Graphene oxide encapsulated forsterite scaffolds to improve mechanical properties and antibacterial behavior.

It is very desirable to have good antibacterial properties and mechanical properties at the same time for bone scaffolds. Graphene oxide (GO) can increase the mechanical properties and antibacterial performance, while forsterite (Mg2SiO4) as the matrix can increase forsterite/GO scaffolds' biological activity for bone tissue engineering. Interconnected porous forsterite scaffolds were developed by space holder processes for bone tissue engineering in this research. The forsterite/GO scaffolds had a porosity of 76%-78% with pore size of 300-450 µm. The mechanism of the mechanical strengthening, antibacterial activity, and cellular function of the forsterite/GO scaffold was evaluated. The findings show that the compressive strength of forsterite/1 wt.% GO scaffold (2.4 ± 0.1 MPa) was significantly increased, in comparison to forsterite scaffolds without GO (1.4 ± 0.1 MPa). Validation of the samples' bioactivity was attained by forming a hydroxyapatite layer on the forsterite/GO surface withinin vitroimmersion test. The results of cell viability demonstrated that synthesized forsterite scaffolds with low GO did not show cytotoxicity and enhanced cell proliferation. Antibacterial tests showed that the antibacterial influence of forsterite/GO scaffold was strongly correlated with GO concentration from 0.5 to 2 wt.%. The scaffold encapsulated with 2 wt.% GO had the great antibacterial performance with bacterial inhibition rate around 90%. As results show, the produced forsterite/1 wt.% GO can be an attractive option for bone tissue engineering.

Illustration of effective parameters on growth of ZnO micro/nano rods, on the borosilicate glass via hydrothermal process.

Hexagonal micro/nanorods of ZnO were synthesized via mild hydrothermal growth method under different conditions. The growth of the rods was accomplished in two manners: firstly, on bare borosilicate glass, and secondly, on ZnO seed layer prepared by sol-gel spin coating process. All the obtained surfaces were studied by scanning electron microscopy (SEM) and X-ray diffraction (XRD). The studies demonstrate that, although with the decrease of concentration of precursor solution on bare borosilicate glass, the diameter of the rods decreases, but the orientation will deteriorate and the density of the rods will decrease. On the other hand, hydrothermal growth on the seed layer causes the decrease in the diameter of the rods, while maintaining the orientation along the c-axis; therefore, the presence of seed layer plays an important role in decreasing the diameter of the rods; so that at a constant concentration, compared with the case without seed layer, the diameter of rods decreased 10 times from approximately 500 nm to approximately 50 nm.