State Annihilation.

Developing novel microelectronic devices for electrochemical measurements and electrochemiluminescence (ECL) study is of great importance. Herein, we fabricated a submicrometer-sized dual carbon electrode (DCE) and investigated its annihilation ECL behavior under steady-state conditions for the first time. The oxidation and reduction of the model luminophore, [Ru(bpy)], occurred separately at the two sides of the DCE, and the electrogenerated ions then diffused to the gap between the two electrodes to generate the excited-state intermediate [Ru(bpy)] and ECL emission.

A Spontaneous Membrane-Adsorption Approach to Enhancing Second Near-Infrared Deep-Imaging-Guided Intracranial Tumor Therapy.

Herein, a functional class of microenvironment-associated nanomaterials is reported for improving the second near-infrared (NIR-II) imaging and photothermal therapeutic effect on intracranial tumors via a spontaneous membrane-adsorption approach. Specific peptides, photothermal agents, and biological alkylating agents were designed to endow the nanogels with high targeting specificity, photothermal properties, and pharmacological effects. Importantly, the frozen scanning electron microscopy technology (cryo-SEM) was utilized to observe the self-association of nanomaterials on tumor cells.

Microenvironment-Triggered Degradable Hydrogel for Imaging Diagnosis and Combined Treatment of Intraocular Choroidal Melanoma.

Human choroidal melanoma (HCM) is one of the most common primary intraocular tumors and easily provokes liver metastases owing to the lack of sensitive and noninvasive therapeutic methods. Concerning the imaging diagnostics and therapeutic predicaments for choroidal melanoma, we designed microenvironment-triggered degradable hydrogels (RENP-ICG@PNIPAM:Dox-FA) based on ultrasmall (<5 nm) rare-earth nanoparticles (RENPs) with enhanced NIR-II luminescence. The ultrasmall diameter can significantly enhance the NIR-II luminescence performance of RENPs.

Concentration-regulated photon upconversion and quenching in NaYF:Yb,Er nanocrystals: nonexponentiality revisited.

Concentration quenching of rare-earth doped upconversion nanoparticles severely limits the dopant concentration, and this greatly hinders their potential applications. Therefore, it is necessary to understand the roles of dopant concentration in photon population and luminescence quenching for materials designed with improved upconversion luminescence (UCL). Herein, the excited-state dynamics of well-accepted NaYF4:Yb3+,Er3+ nanocrystals were investigated as models based on the Kohlrausch-function.

Naturally occurring nanotube with surface modification as biocompatible, target-specific nanocarrier for cancer phototherapy.

Phototherapy has drawn increasing attention including the use of nanocarriers with high drug loading capacity and delivery efficacy for target-specific therapy. We have made use of naturally-occurring halloysite nanotubes (HNTs) to build a biomimetic nanocarrier platform for target-specific delivery of phototherapeutic agents. The HNTs were decorated with poly(sodium-p-styrenesulfonate) (PSS) to enhance the biocompatibility, and were further functionalized by lumen loading the type-II photosensitizer indocyanine green (ICG).

Energy transfer mechanism dominated by the doping location of activators in rare-earth upconversion nanoparticles.

Research on the energy transfer mechanism of rare-earth-doped upconversion nanoparticles (UCNPs) has been an important area due to the increasing demand for tuning multicolor emission and enhancing the upconversion efficiency; however, because of large energy mismatch, many lanthanide activators, such as Eu3+, cannot realize highly efficient near infrared-to-visible upconversion by simple codoping of Yb3+. Therefore, introduction of other ions to assist the energy transfer process is required. Herein, we prepared core-shell nanoparticles with different doping locations to investigate the upconversion energy transfer mechanism.