Manufacture Of Implants Research Articles

A Comprehensive Review on Manufacturing and Characterization of Polyetheretherketone Polymers for Dental Implant Applications.

Aging, tooth trauma, and pathological infections cause partial or total tooth loss, leading to the usage of dental implants for restoration treatments. As such, mechanical and tribological properties play an important role in the osseointegration and durability of these implants. Metallic and ceramic implants are shown to have mechanical properties much higher than the natural teeth structure, leading to stress shielding-related failure of an implant. Stress shielding occurs due to the difference in the elastic modulus between the implant material and the surrounding teeth structure, leading to bone loss and implant failure. The implant's properties (i.e., mechanical) should be as close as human teeth components. To achieve this, various materials and coatings are being developed and investigated. This review is a comprehensive survey of materials, manufacturing, coating techniques, and mechanical and tribological characterizations of dental implants, with a particular focus on polyetheretherketone (PEEK) as a potential alternative dental implant material. PEEK has mechanical properties similar to natural teeth, which make it a promising material for dental implants. The findings of this review suggest that PEEK offers superior biocompatibility, osseointegration, and wear resistance for implant applications. With the help of bioactive coatings, bone growth on the implant surface can be promoted. In addition, PEEK dental implants made using three-dimensional (3D) printing technology can significantly reduce the cost of implants, making them more affordable and increasing access to dental care, which can improve oral health significantly. In summary, this review highlights the potential of PEEK as a promising alternative dental implant material, and provides an overview of various techniques, testing, and future directions for PEEK dental implants.

3D-Printed Bioceramic Scaffolds with High Strength and High Precision

Due to the increasing cases of bone damage and bone graft demand, bone-repair technology has great social and economic benefits and the manufacturing of artificial bone implants has become a focus in the domain of regenerative therapy. Considering that the traditional manufacturing process cannot effectively control the overall size of the scaffold, the diameter and shape of micropores, and the interoperability of micropores, 3D printing technology has emerged as a focal point of research within the realm of bone tissue engineering. However, the printing accuracy of extrusion-based biological 3D printing techniques is low. In this research, we utilized three-dimensional printing technology to develop high-precision magnesium-containing silicate (CSi-Mg) scaffolds. The precision of this innovative method was scrutinized and the influence of pore size on scaffold strength was systematically analyzed. Furthermore, the influence of the pore architecture on the sidewalls of these 3D-printed scaffolds was evaluated in terms of mechanical properties. The CSi-Mg scaffold, post a 3-week immersion in a simulated body of fluid, demonstrated a high modulus of elasticity (exceeding 404 MPa) and significant compressive strength (beyond 47 MPa). Furthermore, it exhibited commendable bioactivity and biodegradability. These results suggest that the high-precision 3D-printed CSi-Mg scaffolds hold great promise for addressing challenging bone defect cases.

Recent advances of metallic bio-materials in additive manufacturing in biomedical implants–A review

During the last three decades, metal additive manufacturing (metal-AM) has evolved significantly. It has become possible to produce prototypes of products using metal-AM in combination with various manufacturing processes since the technology has matured enough to be used for complex geometries. Recent advancements in biomedical implants have attracted increasing attention to additive manufacturing (AM). The use of titanium and its alloys in biomedical implants, cobalt alloys, stainless steel 316L, nickel-titanium, and others is explored. A number of metal additive manufacturing processes are available, including Selective Laser Melting (SLM), Selective Laser Sintering (SLS), and Electron Beam Melting (EBM). Moreover, the paper discusses the latest developments in metal-AM via direct metal laser sintering and the fabrication and characterization of a three-dimensional scaffold. There is increasing use of laser or electron beam melting techniques in the manufacture of metal implants, among all methods of additive manufacturing (AM). In the future, metal-AM is expected to provide various benefits to the biomedical industry.

