Insight from Boric Acid into Bioskeleton Formation: Inscribed Circle Effect on the Edge-Base Plate Growth.

Complex morphologies in nature often arise from the assembly of elemental building blocks, leading to diverse and intricate structures. Understanding the mechanisms that govern the formation of these complex morphologies remains a significant challenge. In particular, the edge-base plate growth of biogenic crystals plays a crucial role in directing the development of intricate bioskeleton morphologies. However, the factors and regulatory processes that govern edge-base plate growth remain insufficiently understood. Inspired by biological skeletons and based on the soluble property of boric acid (BA) in both water and alcohols, we obtained a series of novel BA morphologies, including coccolith, and anemone biological skeletons. Here, we unveil the "inscribed circle effect", a concise mathematical model that reveals the underlying causative factors and regulatory mechanisms driving edge-base plate growth. Our findings illuminate how variations in solvent environments can exert control over the edge-base plate growth pathways, thereby resulting in the formation of diverse and complex morphologies. This understanding holds significant potential for guiding the chemical synthesis of bioskeleton materials.

Different-grain-sized boehmite nanoparticles for stable all-solid-state lithium metal batteries.

PEO is one of the common composite polymer electrolyte vehicles; however, the presence of crystalline phase at room temperature, high interface impedance, and low oxidation resistance (<4.0 V) limit its application in stable all-solid-state lithium metal batteries. Herein, we designed a PEO-based solid polymer electrolyte (SPE) by adding boehmite nanoparticles to address the above-mentioned issues. Different-grain-sized boehmite nanoparticles were synthesized by adjusting the hydrothermal temperature. Moreover, the impacts of these distinct grain-sized boehmite nanoparticles used to fabricate boehmite/PEO polymer electrolytes (BPEs) on the performance of all-solid-state lithium metal batteries were investigated. It was found that with the increase in boehmite's grain size, BPEs show better performance. The best BPE exhibited an improved Li+ transference number (0.59), high ionic conductivity (1.25 × 10-4 S m-1), and wide electrochemical window (∼4.5 V) at 60 °C. The assembled lithium symmetric battery can stably undergo 500 hours of lithium plating/stripping at 0.1 mA cm-2. At the same time, the LiFePO4/BPE/Li battery exhibits excellent cycling stability after 100 cycles at 0.5C. This reasonable design strategy with a superior capacity retention rate (86%) demonstrates great potential in achieving high ionic conductivity and good interface stability for all-solid-state lithium metal batteries simultaneously.

Polarity-dominated chitosan biguanide hydrochloride-based nanofibrous membrane with antibacterial activity for long-lasting air filtration.

Facemasks play a significant role as personal protective equipment during the COVID-19 pandemic, but their longevity is limited by the easy dissipation of electrostatic charge and the accumulation of bacteria. In this study, nanofibrous membranes composed of polyacrylonitrile and chitosan biguanide hydrochloride (PAN@CGH) with remarkable antibacterial characteristics were prepared through the coaxial electrospinning process. Particulate matter could be efficiently captured by the fibrous membrane, up to 98 % or more, via polarity-dominated forces derived from cyano and amino groups. As compared commercial N95 masks, the PAN@CGH was more resistant to a wider variety of disinfection protocols. Additionally, the nanofibrous membrane could kill >99.99 % of both Escherichia coli and Staphylococcus aureus. Based on these characteristics, PAN@CGH nanofibrous membrane was applied to facial mask, which possessed an excellent and long-lasting effect on the capture of airborne particles. This work may be one of the most promising strategies on designing high-performance face masks for public health protection.

Near-Infrared Light-Responsive Multifunctional Photothermal/Photodynamic Titanium Diboride Nanocomposites for the Treatment of Antibiotic-Resistant Bacterial Infections.

