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Alginate (Alg) hydrogels have attracted extensive attention in the biomedical field due to their biocompatibility. However, single Alg hydrogels exhibit weak mechanical strength, poor stability and cell adhesion, which severely restricts their biomedical application. For this reason, we designed alginate/gelatin/cellulose nanocrystals (Alg/G/CNCs) composite hydrogels by combining interpenetrating network (IPN) technology, cellulose nanocrystals (CNCs) reinforcement and in situ cross-linking method to improve the functional defects of Alg hydrogels. The structure and properties of the resultant Alg/G/CNCs composite hydrogels were comprehensively evaluated by FT-IR, TGA, XRD, swelling and degradability measurements, and cytocompatibility experiments. Alg/G/CNCs composite hydrogels with regular three-dimensional porous network (3D) structures was successfully fabricated through the ionic cross-linking of alginate and the covalent cross-linking of gelatin, followed by the reinforcement of colloidal cellulose nanocrystals (CNCs) that were prepared by sulfuric acid hydrolysis of microcrystalline cellulose (MCC). The addition of CNCs could generate interaction force with the polymer in the IPN matrix, which was able to regulate the physicochemical properties of the composite hydrogel to a certain extent. Moreover, with the increase of gelatin (G) content, the compressive strength of Alg/G/CNCs composite hydrogels gradually increased, while the swelling property decreased gradually. Meanwhile, Alg/G/CNCs composite hydrogels exhibited good cell adhesion, proliferation and differentiation properties. In particular, Alg/0.5G/CNCs composite hydrogels displayed the best cell proliferation effect, while Alg/2G/CNCs composite hydrogels revealed the most significant cell differentiation effect. Therefore, Alg/G/CNCs composite hydrogels could exhibit good mechanical properties and biocompatibility, which possessed great application potential in the field of tissue engineering.

Due to the presence of abundant carboxyl and hydroxyl groups on the molecular chain, the raw alginate is too hydrophilic to achieve effective entrapment and controlled release of hydrophobic drug. To broaden the application range of alginate, 1-bromodecane was covalently grafted onto sodium alginate (SA) via bimolecular nucleophilic substitution (SN2) reaction to synthesize decyl alginate ester derivative (DAED). The structure and self-assembly behavior of DAED were characterized by means of FT-IR, 1H NMR, thermogravimetric analysis (TGA), XRD, fluorescence spectrum (FM), surface tension (SFT), TEM, atomic force microscope (AFM), and dynamic light scattering (DLS). Furthermore, the loading and in vitro release of hydrophobic ibuprofen for the self-assembled DAED microcapsules and their cytotoxicity against the murine macrophage RAW264.7 cell were investigated. The FT-IR and 1H NMR analyses showed that the decyl groups were successfully grafted onto the alginate backbone. The results of TGA and XRD showed that due to the grafting decyl side chains, the intramolecular hydrogen bond of DAED was broken, thus resulting in the decrease of its thermal stability and the change of its microcrystalline structure, which improved its molecular flexibility and self-assembly behavior. Therefore, the DAED could reveal good amphiphilic property with the critical aggregation concentration (CAC) of 0.08 g/L, and form micelle-like aggregates with the average hydrodynamic diameter of 185.1 nm (PDI = 0.615) and zeta potential at about −39.2 mV. In addition, from TEM and AFM observation, DAED could generate spherical drug-loaded microcapsules through its self-assembly behavior, which exhibited excellent sustained-release property ascribed to the enhanced affinity of DAED to hydrophobic ibuprofen. And the prepared DAED microcapsules also displayed low cytotoxicity to the murine macrophage RAW264.7 cells. Therefore, it was the good self-assembly behavior of DAED that made it have great potentials as the hydrophobic drug carriers in pharmaceutical field.

To improve the affinity of alginate to the hydrophobic drug molecules, such as ibuprofen, the Ugi four-component condensation reaction involving sodium alginate (SA), tosylmethyl isocyanide, propionaldehyde and octylamine was proposed to synthesize the novel amphiphilic alginate-bisamide derivative (AABD) without any organic solvents and catalysts. The molecular structure and self-aggregate behavior of the resultant AABD was characterized by FT-IR spectrometer, 1H NMR spectrometer, X-ray diffraction, thermal gravimetric analysis, fluorescence spectrophotometer, transmission electron microscope and dynamic light scattering. Meanwhile, the loading and in vitro release of ibuprofen for the AABD microcapsules prepared by the emulsification method as well as their cytotoxicity were also investigated. Experimental results showed that the AABD with the degree of substitution of 19.41% was successfully prepared by the Ugi reaction, and the grafting of hydrophobic side groups on the backbone of alginate was conducive to enhancing its molecular flexibility and colloidal interface activity. Therefore, the AABD could reveal good amphiphilic property with the critical aggregation concentration (CAC) of 0.105 g/L in 0.15 mol/L aqueous NaCl solution, and form the self-aggregated micelle with the average hydrodynamic diameter of 396 nm (PDI = 0.31) and zeta potential at about − 62.4 mV. Furthermore, the prepared AABD microcapsules displayed the high encapsulation efficiency and sustained-release property in comparison with the SA microcapsules for the good affinity of AABD to hydrophobic ibuprofen that retarded the drug diffusion. And it also exhibited low cytotoxicity to the murine macrophage RAW264.7 cells. Therefore, the novel amphiphilic AABD synthesized by the Ugi reaction would be of great potentials as the hydrophobic drug carriers for sustained-release formulations.