A Brief Review of Current Trends in the Additive Manufacturing of Orthopedic Implants with Thermal Plasma-Sprayed Coatings to Improve the Implant Surface Biocompatibility

The demand for orthopedic implants is increasing, driven by a rising number of young patients seeking an active lifestyle post-surgery. This has led to changes in manufacturing requirements. Joint arthroplasty operations are on the rise globally, and recovery times are being reduced by customized endoprostheses that promote better integration. Implants are primarily made from metals and ceramics such as titanium, hydroxyapatite, zirconium, and tantalum. Manufacturing processes, including additive manufacturing and thermal plasma spraying, continue to evolve. These advancements enable the production of tailored porous implants with uniform surface coatings. Coatings made of biocompatible materials are crucial to prevent degradation and enhance biocompatibility, and their composition, porosity, and roughness are actively explored through biocompatibility testing. This review article focuses on the additive manufacturing of orthopedic implants and thermal plasma spraying of biocompatible coatings, discussing their challenges and benefits based on the authors’ experience with selective laser melting and microplasma spraying of metal-ceramic coatings.

Sensor Technology in Fracture Healing.

SMART sensor technology may provide the solution to bridge the gap between the current radiographic determination of fracture healing and clinical assessment. The displacement and rigidity between the fracture ends can be accurately measured using strain gauges. Progressively increasing stiffness is a sign of fracture consolidation which can be monitored using sensors. The design of standard orthopaedic implants can remain the same and needs no major modifications as the sensor can be mounted onto the implant without occupying much space. Data regarding various fracture morphologies and their strain levels throughout the fracture healing process may help develop AI algorithms that can subsequently be used to optimise implant design/materials. The literature search was performed in PubMed, PubMed Central, Scopus, and Web of Science databases for reviewing and evaluating the published scientific data regarding sensor technology in fracture healing. SMART sensor technology comes with a variety of uses such as determining fracture healing progress, predicting early implant failure, and determining fractures liable for non-union to exemplify a few. The main limitations are that it is still in its inception and needs extensive refinement before it becomes widely and routinely used in clinical practice. Nevertheless, with continuous advances in microprocessor technology, research designs, and additive manufacturing, the utilisation and application of SMART implants in the field of trauma and orthopaedic surgery are constantly growing. Mass production of such SMART implants will reduce overall production costs and see its use in routine clinical practice in the future and is likely to make a significant contribution in the next industrial revolution termed 'Industry 5.0' which aims at personalised patient-specific implants and devices. SMART sensor technology may, therefore, herald a new era in the field of orthopaedic trauma.

STUDY OF THE INFLUENCE OF SILVER ALLOYING ON THE MICROSTRUCTURE AND PROPERTIES OF MAGNESIUM ALLOY NZ30K FOR IMPLANTS IN OSTEOSYNTHESIS

Purpose. Study of the influence of silver alloying of magnesium alloy NZ30K on its mechanical properties for use in the manufacture of biodegradable implants. Research methods. The tensile strength and relative elongation of the samples were determined on a P5 tensile machine at room temperature. The microstructure of the samples was studied using a “Carl Zeiss” optical electron microscope using the “Observer.D1m” software. Samples were used after etching with a reagent containing 1 % nitric acid, 20 % acetic acid, 19 % distilled water, and 60 % ethylene glycol. Fractographic analysis of sample fractures was performed on a JSM-6360LA scanning electron microscope. The phase analysis of the structural components of magnesium alloys was studied using an electron microscope – a microanalyzer with an energy dispersive attachment РEMMA 202М and РЕМ 16I. Research on biocorrosion was carried out by keeping the samples in a solution of gelofusin – an artificial blood substitute for 2, 4, 6 weeks, using a TC-20 MICROmed thermostat. Results. The study showed that silver was a part of the complex alloyed intermetallic phases, which were additional crystallization centers. In this case, the average grain size decreases by almost three times compared to the original alloy. It was found that the optimal set of properties is achieved by the introduction of 0.1 % Ag, while the tensile strength increases by 7.9 % and the relative elongation almost doubles. It was found that the magnesium alloy with silver (0.1 %) slows down biocorrosion processes and helps to maintain a high level of tensile strength (σB = 205 MPa) after 6 weeks of exposure to a solution of helofusine. Thus, silver is a promising material for improving the structure and increasing the mechanical properties of biodegradable magnesium alloy implants. Scientific novelty. The silver content for alloying the NZ30K alloy was determined to be 0.1 % Ag, which forms the optimal ratio of strength and ductility, grain structure refinement, and slowing down biocorrosion processes. Practical value. NZ30K alloy with the addition of 0.1 % silver is promising for use in the manufacture of implants. The studied alloy provides the required level of properties until complete fracture consolidation.

