Jinmei He

Improving surface and mechanical properties of alginate films by using ethanol as a co-solvent during external gelation.

Alginate films were prepared by solution casting method and further ionically crosslinked in a calcium chloride (CaCl2) water solution containing different proportions (0-40% v/v) of ethanol as the co-solvent. The addition of ethanol into the CaCl2 water solution was found to improve the visual appearance, thickness, surface homogeneity, and mechanical properties of the films, which can be attributed to the reduced swelling degree of films during crosslinking process. Furthermore, Fourier transform infrared spectroscopy (FTIR) and energy dispersive spectroscopy (EDS) analysis indicated that the incorporation of ethanol into the crosslinking solution did not detract from the uniformity of crosslinking throughout the film matrix. However, the swelling degree and calcium content determination indicated that the Ca(2+) crosslinking degree decreased when the ethanol proportion exceeded 30% v/v. Consequently, this study introduces a green, efficient, and simple technique for the preparation of calcium alginate films with excellent surface appearance and mechanical properties for pharmaceutical products.

Preparation of pH-responsive mesoporous hydroxyapatite nanoparticles for intracellular controlled release of an anticancer drug

A well-defined core-shell nano-carrier (PAA-MHAPNs) was successfully synthesized based on a graft-onto method by using mesoporous hydroxyapatite nanoparticles (MHAPNs) as the core and polyacrylic acid (PAA) as the shell. Given that MHAPNs are regarded as one of the most promising drug delivery vehicles due to their excellent performance and the nature of their cancer cell anti-proliferative effect, and the grafted PAA, as a pH-responsive switch, could improve the loading amount of the drug doxorubicin hydrochloride (DOX) effectively by electrostatic interactions, all these advantages mean that the designed models show promise for application in pH-responsive drug delivery systems. The loading content and entrapment efficiency of DOX could reach up to 3.3% and 76%, respectively. The drug release levels of the constructed DOX@PAA-MHAPNs were low under normal physiological conditions (pH 7.4), but they could be increased significantly with a decrease of pH. Cytotoxicity assays indicated that the PAA-MHAPNs was biocompatible, and more importantly, the DOX@PAA-MHAPNs demonstrated an obvious ability to induce apoptosis of cancer cells. Overall, the synthesized systems should show great potential as drug nanovehicles with excellent biocompatibility, high drug loading, and pH-responsive features for future intracellular drug delivery.

Redox-responsive nanoreservoirs based on collagen end-capped mesoporous hydroxyapatite nanoparticles for targeted drug delivery

Mesoporous hydroxyapatite (MHAp) nanoparticles have great potential in nanoscaled delivery devices due to their excellent biocompatibility, nontoxicity and high surface areas. In order to achieve targeting based on cell-specific recognition and site directed, timed and quantitatively controlled drug release to malignant cells, redox-responsive nanoreservoirs based on MHAp (LA-Col-S-S-MHAp) were fabricated by using lactobionic acid-conjugated collagen (LA-Col) as a cap, disulfide bonds as intermediate linkers and MHAp as nanoreservior. Lactobionic acid (LA) molecules acted as the targeting moiety to achieve the targeted drug delivery. The results of scanning electron microscopy (SEM), transmission electron microscopy (TEM), Brunauer-Emmett-Teller (BET), Barett-Joyner-Halenda (BJH), Fourier transform infrared spectroscopy (FTIR) and zeta potential measurements confirmed the successful preparation of LA-Col-S-S-MHAp step-by-step. Dithiothreitol (DTT) was used as an external stimulus to trigger the redox-responsive release of the drug in order to investigate the controlled release behavior of LA-Col-S-S-MHAp. The result proved that LA-Col-S-S-MHAp nanocomposite has a good end-capping efficiency of the drug under physiological conditions, and it has a characteristic of rapid response and burst drug release when exposed to reducing conditions. Confocal laser scanning microscopy (CLSM) images and flow cytometry assay demonstrated that LA-Col-S-S-MHAp nanoparticles were endocytosed and located in the cytoplasm of cells. Redox-responsive targeted drug delivery could be achieved within cells. The system affords references and ideas for designing novel stimuli responsive nanoreservoir to the clinical therapy of liver cancer.

