Bio-inspired Structure-editing Fluorescent Hydrogel Actuators for Environment-interactive Information Encryption

Many living organisms have the superb structure-editing capacity for better adaptation in dynamic environments over the course of their life cycle. However, it's still challenging to replicate such natural structure-editing capacity into artificial hydrogel actuating systems for enhancing environment-interactive functions. Herein, we learn from the metamorphosis development of glowing octopus to construct proof-of-concept fluorescent hydrogel actuators with life-like structure-editing capacity by developing a universal stepwise inside-out growth strategy. These actuators could perform origami-like 3D shape deformation and also enable the postnatal growth of new structures to adapt additional actuating states for different visual information delivery by using different environment keys (e.g., temperature, pH). This study opens previously unidentified-avenues of bio-inspired hydrogel actuators/robotics and extends the potential uses for environment-interactive information encryption.     

Bioanalytical applications of aptamer and molecular-beacon probes in fluorescence-affinity assays

This critical review summarizes recent developments in highly sensitive, specific assays using nucleic-acid (NA)-affinity probes and fluorescence detection. We emphasize two groups of DNA and RNA probes (i.e. aptamers and molecular beacons) because of the increase in their bioanalytical applications. The affinity and the specificity of these NA probes combined with the diverse detection capability of fluorescence measurements (e.g., intensity, polarization, resonance-energy transfer and decay life-time) enable ultrasensitive assays for proteins, gene mutations, single-nucleotide polymorphisms and molecular-binding events.     

An N,N′-diaryl urea based conjugated polymer model system

An N,N′-diphenyl urea was designed as a model system for aggregation phenomenon in poly(phenyleneethynylenes) (PPEs). The unmethylated N,N′-diphenyl urea adopts an open, unfolded conformation in which the two diphenyl acetylene fluorophores are far enough away, mimicking the unaggregated state. Dimethylation forces the aromatic surfaces together into π-π contact, mimicking the aggregated state of PPEs. Analogous to bulk PPEs, this model system shows dramatic differences in quantum yield between the folded and unfolded states, with the unfolded urea having greater than 400-fold higher fluorescence quantum yield than its folded equivalent.     

基于超分子离子晶体的湿度传感构效关系研究

相对湿度是许多领域的关键参数,环境湿度与人们的生活密切相关,因此对湿度进行测量和控制是各个领域中值得关注的问题之一. 在前期的研究中,作者制备了一种新型的超分子离子材料（SIM）,它是由基于咪唑的双阳离子（如1,10-双（3-甲基咪唑-1-基）癸烷,C₁₀(mim)₂）和电活性二阴离子（如2,2'-连氮基-双（3-乙基苯并噻唑啉-6-磺酸）,ABTS）组成的,发现其对湿度具有敏感且快速的响应. 在此基础上,本文制备了6种不同碳链（C₄,C₆,C₈,C₁₀,C₁₂,C₁₄）的咪唑基化合物,发现其中3种（C₁₀,C₁₂,C₁₄）可与ABTS形成水稳定的SIM. 循环伏安法、计时电流法以及石英晶体微量天平表征了这些超分子离子材料的湿度传感性能,发现基于C12的SIM具有最佳的湿度传感性能. 同时,SEM结果显示随着碳链的增加,离子材料的厚度变薄并且形态变得不规则. 因此,作者认为疏水作用和材料比表面积均会影响湿度传感的灵敏度. 本研究为发展新的湿度响应的离子传感材料奠定了基础.     

Complexation and Sensing Behavior of Dansyl-appended Cyclodextrins and Cyclodextrin Dimers with Bile Salts

The dansyl-modified cyclodextrin derivatives 2 and 3 form complexes with the steroidal bile salts. The selectivity of the monomeric derivative 3 is similar to that of native g -cyclodextrin. All binding constants with 3 are lowered compared to g -cyclodextrin because of the competition for the cavity between the steroids and the dansyl moiety. Cholate ( 4a ) and deoxycholate ( 4b ) form weak complexes, the other bile salts ( 4c - e ) are complexed far more strongly. The difference is attributed to the absence of a 12-hydroxy group in the latter steroids. Data for dimer 2 reveal strongly enhanced binding of 4a and 4b and only slightly stronger complexes with the other steroids. Due to the low binding affinity of 3 for 4a and 4b , this receptor could not be used for their detection by fluorescence spectroscopy. Steroids 4c - e showed a decrease in fluorescence intensity. The detection of all steroids 4a - e was possible using 2 . The fluorescence intensity of the dimer increased or decreased, depending on which steroid was added.     

