Search

Purpose Since the biomedical implants with an improved compressive strength, near bone elastic modulus, controlled porosity, and sufficient surface roughness, can assist in long term implantation. Therefore, the fine process tuning plays its crucial role to develop optimal settings to achieve these desired properties. This paper aims to find applications for fine process tuning in laser powder bed fusion of biomedical Ti alloys for load-bearing implants. Design/methodology/approach In this work, the parametric porosity simulations were initially performed to simulate the process-induced porosity for selective laser-melted Ti6Al4V as per full factorial design. Continually, the experiments were performed to validate the simulation results and perform multiresponse optimization to fine-tune the processing parameters. Three levels of each control variable, namely, laser power – Pl (180, 190, 200) W, scanning speed – Vs (1500, 1600, 1700) mm/s and scan orientation – ϴ{1(0,0), 2(0,67°), 3(0,90°)} were used to investigate the processing performance. The measured properties from this study include compressive yield strength, elastic modulus, process-induced porosity and surface roughness. Finally, confirmatory experiments and comparisons with the already published works were also performed to validate the research results. Findings The results of porosity parametric simulation and experiments in selective laser melting of Ti6Al4V were found close to each other with overall porosity (less than 10%). The fine process tuning was resulted in optimal settings [Pl (200 W), Vs (1500 mm/s), ϴ (0,90°)], [Pl (200 W), Vs (1500 mm/s), ϴ (0,67°)], [Pl (200 W), Vs (1500 mm/s), ϴ (0,0)] and [Pl (200 W), Vs (1500 mm/s), ϴ (0,0)] with higher compressive strength (672.78 MPa), near cortical bone elastic modulus (12.932 GPa), process-induced porosity (0.751%) and minimum surface roughness (2.72 µm). The morphology of the selective laser melted (SLMed) surface indicated that the lack of fusion pores was prominent because of low laser energy density among the laser and powder bed. Confirmatory experimentation revealed that an overall percent improvement of around 15% was found between predicted and the experimental values. Originality/value Since no significant works are available on the collaborative optimization and fine process tuning in laser powder bed fusion of biomedical Ti alloys for different load bearing implants. Therefore, this work involves the comprehensive investigation and multi-objective optimization to determine optimal parametric settings for better mechanical and physical properties. Another novel aspect is the parametric porosity simulation using Ansys Additive to assist in process parameters and their levels selection. As a result, selective laser melted Ti alloys at optimal settings may help in examining the possibility for manufacturing metallic implants for load-bearing applications.

In this work, a series of polylactic acid/thermoplastic polyurethane/polyaniline (PLA/TPU/PANI) blends with different weight ratios were prepared by Fused deposition molding First, six groups of PLA/TPU (U9A1/U8A2/U7A3/U6A4/U5A5/U4A6) and three groups of PLA/TPU/PANI (821/823/825) with different ratios were fabricated by melt blending. Then, the effects of different filament forming and printing process parameters on print resolution and quality were investigated. Next, printed samples were characterized by Fourier transform infrared (FTIR), Thermogravimetric analysis (TGA), Scanning electron microscopy (SEM) and mechanical experiments. The results of FTIR and TGA showed no chemical reaction between different components, and uniform distribution of the material was observed in the SEM. The tensile and compressive curves of the samples showed an inverted U-shape. Finally, the shape-memory property was evaluated by differential scanning calorimetry. For PLA/TPU blends, U8A2 had the best shape memory capability ([Formula: see text] = 80.8% and [Formula: see text] = 100%). Based on the excellent shape memory performance of PLA/TPU, the addition of PANI can introduce a light-actuated mechanism to form a binary-driven shape memory material. The composite materials prepared in this work can be applied to tissue engineering scaffolds, medical devices, soft robots and so on.

Self-healing hydrogels have great application potential in the field of bio-sensors due to their self-healing, flexibility and excellent tensile properties. However, most hydrogel-based sensors are processed by template method, which is unable to fabricate complex three-dimensional (3D) structures, and limits the development of hydrogel-based sensor devices. A simple yet efficient one-pot method was proposed to fabricate polyvinyl alcohol/sodium tetraborate/sodium alginate hydrogel inks (SPB), also a fabricating process of self-healing hydrogel based on 3D printing technology has been proposed. The SPB hydrogel rapidly healed (30 s) at room temperature, while its mechanical properties and conductivity also recovered quickly after healing. Besides, it could be used as wearable strain sensors, whose high stretchability (2800 % strain) and sensitivity (gauge factor: 18.56 at 2000 % strain) could not only detect very large stretch deformations, but also detect the tiny pressure changes in the human body, such as finger flexion, knee flexion, and respiration. This study provides a method for the rapid fabrication of complex-structured hydrogel-based sensors, which is helpful for the hydrogel-based sensor applications in human motion detection and wearable devices.