Diseases caused by bacterial infection have resulted in serious harm to human health. It is crucial to develop a multifunctional antibiotic-independent antibacterial platform for combating drug-resistant bacteria. Herein, titanium diboride (TiB2) nanosheets integrated with quaternized chitosan (QCS) and indocyanine green (ICG) were successfully prepared as a synergetic photothermal/photodynamic antibacterial nanoplatform (TiB2-QCS-ICG). The TiB2-QCS-ICG nanocomposites exhibit effective photothermal conversion efficiency (24.92%) and excellent singlet oxygen (1O2) production capacity simultaneously under 808 nm near-infrared irradiation. QCS improved TiB2 stability and dispersion, while also enhancing adhesion to bacteria and further accelerating the destruction of bacteria by heat and 1O2. In vitro experiments indicated that TiB2-QCS-ICG had excellent antibacterial properties with an inhibition rate of 99.99% against Escherichia coli (E. coli) and methicillin-resistant Staphylococcus aureus (MRSA), respectively. More importantly, in vivo studies revealed that the nanoplatform can effectively inhibit bacterial infection and accelerate wound healing. The effective wound healing rate in the TiB2-QCS-ICG treatment group was 99.6% which was much higher than control groups. Taken together, the as-developed TiB2-QCS-ICG nanocomposite provides more possibilities to develop metal borides for antibacterial infection applications.

Copper-Single-Atom Coordinated Nanotherapeutics for Enhanced Sonothermal-Parallel Catalytic Synergistic Cancer Therapy.

Phototherapy and sonotherapy are recognized by scientific medicine as effective strategies for treating certain cancers. However, these strategies have limitations such as an inability to penetrate deeper tissues and overcome the antioxidant tumor microenvironment. In this study, a novel "BH" interfacial-confined coordination strategy to synthesize hyaluronic acid-functionalized single copper atoms dispersed over boron imidazolate framework-derived nanocubes (HA-NC_Cu) to achieve sonothermal-catalytic synergistic therapy is reported. Notably, HA-NC_Cu demonstrates exceptional sonothermal conversion performance under low-intensity ultrasound irradiation, attained through intermolecular lattice vibrations. In addition, it shows promise as an efficient biocatalyst, able to generate high-toxicity hydroxyl radicals in response to tumor-endogenous hydrogen peroxide and glutathione. Density functional theory calculations reveal that the superior parallel catalytic performance of HA-NC_Cu originates from the CuN4 C/B active sites. Both in vitro and in vivo evaluations consistently demonstrate that the sonothermal-catalytic synergistic strategy significantly improves tumor inhibition rate (86.9%) and long-term survival rate (100%). In combination with low-intensity ultrasound irradiation, HA-NC_Cu triggers a dual death pathway of apoptosis and ferroptosis in MDA-MB-231 breast cancer cells, comprehensively limiting primary triple-negative breast cancer. This study highlights the applications of single-atom-coordinated nanotherapeutics in sonothermal-catalytic synergistic therapy, which may create new opportunities in biomedical research.

Highly efficient metal-free borocarbonitride catalysts for electrochemical reduction of N2 to NH3.

The electrocatalytic nitrogen reduction reaction (NRR) for ammonia (NH3) under ambient conditions is emerging as a potentially sustainable alternative to the traditional, energy-intensive Haber-Bosch process for ammonia production. Currently, metal-based electrocatalysts constitute the majority of reported NRR catalysts. However, they often suffer from the shortcomings of competitive reactions of nitrogen adsorption/activation and hydrogen generation. Therefore, there is an urgent need to develop more environmentally friendly, low energy consumption, and non-polluting high-performance metal-free electrocatalysts. In this study, borocarbonitride (BCN) materials derived from boron imidazolate framework (BIF-20) were used to boost efficient electrochemical nitrogen conversion to ammonia under ambient conditions. The BCN catalyst demonstrated excellent performance in 0.1 M KOH, with an ammonia yield of 21.62 µg h-1 mgcat-1 and a Faradaic efficiency of 9.88% at -0.3 V (Reversible Hydrogen Electrode, RHE). This performance is superior to most metal-free catalysts and even some metal catalysts for NRR. The 15N2/14N2 isotope labeling experiments and density functional theory (DFT) calculations showed that N2 can be adsorbed and converted to NH3 on the surface of BCN, and that the energy barrier can be significantly reduced by structural design for BCN. This work highlights the important role played by the presence of Lewis acid-base pairs in metal-free catalysts for enhancing electrochemical NRR performance.