FURTHER DEVELOPMENT OF THE DESIGN PROCESS FOR HYBRID INDIVIDUAL IMPLANTS

AbstractAdditive manufacturing (AF) is characterised by a high degree of individuality and flexibility with regard to design and product layout. This enables the integration of different functions in a component. Due to these properties, AM has established itself in medical technology for the production of implants. Depending on the application, parameters such as resilience, biocompatibility and manufacturing restrictions play a varying role. So far, however, only limited research has been done on the design, manufacturing and application of hybrid implants (use of several materials). Although initial design and manufacturing guides exist, the problem of removing the hybrid implant from the shaping negative is hardly addressed.The aim is to analyse and evaluate an existing procedure for the design of hybrid implants depending on individual requirements and to further develop it regarding the removability from the shaping negative. In this context, the extent to which the adhesive properties between the elements can be influenced by design changes is to be investigated.

Preparation of pH-sensitive surface based on mixed oxides of titanium and iridium for early detection of inflammation around the implant

The surface of an implant used during operation is a preferred site for the attachment of harmful microorganisms. These subsequently affect the surrounding tissue with their metabolic products, including the tissue's pH. The possibility of sensing the pH around the implant could be a way of detecting the infection in the early stages. Transition metal oxides can be used for these applications. The most common alloys used for the manufacture of implants are titanium alloys which are characterized by a passive TiO2 surface layer that can be modified. In this work, the Ti–6Al–4V alloy whose surface was nanostructured was used. Iridium particles were subsequently deposited on the prepared surface by various methods to increase the sensitivity to pH change. The potentiostatic mode was chosen as the most suitable method of deposition. Energy dispersive analysis and X-ray photoelectron spectroscopy verified the success of iridium particle deposition. The electrochemical response was measured in a physiological saline solution and monitoring the open circuit potential change proved to be the most appropriate sensing method. After subsequent oxidation process, the prepared surface showed a sensitivity of 64 mV/pH at 37 °C.

Effect of Magnesium as Biomaterial in Biodegrdation

Since many years ago, the study of engineering materials—which includes metal alloys, composites, polymers, ceramics, and metallic glasses—has advanced significantly, particularly in the area of biomaterials. Due to their excellent biocompatibility and unique mechanical qualities, alloys derived on magnesium (Mg) now have a wide array of uses in the biomedical sector. By combining Mg with other elements including nanoparticles, polymers, Zinc, Yttrium and Manganese are included with capability to perform suitable reactions. Addictive manufacturing allows the porosity of the scaffolds to be adjusted, allowing for fine-tuning of the scaffold degradation performance and cell response. Specialized equipment will be required to print magnesium in an inert atmosphere while maintaining safe material handling. As a result, due to inherent characteristics of magnesium mixes, such as a higher vapour pressure and a stronger inclination to oxidize, the additive manufacture of disposable magnesium-based implants presents certain challenges. Inadvertent degradation, structural failure, hydrogen evolution, alkalization, and cytotoxicity are caused by the high corrosion rate of Mg-based implants. A number of methods, such as the design of a magnesium alloy and the alteration of the surface properties, are employed to tailor the degradation rate since it is envisaged that biodegradable Mg-based implants will demonstrate regulated degradation and satisfy the needs of specific applications. Biodegradation mechanism along with its controlling aspects and improvement measures with respect to biodegradation are reviewed in this paper.

