Materials advancements for the safety and patency of implantable cardiovascular devices

Implantable cardiovascular devices have revolutionized the management of cardiovascular diseases,significantly enhancing patients’quality of life.With the increasing demand of cardiac implantable electronic devices,the imperative for novel device development is evident.This review article first elaborates the mechanisms underlying foreign body response and infection,elucidating the complex interplay between implanted constructs and host tissues.The discussion then focuses on current advancements in materials science and engineering aimed at mitigating these challenges.Material innovations,such as drugeluting materials,surface modifications,and biomimetic materials,are explored as strategies to modulate these responses and to prevent fibrotic or thrombotic complications and infection.Finally,future directions in materials development for implantable cardiovascular devices are introduced.By addressing safety and patency concerns through innovative material strategies,this article aims to guide the research and development of advanced materials for both current and future cardiovascular implantable devices,ultimately improving patient outcomes and advancing cardiovascular disease treatment.

Cytotoxicity Study of a Novel Implant Material Modified by Microarc Oxidation

This study examined the cytotoxicity of a new implant material modified by microarc oxidation technique. Cells on different surfaces of the implant were evaluated 2, 4 and 6 days after treatment. The results showed that cell attachment, cell morphology, and cell proliferation were influenced by the different surface treatments, and a significant increase in the osteoblast cell activity was observed on the porous MAO-Ti coating. Our results suggest that the porous MAO-Ti surface has a better biocompatibility and electrochemical performance than pure titanium surface.

Materials and applications of bioresorbable electronics

Bioresorbable electronics is a new type of electronics technology that can potentially lead to biodegradable and dissolvable electronic devices to replace current built-to-last circuits predominantly used in implantable devices and consumer electronics. Such devices dissolve in an aqueous environment in time periods from seconds to months, and generate biological safe products. This paper reviews materials, fabrication techniques, and applications of bioresorbable electronics, and aims to inspire more revolutionary bioresorbable systems that can generate broader social and economic impact. Existing challenges and potential solutions in developing bioresorbable electronics have also been presented to arouse more joint research efforts in this field to build systematic technology framework.

Fabrication,microstructure and properties of advanced ceramic-reinforced composites for dental implants:a review

The growing field of dental implant research and development has emerged to rectify the problems associated with human dental health issues. Bio-ceramics are widely used in the medical field, particularly in dental implants, ortho implants, and medical and surgical tools. Various materials have been used in those applications to overcome the limitations and problems associated with their performance and its impact on dental implants. In this article we review and describe the fabrication methods employed for ceramic composites, the microstructure analyses used to identify significant effects on fracture behaviour, and various methods of enhancing mechanical properties. Further, the collective data show that the sintering technique improves the density, hardness, fracture toughness, and flexural strength of alumina- and zirconia-based composites compared with other methods. Future research aspects and suggestions are discussed systematically.

Progress on Medical Implant:A Review and Prospects

Medical implant from different materials such as metals,ceramics,polymers and composites have gained a lot of research attraction due to wide applications in medical industry for treatment,surgical operations and preparing artificial body parts.In this work,we highlight a comprehensive review of medical implant mechanism,various types of implant materials,factors affecting the performance of implant and different characterization techniques.This review provides an overall summary of the state-of-the-art progress on various interesting and promising material-based medical implant.Finally,few new prospects are explained from the established theoretical and experimental results for real-life applications.This study is expected to promote extended interest of scientists and engineers in recent trend of modern biomaterials based medical implant.

On the material dependency of peri-implant morphology and stability in healing bone

The microstructural architecture of remodeled bone in the peri-implant region of screw implants plays a vital role in the distribution of strain energy and implant stability.We present a study in which screw implants made from titanium,polyetheretherketone and biodegradable magnesium-gadolinium alloys were implanted into rat tibia and subjected to a push-out test four,eight and twelve weeks after implantation.Screws were 4 mm in length and with an M2 thread.The loading experiment was accompanied by simultaneous three-dimensional imaging using synchrotron-radiation microcomputed tomography at 5μm resolution.Bone deformation and strains were tracked by applying optical flow-based digital volume correlation to the recorded image sequences.Implant stabilities measured for screws of biodegradable alloys were comparable to pins whereas non-degradable biomaterials experienced additional mechanical stabilization.Peri-implant bone morphology and strain transfer from the loaded implant site depended heavily on the biomaterial utilized.Titanium implants stimulated rapid callus formation displaying a consistent monomodal strain profile whereas the bone volume fraction in the vicinity of magnesium-gadolinium alloys exhibited a minimum close to the interface of the implant and less ordered strain transfer.Correlations in our data suggest that implant stability benefits from disparate bone morphological properties depending on the biomaterial utilized.This leaves the choice of biomaterial as situational depending on local tissue properties.