Class of Boehmite/Polyacrylonitrile Membranes with Different Thermal Shutdown Temperatures for High-Performance Lithium-Ion Batteries.

Nowadays, lithium-ion batteries are required to have a higher energy density and safety because of their wide applications. Current commercial separators have poor wettability and thermal stability, which significantly impact the performance and safety of batteries. In this study, a class of boehmite particles with different grain sizes was synthesized by adjusting hydrothermal temperatures and used to fabricate boehmite/polyacrylonitrile (BM/PAN) membranes. All of these BM/PAN membranes can not only maintain excellent thermal dimensional stability above 200 °C but also have good electrolyte wettability and high porosity. More interestingly, the BM/PAN membranes' thermal shutdown temperature can be adjusted by changing the grain size of boehmite particles. The lithium-ion batteries assembled with BM/PAN separators exhibit different thermal stability phenomena at 150 °C and have excellent rate performance and cycle stability at room temperature. After 120 cycles at 1C, the LiFePO4 half-cell assembled by the best BM/PAN separator has almost unchanged discharge capacity, whereas the capacity retention of Celgard 2325 is only about 85%. Meanwhile, the NCM523 half-cell assembled with the best BM/PAN separator shows superb cycle stability after 500 cycles at 8C, with a capacity retention of 79% compared with 56% for Celgard 2325.

Copper boron-imidazolate framework incorporated chitosan membranes for bacterial-infected wound healing dressing.

Chronic wounds resulting from bacterial infection are a global healthcare challenge as they usually impair the healing process and induce various complications. In this work, a chitosan (CS) membrane loaded with copper boron-imidazolate framework (Cu-BIF) was successfully prepared by self-assembly method for bacterial-infected wound-healing dressing. The as-prepared Cu-BIF/CS membrane possessed desirable biocompatibility. The antibacterial activity of Cu-BIF/CS membrane was evaluated by the spread plate and disc diffusion method, which was also verified by the fluorescence-based viability and morphological changes of bacteria. Moreover, Cu-BIF/CS membrane could increase wound closure rate and accelerate skin regeneration via combination therapy with chitosan, Cu2+ and hydroxyl radicals during infected wound healing process. These results exhibit that Cu-BIF/CS membrane has great potential as wound dressings in the field of clinical treatment of bacterial-infected wounds.

Functionalized boron nanosheets with near-infrared-triggered photothermal and nitric oxide release activities for efficient antibacterial treatment and wound healing promotion.

The spread of bacterial resistance is a rising serious threat to global public health, and has created an urgent need for the development of a new generation of antibacterial nano-agents to take the place of antibiotics. In this work, a multifunctional nanoplatform based on boron nanosheet (B NS)-coated quaternized chitosan (QCS) and the nitric oxide (NO) donor N,N'-di-sec-butyl-N,N'-dinitroso-1,4-phenylenediamine (BNN6) (B-QCS-BNN6) was prepared via a liquid-phase exfoliation and electrostatic adsorption method. The 2D B NSs could convert near-infrared (NIR) light into heat energy as well as assemble positively charged QCS and BNN6 to trap negatively charged bacteria, and the positive charge made it easily captured by bacteria, increasing the opportunities for NO diffusion to the bacterial surface. The B-QCS-BNN6 nanoplatform not only exhibited photothermal therapy (PTT) efficacy but could also control NO release precisely after stimulation with an 808 nm laser for the rapid and effective treatment of typical Gram-negative and Gram-positive bacteria. The enhanced PTT/NO antibacterial function achieved >99.9% inactivation of bacteria within 5 min. Furthermore, this synergetic antibacterial strategy could also be conveniently employed for highly efficient disinfection of a methicillin-resistant Staphylococcus aureus (MRSA) infected wound and promotion of the reconstruction of damaged tissues for in vivo MRSA-infected wound therapy.