Articular cartilage defects are one of the most common clinical diseases of bone articulation. Early repair of damaged joint cartilage can effectively stop the progression of arthritis and restore health to the patient. In recent years, various therapeutic strategies have been developed to repair cartilage defects and make them available for clinical transplantation. However, cartilage defect repair remains a clinically unsolved challenge to date. Although there have been numerous breakthroughs in cartilage defect repair, the limited spatial complexity of tissue-engineered implants in terms of cells, materials, and active factors has limited the success of engineered cartilage so far. Bioprinting technology allows for the construction of three-dimensional tissues drop by drop and layer by layer, where cells, matrices, and active materials can be deposited on demand while maintaining high precision. Therefore, adopting the bioprinting technology in cartilage tissue engineering promises to develop the next generation of engineered cartilage and address the cartilage defect/regeneration problem. In this paper, we reviewed the bioinks and bioprinting technologies used in cartilage tissue engineering, outlined the recent advances of 3D bioprinting technologies in cartilage tissue engineering, and prospected the development direction of next-generation engineered cartilage.

Graphical Abstract Additively manufactured nano-MEH systems are widely used to harvest energy from renewable and sustainable energy sources such as wind, ocean, sunlight, raindrops, and ambient vibrations. A comprehensive study focusing on in-depth technology evolution, applications, problems, and future trends of specifically 3D printed nano-MEH systems with an energy point of view is rarely conducted. Therefore, this paper looks into the state-of-the-art technologies, energy harvesting sources/methods, performance, implementations, emerging applications, potential challenges, and future perspectives of additively manufactured nano-mechanical energy harvesting (3DP-NMEH) systems. The prevailing challenges concerning renewable energy harvesting capacities, optimal energy scavenging, power management, material functionalization, sustainable prototyping strategies, new materials, commercialization, and hybridization are discussed. A novel solution is proposed for renewable energy generation and medicinal purposes based on the sustainable utilization of recyclable municipal and medical waste generated during the COVID-19 pandemic. Finally, recommendations for future research are presented concerning the cutting-edge issues hurdling the optimal exploitation of renewable energy resources through NMEHs. China and the USA are the most significant leading forces in enhancing 3DP-NMEH technology, with more than 75% contributions collectively. The reported output energy capacities of additively manufactured nano-MEH systems were 0.5–32 mW, 0.0002–45.6 mW, and 0.3–4.67 mW for electromagnetic, piezoelectric, and triboelectric nanogenerators, respectively. The optimal strategies and techniques to enhance these energy capacities are compiled in this paper. Supplementary Information The online version contains supplementary material available at 10.1186/s40580-021-00289-0., Highlights The current technology evolution and advancements in 3DP-NMEHs were evaluated.Categorization and comparison of 3DP-NMEHs were performed in terms of inputs and energy conversion.The emerging applications of 3DP-NMEHs were discussed briefly.The potential challenges confronted by 3DP-NMEHs and respective recommendations were summarized.Sustainable use of recyclable waste generated during the COVID-19 pandemic was proposed. Supplementary Information The online version contains supplementary material available at 10.1186/s40580-021-00289-0.

The idea for the Internet of Robotic Things (IoRT) comes from activities. IoRT allows smart devices to combine sensor information from multiple sources, use broader nearby insights to determine the best reason for the activity and display events on-screen. The Internet of Things can connect web applications to other gadgets to make them smarter. Automated engineers combine the two and arm themselves with sensors that can analyze the current situation. Mechanical improvements such as ordinary voice links (PC) vision sensor innovations and artificial intelligence (AI) have resulted in a turn of events and programmed placement frameworks under advanced machinery. This article examines frameworks for arranging programmed objects to assemble robots and innovative patterns in ordinary language programmed programming, and three-dimensional (3D) visual insight. The relevant statement "regulation scene" should describe the combination of all three modules. This computation enables people to relate through a three-tiered information scene and guides managers to use discourse to provide reasonable criteria whenever an order is legitimate. After receiving precise criteria, the robot can use this diary's planned execution calculations and programmed programming to direct the placement of programmed items. The play area provides a context for the natural product, while the landscape design provides a valuable part of the framework.