Improved interfacial properties of carbon fiber/unsaturated polyester composites through coating polyhedral oligomeric silsesquioxane on carbon fiber surface

Carbon fibers were coated with E51 plus Methacryl-POSS together in an attempt to improve the interfacial properties between carbon fibers and unsaturated polyester resins matrix. Atomic force microscopy (AFM), scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS) were performed to characterize the changes of carbon fiber surface. AFM results show that the coating of E51 plus POSS significantly increased the carbon fiber surface roughness. XPS indicates that silicon containing functional groups obviously increased after modification. Dynamic mechanical analysis was carried out to investigate the surface energy of carbon fiber. Force modulation atomic force microscopy (FMAFM) and Interlaminar shear strength (ILSS) were used to characterize the interfacial properties of the composites. ILSS was increased by 21.9 % after treatment.

Intracellular pH-responsive mesoporous hydroxyapatite nanoparticles for targeted release of anticancer drug

The design and synthesis of multifunctional nanocarriers is becoming a more and more interesting topic, and shows promising potential for clinical applications. Mesoporous hydroxyapatite nanoparticles (MHAPNs) have emerged as one of the most promising drug delivery vehicles due to their excellent performance. Herein, we constructed a novel cell-targeting, pH-sensitive nanocarrier based on MHAPNs for intracellular drug delivery (LA-BSA-CBA-MHAPNs), using lactobionic acid-conjugated bovine serum albumin (LA-BSA) molecules as end-caps, and 4-carboxyphenylboronic (CBA) as intermediate linkers. The constructed LA-BSA-CBA-MHAPNs as drug delivery carriers exhibited good loading capacity and high pH-controlled release efficiency. Under normal physiological conditions (pH 7.4), they showed a slow drug release rate, while under acidic subcellular environments (pH 5.0) the release rate was enhanced dramatically due to the breakage of cyclic ester bonds linkages between LA-BSA and MHAPNs which made the pores open. Furthermore, our study also demonstrated that the incorporation of the targeted group lactose acid played a positive role in enhancing HepG2 cell uptake efficiency in the LA-BSA-CBA-MHAPNs system in comparison to that of MHAPNs. All these results imply that the LA-BSA-CBA-MHAPNs system could play a significant role in constructing pH-responsive, controlled drug delivery systems for clinical therapy.

Enhanced oxidized regenerated cellulose with functionalized multiwalled carbon nanotubes for hemostasis applications

Oxidized Regenerated Cellulose (ORC) has been modified by incorporating aminated MWCNTs (MWCNT-NH2)s. The pristine MWCNTs (pMWCNTs) were aminated which introduced aromatic amine groups on the side walls of the MWCNTs. For modification of neat ORC, the MWCNT-NH2s were reacted with neat ORC. To explore the origin of this behavior, amination of MWCNTs, dispersion of MWCNT-NH2s in the ORC matrix and their interfacial interactions were investigated by SEM, FT-IR and XPS. The analytical results show that during functionalization of the MWCNTs, the amine groups grafted onto the surface of the MWCNTs. In addition, the FT-IR and XPS results revealed that a relatively strong interaction existed between the aminated MWCNTs and the ORC macromolecules. The hydrophilicity test results revealed a significant increment in water uptake of the MWCNT-NH2s/ORC composites with increasing concentration of MWCNT-NH2s in the composites. The haemostatic evaluation of the MWCNT-NH2s/ORC composites in rabbits shows that the aminated MWCNTs increase the rate of blood stopping and hence decrease the blood loss from injured sites.