Silver(I) metal-organic framework-embedded polylactic acid electrospun fibrous membranes for efficient inhibition of bacteria.

With recent outbreaks of fatal strains of diseases and the emergency of antibiotic resistance, there is a pressing demand to discover bactericidal materials that can effectively reduce or prevent infections by pathogenic bacteria. Herein, silver(I) metal organic frameworks Ag2(HBTC) were embedded into biocompatible polylactic acid (PLA) fibrous membranes through an electrospinning process as an antibiotic-free material for effective bacterial killing. The as-synthesized Ag2(HBTC)/PLA composite membrane showed an inactivation efficiency of more than 99.9% against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) at a concentration of 200-250 mg L-1. Mechanistic investigation indicated that the steady release of Ag+ ions and ˙OH generation from the composites contributed to the efficient antibacterial activities through irreversible damage to the bacterial cell membranes. In-depth proteomic analysis demonstrated that Ag2(HBTC)/PLA exerted a biological effect towards bacterial cells through down-regulating functional proteins, thereby destroying the central biochemical pathways of the cellular energy metabolism process, reducing resistance to oxidative damage and inhibiting cell division. In general, this study shows a promising perspective on designing MOF/PLA membranes with broad-spectrum disinfection capability for potential environmental sterilization and public healthcare protection.

Infection microenvironment-activated core-shell nanoassemblies for photothermal/chemodynamic synergistic wound therapy and multimodal imaging.

The development of intelligent designs of new antibacterial modalities for diagnosing and treating chronic multidrug-resistant bacterial infections is an urgent need, but achieving the precisive theranostic in response to specific inflammatory microenvironments remains a great challenge. This paper describes our work designing and demonstrating infection microenvironment-activated core-shell Gd-doped Bi2S3@Cu(II) boron imidazolate framework (Bi2S3:Gd@Cu-BIF) nanoassemblies. Upon exposure to a single beam of 808 nm laser, Bi2S3:Gd@Cu-BIF nanoassemblies showed exceptional photothermal conversion (η = 52.6%) and produced several cytotoxic reactive oxygen species, such as singlet oxygen and hydroxyl radicals, by depleting the intracellular glutathione and in-situ catalyzing the decomposition of endogenous hydrogen peroxide in the inflammatory microenvironment. The broad-spectrum antibacterial properties of nanoassemblies were confirmed to be effective against Escherichia coli (E. coli) and methicillin-resistant Staphylococcus aureus (MRSA) with an inhibition rate of 99.99% in vitro. Additionally, in vivo wound-healing studies revealed that Bi2S3:Gd@Cu-BIF nanoassemblies could serve as an effective wound spray to accelerate healing following MRSA infections via photothermal/chemodynamic (PTT/CDT) synergistic therapy. The effective wound healing rate in the synergistic treatment group was 99.8%, which is higher than the 69.5% wound healing rate in the control group. Furthermore, magnetic resonance and computed tomography dual-modal imaging mediated by Bi2S3:Gd@Cu-BIF nanoassemblies also exhibits promising potential as an integrated diagnostic nanoplatform. Overall, this work provides useful insights for developing all-in-one theranostic nanoplatforms for clinical treatment of drug-resistant bacterial infections. STATEMENT OF SIGNIFICANCE: New treatments and effective diagnostic strategies are critical for fighting drug-resistant bacterial infections. Infection microenvironment-activated Bi2S3@Cu-BIF nanoassemblies can simultaneously increase eigen temperature and generate cytotoxic reactive oxygen species, such as singlet oxygen and hydroxyl radicals, under near-infrared laser irradiation, achieving the synergistic effect of photothermal and chemodynamic therapy, which has been proven to be highly effective for inhibiting bacterial activity and speeding wound healing from methicillin-resistant Staphylococcus aureus infection. More importantly, the nanoassemblies could enable early precise visualized detection of bacterial abscess using magnetic resonance/computed tomography dual-modal bio-imaging techniques.

