The design of novel hybrid nanostructures has been seen as an effective route to tune the properties of materials. Herein, we provide an in situ growth strategy to efficiently construct kebab-like hybrids, which are composed of one-dimensional SiC nanowires stringing polyhedral metal organic frameworks (MOFs). Through a heat-treatment process regardless of under air or argon, these hybrids generate an excellent electromagnetic absorption (EMA) ability. We comprehensively explored the growth and calcination process of these hybrids as well as their EMA enhanced mechanism. The results indicate that the MOFs kept as shrunken polyhedrons under air but decomposed to small particles under argon, due to the different calcination mechanism. In addition, the enhanced EMA ability should be attributed to the combined influences of the reduced dielectric constant, enlarged aspect ratio, and enhanced interface polarization. This research opens up the rational designs and applications of novel materials by the hybridizing of nanomaterials in multidimensions.Keywords: calcination; electromagnetic absorption; hybridization; metal organic frameworks; SiC nanowires;

Heteroatom doping is one of the most effective routes to adjust the physicochemical and optical properties of carbon dots (CDs). However, fluorine (F) doped CDs have been barely achieved. In this work, a F-doping strategy was proposed and adopted to modulate optical properties of CDs. A kind of F-doped CDs was synthesized by a solvothermal process using aromatic F bearing moiety as the F source and shows much longer maximum emissions (up to 600 nm, red fluorescence) than that of undoped CDs, indicating a large emission red-shift effect by F-doping. In addition, the F-doped CDs have remarkable water-solubility, high biocompatibility, as well as excellent stability even under broad pH range, ionic strengths, and light illumination and thus can be used as a novel probe for the highly efficient cell imaging of various normal cells and cancer cells. The F-doped CDs can selectively bind to Ag+. It therefore makes the F-doped CDs be a highly sensitive probe for the detection of Ag+ under both aqueous solution and various biological systems. The huge potential of this F-doping strategy is indicated in the rational design of high-performance CDs, as well as in applications of clinical diagnosis and ion detection.

Stimuli-responsive polymeric hydrogels are promising and appealing delivery vehicles for protein/peptide drugs and have made protein/peptide delivery with both dosage- and spatiotemporal-controlled manners possible. Here a series of new Salecan-based pH-sensitive hydrogels were fabricated for controlled insulin delivery via the graft copolymerization reaction between Salecan and 2-acrylamido-2-methyl-1-propanesulfonic acid. In this study, on one hand, Salecan played a key role in modifying the structure and the pore size of the developing hydrogel. On the other hand, Salecan tuned the water content and the water release rate of the obtained hydrogel, leading to a controllable release rate of the insulin. More importantly, in vitro release experiments validated that the release of insulin from this intelligent system could be also tailored by the environmental pH of the release medium. For SGA2, the amount of encapsulated insulin released at gastric conditions (pH 1.2) was relatively low (about 26.1 wt % in 24 h), while that released at intestinal conditions (pH 7.4) increased significantly (over 50 wt % in 6 h). Furthermore, toxicity assays demonstrated that the designed hydrogel carriers were biocompatible. These characteristics make the Salecan-based hydrogel a promising candidate for protein/peptide drug delivery device.Keywords: 2-acrylamido-2-methyl-1-propanesulfonic acid; drug delivery; insulin; pH-sensitive hydrogels; salecan;

Salecan, a new water-soluble β-glucan, has excellent physicochemical and biological characteristics. Here, a series of pH-sensitive hydrogels based on Salecan grafted with [2-(methacryloxy)ethyl]trimethylammonium chloride were developed for controlled drug delivery. The successful preparation of the grafted hydrogels was confirmed by Fourier transform infrared spectroscopy, X-ray diffraction, and thermogravimetric analysis. After that, rheology and scanning electron microscopy tests showed that the mechanical and morphological properties of these hydrogels were strongly influenced by the Salecan content. Moreover, the swelling behavior of the resulting hydrogels was systematically studied, and the results suggested that they exhibited pH sensitivity. Loading and delivery experiments demonstrated that 5-fluorouracil was efficiently encapsulated into the hydrogel matrices and released in a predictable manner via pH and Salecan dose control. Finally, cell viability and adhesion assays verified the cell compatibility of the designed hydrogels. Altogether, these attributes make the Salecan-based graft hydrogel a promising platform for controlled 5-fluorouracil delivery.

