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.

Customized Additive Manufacturing in Bone Scaffolds-The Gateway to Precise Bone Defect Treatment

In the advancing landscape of technology and novel material development,additive manufacturing(AM)is steadily making strides within the biomedical sector.Moving away from traditional,one-sizefits-all implant solutions,the advent of AM technology allows for patient-specific scaffolds that could improve integration and enhance wound healing.These scaffolds,meticulously designed with a myriad of geometries,mechanical properties,and biological responses,are made possible through the vast selection of materials and fabrication methods at our disposal.Recognizing the importance of precision in the treatment of bone defects,which display variability from macroscopic to microscopic scales in each case,a tailored treatment strategy is required.A patient-specific AM bone scaffold perfectly addresses this necessity.This review elucidates the pivotal role that customized AM bone scaffolds play in bone defect treatment,while offering comprehensive guidelines for their customization.This includes aspects such as bone defect imaging,material selection,topography design,and fabrication methodology.Additionally,we propose a cooperative model involving the patient,clinician,and engineer,thereby underscoring the interdisciplinary approach necessary for the effective design and clinical application of these customized AM bone scaffolds.This collaboration promises to usher in a new era of bioactive medical materials,responsive to individualized needs and capable of pushing boundaries in personalized medicine beyond those set by traditional medical materials.

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.

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.

Orthopedic implants and devices for bone fractures and defects:Past,present and perspective

Bone is a unique tissue that is capable of repairing itself after damage.However,there are certain instances of fractures and defects that require clinical intervention for proper alignment and healing.As with any implant,careful consideration of the material used to create the implants to treat these problems is needed.If the incorrect material is chosen,the implants themselves can lead to bone fractures or defects,or bone healing may not take place at all.All three classes of biomaterials-metals,ceramics,and polymers-have been used in the treatment of both bone fractures and bone defects,and each has its own unique benefits and limitations for its applications.Furthermore,composites of these different materials have also been created to try to take advantage of all the different benefits offered by each different material.This review highlights different materials that have been used for the development of internal fixators and bone graft substitutes to treat fracture and bone defects as well as their limitations and needed future research.

Nanoparticles as delivery vehicles for antiviral therapeutic drugs

With the ongoing COVID-19 pandemic still escalating,many researchers are turning to nanotechnology as a method of treatment not only for this pandemic,but in preparation for the pandemics of the future.Given both a wide variety of biomaterials at their disposal and the recent rise of nanotechnology,scientists now have the means to release and distribute therapeutic drugs in a variety of ways.Such a variety permits medical professionals the ability to choose biomaterials and methods that would provide the best release and treatment methodologies for the viral ailment they are attempting to remedy.This integrative review discusses context of previous pandemics,viral pathogenesis,issues associated with the current state of antiviral delivery systems,numerous biomaterials used for this purpose,and further information regarding the ongoing global COVID-19 pandemic.

Design of imaging system for CSNS near-target beam diagnostics

Introduction China Spallation Neutron Source(CSNS)is an accelerator-based pulsed neutron source which produces neutron with spallation reaction induced by proton bombarding tungsten target.With increasing beam powers and influences on target,near-target monitoring becomes extreme necessary.In this situation,an optical imaging system for proton beam diagnostics and monitoring near the target is being developed at CSNS,which can provide real-time images of the beam on target and beam distribution information.Target imaging system design and development In the design of CSNS target imaging system,coating of Cr^(3+):Al_(2)O_(3) is used to convert particle radiation into emission light.According to the geometry limits of CSNS target station,a special optical system was designed and fabricated to collect the emission light.When the proton beams strike on the target,the coating on the target will be excited,emitting luminescence at the same time.The mirrors and lenses of the optical system image the distribution of emission light into a radiation-hard imaging fiber,which transmits the images to the GigE camera located at low-dose area outside of the target station.Software was written on the LabView platform to control the camera and analyze the images on line.Mock-up of the imaging system was manufactured to test and evaluate the performances of the system.Some important characteristics of the system were obtained and studied.Conclusion Tests on the mock-up of the system present reliably expectation for beam diagnostics.The imaging system has been installed at CSNS recently.More work will be continued to improve the properties of the system.

Applications of 3D printed chimeric DNA biomaterials

The influence of genetic engineering on daily life is prominent,from genetically modified food to transgenic,antibiotic resistant plants.The direct manipulation of an organism’s genotype has opened the door to a myriad of applications in an effort to treat chronic diseases.This paper proposes the unification of chimeric DNA technology and three-dimensional bioprinting to spark the development of new therapies.While studies of chimeric DNA,i.e.recombinant DNA,have been conducted since 1970,bioprinting is a budding method for tissue engineering and regenerative medicine.Both technologies are further described in the background section of this paper,and followed by a detailed analysis into current research,benefits,and limitations of 3D printed chimeric biomate-rials.Major benefits include low-cost and effective treatments for cancer,bio-morphological nanostructures for targeted drug delivery,personalized medicine with the use of stem cells,and a significantly reduced rate of addi-tional surgeries and transplant rejection after implantation.However,there are several shortcomings with current chimeric DNA applications,e.g.CAR-T cell therapies,and ethical dilemmas regarding the creation and regulation of human-animal chimeras.This review then presents future directions,in which inks made from chimeric DNA and live cells can be printed into bioactive engineered tissue,or biodegradable vehicles for targeted delivery of hiPSCs or CAR T-cells.Finally,this review concludes with a reaffirmation of its main points and the authors’thoughts on the potential of 3D printed chimeric biomaterials.