Titanium carbide/zeolite imidazole framework-8/polylactic acid electrospun membrane for near-infrared regulated photothermal/photodynamic therapy of drug-resistant bacterial infections.

Bacteria induced wound infection has become fatal healthcare issues needed to be resolved urgently. It is of vital importance to develop multifunctional therapeutic platforms to fight against increased bacterial antibiotic resistance. Herein, a titanium carbide (MXene)/zeolite imidazole framework-8 (ZIF-8)/polylactic acid (PLA) composite membrane (MZ-8/PLA) was fabricated through in-situ growth of ZIF-8 on MXene and the subsequent electrospinning process. It indicated MZ-8 can generate singlet oxygen and hyperthermia at photothermal (PTT) convention efficiency of 80.5% with bactericidal rate of more than 99.0%. In addition, MZ-8 showed remarkable antitumor efficiency in vitro and in vivo based on the combined photodynamic/photothermal therapy. Theoretical calculation illustrated MZ-8 could improve the laser activation process by acceleration of intermolecular charge transfer, reducing excitation energy, stabilizing excited states and increasing intersystem crossing rate. After incorporated into electrospun scaffolds, MZ-8/PLA exhibited potent PTT and photodynamic therapy (PDT) properties under 808 nm laser irradiation. The antibacterial rates of MZ-8/PLA were up to 99.9% and 99.8% against Escherichia coli and Methicillin-resistant staphylococcus aureus, respectively. In-vivo experimental results further confirmed that MZ-8/PLA can accelerate bacteria infected wound healing without observable resistance. This work opens a new avenue to design promising platforms for fighting against extremely drug resistant bacterial infection.

A flexible fibrous membrane based on copper(II) metal-organic framework/poly(lactic acid) composites with superior antibacterial performance.

A flexible antibacterial fibrous membrane employing high antibacterial efficiency has great potential in healthcare applications. Herein, a three-dimensional copper(ii) metal-organic framework [Cu2(CA)(H2O)2, Cu-MOF-1] and poly(lactic acid) (PLA) composite fibrous membrane was prepared through a facile electrospinning method. The sphere-like Cu-MOF-1 was rapidly synthesized by a microwave-assisted hydrothermal reaction of Cu(ii) salts with citric acid (H4CA) in the presence of polyvinyl pyrrolidone (PVP). The surface morphology, thermal stability, mechanical properties and hydrophilicity test of the as-prepared Cu-MOF-1/PLA fibrous membrane were studied systematically. Compared with commercial copper nanoparticles (Cu-NPs), citric acid and copper citrate, Cu-MOF-1 showed higher antibacterial properties with the bacteriostatic rates of 97.9% and 99.3% against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus), respectively, when the used dose was 250 µg mL-1. The Cu-MOF-1/PLA fibrous membrane also exhibited outstanding bactericidal activities against E. coli and S. aureus with the antibacterial rates up to 99.3% and 99.8%, respectively. Mechanism investigation indicated that the slowly released Cu2+ ions could destroy the microenvironment of bacteria cells and destroy the integrity and permeability of the cell membrane, leading to enzyme inactivation. Therefore, the as-prepared flexible fibrous membrane will advance progress toward developing a broad spectrum antibacterial textile for healthcare protection related applications.

An anthracene extended viologen-incorporated ionic porous organic polymer for efficient aerobic photocatalysis and antibacterial activity.

A new conjugated ionic porous organic polymer (AN-POP), incorporated with anthracene-extended viologen, has been rationally designed and prepared to explore its dual functions in photocatalytic oxidation and bacterial killing. Compared with its anthracene-free counterpart (BD-POP), AN-POP showed a superior photocatalytic oxidation performance and antibacterial activity demonstrating the critical role of an anthracene-extended viologen structure.