To achieve the poly(propylene carbonate trimellitic anhydride) (PPCTMA) with excellent performance, high molecular weight, enhanced yield and good thermal stability, the ternary composite catalyst system of zinc glutarate/rare earth ternary complex/double metal cyanide (ZnGA/RET/DMC) was proposed to perform the terpolymerization of CO2, propylene oxide and trimellitic anhydride. Since the crystallinity and surface activity point of Zn–Co DMC could significantly influence the catalytic ability, mechanical ball milling was applied to increase the surface area of the Zn–Co DMC catalyst with better surface activity point. Moreover, the ZnGA/RET/DMC composite catalytic system and polycarbonate products were comparatively evaluated by XRD, SEM, FT-IR, TGA, NMR, XPS and TEM. Experimental results showed that the ZnGA/RET/DMC composite catalyst system displayed outstanding synergistic effect on the terpolymerization of CO2, PO and TMA with better selectivity, activity, and higher molecular weight (Mw) tercopolymer than those of the individual catalyst. According to optimum reaction conditions, the Mw of PPCTMA could be up to 8.29 × 104 g mol−1, and the yield could be up to 66 gpolym/gcat. The alternating tercopolymer, PPCTMA, showed wonderful thermal stability and high decomposition temperature (TGA10% = 313 °C). A possible synergistic catalytic mechanism of the ZnGA/RET/DMC ternary composite catalyst system was also conjectured.

In this paper, we developed an organic solvent-free, eco-friendly, simple and efficient one-pot approach for the preparation of amphiphilic conjugates (Ugi-OSAOcT) by grafting octylamine (OCA) to oxidized sodium alginate (OSA). The optimum reaction parameters that were obtained based on the degree of substitution (DS) of Ugi-OSAOcT were a reaction time of 12 h, a reaction temperature of 25 °C and a molar ratio of 1:2.4:3:3.3 (OSA:OCA:HAc:TOSMIC), respectively. The chemical structure and composition were characterized by Fourier transform infrared spectroscopy (FTIR), 1H nuclear magnetic resonance (1H NMR), X-ray diffraction (XRD), thermogravimetry analyser (TGA), gel permeation chromatography (GPC) and elemental analysis (EA). It was found that the Ugi-OSAOcT conjugates with a CMC value in the range of 0.30–0.085 mg/mL could self-assemble into stable and spherical micelles with a particle size of 135.7 ± 2.4–196.5 ± 3.8 nm and negative surface potentials of −32.8 ± 0.4–−38.2 ± 0.8 mV. Furthermore, ibuprofen (IBU), which served as a model poorly water-soluble drug, was successfully incorporated into the Ugi-OSAOcT micelles by dialysis method. The drug loading capacity (%DL) and encapsulation efficiency (%EE) of the IBU-loaded Ugi-OSAOcT micelles (IBU/Ugi-OSAOcT = 3:10) reached as much as 10.9 ± 0.4–14.6 ± 0.3% and 40.8 ± 1.6–57.2 ± 1.3%, respectively. The in vitro release study demonstrated that the IBU-loaded micelles had a sustained and pH-responsive drug release behavior. In addition, the DS of the hydrophobic segment on an OSA backbone was demonstrated to have an important effect on IBU loading and drug release behavior. Finally, the in vitro cytotoxicity assay demonstrated that the Ugi-OSAOcT conjugates exhibited no significant cytotoxicity against RAW 264.7 cells up to 1000 µg/mL. Therefore, the amphiphilic Ugi-OSAOcT conjugates synthesized by the green method exhibited great potential to load hydrophobic drugs, acting as a promising nanocarrier capable of responding to pH for sustained release of hydrophobic drugs.

On account of the rigid structure of alginate chains, the oxidation-reductive amination reaction was performed to synthesize the reductive amination of oxidized alginate derivative (RAOA) that was systematically characterized for the development of pharmaceutical formulations. The molecular structure and self-assembly behavior of the resultant RAOA was evaluated by an FT-IR spectrometer, a 1H NMR spectrometer, X-ray diffraction (XRD), thermal gravimetric analysis (TGA), a fluorescence spectrophotometer, rheology, a transmission electron microscope (TEM) and dynamic light scattering (DLS). In addition, the loading and in vitro release of ibuprofen for the RAOA microcapsules prepared by the high-speed shearing method, and the cytotoxicity of the RAOA microcapsules against the murine macrophage RAW264.7 cell were also studied. The experimental results indicated that the hydrophobic octylamine was successfully grafted onto the alginate backbone through the oxidation-reductive amination reaction, which destroyed the intramolecular hydrogen bond of the raw sodium alginate (SA), thereby enhancing its molecular flexibility to achieve the self-assembly performance of RAOA. Consequently, the synthesized RAOA displayed good amphiphilic properties with a critical aggregation concentration (CAC) of 0.43 g/L in NaCl solution, which was significantly lower than that of SA, and formed regular self-assembled micelles with an average hydrodynamic diameter of 277 nm (PDI = 0.19) and a zeta potential of about −69.8 mV. Meanwhile, the drug-loaded RAOA microcapsules had a relatively high encapsulation efficiency (EE) of 87.6 % and good sustained-release properties in comparison to the drug-loaded SA aggregates, indicating the good affinity of RAOA to hydrophobic ibuprofen. The swelling and degradation of RAOA microcapsules and the diffusion of the loaded drug jointly controlled the release rate of ibuprofen. Moreover, it also displayed low cytotoxicity against the RAW264.7 cell, similar to the SA aggregates. In view of the excellent advantages of RAOA, it is expected to become the ideal candidate for hydrophobic drug delivery in the biomedical field.