3D Bioprinting with Live Cells

In recent years,the shortage of available organs for transplant patients has grown exponentially across the globe.Consequently,the healthcare industry is in dire need of artificial substitutes.Many recent research studies and tissue engineering groups have decided to utilize 3D bioprinting to produce these artificial organs.This synthetic organ printing is made possible by advancements in the materials required for the constructs,the printing method-ologies used to produce them,and the final physical structures’varying properties.The cutting-edge research and technology related to 3D and 4D live cell bioprinting have recently allowed researchers to produce multiple types of artificial organs and tissues.These tissues can be utilized for drug screening and organ replacement applica-tions.This article provides an extensive review of all the pertinent 3D live cell bioprinting technologies.First,we describe scaffolding methods and their comparison with the traditional technologies.Second,we explain the 3D bioprinting technology,its evolution,and its multiple types.Moreover,we describe the pros and cons of each bioprinting method.Third,we have discussed the critical bioink properties and their impact on the formation of 3D bioprinting models.In addition,we also describe the mechanical properties of bioprinters.Fourth,we have thoroughly discussed the various types of hydrogels and their properties.Every kind of hydrogel is utilized in specific applications,and we have presented a comprehensive list of its advantages and disadvantages.Fifth,we have discussed various applications of 3D bioprinting technology.We have considered a case study of human or-gans and elaborated on how bioprinters can revolutionize the organ replacement industry.Finally,we evaluated the possibility of 4D printing in the future organ industry,incorporating temporal factors into the bioprinting process.

Hernia Mesh and Hernia Repair:A Review

Hernia repair for primary and incisional hernia is the most commonly performed abdominal surgery done with extremely high costs.Treatment for hernia requires surgery to close the defect;however,there are post-operative complications like chronic pain,adhesion,and infection that are common.Hernia repair involves two types of biomaterials:a fixation biomaterial and a mesh biomaterial to close the defect.Synthetic meshes,mostly made from different polymers,provide adequate mechanical support but are associated with postoperative complications like infection.Biological meshes are derived from allografts and xenografts that are prone to less infection;however,their mechanical strength may be too weak depending the characteristics of the hernia defect.Novel meshes being developed try to combat the post-operative complications of current surgical meshes.Composite meshes that have two different surfaces have shown to have less adhesion effects but still produce varying inflammatory responses.Drug-loaded meshes are also a novel mesh that is designed to reduce infection with antibiotics.This review will highlight the different fixation methods as well as the pros and cons of different mesh options.Possible future improvements will be highlighted as well.

3D Printing of Ceramic Biomaterials

Bioceramics are a popular class of materials used in biomedical applications due to their mechanical stability and biocompatibility.They exist in a variety of fields including hip joints for orthopedics,tooth fillings for dentistry,and scaffolds for tissue engineering;however,the standard processes currently used to manufacture these ce-ramic products can be time-consuming and costly.In response,current literature alternatively proposes additive manufacturing(3D printing)strategies to fabricate bioceramic materials in a cost-effective and efficient man-ner.Herein,we briefly cover five common processes and materials used in additive manufacturing bioceramics:fused deposition modeling,material jetting,binder jetting,powder bed fusion,and vat photopolymerization.Fur-thermore,we discuss the potential of these 3D printed ceramic structures when applied to different biomedical technologies such as bone tissue scaffolds and structural implants.

Additive manufacturing and 3D printing of metallic biomaterials

The advancements of 3D printing technology have been combined with the use of metallic biomaterials to cre-ate devices and products for the biomedical field.3D printing has been a revolutionary process that makes the fabrication of metallic biomedical devices highly specific and simultaneously easier than other fabrication methods.The purpose and overall function of each medical device created is dependent on the type of metal used along with its fabrication method.In this review paper,the major characteristics of metallic biomaterials,includ-ing iron,magnesium,zinc,titanium,cobalt,and stainless steel,will be discussed.Major considerations of these metallic biomaterials include degradation rate,biocompatibility,and mechanical properties will be addressed.Importantly,various additive manufacturing processes will be described.Depending on the 3D printing method and the use of specific alloys,these properties can be altered to optimize their functionality for purposes such as bone implants,stents,and other devices.

Hydrogen generating patch improves skin cell viability,migration activity,and collagen expression

Molecular hydrogen recently attracted lots of attention in biomedical community because of its abilities to mod-ulate signal transduction,protein phosphorylation,and gene expression that enable its anti-inflammatory,anti-allergy,and anti-apoptotic activities.However,controllable and local delivery of hydrogen molecules to tissues still remains challenging.Here,we propose a new method of delivering molecular hydrogen directly to human skin cells by designing a hydrogen-generating patch that releases hydrogen in surrounding environment as a product of chemical reaction of aluminum and carbon hydroxide in presence of water.We show that in the pres-ence of molecular hydrogen the cells viability,expression of collagen,and migration efficiency of cells increase,thus suggesting that hydrogen can be used to promote better and faster healing of skin issues such as wounds and bruises.

Corrigendum to“Hernia Mesh and Hernia Repair:A Review”[Engineered Regeneration,1(2020)19-33]

The authors regret that interpretation of the work of Holmdahl et al.1 was misinterpreted in section“5.2 Biological Meshes for Abdominal Repair”.The correct interpretation is that there is no statistical difference in hernia recurrence rate for both groups in the study.The corrected work does not change the conclusion that biological meshes perform the same or worst then synthetic meshes.The authors would like to apologise for any inconvenience caused.

Editorial

We are honoured to introduce Engineered Regeneration(ER)and wel-come you all to the inaugural issue.ER publishes cutting-edge work in the interdisciplinary field that applies engineering and life science the-ories and techniques to modulate cell microenvironments,control cell behaviours and generate engineered tissues and organs,to ultimately address clinical problems,for example,to enhance or replace compro-mised or damaged tissues and organs due to age,disease,or trauma,as well as to normalize congenital defects.