自交联共轭亚油酸囊泡基荧光纳米点的构筑及其荧光特性

提出了一种生物质碳源借助自组装和自交联手段“构筑”碳基荧光纳米点(FNDs)的新策略,不同于经历裂解、脱水、缩聚和碳化等复杂且不可控反应的“合成”途径。本文以共轭亚油酸(CLA)为碳源,利用其表面活性和聚合活性制得呈蓝绿光发射的自交联共轭亚油酸囊泡基荧光纳米点(SCU-FNDs),粒径易控(平均粒径为17 nm)且具有良好水分散性,FNDs产率高达73.9%。该法简便温和、绿色经济、有利于大规模制备。荧光实验结果显示SCU-FNDs的荧光强度随囊泡表面羧酸基团减少而减弱,随自交联度增大而增大; 同时其荧光强度具有良好的温度线性响应性,升/降温过程均符合I/I₀ = -0.00977T+ 1.229 (T = 25-85 ℃, R² = 0.99)。这些荧光特性皆可以用SCU-FNDs的自组装和自交联结构特性予以解释。     

Recovery of PET-quenched fluorescent conjugated polymers with aza-15-crown-5 as pendant groups on interaction with ions

Novel conjugated polymers with aza-15-crown-5 as pendant groups, P1 were synthesized by the Sonogashira coupling reaction. The polymer P1 was found to show fluorescence en-hancement response towards Ba2＋. The gradual recovery and turning-point of emission intensity of polymers appeared in the addition of Ba2＋, which provided good evidence for the fluorescence amplification mechanism of conjugated polymers.     

Potentially useful antimicrobial and antiviral phototoxins from plants

The wide range of naturally occurring compounds from microorganisms and plants which are phototoxic in UV-A light (320-400 nm) includes cinnamyl esters, coumarins and furanocoumarins, furanochromones, benzofurans, alkaloids, based on tryptophan or phenylalanine, extended naptho-and anthraquinones, polyacetylenes and their thiophene derivatives. The cellular targets are cell membranes, e.g., acetylenes, or the nucleus, e.g., furanocoumarins. Compounds reacting with cell membranes in light either generate singlet oxygen, e.g., alpha-terthienyl, or react by a free radical mechanism, e.g., phenylheptatriyne, or do both. Those that react with nucleic acids intercalate with these macromolecules forming photoadducts, e.g., furanocoumarins, furanochromones and furanoquinolines. With others, such as the beta-carbolines, the explanation for their photogenotoxicity is unknown. A number of these natural photosensitizers have been examined with bacteria, yeasts, and viruses and the mechanisms of phototoxicity have been elucidated. Some of the sulfur-containing acetylenes may be useful in photochemotherapy.     

A Space-Confined Polymerization Templated by Ice Enables Large-Scale Synthesis of Two-Dimensional Polymer Sheets

Despite significant progress in the preparation and characterization of two-dimensional (2D) materials, the synthesis of 2D organic materials remains challenging. Here, we report a novel space-confined polymerization method that enables the large-scale synthesis of 2D sheets of a functional conjugated polymer, namely, poly(3,4-ethylenedioxythiophene) (PEDOT). A key step in this method is the confinement of monomer to the boundaries of ice crystals using micelles. This spatial confinement directs the polymerization to form 2D PEDOT sheets with high crystallinity and controlled morphology. Supercapacitors prepared from the 2D PEDOT sheets exhibit outstanding performance metrics. In aqueous electrolyte, a high areal specific capacitance of 898 mF cm⁻² at 0.2 mA cm⁻² along with an excellent rate capability is achieved (e.g., capacitance retention of 67.6 % at a 50-fold higher current). Moreover, the 2D PEDOT-based supercapacitors exhibit outstanding cycling stability (capacitance retention of 98.5 % after 30,000 cycles). Device performance is further improved when an organic electrolyte is used.     

Monitoring photopolymerization reactions through thermal imaging: A unique tool for the real‐time follow‐up of thick samples, 3D printing,and composites

The ever increasing applications of photopolymers from historical thin (<50 µm) coatings to very deep samples (>1 cm) require the development of robust 4D monitoring strategies able to assess photopolymerization efficiencies (first dimension) as a function of time (second dimension) and position (third and fourth dimensions). Therefore, here, we demonstrated that thermal imaging is a valuable photopolymerization monitoring device showing: (a) very high response times (<1 s); (b) high repeatability of the measurement; (c) strong adaptability of the setup to various conditions (e.g., onto irregular surfaces or inside a real time Fourier transformed infrared spectrometer (RT‐FTIR)); (d) extremely deep photopolymerization follow‐ups (and subsequent rationalization) with good resolution in time and in space (real‐time thermal imaging microscopy experiments); (e) adaptability to applied materials. This monitoring strategy was found particularly robust when taking into account all the heat generating phenomena (i.e., direct heating from the lamp vs. temperature raised due to monomer conversion). As a result, we propose thermal imaging as the next reference monitoring system for the new ranges of thick and/or filled samples (e.g., 3D objects, composites) and/or applied photopolymerizations (e.g., 3D printing) more and more present in the literature. © 2018 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2018 , 56, 889–899     