Purpose Additive manufacturing (AM) technology has a huge influence on the real world because of its ability to manufacture massively complicated geometrics. The purpose of this study is to use CiteSpace (CS) visual analysis to identify fused deposition modeling (FDM) research and development patterns to guide researchers to decide future research and provide a framework for corporations and organizations to prepare for the development in the rapid prototyping industry. Three-dimensional printing (3DP) is defined to budget minimize manufactured input and output for aviation and the medical product industrial sectors. 3DP has implemented its potential in the Coronavirus Disease of 2019 (COVID-19) reaction. Design/methodology/approach First, 396 original publications were extracted from the web of science (WOS) with the comprehensive list and did scientometrics analysis in CS software. The parameters are specified in CS including the span (from 2011 to 2019, one year slice for the co-authorship and the co-accordance analysis), visualization (show the merged networks), specific criteria for selection (top 20%), node form (author, organization, region, reference cited; cited author, journal and keywords) and pruning (pathfinder and slicing network). Finally, correlating data was studied and showed the results of the visualization study of FDM research were shown. Findings The framework of FDM information is beginning to take shape. About hot research topics, there are “Morphology,” “Tensile Property by making Blends,” “Use of Carbon nanotube in 3DP” and “Topology optimization.” Regarding the latest research frontiers of FDM printing, there are “Fused Filament Fabrication,” “AM,” in FDM printing. Where “Post-processing” and “environmental impact” are the research hotspots in FDM printing. These research results can provide insight into FDM printing and useful information to consider the existing studies and developments in FDM researchers’ analysis. Research limitations/implications Despite some important obtained results through FDM-related publications’ visualization, some deficiencies remain in this research. With >99% of articles written in English, the input data for CS was all downloaded from WOS databases, resulting in a language bias of papers in other languages and neglecting other data sources. Although, there are several challenges being faced by the FDM that limit its wide variety of applications. However, the significance of the current work concerning the technical and engineering prospects is discussed herein. Originality/value First, the novelty of this work lies in describing the FDM approach in a Scientometric way. In Scientometric investigation, leading writers, organizations, keywords, hot research and emerging knowledge points were explained. Second, this research has thoroughly and comprehensively examined the useful sustainability effects, i.e. economic sustainability, energy-based sustainability, environmental sustainability, of 3DP in industrial development in qualitative and quantitative aspects by 2025 from a global viewpoint. Third, this work also described the practical significance of FDM based on 3DP since COVID-19. 3DP has stepped up as a vital technology to support improved healthcare and other general response to emergency situations.

Toughness is a prerequisite for bone scaffold matrix material if such material is to be used in clinic. Blending with polycaprolactone (PCL) is the most used method to improve the toughness of polylactic acid (PLA), while improving their miscibility in the absence of the compatibilizer is always a challenge. To address this issue, the printing process was proposed to improve the miscibility of PLA and PCL. PLA/PCL Blends at different compositions were extruded into filaments and used to print samples. The results of Fourier transform infrared and thermogravimetric analysis indicate that the processing temperatures of the extruder and FDM printer do not cause the degradation of PCL in blend. Following, the influence of FDM printing process on their miscibility was investigated in terms of mechanical properties, surface morphology and melting behavior. Results show that the printing process can effectively improve the miscibility and toughness, and the most appropriate PCL concentration used to blend with PLA is 20 wt.%. At 20 wt.% PCL concentration, the printed blend has an elongation of 189%, which is an increase of about 950% compared with pure PLA. This research not only expands the PLA/PCL blend research, but also provides a process guidance for FDM printing PLA/PCL bone scaffolds.

Purpose Human aging is becoming a common issue these days as it results in orthopaedic-related issues such as joints disorderness, bone-fracture. People with age = 60 years suffer more from these aforesaid issues. It is expected that these issues in human beings will ultimately reach 2.1 billion by 2050 worldwide. Furthermore, the increase in traffic accidents in young people throughout the world has significantly emerged the need for artificial implants. Their implantation can act as a substitute for fractured bones or disordered joints. Therefore, this study aims to focus on electron beam melted titanium (Ti)-based orthopaedic implants along with their recent trends in the field. Design/methodology/approach The main contents of this work include the basic theme and background of the metal-based additive manufacturing, different implant materials specifically Ti alloys and their classification based on crystallographic transus temperature (including α, metastable β, β and α + β phases), details of electron beam melting (EBM) concerning its process physics, various control variables and performance characteristics of EBMed Ti alloys in orthopaedic and orthodontic implants, applications of EBMed Ti alloys in various load-bearing implants, different challenges associated with the EBMed Ti-based implants along with their possible solutions. Recent trends and shortfalls have also been described at the end. Findings EBM is getting significant attention in medical implants because of its minor issues as compared to conventional fabrication practices such as Ti casting and possesses a significant research potential to fabricate various medical implants. The elastic modulus and strength of EBMed ß Ti-alloys such as 24Nb-4Zr-8Sn and Ti-33Nb-4Sn are superior compared to conventional Ti for orthopaedic implants. Beta Ti alloys processed by EBM have near bone elastic modulus (approximately 35–50 GPa) along with improved tribo-mechanical performance involving mechanical strength, wear and corrosion resistance, along with biocompatibility for implants. Originality/value Advances in EBM have opened the gateway Ti alloys in the biomedical field explicitly ß-alloys because of their unique biocompatibility, bioactivity along with improved tribo-mechanical performance. Less significant work is available on the EBM of Ti alloys in orthopaedic and orthodontic implants. This study is directed solely on the EBM of medical Ti alloys in medical sectors to explore their different aspects for future research opportunities.

