Seyed Hassan Hosseini

A number of synthetic hydrogels suffer from low mechanical strength. Despite of the recent advances in the fabrication of tough hydrogels, it is still a great challenge to simultaneously construct high stretchability, and self‐adhesive and self‐healing capability in a hydrogel. Herein, a new type of double network hydrogel was prepared based on irreversible cross‐linking of polyacrylamide chains and Schiff‐base reversible cross‐linking between glycidyl methacrylate‐grafted ethylenediamine and oxidized sodium alginate (OSA). The combination of both cross‐linkings and their synergistic effect provided a novel hydrogel with high strength, stretchable, rapid self‐healing, and self‐adhesiveness to different material. Besides, the hydrogels with diverse OSA content could maintain their original shapes after loading–unloading tensile test. The resulting hydrogel has a great potential in various fields for supporting and load‐bearing substance.

In this study, a nanocarrier was prepared for co-delivery of hydrophilic (doxorubicin) and hydrophobic drug (curcumin) to cancer cells. In this nanocarrier the edges of graphene oxide sheets were decorated by magnetic functionalized polyamidoamine dendrimer with the hydrazone groups at the end of polymer. The edge functionalization of graphene sheets not only improved the solubility and dispersibility of graphene sheets but also induced the magnetic properties to the nanocarrier. The resulted nanocarrier was loaded by doxorubicin through the covalent linkage and curcumin through the π-π stacking. The nanocarrier showed a pH-sensitive release for both drugs and the drug release behavior was also improved by co-immobilization of both drugs. The cytotoxicity assay of nanocarier showed low toxicity toward MCF-7 cell compared to un-modified graphene oxide which was attributed to the presence of magnetic dendrimer. Besides, the drugs loaded nanocarrier was highly toxic for cells even more than the free drugs. The cellular uptake images revealed higher drug internalization for co-loaded nanocarrier than the nanocarrier loaded with one drug alone. All of the results showed that the co-delivery of curcumin and doxorubicin by the presence nanocarrier was more effective in chemotherapy than the nanocarrier loaded with one drug.

Herein we developed a magnetic drug delivery system based on magnetic Fe3O4 nanoparticles with double shells of modified salep polysaccharide for delivery of doxorubicin (Dox). The drug loaded nanocarrier was synthesized in an easily way and large amounts of drug molecules was loaded into the nanocarrier. The drug loaded nanocarrier showed excellent pH responsibility in vitro and large amounts of Dox was released at lower pH (60% release) while the nanocarrier was stable at neutral pH. The hemolysis assay results showed that the nanocarrier has negligible hemolytic effects on human red blood cells and showed good biocompatibility. Moreover, the result of coagulation assays showed that the nanocarrier did not active any coagulation pathways. Cytotoxicity assays of nanocarrier and drug loaded nanocarrier toward HeLa cells demonstrated that nanocarrier has negligible toxicity while drug loaded nanocarrier kills more than 90% of cells during 48 h. The flow cytometry analysis also showed that the uptake of drug loaded nanocarrier into the cancerous cells is time dependent and higher concentrations of drug internalized into the cells at longer incubation time. Based on the results, we suggest that the present nanocarrier can be applicable for in vivo drug delivery as an easy made and cheap nanocarrier.

A magnetic nanocomposite was prepared based on magnetic Fe ₃ O ₄ nanoparticles entrapped into a cross‐linked nitrogen rich polymer which has high loading capacity for immobilization of gold nanoparticles. The synthesized catalyst was characterized using various methods including Atomic absorption spectroscopy (AAS), Transmission electron microscopy (TEM), Fourier‐transform infrared spectroscopy ( FT‐IR), Energy‐dispersive X‐ray spectroscopy (EDX), Thermogravimetric analysis (TGA), scanning electron microscope (SEM), Brunauer–Emmett–Teller (BET), VSM and X‐ray diffraction (XRD) techniques. The catalyst was proven to be highly efficient for reduction of nitroarenes as well as Suzuki–Miyaura coupling reaction. The reduction of nitroarenes and Suzuki–Miyaura coupling reaction were performed in water medium and excellent yields of the products were achieved. The catalyst was easily recovered and recycled several times without any significant loss of catalytic activity.

A magnetic nanocomposite was prepared by entrapment of Fe3O4 nanoparticles into the cross-linked ionic liquid/epoxy type polymer. The resulting support was used for covalent immobilization cellulase through the reaction with epoxy groups. The ionic surface of the support improved the adsorption of enzyme and a large amount of enzyme (106.1 mg/g) was loaded onto the support surface. The effect of the presence of ionic monomer and covalent binding of enzyme was also investigated. The structures of supports were characterized by various instruments such as FT-IR, TGA, VSM, XRD, TEM, SEM and DLS. The activity and stability of immobilized cellulase were investigated in the prepared supports. The results showed that the ionic surface and covalent binding of enzyme onto the support improved the activity, thermal stability and reusability of cellulase compared to free cellulase.