Supplemental mineral ions for bone regeneration and osteoporosis treatment

Mineral ions play a crucial role in various biological processes in the human body,particularly in bone repair and regeneration.Supplementation with mineral ions offers several advantages over other therapies or treatments for bone repair and regeneration,such as higher biosafety,universal applicability,and compatibility with the immune system.Additionally,supplementation with mineral ions may avoid the need for invasive surgical procedures.The aim of this review is to provide a comprehensive overview of the functions of potentially beneficial mineral ions and their effects on bone regeneration and osteoporosis treatment.By examining previous studies,including in vitro cellular experiments,in vivo animal models,and clinical trials,this review compares the benefits and potential adverse effects of these mineral ions.Moreover,the review provides guidelines for suggested daily supplementation of these mineral ions to assist future preclinical and clinical studies in bone regeneration and osteoporosis treatment.

Blending with transition metals improves bioresorbable zinc as better medical implants

Zinc(Zn)is a new class of bioresorbable metal that has potential for cardiovascular stent material,orthopedic implants,wound closure devices,etc.However,pure Zn is not ideal for these applications due to its low mechanical strength and localized degradation behavior.Alloying is the most common/effective way to overcome this limitation.Still,the choice of alloying element is crucial to ensure the resulting alloy possesses sufficient mechanical strength,suitable degradation rate,and acceptable biocompatibility.Hereby,we proposed to blend selective transition metals(i.e.,vanadium-V,chromium-Cr,and zirconium-Zr)to improve Zn’s properties.These selected transition metals have similar properties to Zn and thus are beneficial for the metallurgy process and mechanical property.Furthermore,the biosafety of these elements is of less concern as they all have been used as regulatory approved medical implants or a component of an implant such as Ti6Al4V,CoCr,or Zr-based dental implants.Our study showed the first evidence that blending with transition metals V,Cr,or Zr can improve Zn’s properties as bioresorbable medical implants.In addition,three in vivo implantation models were explored in rats:subcutaneous,aorta,and femoral implantations,to target the potential clinical applications of bioresorbable Zn implants.

Calcium phosphate coatings enhance biocompatibility and degradation resistance of magnesium alloy:Correlating in vitro and in vivo studies

Magnesium(Mg)and its alloys are promising biodegradable materials for orthopedic applications.However,one of the major problems is their rapid degradation rate with quick evolution of hydrogen gas.To overcome this problem,calcium phosphate(CaP)coatings have been used to improve the degradation resistance and the biocompatibility of Mg materials.This study focuses on the comparison and correlation of the in vitro and in vivo degradation and biocompatibility behaviors of these materials.A CaP coating consisting of dicalcium phosphate dihydrate(DCPD)was deposited on an AZ60 Mg alloy by the chemical conversion method.Then,the in vitro degradation testing including electrochemical and immersion tests,and in vivo implantation of the CaP coated Mg alloy were conducted to compare the degradation behaviors.Next,the in vitro cell behavior and in vivo bone tissue response were also compared on both uncoated and CaP-coated Mg samples.Data showed that the CaP coating provided the Mg alloy with significantly better biodegradation behavior and biocompatibility.The in vitro and in vivo biocompatibility tests exhibited good consistency while not the case for biodegradation.Results showed that the in vitro electrochemical test could be a quick screening tool for the biodegradation rate,while the in vitro immersion degradation rate was often 2-4 folds faster than the in vivo degradation rate.

Biofunctionalization of metallic implants by calcium phosphate coatings

Metallic materials have been extensively applied in clinical practice due to their unique mechanical properties and durability.Recent years have witnessed broad interests and advances on surface functionalization of metallic implants for high-performance biofunctions.Calcium phosphates(CaPs)are the major inorganic component of bone tissues,and thus owning inherent biocompatibility and osseointegration properties.As such,they have been widely used in clinical orthopedics and dentistry.The new emergence of surface functionalization on metallic implants with CaP coatings shows promise for a combination of mechanical properties from metals and various biofunctions from CaPs.This review provides a brief summary of state-of-art of surface biofunctionalization on implantable metals by CaP coatings.We first glance over different types of CaPs with their coating methods and in vitro and in vivo performances,and then give insight into the representative biofunctions,i.e.osteointegration,corrosion resistance and biodegradation control,and antibacterial property,provided by CaP coatings for metallic implant materials.

Bioactive glass coatings on metallic implants for biomedical applications

Metallic implant materials possess adequate mechanical properties such as strength,elastic modulus,and ductility for long term support and stability in vivo.Traditional metallic biomaterials,including stainless steels,cobalt-chromium alloys,and titanium and its alloys,have been the gold standards for load-bearing implant materials in hard tissue applications in the past decades.Biodegradable metals including iron,magnesium,and zinc have also emerged as novel biodegradable implant materials with different in vivo degradation rates.However,they do not possess good bioactivity and other biological functions.Bioactive glasses have been widely used as coating materials on the metallic implants to improve their integration with the host tissue and overall biological performances.The present review provides a detailed overview of the benefits and issues of metal alloys when used as biomedical implants and how they are improved by bioactive glass-based coatings for biomedical applications.

Improved mechanical, degradation, and biological performances of Zn–Fe alloys as bioresorbable implants

Zinc(Zn)is a promising bioresorbable implant material with more moderate degradation rate compared to magnesium(Mg)and iron(Fe).However,the low mechanical strength and localized degradation behavior of pure Zn limit its clinical applications.Alloying is one of the most effective ways to overcome these limitations.After screening the alloying element candidates regarding their potentials for improvement on the degradation and biocompatibility,we proposed Fe as the alloying element for Zn,and investigated the in vitro and in vivo performances of these alloys in both subcutaneous and femoral tissues.Results showed that the uniformly distributed secondary phase in Zn–Fe alloys significantly improved the mechanical property and facilitated uniform degradation,which thus enhanced their biocompatibility,especially the Zn-0.4Fe alloy.Moreover,these Zn–Fe alloys showed outstanding antibacterial property.Taken together,Zn–Fe alloys could be promising can-didates as bioresorbable medical implants for various cardiovascular,wound closure,and orthopedic applications.