•A smart polysaccharide hydrogel was synthesized and characterized for drug delivery.•Semi-IPN technique was used to keep properties of both polymers.•Hydrogel sensitive to temperature, pH, and ionic strength.•The hydrogel is cell compatible.•Drug release rates can be controlled.Salecan is a novel water soluble polysaccharide produced by a salt-tolerant strain Agrobacterium sp. ZX09. Poly(dimethylaminoethyl methacrylate) (PDMAEMA) is a pH, thermo, and ionic strength multi-sensitive polymer with anti-bacterial property. Here, we report a semi-interpenetrating polymer network (semi-IPN) hydrogel based on salecan and PDMAEMA. The obtained hydrogel is simultaneous sensitive to pH, ionic strength and temperature: the swelling ratio maximizes at pH 1.2 and shrinks at pH value greater than 3; besides, water content of the hydrogel decreases as the ionic strength increases; in terms of temperature, the hydrogel swells/deswells at temperatures below/above 40 °C. Cytotoxicity test shows the hydrogel is non-cytotoxic to COS-7 cells. Protein drug insulin was selected as model drug to test the in vitro release behavior of the hydrogel. Results show the release rate increases with the swelling ratio of the hydrogel. In addition, when the temperature is higher than the lower critical solution temperature (LCST) of PDMAEMA, the hydrogel shrinks to extrude more drug molecules. Moreover, the release rate and release amount were higher in acid condition (pH 1.2) than at pH 7.4. In summary, this polysaccharide hydrogel is a promising material for drug delivery.

A fast and facile approach to synthesize orange luminescent carbon dots by hydrothermal method, while 1,2-benzenediamine and carbamaldehyde serve as precursors. In order to get stronger fluorescence emission, doping N heteroatoms to make N-CDs. The N-CDs exhibit a high quantum yield of 14.3% along with the fluorescence lifetime of 2.86 ns. Because the emission of N-CDs is quenched by Ag+ efficiently, N-CDs can be employed as a highly sensitive and selective detection for Ag+ detection and N-CDs were exploited for the determination of Ag+ in environmental water samples with satisfactory results. Significantly, using MTT assay, N-CDs have low toxicity against 293 T cells and N-CDs have been applied for A549 cell imaging successfully.

•Green synthesis of N-CDs from hydrothermal treatment of Salecan•The N-CDs was demonstrated to detect Ag+ in environmental water sample.•The method was applied to the determination of Ag+ dissolved in water.We report that nitrogen doped carbon dots (N-CDs) represent a viable fluorescent probe for the determination of Ag+. The N-CDs can be fairly easily prepared by a hydrothermal treatment method using Salecan and dicyandiamide as the precursors, display excitation/emission maxima of 350/438 nm. The N-CDs have an average diameter of about 3.8 nm. The N-CDs exhibited blue fluorescence (quantum yield of 13.2%) and could response to Ag+ selectively and sensitively. Other ions nearly had no interference. The probe has excellent selectivity, high sensitivity, and a linear response range that extends from 0 to 40 μM. The limit of detection is as low as 1.12 × 10− 7 mol/L. The method was applied to the determination of Ag+ dissolved in water.

The authors describe the synthesis of carbon dots (CDs) that are highly doped with both nitrogen and phosphorus. Synthesis is accomplished via a hydrothermal reaction starting from diethylenetriaminepenta(methylenephosphonic acid) and m-phenylenediamine as the precursors. The high N,P-doping ratios renders the codoped CDs excellently water soluble, photostable over a wide range of pH values, and photostable in the presence of various metal ions. Ferric ions acts as a strong quencher of fluorescence. Their low cytotoxicity and strong green fluorescence (with excitation/emission peaks at 440/510 nm and a quantum yield of 0.32) make the CDs well suited for purposes of cell imaging, and this is demonstrated by fluorescent bioimaging of human lung carcinoma cells (type A549) and human breast cancer cells (type KB). Furthermore, the CDs were used as an effective probe for monitoring Fe(III) in both aqueous solution and living cells.