To extend the alginate applicability for the sustained release of hydrophobic medicine in drug delivery systems, the alkyl alginate ester derivative (AAD), including hexyl alginate ester derivative (HAD), octyl alginate ester derivative (OAD), decyl alginate ester derivative (DAD), and lauryl alginate ester derivative (LAD), were synthesized using the alkyl bromides with different lengths of carbon chain as the hydrophobic modifiers under homogeneous conditions via the bimolecular nucleophilic substitution (SN2) reaction. Experimental results revealed that the successful grafting of the hydrophobic alkyl groups onto the alginate molecular backbone via the SN2 reaction had weakened and destroyed the intramolecular hydrogen bonds, thus enhancing the molecular flexibility of the alginate, which endowed the AAD with a good amphiphilic property and a critical aggregation concentration (CAC) of 0.48~0.0068 g/L. Therefore, the resultant AAD could form stable spherical self-aggregated micelles with the average hydrodynamic diameter of 285.3~180.5 nm and zeta potential at approximately −44.8~−34.4 mV due to the intra or intermolecular hydrophobic associations. With the increase of the carbon chain length of the hydrophobic side groups, the AAD was more prone to self-aggregation, and therefore was able to achieve the loading and sustained release of hydrophobic ibuprofen. Additionally, the swelling and degradation of AAD microcapsules and the diffusion of the loaded drug jointly controlled the release rate of ibuprofen. Meanwhile, the AAD also displayed low cytotoxicity to the murine macrophage RAW264.7 cells. Thanks to the good amphiphilic property, colloidal interface activity, hydrophobic drug-loading performance, and cytocompatibility, the synthesized AAD exhibited a great potential for the development of hydrophobic pharmaceutical formulations.

In this work, the interfacial assembly of amphiphilic bacterial cellulose nanocrystals (BCNs) by Pickering emulsion method was proposed to improve the compatibility between the alginate and hydrophobic drug. BCNs prepared by sulfuric acid hydrolysis of biosynthesized bacterial cellulose was used as the particulate emulsifiers, whereas the model drug, alfacalcidol, dissolved in CH2Cl2 was used as the oil phase. The oil-in-water Pickering emulsions were prepared by ultrasonic dispersion method and then they were well dispersed in alginate solution. Ultimately, the drug-loaded alginate composite beads were successfully fabricated by external gelation. The characterization results revealed that BCNs possessed good colloidal property and could form flocculated fibril network, which was beneficial to stabilize Pickering emulsions. The irreversible adsorption of BCNs at the oil-water interface could make the Pickering emulsions preserve the droplets against coalescence and Ostwald ripening when they were dispersed in alginate solution. The interfacial assembly of amphiphilic BCNs and the hydrogel shells of the alginate composite beads formed by external gelation achieved the loading and sustained release of alfacalcidol. The release curves were well fitted by Korsmeyer Peppas model and the release mechanism of alfacalcidol from the composite beads was attributed to non-Fickian transport. In addition, the resultant alginate composite beads exhibited low cytotoxicity and good capabilities for osteoblast differentiation.

The bare silica nanoparticles (SiO2 NPs) synthesized by Stober method is very hydrophilic and chemically inert, which may suffer from particles aggregation and low biocompatibility when they are used in physiological media. For this case, we attempted to conduct surface functionalization of SiO2 NPs by Ugi multicomponent reaction, using amphiphilic amidic alginate derivative (AAD) as the modifier. The successful synthesis of amidic alginate derivative-functionalized silica nanoparticles (AAD-SiO2 NPs) was confirmed by FT-IR spectroscopy, 1H NMR spectrometer, X-ray photoelectron spectroscopy and thermal gravimetric analysis. The covalent bonding of alginate derivative onto the surface of SiO2 NPs increased their average diameter and zeta potential, which effectively improved their colloidal stability in PBS. Additionally, surface tension measurements and cell studies results revealed that the resultant AAD-SiO2 NPs possessed relatively high surface activity and cytocompatibility, which exhibited great potential in the biomedical field.

