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A simple 2‐step method, consisting of film casting and polyvinyl alcohol leaching, is proposed to prepare magnesium oxide (MO) nanoparticle‐reinforced sodium alginate scaffolds with right properties for bone tissue engineering. The cytocompatibility of the as‐prepared scaffolds was also evaluated using the 3‐(4,5‐dimethylthiazol‐2‐yl)‐2,5‐diphenyltetrazolium‐bromide yellow tetrazole assay test, wherein chondrocyte cells had been considered as target cells. According to the results, the ensuing sodium alginate nanocomposites, containing 4‐wt% MO nanoparticles, demonstrated the highest physical and mechanical properties after leaching step. The Young modulus of sodium alginate/4‐wt% MO was improved about 44%, in comparison with that of the pure alginate sample. Furthermore, incorporating MO nanoparticles up to 4 wt% controlled the liquid uptake capacity of scaffolds vis‐à‐vis the resultant pure sodium alginate sample. Moreover, with increasing the nanoparticle content, the antibacterial properties of scaffolds enhanced, but their degradation rates under in vitro conditions tapered off. With the introduction of 3‐ and 4‐wt% MO, the average diameter of the bacterial zone of the scaffold samples reduced to less than 10 mm2, suggesting an insensitive antimicrobial performance, compared with the pure sodium alginate and the samples with 1‐ and 2‐wt% MO content, which exhibit antimicrobial sensitivity. 3‐(4,5‐Dimethylthiazol‐2‐yl)‐2,5‐diphenyltetrazolium‐bromide assay test also revealed the cultivated chondrocyte cells on the 4‐wt% MO nanoparticle‐reinforced scaffold possessed better interaction as well as appropriate cell attachment and proliferation than the pristine sodium alginate sample.

The present study describes a novel and very sensitive electrochemical assay for determination of hydrogen peroxide (H2O2) based on synergistic effects of reduced graphene oxide‐ magnetic iron oxide nanocomposite (rGO‐Fe3O4) and celestine blue (CB) for electrochemical reduction of H2O2. rGO‐Fe3O4 nanocomposite was synthesized and characterized by Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), X‐ray diffraction (XRD), electrochemical impedance spectroscopy and cyclic voltammetry. Chitosan (Chit) was used for immobilization of amino‐terminated single‐stranded DNA (ss‐DNA) molecules via a glutaraldehyde (GA) to the surface of rGO‐Fe3O4. The MTT (3‐(4,5‐Dimethylthiazol‐2‐yl)‐2,5‐diphenyltetrazolium bromide) results confirmed the biocompatibility of nanocomposite. Experimental parameters affecting the ss‐DNA molecules immobilization were optimized. Finally, by accumulation of the CB on the surface of the rGO‐Fe3O4‐Chit/ssDNA, very sensitive amperometric H2O2 sensor was fabricated. The electrocatalytic activity of the rGO‐Fe3O4‐Chit/DNA‐CB electrode toward H2O2 reduction was found to be very efficient, yielding very low detection limit (DL) of 42 nM and a sensitivity of 8.51 μA/μM. Result shows that complex matrices of the human serum samples did not interfere with the fabricated sensor. The developed sensor provided significant advantages in terms of low detection limit, high stability and good reproducibility for detection of H2O2 in comparison with recently reported electrochemical H2O2 sensors.

Bioactive Polycaprolactone/Collagen nanofibers containing gehlenite Nano-powder were fabricated using electrospinning for bone tissue engineering. The physicochemical properties of scaffolds measured using scanning electron microscopy, tensile test, FTIR spectroscopy, and water contact angle measurement test. A slight enhancement (~20 nm) in fibers diameter was observed by adding gehlenite nanoparticles to the scaffolds, but the fiber diameter distributions for both scaffolds were within the normal range of extracellular matrix (50-500 nm). In vitro experiments demonstrated well attachment and higher proliferation of MG-63 cells on gehlenite nanoparticles containing scaffolds. Besides, the stimulatory cell differentiation effects of Polycaprolactone/Collagen/gehlenite scaffolds were demonstrated by Alizarin red staining. This study represents for advanced of the natural and synthetic polymers for bone tissue engineering.