Temperature Feedback-Controlled Photothermal/Photodynamic/Chemodynamic Combination Cancer Therapy Based on NaGdF4 :Er,Yb@NaGdF4 :Nd@Cu-BIF Nanoassemblies.

The intelligent design of multifunctional nanoplatforms is critical for cancer therapy. Herein, NaGdF4 :Er,Yb@NaGdF4 :Nd@Cu(II) boron-imidazolate frameworks (denoted as CSNPs@Cu-BIF) nanoassemblies are designed and fabricated. Upon a single 808 nm laser irradiation, the nanoassemblies not only show the outstanding photothermal conversion capacity (η = 41.7%) but also generate cytotoxic reactive oxygen species through an in situ Fenton-like reaction and fluorescence resonance energy transfer. Importantly, the nanoassemblies simultaneously introduce remarkable antitumor efficacy via photothermal/photodynamic/chemodynamic combination therapy both in vitro and in vivo. To improve the therapeutic effect of solid tumor ablation, it is highly desirable to monitor the treatment process in real-time. Multiclinical imaging modalities of ultrasonography are employed to systematically investigate the ablation mechanism of solid tumors in vivo. Furthermore, the significant difference between the eigen temperature of CSNPs@Cu-BIF nanoassemblies obtained by the temperature-sensitive emission bands signal changes and the apparent temperature recorded by the thermal imaging camera is 14.55 K at equilibrium. This current work therefore supplies an alternative strategy in temperature feedback-controlled accurate cancer therapy.

Superior antibacterial activity of Fe3O4@copper(ii) metal-organic framework core-shell magnetic microspheres.

With the rapid evolution of antibiotic resistant bacteria, it has become more and more difficult to treat bacterial infection with traditional antibiotics. Therefore, new strategies with high antibacterial efficiency are urgently needed to combat bacteria effectively. Herein, Fe3O4@copper(ii) metal-organic framework Cu3(BTC)2 (Cu-BTC) core-shell structured magnetic microspheres were prepared via a layer by layer growth process. The as-prepared Fe3O4@Cu-BTC possessed a unique broad-spectrum antibacterial potency against Gram-negative Escherichia coli (E. coli) and Gram-positive Staphylococcus aureus (S. aureus). The slowly released copper ions and enhanced reactive oxygen species (ROS) generation by facilitating the effective separation and transfer of photoexcited electron-hole pairs played a role in the antibacterial activity of Fe3O4@Cu-BTC. Copper ions released from Fe3O4@Cu-BTC adhered to the negatively charged bacterial cell, interacted with the bacterial membrane, destroyed the integrity of the membrane which resulted in leakage of bacterial content and then generated ROS to damage DNA, thus leading to cell death. Accordingly, this study provides a competitive strategy for preparing recyclable antibacterial materials that are endowed with targeted antibacterial therapy.

In-situ synthesis of metal nanoparticles@metal-organic frameworks: Highly effective catalytic performance and synergistic antimicrobial activity.

M-NP@Zn-BIF (M-NP = Ag or Cu nanoparticle; Zn-BIF is a zinc-based boron imidazolate framework, Zn2(BH(2-mim)3)2(obb); 2-mim = 2-methylimidazole; obb = 4,4'-oxybis(benzoate)) composites were successfully in-situ synthesized by utilizing the reducing ability of the BH bond contained in the Zn-BIF at room temperature without any additional chemical reduction reagents. These composites (225 µg/mL) exhibited excellent catalytic activity to convert 4-nitrophenol to 4-aminophenol in 2.5 min and 6 min with a conversion rate of 99.9 %, respectively. In addition, Ag@Zn-BIF (50 µg/mL) showed highly synergistic antibacterial activity against both Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) with a bactericidal rate of approximately 99.9 %. An antibacterial mechanism was proposed for the generation of intracellular reactive oxygen species (ROS) levels. Superoxide radicals (O2-) and hydroxyl radicals (OH) formed during the antibacterial process were shown to accelerate the death of bacteria. They also exhibited highly photocatalytic activity for Rhodamine B (RhB). When the concentration of the composites is 1000 µg/mL, the photocatalytic efficiency of Ag@Zn-BIF and Cu@Zn-BIF increased by 31.62 and 18.13 times compared with Zn-BIF, respectively. All in all, this study developed a simple and versatile integrated platform for the removal of nitrophenols, organic dyes, and the effective inactivation of bacteria in water.