To achieve the poly(propylene carbonate trimellitic anhydride) (PPCTMA) with excellent performance, high molecular weight, enhanced yield and good thermal stability, the ternary composite catalyst system of zinc glutarate/rare earth ternary complex/double metal cyanide (ZnGA/RET/DMC) was proposed to perform the terpolymerization of CO

To investigate the situation of antibiotic consumption and to assess the inappropriate use on pediatric inpatients of different types hospitals in Sichuan, China. A cross-sectional survey of antibiotic prescriptions among hospitalized children aged 1month -14years were conducted from April 2018 to June 2018 in southwestern China. Antibiotic prescriptions were extracted from electronic records during hospitalization of each inpatient in five different types hospitals. In this study, the antibiotic prescription rate of hospitalized children was 66.9% (1176/1758). Compared with tertiary children hospital (TC) (46.1%), general hospitals and non-tertiary children hospitals has higher rate of antibiotic prescription (almost 85%) (P

Since the direct electron transfer of myoglobin (Mb) is hardly realized on the bare electrode, the electrodeposition of the mixture of novel MnO2–C composite microsphere, sodium alginate (SA) and Mb on the surface of the carbon ionic liquid electrode (CILE) was conducted to fabricate the modified electrode, denoted as Nafion/Mb–SA–MnO2–C/CILE. The biological activity of Mb in the Mb–SA–MnO2–C composite was confirmed by FTIR and UV–Vis absorption spectra. The fabricated Nafion/Mb–SA–MnO2–C/CILE exhibited a fast electron transfer process with a pair of well-defined redox peaks attributed to the excellent electrochemical property of MnO2–C composite microsphere and good biocompatibility of SA that could provide Mb suitable microenvironment to keep its biological activity and facilitate the electron transfer. Additionally, the modified electrode also exhibited a wider linear range and a low detection limit toward the electrocatalytic reduction in trichloroacetic acid with good stability, reproducibility and accurate detection for the real samples.

TiO2 nanoparticles (nano-TiO2) as one of the most extensively used nanoscale materials easily undergo spontaneous aggregation and gravity sedimentation ascribed to their high adsorption energy, which significantly restricts their actual applications. For this reason, a benzyl-grafted alginate derivative (BAD) with good colloidal interface activity, prepared by a bimolecular nucleophilic substitution (SN2) reaction, was used as the dispersant to stabilize nano-TiO2. The structure and colloidal properties of BAD was evaluated by FT-IR spectroscopy, 1H NMR spectroscopy, thermal gravimetric analysis (TGA) and dynamic light scattering (DLS). The effects of pH and ionic strength on the dispersion stability of BAD/nano-TiO2 suspensions were also examined by DLS. To further probe its feasibility as a drug delivery system, the BAD/nano-TiO2 complex was applied as particulate emulsifiers to fabricate drug-loaded Pickering emulsions. Meanwhile, the morphology properties and the sustained release performance of the drug-loaded Pickering emulsions were also investigated. Experimental results showed that the adsorption of BAD on nano-TiO2 was achieved by an intermolecular hydrogen bond between the carboxylic functional groups of BAD and the Ti–OH of TiO2. The adsorption of BAD enhanced the electrostatic repulsion and steric hindrance between nano-TiO2 improving the dispersion stability of nano-TiO2 at different pH and ionic strength. Additionally, the obtained Pickering emulsions displayed good drug-loading capacity and sustained release performance with the release mechanism of non-Fickian transport, which exhibited great potential in the pharmaceutical field.

To achieve the dispersion of the hydrophobic graphene (GR), the amphiphilic alginate caprylamide (ACA) was synthesized to fabricate electroactive Nafion/Mb–ACA–GR/CILE for the accurate determination of trichloroacetic acid (TCA). SEM observation, FT-IR and UV-Vis spectroscopic analysis indicated that ACA could tightly immobilize Mb and GR on the electrode surface by constructing biointerfaces, which not only provided Mb a suitable microenvironment to maintain its biological activity, but also shortened the distances between the active centers of Mb with carbon ionic liquid electrode (CILE), thus promoting the electron transfer rate. The electrochemical characterization of Nafion/Mb–ACA–GR/CILE showed that the direct electron transfer of Mb was realized on the modified electrode, which was attributed to the high electrical conductivity and excellent electrocatalytic activity of GR and good biocompatibility of ACA. Moreover, Nafion/Mb–ACA–GR/CILE exhibited good electrocatalytic activity towards TCA with the linear range from 2.5 to 47.3 mmol L−1 and lower KMapp value of 8.3 mmol L−1. Moreover, the modified electrode also revealed good stability, reproducibility and accurate detection of tap-water, exhibiting great potential for the applications as the third-generation electrochemical biosensors.