Biodegradable collagen sponge reinforced with chitosan/calcium pyrophosphate nanoflowers for rapid hemostasis

Efficient and biodegradable hemostatic materials become increasingly important in civilian and military clinical. However, traditional hemostatic materials are difficult to achieve expected effects especially in parenchymal organs with rich vascularity. In facing these challenges, we designed a biodegradable collagen sponge reinforced with chitosan/calcium pyrophosphate nanoflowers (CPNFs-Col sponge) for rapid hemostasis. With specific performances, such as rapid water absorption ability, the positive surface rich in amino groups and high specific surface area (952.5m2g-1), the obtained CNPFs-Col sponge with optimized composition could activate the intrinsic pathway of coagulation cascade, induce haemocytes and platelets adherence, promote the blood clotting and achieve hemorrhage control in vitro and in vivo. In addition, the CNPFs-Col sponge can be completely biodegraded in 3 weeks, which is suitable for post-operative treatment and peritoneal adhesion prevention. It can be concluded that the CPNFs-Col sponge would become a promising candidate for clinical hemostatic applications.

Role of alginate in antibacterial finishing of textiles.

Antibacterial finishing of textiles has been introduced as a necessary process for various purposes especially creating a fabric with antimicrobial activities. Currently, the textile industry continues to look for textiles antimicrobial finishing process based on sustainable biopolymers from the viewpoints of environmental friendliness, industrialization, and economic concerns. This paper reviews the role of alginate, a sustainable biopolymer, in the development of antimicrobial textiles, including both basic physicochemical properties of alginate such as preparation, chemical structure, molecular weight, solubility, viscosity, and sol-gel transformation property. Then different processing routes (e.g. nanocomposite coating, ionic cross-linking coating, and Layer-by-Layer coating) for the antibacterial finishing of textiles by using alginate are revised in some detail. The achievements in this area have increased our knowledge of alginate application in the field of textile industry and promoted the development of green textile finishing.

Effective co-delivery of doxorubicin and curcumin using a glycyrrhetinic acid-modified chitosan-cystamine-poly(ε-caprolactone) copolymer micelle for combination cancer chemotherapy.

A glycyrrhetinic acid-modified chitosan-cystamine-poly(ε-caprolactone) copolymer (PCL-SS-CTS-GA) micelle was developed for the co-delivery of doxorubicin (DOX) and curcumin (CCM) to hepatoma cells. Glycyrrhetinic acid (GA) was used as a targeting unit to ensure specific delivery. Co-encapsulation of DOX and CCM was facilitated by the incorporation of poly(ε-caprolactone) (PCL) groups. The highest drug loading content was 19.8% and 8.9% (w/w) for DOX and CCM, respectively. The PCL-SS-CTS-GA micelle presented a spherical or ellipsoidal geometry with a mean diameter of approximately 110nm. The surface charge of the micelle changed from negative to positive, when the pH value of the solution decreased from 7.4 to 6.8. Meanwhile, it also exhibited a character of redox-responsive drug release and GA/pH-mediated endocytosis in vitro. In simulated body fluid with 10mM glutathione, the release rate in 12h was 80.6% and 67.2% for DOX and CCM, respectively. The cell uptake of micelles was significantly higher at pH 6.8 than pH 7.4. The combined administration of DOX and CCM was facilitated by PCL-SS-CTS-GA micelle. Results showed that there was strong synergic effect between the two drugs. The PCL-SS-CTS-GA micelle might turn into a promising and effective carrier for improved combination chemotherapy.

Water soluble carboxymethylcellulose fibers derived from alkalization-etherification of viscose fibers

Carboxymethylcellulose (CMC) fibers have been successfully prepared from viscose fibers through the process of alkalization-etherification. Parameters including reaction temperature, mass ratio of NaOH to the viscose fibers, and mass ratio of the viscose fibers to ethanol are studied. The degree of substitution (DS) and the inherent viscosity of the CMC fibers are determined. The CMC fibers are characterized by using Fourier transform infrared spectroscopy (FT-IR), 1H-nuclear magnetic resonance spectroscopy (1H-NMR), scanning electron microscopy (SEM), and the X-ray diffraction (XRD). The analysis demonstrates that under the experimental conditions where the reaction temperature is 40 °C, mass ratio of NaOH to the viscose fibers is 2.0, and mass ratio of the viscose fibers to ethanol is 1:15, the obtained CMC fibers possess an appropriate DS, better water-solubility, and lower degree of etching, thus they can be used as absorbable hemostatic fibers.