Poly(N,N-diethylacrylamide) is not only a thermosensitive polymer, but also a good hydrogen bond acceptor. Therefore, drugs with carboxyl groups can serve as hydrogen bond donors and form interactions with the tertiary amide groups in N,N-diethylacrylamide. Herein, we report a novel drug delivery system for anionic drugs composed of poly(N,N-diethylacrylamide) and salecan. Salecan was used to improve the hydrophilicity and accelerate the responsive rate of this system. As expected, salecan-enriched hydrogels exhibited higher swelling ratios and were more sensitive to temperature. Moreover, scanning electron microscopy images showed that the hydrogels are superporous structures, with pore-sizes that increase with salecan concentration. The swelling ratios decreased continuously with the increase of temperature in the range 25–37 °C. MTT assay for cell viability and cell adhesion studies confirm the cell compatibility of the system. Delivery tests using diclofenac sodium, an anti-inflammatory drug, indicate that the thermosensitive property of this system is favorable for anionic drug delivery. Interestingly, the release rates of diclofenac sodium from the hydrogels were temperature dependent, with higher temperatures contributing toward faster release rate.Keywords: cell compatible; drug delivery; polysaccharidic hydrogel; salecan; smart device

•A cyanide sensor based on a conjugated pyrene–benzothiazol system.•The sensor L recognizes CN− selectively in aqueous solution.•Benzothiazol CN is an effective target for the nucleophilic analytes.•A ICT dual-channel sensor displayed excellent orange fluorescent.Herein a cyanide sensor has been synthesized and evaluated by UV–vis and fluorescent method. This sensor is based on a conjugated pyrene–benzothiazol system, which was found to show rapid response, high selectivity and sensitivity for cyanide anions with significant dual colorimetric and fluorescent signal changes in aqueous solution. A large blue shift was also observed in the absorption spectra in response to CN−. The bleaching of the color could be clearly observed by the naked eye. By the nucleophilic attacking of CN− to the benzothiazol CN bond of the sensor, the intramolecular charge transfer progress was blocked with both color and fluorescence changes. The mechanism of the reaction of the sensor with the cyanide ion was established by using 1H NMR and mass spectrometry.

•A cyanide sensor based on a conjugated naphthopyran-benzothiazol system.•The sensor L recognizes CN− selectively in aqueous solution.•A ICT dual-channel sensor displayed excellent red fluorescent.A selective and sensitive red-emitting fluorescent and colorimetric dual-channel sensor, which could be used for the detection of cyanide, was developed based on a conjugated naphthopyran–benzothiazol system. Upon the addition of CN− anion, the sensor displayed very large blue-shift in both fluorescence (130 nm) and absorption (100 nm) spectra. The bleaching of the solution’s color could be clearly observed by the naked eye. Other anions nearly had no interference. By the nucleophilic attacking of CN− to the benzothiazol CN bond of the sensor, the intramolecular charge transfer was blocked with color and spectra changed. The detection limit of sensor for CN− was found to be 0.29 μmol/L.

•A highly selective and sensitive cyanide ion sensor.•Fluorescent “turn on” response CN− with detection limit as 1.8 × 10−7 mol/L.•The sensor L recognizes CN− selectively in aqueous solution.A new dual-channel sensor for the detection of cyanide was developed based on the conjugated of naphthalene and malononitrile. Upon the addition of CN−, the sensor displayed very large blue-shift in both fluorescence (80 nm) and absorption (120 nm) spectra. The sensor of cyanide was performed via the nucleophilic attack of cyanide anion to vinylic groups of the sensor with a 1:1 binding stoichiometry and the color changed of the sensor is mainly due to the intramolecular charge transfer process improvement. The intramolecular charge transfer progress was blocked with color changed and fluorescence blue-shift. The mechanism of sensor reaction with CN− ion was studied using 1H NMR and mass spectrometry.

