Spinel ferrite magnetic nanoparticles have attracted considerable attention because of their high and flexible magnetic properties and biocompatibility. In this work, a set of magnetic nanoparticles of cobalt ferrite doped with zinc was synthesized via the eco-friendly sol-gel auto-combustion method. Obtained particles displayed a room-temperature ferromagnetic behavior with tuned by chemical composition values of saturation magnetization and coercivity. The maximal values of saturation magnetization ~74 Am²/kg were found in cobalt ferrite nanoparticles with a 15–35% molar fraction of cobalt replaced by zinc ions. At the same time, the coercivity exhibited a gradually diminishing trend from ~140 to ~5 mT whereas the concentration of zinc was increased from 0 to 100%. Consequently, nanoparticles produced by the proposed method possess highly adjustable magnetic properties to satisfy the requirement of a wide range of possible applications. Further prepared nanoparticles were tested with bacterial culture to display the influence of chemical composition and magnetic structure on nanoparticles-bacterial cell interaction.

It is well known that chitosan composites are good candidates for novel orthopedic applications. Herein, a comprehensive in vitro comparison between neat and carbon nanotube (CNT) containing chitosan scaffolds will be reported for the first time. Functionalized multiwalled carbon nanotubes (f-MWCNTs) prepared by the acid treatment of CNTs were used as reinforcement agents. In this study, a group of chitosan scaffolds was manufactured reinforced by different amounts of the f-MWCNTs. Analysis of the FTIR spectra of the scaffolds confirmed the presence and functionalization of MWCNTs in polymer matrices. A high degree of crystallinity in the engineered scaffolds was noted in XRD patterns. Further, XRD results were used to study the structural properties. In order to survey the morphology of the chitosan/MWCNT scaffold, a FESEM micrograph was taken. The values of porosity ranged between 93.6 and 94.5%. The mechanical characteristics of the chitosan scaffolds were boosted by introducing f-MWCNTs. As expected, pore size on crystallinity index (CrI) of the scaffolds were decreased after introducing the f-MWCNTs. PBS was used to investigate the water uptake and water stability of the products. MTT assay results of the scaffolds’ cell viability shows the non-toxicity and satisfactory biocompatibility of the CNT enriched scaffolds. The electrical conductivity test showed stepwise increases in electrical conductivity with the increase in CNT content. This work demonstrates that f-MWCNTs can improve the capabilities of the chitosan scaffolds in low concentrations without endangering cell proliferation on the scaffolds.