In the last decade, biodegradable metals have emerged as a topic of interest for particular biomedical applications which require high strength to bulk ratio, including for cardiovascular stents. The advantages of biodegradable materials are related to the reduction of long term risks associated with the presence of permanent metal implants, e.g. chronic inflammation and in-stent restenosis. From a structural point of view, the analysis of the literature reveals that iron-based alloys used as temporary biodegradable stents have several advantages over Mg-based alloys in terms of ductility and strength. Efforts on the modification and tunability of iron-based alloys design and compositions have been mainly focused on controlling the degradation rate while retaining the mechanical integrity within a reasonable period. The early pre-clinical results of many iron-based alloys seem promising for future implants developments. This review discusses the available literature focusing mainly on: (i) Fe and Fe-based alloys design and fabrication techniques; (ii) in vitro and in vivo performance; (iii) cytotoxicity and cell viability tests.

Electrospun hybrid scaffolds are an effective platform to deliver drugs site specifically for the prevention and treatment of diseases in addition to promote tissue regeneration because of the flexibility to load drugs therein. In the present study, electrospun hybrid scaffolds containing antibiotics were developed to support cellular activities and eliminate potential postoperative inflammation and infection. As a model drug, levofloxacin (LFX) was successfully incorporated into pure polyhydroxybutyrate/poly(ε-caprolactone) (PHB/PCL) scaffolds and PHB/PCL/sol–gel-derived silica (SGS) scaffolds. The influence of LFX on the morphology, mechanical performance, chemical structure, drug release profile, and antibacterial effect of the scaffolds was thoroughly and comparatively investigated. MG-63 osteoblast-like cell cultivation on both scaffolds certified that LFX inclusion did not impair the biocompatibility. In addition to the favorable cellular proliferation and differentiation, scaffolds containing both LFX and SGS displayed highly increased mineralization content. Therefore, the present multifunctional hybrid scaffolds are promising in tissue engineering applications.

Bioactive glass nanoparticles containing copper (Cu-BGNs) were introduced into polycaprolactone (PCL) coating systems to improve the bioactivity, antibacterial properties, and corrosion resistance of vulnerable magnesium matrices under physiological conditions. The influence of different amounts of Cu-BGNs in PCL coatings was thoroughly investigated in determining the wettability, electrochemical properties, and antibacterial effects against Staphylococcus carnosus and Escherichia coli, as well as their cyto-compatibility. Cu-BGNs were observed randomly scattered in PCL coatings. Increasing the concentration of Cu-BGNs resulted in a slight decrease of the water contact angle, and a reduction in anticorrosion properties of the Cu-BGN composite coatings. Yet higher Cu-BGN content in coatings led to more calcium phosphate formation on the surface after 7 days of immersion in Dulbecco's modified Eagle's medium, which was confirmed by Fourier-transform infrared spectroscopy and x-ray photoelectron spectroscopy. The growth of S. carnosus and E. coli was inhibited by Cu ions released from the Cu-BGN coatings. In addition, both direct and indirect cyto-compatibility experiments showed that the viability and proliferation of MG-63 cells on Cu-BGN coatings were highly increased compared to pure magnesium; however, an additional increase of Cu-BGN concentration showed a slight decrease of cell proliferation and cell activity. In summary, Cu-BGN/PCL composite coatings impart magnesium-based biomaterials with antibacterial and anticorrosive properties for clinical applications.

Based on a novel Golgi-targeting phenylsulfonamide group, a two-photon (TP) fluorescent probe, Np-Golgi, was developed for in situ H2O2 ratiometric imaging in living systems.