Design and manufacturing of patient-specific Ti6Al4V implants with inhomogeneous porosity

Stress shielding remains a challenge in orthopaedic implants, including total hip arthroplasty. Recent development in printable porous implants offers improved patient-specific solutions by providing adequate stability and reducing stress shielding possibilities. This work presents an approach for designing patient-specific implants with inhomogeneous porosity. A novel group of orthotropic auxetic structures is introduced, and their mechanical properties are computed. These auxetic structure units were distributed at different locations on the implant along with optimized pore distribution to achieve optimum performance. A computer tomography (CT) based finite element (FE) model was used to evaluate the performance of the proposed implant. The optimized implant and the auxetic structures were manufactured using laser powder bed-based laser metal additive manufacturing. Validation was done by comparing FE results with experimentally measured directional stiffness and Poisson's ratio of the auxetic structures and strain on the optimized implant. The correlation coefficient for the strain values was within a range of 0.9633–0.9844. Stress shielding was mainly observed in Gruen zones 1, 2, 6, and 7. The average stress shielding on the solid implant model was 56%, reduced to 18% when the optimized implant was used. This significant reduction in stress shielding can decrease the risk of implant loosening and create an osseointegration-friendly mechanical environment on the surrounding bone. The proposed approach can be effectively applied to the design of other orthopaedic implants to minimize stress shielding.

Experimental study of manufacturing of human mandible using fusion deposit modeling (rapid prototyping)

Rapid prototyping method is used, for the manufacture of human mandible for replacement for accident victims. Rapid prototyping will make the manufacture of implants much easier and more exact than conventional methods such as titanium implant manufacturing in Alveolar ridge augmentation. After performing the necessary tests, the material selected for usage in the implants was ABS (Acrylonitrile Butadiene Styrene). Tensile tests are performed on ABS for implant manufacturing. Structured Light 3D Scanner is used to scan a life-size human mandible and the Standard Triangular Language (STL) file was created that file has been used in all the processes involved in the modeling and manufacturing of the Human Mandible by Rapid prototyping on ABS. FEM analysis is done on said material at different orientations using ANSYS 2021. From the test results it is found that the ABS material can sustain more than the required average bite force. Furthermore, a comparison of stress and load-bearing ability of bone and ABS is done to confirm the viability as a replacement material for bone in the mandible, which was found to be positive. The biocompatibility of ABS with the bloodstream and the body is researched and found to be positive. Implantation methods and bone powder coating variants are researched, to be able to fit the implant in the temporomandibular joint with the fastest recovery time.

Bespoke Implants for Cranial Reconstructions: Preoperative to Postoperative Surgery Management System.

Traumatic brain injury is a leading cause of death and disability worldwide, with nearly 90% of the deaths coming from low- and middle-income countries. Severe cases of brain injury often require a craniectomy, succeeded by cranioplasty surgery to restore the integrity of the skull for both cerebral protection and cosmetic purposes. The current paper proposes a study on developing and implementing an integrative surgery management system for cranial reconstructions using bespoke implants as an accessible and cost-effective solution. Bespoke cranial implants were designed for three patients and subsequent cranioplasties were performed. Overall dimensional accuracy was evaluated on all three axes and surface roughness was measured with a minimum value of 2.209 μm for Ra on the convex and concave surfaces of the 3D-printed prototype implants. Improvements in patient compliance and quality of life were reported in postoperative evaluations of all patients involved in the study. No complications were registered from both short-term and long-term monitoring. Material and processing costs were lower compared to a metal 3D-printed implants through the usage of readily available tools and materials, such as standardized and regulated bone cement materials, for the manufacturing of the final bespoke cranial implants. Intraoperative times were reduced through the pre-planning management stages, leading to a better implant fit and overall patient satisfaction.

OPTIMIZATION OF MACHINING CHARACTERISTICS OF TITANIUM-BASED BIOMATERIALS: APPROACH TO OPTIMIZE SURFACE INTEGRITY FOR IMPLANTS APPLICATIONS