Conjugated carbazole dimer as fluorescence carrier for preparation of iodine-sensitive chemical sensor

The carbazole derivative, 9-ethyl-3-carbazylidene carbazole hydrazone (ECCH) with two conjugated carbazole rings have been applied as a fluorescence carrier for preparation of an iodine sensitive optical chemical sensor. The response of the sensor is based on quenching of the fluorescence of ECCH by iodine. The conjugated carbazole dimer based sensor shows a linear response toward iodine in the concentration range 1.0 × 10⁻⁶ to 1.0 × 10⁻⁴ mol L⁻¹, with a detection limit of 8.0 × 10⁻⁷ mol L⁻¹ at pH of 7.0. The effect of composition of the sensor membrane was studied, and the experimental conditions were optimized. Most commonly coexisting ions do not interfer with the iodine assay. The sensor shows sufficient repeatability, selectivity, operational lifetime of two months and a fast response of less then 50 s. The sensor has been used for determination of iodine in water samples.     

Antibiotics and the Nervous System—Which Face of Antibiotic Therapy Is Real,Dr. Jekyll (Neurotoxicity) or Mr. Hyde (Neuroprotection)?

Antibiotics as antibacterial drugs have saved many lives, but have also become a victim of their own success. Their widespread abuse reduces their anti-infective effectiveness and causes the development of bacterial resistance. Moreover, irrational antibiotic therapy contributes to gastrointestinal dysbiosis, that increases the risk of the development of many diseases, including neurological and psychiatric. One of the potential options for restoring homeostasis is the use of oral antibiotics that are poorly absorbed from the gastrointestinal tract (e.g., rifaximin alfa). Thus, antibiotic therapy may exert neurological or psychiatric adverse drug reactions which are often considered to be overlooked and undervalued issues. Drug-induced neurotoxicity is mostly observed after beta-lactams and quinolones. Penicillin may produce a wide range of neurological dysfunctions, including encephalopathy, behavioral changes, myoclonus or seizures. Their pathomechanism results from the disturbances of gamma-aminobutyric acid-GABA transmission (due to the molecular similarities between the structure of the β-lactam ring and GABA molecule) and impairment of the functioning of benzodiazepine receptors (BZD). However, on the other hand, antibiotics have also been studied for their neuroprotective properties in the treatment of neurodegenerative and neuroinflammatory processes (e.g., Alzheimer’s or Parkinson’s diseases). Antibiotics may, therefore, become promising elements of multi-targeted therapy for these entities.     

Cu‐Based Nanoparticles as Emerging Environmental Catalysts

This account provides an overview of current research activities on nanoparticles containing the earth‐abundant and inexpensive element copper (Cu) and Cu‐based nanoparticles, especially in the field of environmental catalysis. The different synthetic strategies with possible modification of the chemical/ physical properties of these nanoparticles using such strategies and/or conditions to improve catalytic activity are presented. The design and development of support and/or bimetallic systems (e. g., alloys, intermetallic, etc.) are also included. Herein, we report synthetic approaches of Cu and Cu‐based nanoparticles (monometallic copper, bimetallic copper and copper (II) oxide nanoparticles/nanostructures) and impregnation of such nanoparticles onto support material (e. g., Co₃O₄ nanostructure), along with their applications as environmental catalyst for various oxidation and reduction reactions. Finally, this account provides necessary advances and perspectives of Cu‐based nanoparticles in the environmental catalysis.     

Poly(benzimidazobenzophenanthroline)-Ladder-Type Two-Dimensional Conjugated Covalent Organic Framework for Fast Proton Storage**

Electrochemical proton storage plays an essential role in designing next-generation high-rate energy storage devices, e.g., aqueous batteries. Two-dimensional conjugated covalent organic frameworks (2D c-COFs) are promising electrode materials, but their competitive proton and metal-ion insertion mechanisms remain elusive, and proton storage in COFs is rarely explored. Here, we report a perinone-based poly(benzimidazobenzophenanthroline) (BBL)-ladder-type 2D c-COF for fast proton storage in both a mild aqueous Zn-ion electrolyte and strong acid. We unveil that the discharged C−O⁻ groups exhibit largely reduced basicity due to the considerable π-delocalization in perinone, thus affording the 2D c-COF a unique affinity for protons with fast kinetics. As a consequence, the 2D c-COF electrode presents an outstanding rate capability of up to 200 A g⁻¹ (over 2500 C), surpassing the state-of-the-art conjugated polymers, COFs, and metal–organic frameworks. Our work reports the first example of pure proton storage among COFs and highlights the great potential of BBL-ladder-type 2D conjugated polymers in future energy devices.     