In this work, Zn–Fe double metal cyanide (DMC) catalysts were successfully synthesized via clean and efficient ball milling. Imidazolium-based ionic liquids as cocatalysts were incorporated into the structure of the DMC catalysts during the grinding process. The modified Zn–Fe DMC catalysts were effective for the alternating copolymerization of carbon dioxide and propylene oxide under controlled reaction conditions. The properties and structures of the Zn–Fe DMC catalysts and the resulting polymers were characterized by Fourier transform infrared spectroscopy, scanning electron microscopy, X-ray diffraction, elemental analysis, 1H and 13C NMR spectroscopy, gel permeation chromatography, and thermogravimetric analysis. The results indicate that the Zn–Fe DMC catalysts exhibit higher thermal stability compared to the DMC catalysts without imidazolium-based ionic liquids (DMC-Blank). We determined that the introduction of a small amount of imidazolium-based ionic liquids can increase the carbonate content of the poly(propylene carbonate) (PPC) copolymer in the range of 18.48–29.00%. The turnover numbers of PPC were ∼4.40. In addition, the measured number-average relative molecular mass was in the range of 2.96 × 103–4.98 × 103 with a narrow polydispersity index of 1.00–1.08.

Alginate hydrogel undergoes the poor and unstable mechanical strength, and the lack of cell recognition sites for bone tissue engineering. For this reason, we attempted to fabricate alginate/bacterial cellulose nanocrystals-chitosan-gelatin (Alg/BCNs-CS-GT) composite scaffold by the combined method involving the incorporation of bacterial cellulose nanocrystals (BCNs) in alginate matrix, internal gelation by hydroxyapatite- d -glucono-δ-lactone (HAP-GDL) complex and layer-by-layer (LBL) electrostatic assembly of positively charged chitosan (CS) and negatively charged gelatin (GT). The characterization results revealed that Alg/BCNs-CS-GT composite scaffold exhibited good 3D architecture with well-defined porous structure, improved compressive strength and regulated biodegradation. In particular, the excellent biocompatibility and the reinforcing effect of BCNs, and the outer GT chains containing repetitive motifs of arginine-glycine-aspartic (RGD) sequences favored the attachment, proliferation and differentiation of osteoblastic MC3T3-E1 cells.

Although bacterial cellulose (BC) and bacterial cellulose nanocrystals (BCNs) have considered to be edible, non-toxic, biocompatible and biodegradable, there is still the dearth of reports of BC and BCNs as the emulsifiers of Pickering emulsions with respect to the applications in foods, cosmetics and medicines. In this work, BC with ultrafine network architecture and 8–40 nm crystalline microfibrils in diameter was produced by Acetobacter xylinum , and then it was hydrolyzed by sulfuric acid followed by the oxidation of hydrogen peroxide to prepare BCNs. The physicochemical properties of BC and BCNs were contrastively evaluated by FT-IR, XRD, TGA and dynamic light scattering (DLS). The emulsifying performances of BC and BCNs in the stabilization of olive oil Pickering emulsion were further evaluated by optical microscope (OM) and fluorescent microscope (FM). Experimental results showed that the sulfuric acid hydrolysis of BC induced the removal of the amorphous components and the cleavage of the crystalline microfibrils, making BCNs possess the initiating decomposition temperature of 350 °C, the crystallinity index (CrI) of 89.6%, average size of 259.6 nm with PDI of 0.26 and zeta potential at about −34.8 mV, which exhibited high thermal stability and good emulsifying performance in comparison with BC. Furthermore, the effects of pH and ionic strength on emulsion stability were also investigated. In comparison to BC, BCNs were more sensitive in response to the change of pH and ionic strength.

It is common knowledge that pure alginate hydrogel is more likely to have weak mechanical strength, a lack of cell recognition sites, extensive swelling and uncontrolled degradation, and thus be unable to satisfy the demands of the ideal scaffold. To address these problems, we attempted to fabricate alginate/bacterial cellulose nanocrystals-chitosan-gelatin (Alg/BCNs-CS-GT) composite scaffolds using the combined method involving the incorporation of BCNs in the alginate matrix, internal gelation through the hydroxyapatite-d-glucono-δ-lactone (HAP-GDL) complex, and layer-by-layer (LBL) electrostatic assembly of polyelectrolytes. Meanwhile, the effect of various contents of BCNs on the scaffold morphology, porosity, mechanical properties, and swelling and degradation behavior was investigated. The experimental results showed that the fabricated Alg/BCNs-CS-GT composite scaffolds exhibited regular 3D morphologies and well-developed pore structures. With the increase in BCNs content, the pore size of Alg/BCNs-CS-GT composite scaffolds was gradually reduced from 200 μm to 70 μm. Furthermore, BCNs were fully embedded in the alginate matrix through the intermolecular hydrogen bond with alginate. Moreover, the addition of BCNs could effectively control the swelling and biodegradation of the Alg/BCNs-CS-GT composite scaffolds. Furthermore, the in vitro cytotoxicity studies indicated that the porous fiber network of BCNs could fully mimic the extracellular matrix structure, which promoted the adhesion and spreading of MG63 cells and MC3T3-E1 cells on the Alg/BCNs-CS-GT composite scaffolds. In addition, these cells could grow in the 3D-porous structure of composite scaffolds, which exhibited good proliferative viability. Based on the effect of BCNs on the cytocompatibility of composite scaffolds, the optimum BCNs content for the Alg/BCNs-CS-GT composite scaffolds was 0.2% (w/v). On the basis of good merits, such as regular 3D morphology, well-developed pore structure, controlled swelling and biodegradation behavior, and good cytocompatibility, the Alg/BCNs-CS-GT composite scaffolds may exhibit great potential as the ideal scaffold in the bone tissue engineering field.