Polymeric micelles with surface immobilized galactose (Gal) are promising candidates for hepatoma-targeted drug delivery. Herein, a novel hepatoma-targeted micellar system was prepared through the non-covalent attachment of Gal to the micellar surface. A series of pH-responsive methoxyl poly(ethylene glycol)-b-poly(β-amino ester) (MPEG-PBAE) consisting of a hydrophobic alkyl chain were easily synthesized through Michael addition between amine monomer and diarcrylate. The micelles of the pH-responsive polymers exhibited stability at physiological pH and accelerated doxorubicin (DOX) release without burst release in response to an acidic pH environment. Furthermore, N-(1-deoxylactitol-1-yl) dodecylamine (Gal-C12) as a targeting ligand was successfully bound to the micellar surface by hydrophobic interaction. The results of cellular uptake, in vitro cytotoxicity and cell cycle analysis indicated that the Gal functionalized micelles effectively transferred DOX to hepatoma cells (e.g. HepG2 cells) via asialoglycoprotein receptor (ASGPR) mediated endocytosis, released DOX from the micelles and resulted in enhanced proliferation inhibition efficacy. The ease of surface functionalization and enhanced drug efficacy make the present platform promising for hepatoma-targeted drug delivery in cancer therapy.

In this study, a releasable disulfide carbonate linker is used to prepare disulfide-containing crosslinked polyethyleneimines (PEI-SS-CLs) for gene delivery. ESI-MS analysis shows that after being incubated with 1,4-dithio-DL-threitol (DTT), the degradable linkages in the polyethyleneimine (PEI) derivatives undergo disulfide bond cleavage followed by intramolecular cyclization and cleavage of the neighboring carbamate bond. Moreover, it is observed that thiol/polyanions trigger the release of DNA from polyplexes via the reductive degradability of PEI-SS-CLs and ion-exchange. In vitro transfection results indicate that PEI-SS-CL-1.5 (at a crosslinker/PEI feed molar ratio of 1.5) exhibits higher transfection efficacy than the commercially available reagents such as the high molecular weight PEI with a molecular weight of 25 kDa (PEI 25k) and the versatile liposomes Lipofectamine 2000. PEI-SS-CL-1.5 also demonstrates significantly lower cytotoxicity, compared with PEI 25k and Lipofectamine 2000. Our study indicates that incorporating the thiol-specific cleavable disulfide bond into crosslinked PEIs and implementing regulated release of DNA are effective strategies for designing safe and effective gene vectors.

Salecan is a biological macromolecular and biocompatible polysaccharide that has been investigated for recent years. Herein, we report a novel cationic hydrogel fabricated by graft-polymerizing 3-(methacryloylamino)propyl-trimethylammonium chloride (MAPTAC) onto salecan chains. The obtained hydrogels were transparent, solid-elastic, macro-porous, ion-sensitive, and non-cytotoxic. The swelling ratios increased with salecan content, while mechanical strength does the opposite. Moreover, drug delivery test was studied as a potential application. Diclofenac sodium (DS) and insulin were selected as model drugs. Interestingly, in drug loading process, DS molecules exhibited highly affinity to these cationic hydrogels. Almost all the DS molecules in loading solution were absorbed and spread into the hydrogel. For drug release profiles, insulin-loaded hydrogel showed an initial rapid release and a sustained release. As a comparison, DS-loaded hydrogel exhibited a more sustained release profile. Results suggested salecan-g-PMAPTAC hydrogel could be a good candidate for anionic drug loading and delivery.

•Salecan is a new water-soluble microbial polysaccharide.•Salecan-containing semi-IPN hydrogels were synthesized.•Effect of Salecan content on the properties of the hydrogels were studied.•The Salecan-based hydrogel was an effective vehicle for drug encapsulation/release.Salecan is a new linear extracellular β-glucan. The unique structure and beneficial properties of Salecan makes it an appealing material in biomedical applications. In this work, novel drug devices based on Salecan in a hydrogel matrix of poly(N-(3-dimethylaminopropyl)acrylamide-co-acrylamide) (Salecan/PDA) were fabricated via free radical polymerization for controlled release of amoxicillin. It was demonstrated that amoxicillin was efficiently encapsulated into the developed hydrogels and released in a Salecan dose-dependent and pH-sensitive manner. Furthermore, cell toxicity and adhesion assays confirmed that these drug carriers were biocompatible. Altogether, this study opens a new avenue to fabricate hydrogel devices for controlled delivery of drug.