Nowadays, there has been continuous development of metallic biomaterials to meet special needs in the manufacturing of biomedical implants, units and systems so as to function well in the required environment. Developed biomaterials which possess exceptional properties in terms of biocompatibility and biomechanical compatibility require precision processing and machining to obtain the desired dimensional tolerances. Electrical discharge machining (EDM) is the noncontact or nontraditional process of machining that suits the precision machining of biomaterials. In this work, an effort was made to optimize the EDM parameters during machining of titanium-based biomaterials Ti-6AL-4V, so that the multi-objective responses could be obtained. The response surface method was used in designing the experiment, while the grey relational method was used to analyze the effect of multiple objectives into a single unit. The electrical parameters that were considered in this study include peak current, gap voltage, pulse turn-on and duty cycle. These parameters were set within the acceptable limits of the equipment. Three responses were studied, which are tool wear rates (TWRs), material removal rate (MRR) and surface roughness (SR). Using the signal-to-noise ratio and ANOVA optimum tool/electrode wear rate (TWR) is obtained at [Formula: see text][Formula: see text]g/min with process parameters [Formula: see text] A, [Formula: see text][Formula: see text]V, [Formula: see text][Formula: see text][Formula: see text]s, [Formula: see text]%. Optimum values of material removal rate (MRR) are obtained as 0.01035[Formula: see text]g/min with process parameters [Formula: see text] A, [Formula: see text][Formula: see text]V, [Formula: see text][Formula: see text][Formula: see text]s, [Formula: see text]%. Optimum SR is observed as 2.258[Formula: see text][Formula: see text]m with EDM process parameters [Formula: see text] A, [Formula: see text][Formula: see text]V, [Formula: see text][Formula: see text][Formula: see text]s, [Formula: see text]%. Surface characteristics are verified with SEM micrographs. Whereas, grey relation analysis predicted the multi-objective optimum response characteristics. Based on the grey relation grade, experiment number 7 ([Formula: see text][Formula: see text]A, [Formula: see text][Formula: see text]V, [Formula: see text][Formula: see text][Formula: see text]s, [Formula: see text]%) secured the first rank among the experiments/trails.

Low cycle fretting and fretting corrosion properties of low carbon CoCrMo and additively manufactured CoCrMoW alloys for dental and orthopedic applications.

Additive manufacturing (AM) of CoCrMo metallic implants is growing in the orthopedic and dental fields. This is due to the traditional alloy's excellent corrosion resistance and mechanical properties. AM processes like selective laser melting (SLM) require less time, materials, and waste than casting or subtractive manufacturing complex-geometry structures (bridges, partial dentures, etc.). The objective of this work was to investigate the low cycle tribological and tribocorrosion characteristics of AM CoCrMoW alloys compared to wrought LC CoCrMo (ASTM F-1537) to assess this AM alloy's performance. Fretting and tribocorrosion testing was performed in air (wear only), PBS (wear + corrosion), and PBS with 10 mM H2 O2 (wear + corrosion + inflammation) by a single diamond asperity. No variation between alloys in volume of material removed (p = .12), volume of plastic deformation (p = .13), and scratch depth (p = .84) showed that AM was substantially similar in wear resistance to LC in air and PBS. AM exhibited significantly higher fretting currents (p < .01) at loads up to 100 mN ( = 57 nA and = 49 nA) than LC CoCrMo ( = 30 nA) and ( = 29 nA). In PBS, wear track depth linearly correlates to fretting current, averaged over 100 cycles. Additionally, fretting currents of both alloys were significantly lower in simulated inflammatory conditions compared to PBS alone. AM alloy has generally similar wear and tribocorrosion resistance to wrought LC CoCrMo and would be ideal for patient specific dentistry or orthopedics where precise, complex geometries are required.

Study on 3D printing process of continuous polyglycolic acid fiber-reinforced polylactic acid degradable composites.

A continuous polyglycolic acid (PGA) fiber-reinforced polylactic acid (PLA) degradable composite was proposed for application in biodegradable load-bearing bone implant. The fused deposition modeling (FDM) process was used to fabricate composite specimens. The influences of the printing process parameters, such as layer thickness, printing spacing, printing speed, and filament feeding speed on the mechanical properties of the PGA fiber-reinforced PLA composites, were studied. The thermal properties of the PGA fiber and PLA matrix were investigated by using differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). The internal defects of the as-fabricated specimens were characterized by the micro-X- ray 3D imaging system. During the tensile experiment, a full-field strain measurement system was used to detect the strain map and analysis the fracture mode of the specimens. A digital microscope and field emission electron scanning microscopy were used to observe the interface bonding between fiber and matrix and fracture morphologies of the specimens. The experimental results showed that the tensile strength of specimens was related to their fiber content and porosity. The printing layer thickness and printing spacing had significant impacts on the fiber content. The printing speed did not affect the fiber content but had a slight effect on the tensile strength. Reducing the printing spacing and layer thickness could increase the fiber content. The tensile strength (along the fiber direction) of the specimen with 77.8% fiber content and 1.82% porosity was the highest, reaching 209.32 ± 8.37 MPa, which is higher than the tensile strength of the cortical bone and polyether ether ketone (PEEK), indicating that the continuous PGA fiber-reinforced PLA composite has great potential in the manufacture of biodegradable load-bearing bone implants.