Alginate is a well-known biomaterial which has been widely used in tissue engineering due to its excellent property. However, there are still several drawbacks, such as weak mechanical strength, the lack of cell recognition sites for cell adhesion, extensive swelling and uncontrolled degradation that limit its practical application. Therefore, the internal gelation using CaCO3–GDL complex and the incorporation of bacterial cellulose nanocrystals (BCNs) and type I collagen (COL) as the reinforcing component into alginate matrix were proposed to prepare the novel and homogeneous alginate/bacterial cellulose nanocrystals/collagen composite scaffold (ALG/BCNs/COL). The morphology, porosity, mechanical property, swelling and degradation behavior, and cytotoxicity of the resultant scaffold were investigated. The experimental results showed that ALG/BCNs/COL revealed good three-dimensional (3D) architecture as well as lamellar and porous morphologies. The incorporation of BCNs into alginate matrix obviously decreased the pore size and maintained the porosity of ALG/BCNs/COL, which was in favour of mechanical integrity. FT-IR spectra and XRD analysis revealed that the components of ALG/BCNs/COL, such as SA, BCNs and COL were combined together by intermolecular hydrogen bonds, which could effectively inhibit large swelling and retard the biodegradation of the composite scaffold. Finally, cell studies results indicated that both MC3T3-E1 and h-AMS cells were viable and proliferate well on the composite scaffold.

The rare earth ion doped upconversion nanoparticles (UCNPs) synthesized by hydrophobic organic ligands possess poor solubility and low fluorescence quantum yield in aqueous media. To conquer this issue, NaYF4:Yb3+/Tm3+ UCNPs, synthesized by a hydrothermal method, were coated with F127 and then assembled with chitosan to fabricate the chitosan/NaYF4:Yb3+/Tm3+ composite beads (CS/NaYF4:Yb3+/Tm3+ CBs) by Pickering emulsion system. The characterization results revealed that the as-synthesized NaYF4:Yb3+/Tm3+ UCNPs with an average size of 20nm exhibited spherical morphology, high crystallinity and characteristic emission upconversion fluorescence with an overall blue color output. The NaYF4:Yb3+/Tm3+ UCNPs were successfully conjugated on the surface of chitosan beads by the gelling of emulsion droplets. The resultant CS/NaYF4:Yb3+/Tm3+ CBs showed good upconversion luminescent property, drug-loading capacity, release performance and excellent biocompatibility, exhibiting great potentials in targeted drug delivery and tissue engineering with potential tracking capability and lasting release performance.

Lanthanide-doped upconversion nanoparticles (UCNPs) synthesized with hydrophobic organic ligands lacks solubility in aqueous media. To address this problem, we attempted to fabricate chitosan/NaYF 4 :Yb/Tm UCNPs hybrid microspheres (CS/NaYF 4 :Yb/Tm HMs) by use of a Pickering emulsion system to expand their applications in the biomedical field. The characterization of samples revealed that as-synthesized UCNPs coated with F127, a nonionic surfactant, exhibited good colloidal properties, high crystallinity and characteristic emission upconversion fluorescence, displaying an overall blue color output. The NaYF 4 :Yb/Tm UCNPs were successfully entrapped on the surface of chitosan microspheres by the gelling of Pickering emulsion droplets, preserving good upconversion luminescent properties. The CS/NaYF 4 :Yb/Tm HMs combine the biological compatibility of chitosan and photoluminescence of UCNPs, possessing great potential in biomedical applications.

The research goal of the present study was to develop a carrier for loading and controlled -release of the hydrophobic drug with the combined use of organo-montmorillonite (OMMT) and alginate. The OMMT was synthesized through the intercalation modification of sodium montmorillonite (Na-MMT) with cationic cetyltrimethylammonium bromide (CTAB), nonionic nonylphenol polyoxyethylene ether (NPE) and the mixture of them via simple and convenient wet ball-milling method. Furthermore, the organo-montmorillonite/alginate (OMMT/Alg) composite hydrogel beads with slow and controlled release properties were constructed by using alginate as a coating material under the exogenous cross-linking of calcium ions. The physical and chemical properties of OMMT were comparatively evaluated by scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), transmission electron microscopy (TEM), dynamic light scattering (DLS), thermogravimetric analyzer (TGA), BET-specific surface area measurements, and drug adsorption experiments. Experimental results showed that the presence of CTAB was able to facilitate the intercalation of CTAB/NPE into Na-MMT through the cation exchange reaction. And the cationic CTAB and nonionic NPE were adsorbed or intercalated into the MMT lamellar structure through the wet ball-milling process, which could change the hydrophilic nature of Na-MMT and improve its affinity to the hydrophobic drug molecules. In addition, the OMMT/Alg composite hydrogel beads displayed superior sustained-release properties than Na-MMT/Alg, mainly ascribed to the good affinity of OMMT to hydrophobic drug that retarded the drug diffusion. In particular, CTA/NPE-MMT/Alg with the highest loading capacity (LC) and encapsulation efficiency (EE) revealed the optimal controlled performance for the release of hydrophobic ibuprofen. The release followed the Korsmeyer-Peppas model suggested non-Fickian diffusion release mechanism. Based on the high drug loading capacity and excellent controlled drug release properties, the CTA/NPE-MMT/Alg incorporating hydrophobic drugs into hydrophilic matrices could be a highly promising material for use in hydrophobic drug delivery.