Effect of extended conjugation with a phenylethynyl group on the fluorescence properties of water-soluble arylboronic acids

Boronic acids that change fluorescence properties upon sugar binding are very important reporter units for the development of small molecule lectin mimics (boronolectins). Aimed at developing long wavelength fluorescent boronic acid reporter compounds, we have designed and synthesized a series of boronic acid analogs 2a-d with an extended π conjugation. Such designs are based on earlier fluorescent boronic acids that change fluorescence properties upon sugar binding. Compared with the corresponding parent chromophores, these new compounds with extended conjugations show longer excitation and emission wavelengths as designed. The patterns of fluorescence changes for the new compounds are also different from that of the corresponding parent compounds.     

Current status of multiple antigen-presenting peptide vaccine systems: Application of organic and inorganic nanoparticles

Many studies are currently investigating the development of safe and effective vaccines to prevent various infectious diseases. Multiple antigen-presenting peptide vaccine systems have been developed to avoid the adverse effects associated with conventional vaccines (i.e., live-attenuated, killed or inactivated pathogens), carrier proteins and cytotoxic adjuvants. Recently, two main approaches have been used to develop multiple antigen-presenting peptide vaccine systems: (1) the addition of functional components, e.g., T-cell epitopes, cell-penetrating peptides, and lipophilic moieties; and (2) synthetic approaches using size-defined nanomaterials, e.g., self-assembling peptides, non-peptidic dendrimers, and gold nanoparticles, as antigen-displaying platforms. This review summarizes the recent experimental studies directed to the development of multiple antigen-presenting peptide vaccine systems.     

Resistive pulse sensing as particle counting and sizing method in microfluidic systems: Designs and applications review

Resistive pulse sensing is a well‐known and established method for counting and sizing particles in ionic solutions. Throughout its development the technique has been expanded from detection of biological cells to counting nanoparticles and viruses, and even registering individual molecules, e.g., nucleotides in nucleic acids. This technique combined with microfluidic or nanofluidic systems shows great potential for various bioanalytical applications, which were hardly possible before microfabrication gained the present broad adoption. In this review, we provide a comprehensive overview of microfluidic designs along with electrode arrangements with emphasis on applications focusing on bioanalysis and analysis of single cells that were reported within the past five years.     

Electrophoretic methods for the analysis of nanoparticles

With the development of nanotechnology, there is a need for methodologies to determine and characterize nanomaterials. Electrophoresis has emerged as a useful tool, which has been employed in various formats (e.g., capillary-zone electrophoresis, gel electrophoresis or isotachophoresis) for the size- or shape-based separation of different types of nanoparticle (NP) (e.g., metallic, semi-metallic or carbon). This article reviews the main progress in electrophoresis techniques in order to achieve separation of NPs.     

Synthesis and biological evaluation of dihydrotriazine derivatives as potential antibacterial agents

A series of 1,4-dihydro-1,3,5-triazine derivatives were designed and synthesized and their antibacterial and antifungal activities were evaluated. Most of the synthesized compounds showed potent inhibition of several Gram-positive bacterial strains(including multidrug-resistant clinical isolates) and Gramnegative bacterial strains, with minimum inhibitory concentrations(MICs) in the range of 2.1–181.2 mmol/L. Compounds 7a and 7c presented the most potent inhibitory activities against Grampositive bacteria(e.g., Staphylococcus aureus 4220), Gram-negative bacteria(e.g., Escherichia coli 1924),and the fungus Candida albicans 7535, with MICs of 2.1 or 4.1 mmol/L. Especially, compound 7a was the most potent, with an MIC of 2.1 mmol/L against four multidrug-resistant, Gram-positive bacterial strains.The cytotoxic activity of the compound 7a, 7c and 7f was assessed in HepG2 cells, and the results suggest that 1,4-dihydro-1,3,5-triazine derivatives bearing a 6-benzyloxynaphthalen moiety are interesting scaffolds for the development of novel antibacterial agents.     

Metal ion binding of photoactive poly-(arylene ethynylene) co-polymers

The metal ion binding properties of three photoactive poly-(arylene ethynylene) co-polymers with potentially complexing units have been described. Upon protonation or complexation, the intensity of the luminescence typical of these conjugated polymers is completely quenched, due to the extended electronic conjugation of the polymer backbones. In the case of the formation of complexes with Yb³⁺ and Er³⁺, one of the studied polymers gives rise to an efficient sensitization of their typical metal centred NIR emission. This feature is of particular interest for the preparation of new materials that are the subject of active research for their possible applications in optical imaging and in optical amplification for telecommunication purposes.