Nitrilotriacetic Acid Improves Plasma Electrolytic Oxidation of Titanium for Biomedical Applications.

Dental implants have become a routine, affordable, and highly reliable technology to replace tooth loss. In this regard, titanium and its alloys are the metals of choice for the manufacture of dental implants because they are chemically inert and biocompatible. However, for special cohorts of patients, there is still a need for improvements, specifically to increase the ability of implants to integrate into the bone and gum tissues and to prevent bacterial infections that can subsequently lead to peri-implantitis and implant failures. Therefore, titanium implants require sophisticated approaches to improve their postoperative healing and long-term stability. Such treatments range from sandblasting to calcium phosphate coating, fluoride application, ultraviolet irradiation, and anodization to increase the bioactivity of the surface. Plasma electrolytic oxidation (PEO) has gained popularity as a method for modifying metal surfaces and delivering the desired mechanical and chemical properties. The outcome of PEO treatment depends on the electrochemical parameters and composition of the bath electrolyte. In this study, we investigated how complexing agents affect the PEO surfaces and found that nitrilotriacetic acid (NTA) can be used to develop efficient PEO protocols. The PEO surfaces generated with NTA in combination with sources of calcium and phosphorus were shown to increase the corrosion resistance of the titanium substrate. They also support cell proliferation and reduce bacterial colonization and, hence, lead to a reduction in failed implants and repeated surgeries. Moreover, NTA is an ecologically favorable chelating agent. These features are necessary for the biomedical industry to be able to contribute to the sustainability of the public healthcare system. Therefore, NTA is proposed to be used as a component of the PEO bath electrolyte to obtain bioactive surface layers with properties desired for next-generation dental implants.

A PROTOCOL TO EVALUATE AND VALIDATE IMPLANT INTERNAL FORCES AND MOMENTS

Implant manufacturers develop new products to improve existing fracture fixation methods or to approach new fracture challenges. New implants are commonly tested and approved with respect to their corresponding predecessor products, because the knowledge about the internal forces and moments acting on implants in the human body is unclear. The aim of this study was to evaluate and validate implant internal forces and moments of a complex physiological loading case and translate this to a standard medical device approval test.A finite elements model for a transverse femur shaft fracture (AO/OTA type 32-B2) treated with a locked plate system (AxSOS 3 Ti Waisted Compression Plate Broad, Stryker, Kalamazoo, USA) was developed and experimentally validated. The fractured construct was physiologically loaded by resulting forces on the hip joint from previously measured in-vivo loading experiments (Bergmann et. al). The forces were reduced to a level where the material response in the construct remained linear elastic. Resulting forces, moments and stresses in the implant of the fractured model were analysed and compared to the manufacturers’ approval data.The FE-model accurately predicted the behaviour of the whole construct and the micro motion of the working length of the osteosynthesis. The resulting moment reaction in the working length was 24 Nm at a load of 400 N on the hip. The maximum principle strains on the locking plate were predicted well and did not exceed 1 %.In this study we presented a protocol by the example of locked plated femur shaft fracture to calculate and validate implant internal loading using finite element analysis of a complex loading. This might be a first step to move the basis of development of new implants from experience from previous products to calculation of mechanical behaviour of the implants and therefore, promote further optimization of the implants’ design.