Although several approaches have been reported on the development of nanoemulsions over the last few years, studies on the formation of biodiesel nanoemulsions for bifenthrin formulation by the low-energy phase inversion composition (PIC) method are still scarce. Herein, the preparation of oil-in-water (O/W) nanoemulsions suitable for pesticide application has been achieved in biodiesel by dissolving a bifenthrin/mixture of a non-ionic surfactant (NP-6) and an anionic surfactant (ABSCa)/water system by the PIC method. The mechanism of the formation of bifenthrin nanoemulsions by dripping the water phase into the oil–surfactant phase was exemplified via the pseudo-ternary phase diagram. The effects of the mass ratio of NP-6 and ABSCa, mROS, stirring rate, the addition rate of water and the emulsification temperature on the mean droplet size of the nanoemulsion were investigated by dynamic light scattering (DLS). In addition, the interfacial tension and the contact angle of bifenthrin nanoemulsions for the spraying application were investigated. The insecticidal activity of bifenthrin nanoemulsions against cabbage maggots was further studied. Moreover, the emulsion stability of the bifenthrin nanoemulsions against Ostwald ripening behavior was evaluated, and the long-term stability of the bifenthrin formulation was studied by the HPLC method to assess the shelf life of the pesticide formulation. Experimental results showed that the optimum emulsification conditions for the mass ratio of NP-6 and ABSCa, mROS, stirring rate, the addition rate of water and the emulsification temperature were respectively 5/5, 1.4, 8000 rpm, 0.7 mL min−1 and 25 °C. The bifenthrin nanoemulsion with low interfacial tension and contact angle, easy adsorption on plant leaf surfaces and good shelf life has great potential for use as a pesticide formulation.

The cellulose nanocrystals (CNCs) synthesized by sulfuric acid hydrolysis are highly hydrophilic and prone to form the agglomerations due to the hydrogen bonding, which limit their applications in the formulations of Pickering emulsions. For this reason, we selected microcrystalline cellulose (MCC) as the raw material for the extraction of CNCs through sulfuric acid hydrolysis and hydrogen peroxide oxidation, and then combined the surfactants of cetyltrimethylammonium bromide (CTAB) and CNCs to prepare the (O/W) Pickering emulsions by high-speed shearing method. The physicochemical properties of the resultant CNCs were evaluated by scanning electron microscopy (SEM), atomic force microscope (AFM), transmission electron microscopy (TEM), dynamic light scattering (DLS), Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD) and thermal gravimetric analysis (TGA). The formed emulsions were characterized by fluorescent microscope (FM). And the effects of the CTAB concentration, pH and ionic strength on the stability of the formed Pickering emulsions were also investigated. Experimental results showed that the sulfuric acid hydrolysis of MCC induced the removal of the amorphous components and the cleavage of the crystalline microfibrils, making CNCs exhibit the curled and rod-like shape with the average hydrodynamic diameter of 460.5 nm (PDI = 0.585), zeta potential of -34.1 mV and the crystallinity index (CrI) of 77.3 %, which revealed good colloidal properties. In addition, the optimal emulsification conditions for CTAB concentration, pH and ionic strength were respectively 0.5 CMC, 11 and 20∼60 mmol/L. On the basis of the above results, the Pickering emulsions stabilized by CTAB/CNCs complex may have potential for large applications in foods, cosmetics and medicines.

A pH-responsive anionic wormlike micellar (WLM) system formed by sodium oleate (NaOA) and benzyltrimethyl ammonium bromide were studied via rheological measurements and dynamic light scattering measurements. The anionic WLMs were used as templates to synthesize mesoporous silicas (MSs). The microstructures of the WLM system can be controlled by altering the pH. The transformation between NaOA and oleic acid changes the charges on the micelle surface and affects the viscoelasticity of the system. High NaOA concentration increases the activation energy (Ea) of the system, whereas a high pH value promotes the formation of spherical micelles and reduces the Ea of the solutions. By contrast, a low pH value increases the viscosity of the system given that the electrostatic repulsion between NaOA head-groups is weakened. However, if numerous NaOAs transform into insoluble oleic acids, the viscosity of the system will dramatically decrease. In addition, micelle length and NaOA concentration affect the microstructure of MSs.