Copper(ii)-based coordination polymer nanofibers as a highly effective antibacterial material with a synergistic mechanism.

Nanofibers of a copper(ii)-based coordination polymer [Cu(HBTC)(H2O)3] were synthesized via a microwave-assisted hydrothermal process, while macroparticles and bulk crystals were prepared via a hydrothermal method. X-ray analysis revealed that this compound possesses one-dimensional zig-zag chains, in which the coordination polyhedron of the copper(ii) center is a five-coordinate distorted square-pyramid. The width of the as-prepared nanofibers was about 150 nm, while the size of the macroparticles was about 200 µm. The antibacterial activities of the nanofibers and macroparticles against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) were evaluated by determining the minimal inhibitory concentration (MIC), the growth curve of the bacteria and the bacterial reduction assay. The nanofibers showed higher antibacterial performance as compared with macroparticles, commercial copper nanoparticles, and pure ligands alone. The bacteriostatic rates of nanofibers and macroparticles were up to 99.9% and 96.7% against E. coli, while 99.1% and 96.2% against S. aureus, respectively, when the concentration was 250 µg mL-1. The synergistic antibacterial mechanism was also proposed based on the generation of reactive oxygen species (ROS) and the release of Cu2+ ions.

An anionic layered europium(iii) coordination polymer for solvent-dependent selective luminescence sensing of Fe3+ and Cu2+ ions and latent fingerprint detection.

An anionic layered coordination polymer [Eu(BTEC)0.5(HCOO)(H2O)2] (1) has been successfully synthesized via a solvothermal method (H4BTEC = 1,2,4,5-benzenetetracarboxylic acid, HCOOH = formic acid). Compound 1 possesses two-dimensional layers, which further generate a three-dimensional supramolecular network by hydrogen bonds existing between carboxylic oxygen, formate anion and H2O molecules of two adjacent layers. Interestingly, 1 shows high luminescence quenching efficiency upon addition of Fe3+ ions when it was dispersed in water even in the presence of interfering ions such as Na+, Ag+, Ca2+, Cd2+, Co2+, Cu2+, Mg2+, Mn2+, Zn2+ and Al3+. When dispersed in DMSO solution, 1 displays excellent sensitivity and selectivity towards both Cu2+ and Fe3+ ions. Possible quenching mechanisms for detection of Fe3+ and Cu2+ ions were carefully investigated and proposed based on a dynamic quenching process, static quenching process and fluorescence inner filter effect. Moreover, the as-prepared particles can be used for visualizing latent fingerprints on various substrates. These results indicate that a Eu(iii)-based coordination polymer has great potential in detection and security application.

Aggregation-Induced Emission (AIE) Fluorophore Exhibits a Highly Ratiometric Fluorescent Response to Zn2+ in vitro and in Human Liver Cancer Cells.

Two novel organic fluorophores, containing bis-naphthylamide and quinoline motifs, have been designed and synthesized. One of the fluorophores contains an isobutylene unit and exhibits a significant aggregation-induced emission (AIE) and a remarkable highly selective ratiometric fluorescence response towards Zn2+ in solution as well as in human liver cancer cells. The AIE behavior of this fluorophore was fully verified by fluorescence and UV/Vis spectroscopy, quantum yield calculations, and single-crystal X-ray diffraction, which revealed an intricate crystal packing system. Conversely, a fluorophore that lacks the isobutylene moiety did not exhibit any significant fluorescent properties as a result of its more flexible molecular structure that presumably allows free intramolecular rotational processes to occur.