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.

Wear Behavior of Plasma Oxidized CoCrMo Alloy under Dry and Simulated Body Fluid Conditions

In this study, CoCrMo alloy was oxidized in plasma environment at the temperatures of 600 ℃ to 800 ℃ for 1 h to 5 h with 100% 02 gas and its tribological behavior was investigated. After the plasma oxidizing process, the compound and diffusion layers were formed on the surface. XRD results show that Cr203, a-Co and ε-Co phases diffracted from the modified layers after plasma oxidizing. The untreated and treated CoCrMo samples were subjected to wear tests both in dry and simulated body fluid conditions, and normal loads of 2 N and 10 N were used. For the sliding wear test, alumina balls were used as counter materials. It was observed that the wear resistance of CoCrMo alloy was increased after the plasma oxidizing process. The lowest wear rate was obtained from the samples that were oxidized at 800 ℃ for 5 h. It was detected that both wear environment and load have significant effects on the wear behavior of this alloy, and the wear resistance of oxidized CoCrMo alloy is higher when oxide-based counterface is used. The wear rates of both untreated and plasma oxidized samples increase under high loads.

Porous silicon carbide coated with tantalum as potential material for bone implants

Porous silicon carbide(SiC)has a specific biomorphous microstructure similar to the trabecular microstructure of human bone.Compared with that of bioactive ceramics,such as calcium phosphate,SiC does not induce spontaneous interface bonding to living bone.In this study,bioactive tantalum(Ta)metal deposited on porous SiC scaffolds by chemical vapour deposition was investigated to accelerate osseointegration and improve the bonding to bones.Scanning electron microscopy indicated that the Ta coating evenly covered the entire scaffold structure.Energy-dispersive spectroscopy and X-ray diffraction analysis showed that the coating consisted of Ta phases.The bonding strength between the Ta coating and the SiC substrate is 88.4MPa.The yield strength of porous SiC with a Ta coating(pTa)was 45.862.9MPa,the compressive strength was 61.463.2MPa and the elasticmodulus was4.8GPa.When MG-63 human osteoblasts were co-cultured with pTa,osteoblasts showed good adhesion and spreading on the surface of the pTa and its porous structure,which showed that it has excellent bioactivity and cyto-compatibility.To further study the osseointegration properties of pTa.PTa and porous titanium(pTi)were implanted into the femoral neck of goats for 12weeks,respectively.The Van-Gieson staining of histological sections results that the pTa group had better osseointegration than the pTi group.These results indicate that coating bioactive Ta metal on porous SiC scaffolds could be a potential material for bone substitutes.

Investigation of Microstructure and Corrosion of TiNbTaZrMo High-Entropy Alloy in the Simulated Body Fluid

Microstructures and corrosion of TiNbTaZrMo(Ti_(20)Nb_(20)Ta_(20)Zr_(20)Mo_(20))High-Entropy Alloy(HEA)were investigated in the Simu-lated Body Fluid(SBF).Microstructure of this alloy was investigated by X-Ray Difiraction(XRD)and Scanning Electron Microscopy(SEM)techniques.Our observations confirmed the presence of two bcc phases as the major matrix as well as another minor phase in themicrostructure of the alloy.Concentration of some elements,such as tantalum,niobium,and molybdenum in the dendritic branches and thepresence of zirconium and titanium in the inter-dendritic branches were clearly evidenced by Energy Dispersive X-ray(EDX)analysis.Given importance of corrosion of implant alloys in the human's body,elctrochemical impedance and cyclic polarization tests werepcerformed on the alloy in SBF.Through the corrosion tests,corrosion potential,current,and resistance were obtained as E_(corr)=-0.42 V,i_(corr)=0.34μA·cm^(-2),and R_(p)=27.44 k ohm·cm^(2),respectively.The results revealed that the rate of corrosion in TiNbTaZrMo HEA is about 26 times better than that of Ti_(6)Al_(4)V alloy.Also,both alloys had no pitting corrosion in the SBF solution.

Abnormal Blood Glucose Concentration on Degradation Behavior of AZ31 Magnesium Alloy

In order to evaluate the effect of blood glucose concentration on the reliability of AZ31 magnesium alloy medical implant,the corrosion of AZ31 alloy was studied in a simulated physiological saline solution.It is found that when the glucose concentration is in the normal range of ca.1g/L,the corrosion of AZ31 alloy can be inhibited However,when the glucose concentration becomes higher like that of diabetic patients,the degradation of AZ31 alloy is significantly accelerated.Therefore,for diabetic patients,the change in glucose concentration must be taken into consideration in order to ensure the reliability ofAZ31 medical implants.