A novel biosensor based on electro-co-deposition of myoglobin (Mb), sodium alginate (SA), Fe3O4-graphene (Fe3O4-GR) composite on the carbon ionic liquid electrode (CILE) was fabricated using Nafion as the film forming material to improve the stability of protein immobilized on the electrode surface, and the modified electrode was abbreviated as Nafion/Mb-SA-Fe3O4-GR/CILE. FT-IR and UV–vis absorption spectra suggested that Mb could retain its native structure after being immobilized in the SA-Fe3O4-GR composite film. The electrochemical behavior of the modified electrode was studied by cyclic voltammetry, and a pair of symmetric redox peaks appeared in the cyclic voltammograms, indicating that direct electron transfer of Mb was realized on the modified electrode, which was ascribed to the good electrocatalytic capability of Fe3O4-GR composite, the good biocompatibility of SA and the synergistic effects of SA and Fe3O4-GR composite. The electrochemical parameters of the electron transfer number (n), the charge transfer coefficient (α) and the electron transfer rate constant (k s) were calculated as 0.982, 0.357 and 0.234 s−1, respectively. The modified electrode exhibited good electrocatalytic ability to the reduction of trichloroacetic acid (TCA) with wide linear range from 1.4 to 119.4 mmol/L, low detection limit as 0.174 mmol/L (3σ), good stability and reproducibility.

In this work, electrodeposition of the mixture of myoglobin (Mb), sodium alginate (SA), and TiO2 nanoparticles on the carbon ionic liquid electrode (CILE) was performed to fabricate the modified electrode which was abbreviated as Nafion/Mb-SA-TiO2/CILE. FT-IR and UV-vis absorption spectra confirmed that Mb could retain its native structure after being immobilized in the SA-TiO2 composite film. The electrochemical characterization of Nafion/Mb-SA-TiO2/CILE revealed that a pair of symmetric redox peaks appeared in the cyclic voltammograms, indicating that direct electron transfer of Mb was realized on the modified electrode. The good biocompatibility of SA, the good electrocatalytic capability of TiO2 nanoparticles, and their synergistic effects were beneficial to the electron transfer between Mb and CILE. The electrochemical parameters of the electron transfer number (n), the charge transfer coefficient (α), and the electron transfer rate constant (k s ) were calculated as 1.032, 0.402, and 0.511 s−1, respectively. The modified electrode exhibited good electrocatalytic ability to the reduction of trichloroacetic acid (TCA) and displayed wide linear range from 5.3 to 114.2 mmol/L and low detection limit as 0.152 mmol/L (3σ). The apparent Michaelis-Menten constant K M app was 32.3 mmol/L. The proposed electrode with good stability and reproducibility had the potential application in the third-generation electrochemical biosensors.

The interaction of cholesteryl-grafted sodium alginate derivative (CSAD) and decyl-β-D-glucopyranoside (DGP) in solution was studied through the surface tension method, fluorescence spectroscopy, electron paramagnetic resonance (EPR), and dynamic light scattering. Results showed that DGP and CSAD exhibit competitive adsorption behaviour at the water–gas interface and that this competitive behaviour can be intensified by NaCl. EPR revealed that the cholesterol groups of CSAD participate in the formation of micellar structures. The steric effect of the cholesterol groups reduces the microviscosity of the micellar structure, but high-concentration NaCl can weaken the polarity and increase the microviscosity of the formed micellar structure. In addition, at a high DGP concentration, high-concentration NaCl can facilitate DGP precipitation; this condition causes abnormal phenomena of surface tension, fluorescence spectroscopy, and EPR. For the emulsion system, analysis of particle size and rheology indicated that DGP and CSAD form a network structure between oil and water interfaces through interaction and thus enhance the non-Newtonian fluid properties of the emulsion. Owing to the competitive adsorption between CSAD and DGP at the oil–water interface, DGP gradually replaces CSAD with the increase in DGP concentration. With a further increase in DGP concentration, the stable steric effect of polymers between oil drops may disappear, and oil drops may aggregate mutually.

To fabricate a hydrophobic pharmaceutical formulation with the use of montmorillonite (MMT), the strong polarity and structural properties of montmorillonite were modified by via simple and convenient wet ball-milling method using the nonionic surfactant, octyl phenyl polyoxyethylene ether, as the modifier, to improve the MMT's affinity to hydrophobic organic drug, ibuprofen. The resultant organo-montmorillonite (OPP-MMT) was characterized by the means of scanning electron microscopy, dynamic light scattering, Fourier transform infrared spectroscopy, X-ray diffraction, transmission electron microscopy, thermogravimetric analyzer, BET-specific surface area measurements, drug adsorption and in vitro release experiments, and in vitro cell viability assay. Experimental results showed that octyl phenyl polyoxyethylene ether was successfully inserted into the interlayer of the raw Na-MMT during the wet ball-milling process. The adsorption and intercalation modification of octyl phenyl polyoxyethylene ether destroyed the rigid structure of Na-MMT, enlarged the interlayer spacing of Na-MMT, and enhanced its specific surface area, pore volume and mean mesopore size, which made it be more conducive to the loading of hydrophobic organic drugs. The adsorption analysis of OPP-MMT on ibuprofen showed that the affinity of OPP-MMT to hydrophobic drugs was better than that of Na-MMT, which was beneficial to the loading of ibuprofen. Moreover, the good affinity of OPP-MMT to hydrophobic drug allowed it to exhibit good controlled release properties for the drug delivery.