metal-organic framework (mof) coatings on az91 magnesium implants for biodegradation control in physiological environments

Recently, biodegradable implants in orthopedic therapies has attracted a great attention. in spite of elastic modulus close to that of bone, magnesium-based implants undergo a high biodegradation rate in body which restricts their biomedical applications. in the present study, it is intended to reduce the corrosion rate of the az91 magnesium based alloy through a porous and biocompatible coating containing metal-organic framework, zif-8 nanoparticles (bet surface area=1837 m2.g-1). zif-8 is synthesized through solvothermal method, dispersed in chitosan (10%w/w) then coated on the surface of the az91 alloy by electrospinning technique.the physico-chemical properties of the nanofibrous coating is characterized by sem, ft-ir and xrd techniques. corrosion resistance is also evaluated by potentiodynamic polarization and electrochemical impedance spectroscopy in simulated body fluid. it is revealed that the corrosion resistance of the nanocomposite chitosan/zif-8 coated sample is about 1700 ω〖cm〗^2 more than that of the chitosan coated one. however, corrosion resistance for the bare mg az91 is about 300 ω〖cm〗^2. the corrosion rate of the sample coated with chitosan/nanoparticle zif-8 is about 20 times less than that of bare sample. furthermore, the ph changes of the chitosan/zif-8 coated specimens after 3 days is about 8.5 which is slightly lower than that of the uncoated specimen (about 9.3). contact angle of chitosan/zif-8 and chitosan coated samples are 38º, and 55 º, respectively. the improved hydrophilicity, and higher corrosion resistance of chitosan-based nanofibrous highly porous coating developed in this study reveals that nanofibrous electrospun coatings are potentially promising for biodegradation control of az91 magnesium implants.

Metal-organic framework (MOF) coatings on AZ91 magnesium implants for biodegradation control in physiological environments

Recently, biodegradable implants in orthopedic therapies has attracted a great attention. In spite of elastic modulus close to that of bone, magnesium-based implants undergo a high biodegradation rate in body which restricts their biomedical applications. In the present study, it is intended to reduce the corrosion rate of the AZ91 magnesium based alloy through a porous and biocompatible coating containing metal-organic framework, ZIF-8 nanoparticles (BET surface area=1837 m2.g-1). ZIF-8 is synthesized through solvothermal method, dispersed in chitosan (10%w/w) then coated on the surface of the AZ91 alloy by electrospinning technique.The physico-chemical properties of the nanofibrous coating is characterized by SEM, FT-IR and XRD techniques. Corrosion resistance is also evaluated by potentiodynamic polarization and electrochemical impedance spectroscopy in simulated body fluid. It is revealed that the corrosion resistance of the nanocomposite chitosan/ZIF-8 coated sample is about 1700 Ω〖cm〗^2 more than that of the chitosan coated one. However, corrosion resistance for the bare Mg AZ91 is about 300 Ω〖cm〗^2. The corrosion rate of the sample coated with chitosan/nanoparticle ZIF-8 is about 20 times less than that of bare sample. Furthermore, the pH changes of the chitosan/ZIF-8 coated specimens after 3 days is about 8.5 which is slightly lower than that of the uncoated specimen (about 9.3). Contact angle of chitosan/ZIF-8 and chitosan coated samples are 38º, and 55 º, respectively. The improved hydrophilicity, and higher corrosion resistance of chitosan-based nanofibrous highly porous coating developed in this study reveals that nanofibrous electrospun coatings are potentially promising for biodegradation control of AZ91 magnesium implants.