Laser powder bed fusion of Alumina/Fe–Ni ceramic matrix particulate composites impregnated with a polymeric resin

Additive Manufacturing (AM) plays a key role in meeting the vital demands of Industry. The AM industry needs the range of applicable materials to be expanded by conducting research on novel ones. In the present investigation, alumina/Fe–Ni (steel) ceramic matrix particulate composite was fabricated employing laser powder bed fusion (LPBF) additive manufacturing (AM) technology. The quality of the printed samples was associated with the LPBF process parameters, which were optimized for this process. In general, the fabricated samples showed a microstructure of alumina matrix with uniform distribution of steel (Fe–Ni) particles. The as-printed samples exhibited pores. Thus, they were subjected to a sintering heat treatment cycle under an inert atmosphere. Although the sintering cycle considerably increased the average Vickers hardness, pores were not eliminated entirely. Therefore, polymer impregnation of the as-sintered samples was carried out to reduce porosities and microcracks. The mercury porosimeter showed that the porosity decreased sequentially after sintering and polymer impregnation. In addition, mechanical investigations revealed that the polymer impregnation improved the compressive strength of the sintered samples (from 56 to 120 MPa). Alumina-based materials find wide applications in various fields, including the manufacturing of electronic components, cutting tools, biomedical implants, and catalyst converters, owing to their low density, high hardness, wear and corrosion resistance, and biocompatibility. This study presents a viable approach for the fabrication of these materials, with developed samples exhibiting promising properties. The study emphasizes the potential of additive manufacturing as an approach for the fabrication of ceramic matrix composites reinforced with metallic particulates in future research.

Legal regulation of additive technologies in modern biomedicine

Research reveals the legal problems that arise due to the rapid pace of development of additive technologies (3D printing) in biomedicine (bioprinting). The purpose of the research is to analyze the legislation that defines the legal regime of additive technologies, identify the main gaps in regulation, carry out a comparative legal study, which allows to formulate recommendations to improve Russian legislation. Special strategies are used as an object of comparative research; they contribute to fix the priority development of 3D printing. The employed methods are as follows: the method of analysis of legal regulation, comparative legal and formal legal. Results. Attention is paid to the main trends and risks of progress in this direction, which are reflected in decentralization of production; improving its efficiency and reducing waste; reduction of development time and their introduction into mass production with a simultaneous rise in quality of the finished product; expanding the population's access to material goods; minimizing the state control. Particular attention is paid to the legal assessment of the applicability of bioprinting in transplantology, the manufacture of implants, surgical planning, and the use of printed organs for experiments. Conclusions: when adjusting the legal framework, institutional readiness should be taken into account - the ability of the entire Russian healthcare system to use additive technologies properly (which will require significant changes in healthcare legislation). An independent direction is the use of bioprinting in the testing of drugs. 3D printing creates small organ-like structures (they are called organoids) on which experiments can be carried out for the screening of pharmaceuticals. This will require changes in the legal regime for the circulation of medicines, as well as the main functions of the state regulator (the Russian Ministry of Health and Roszdravnadzor). It is noted that additive technologies make it possible to manufacture medicines, but world experience indicates a cautious attitude towards this type of production. Research argues for the need to follow a risk-based approach in the legal regulation of bioprinting, as well as to introduce the general approach of Hospital Exemption (pharmaceutical exclusion) used in the countries of the European Union, as well as some other countries aimed at the development of regenerative medicine.

Volumetric Printing of Thiol-Ene Photo-Cross-Linkable Poly(ε-caprolactone): A Tunable Material Platform Serving Biomedical Applications.

Current thoroughly described biodegradable and cross-linkable polymers mainly rely on acrylate cross-linking. However, despite the swift cross-linking kinetics of acrylates, the concomitant brittleness of the resulting materials limits their applicability. Here, photo-cross-linkable poly(ε-caprolactone)networks through orthogonal thiol-ene chemistry are introduced. The step-growth polymerized networks are tunable, predictable by means of the rubber elasticity theory and it is shown that their mechanical properties are significantly improved over their acrylate cross-linked counterparts. Tunability is introduced to the materials, by altering Mc (or the molar mass between cross-links), and its effect on the thermal properties, mechanical strength and degradability of the materials is evaluated. Moreover, excellent volumetric printability is illustrated and the smallest features obtained via volumetric 3D-printing to date are reported, for thiol-ene systems. Finally, by means of in vitro and in vivo characterization of 3D-printed constructs, it is illustrated that the volumetrically 3D-printed materials are biocompatible. This combination of mechanical stability, tunability, biocompatibility, and rapid fabrication by volumetric 3D-printing charts a new path toward bedside manufacturing of biodegradable patient-specific implants.