Sustainable and cleaner manufacturing systems have found broad applications in industrial processes, especially aerospace, automotive and power generation. Conventional manufacturing methods are highly unsustainable regarding carbon emissions, energy consumption, material wastage, costly shipment and complex supply management. Besides, during global COVID-19 pandemic, advanced fabrication and management strategies were extremely required to fulfill the shortfall of basic and medical emergency supplies. Three-dimensional printing (3DP) reduces global energy consumption and CO2 emissions related to industrial manufacturing. Various renewable energy harvesting mechanisms utilizing solar, wind, tidal and human potential have been fabricated through additive manufacturing. 3D printing aided the manufacturing companies in combating the deficiencies of medical healthcare devices for patients and professionals globally. In this regard, 3D printed medical face shields, respiratory masks, personal protective equipment, PLA-based recyclable air filtration masks, additively manufactured ideal tissue models and new information technology (IT) based rapid manufacturing are some significant contributions of 3DP. Furthermore, a bibliometric study of 3D printing research was conducted in CiteSpace. The most influential keywords and latest research frontiers were found and the 3DP knowledge was categorized into 10 diverse research themes. The potential challenges incurred by AM industry during the pandemic were categorized in terms of design, safety, manufacturing, certification and legal issues. Significantly, this study highlights the versatile role of 3DP in battle against COVID-19 pandemic and provides up-to-date research frontiers, leading the readers to focus on the current hurdles encountered by AM industry, henceforth conduct further investigations to enhance 3DP technology.

The Internet of Things has provided people with a seamless, automated home and industrial experience. The concept is now integrated into more domains like Internet of robotic things (IoRT), Internet of medicine Things (IoMT), etc., to improve domain-specific outcomes. For IoRT, which is the robotics implementation of Internet of Things (IoT), poor network security could cause economic and physical damage to both the networked devices and human users of the network. Also, the tendency for data and privacy breaches becomes more prevalent with an increase in the number of devices in the network. Hence, these identified vulnerabilities are the limiting elements for proper IoRT implementation. Various works have proposed security schemes for ensuring the realization of a secure and efficient IoRT network, but with computational time and complexity limitations. However, machine learning methodologies have shown the best promise for identifying malicious traffic in an IoRT network. This work proposes a security architecture using a Deep Neural Network and an ensemble of Decision Trees. This architecture can be implemented online or offline with minimal trade-offs between resources and efficiency. Also, the proposed machine learning models are compared with other commonly implemented schemes using the IoT-23 Dataset. Experimentation and comparison show that the proposed model and architecture are optimal for the malware detection task and security of a typical IoRT network. These contributions are significant for realizing secure and efficient IoRT networks for the future of industrial automation in this post-COVID era.

As known, the poor toughness of Polylactic acid (PLA) limits its further application, especially as a bone implant withstanding complex loadings. Blending PLA with Poly (e-caprolactone) (PCL) under the action of compatibilizers is a proven method to improve the toughness of PLA, while the excess compatibilizers is hard to remove and easy to contaminate the matrix material. This study employed a molecular dynamics simulation combining experimental testing method to investigate the miscibility, mechanical properties and printability of PLA/PCL blends at different compositions without adding any compatibilizers, so as to obtain an ideal PLA/PCL filament for FDM printing bone scaffolds. Results of binding energy distribution and intermolecular interaction show that the miscibility of PLA and PCL is not very good, only the blend of 9PLA/1PCL is miscible. The calculated static mechanical properties and tensile testing results indicate the stiffness or hardness of blends decrease with the addition of PCL, while the toughness firstly increases and then decreases with the introduction of PCL, and the blend of 9PLA/1PCL possesses the best ductility and toughness. Moreover, the results of surface morphology confirm the miscible of 9PLA/1PCL blend and explain why the tensile properties of 9PLA/1PCL is the best, a better miscibility indicating better mechanical properties. Finally, the results of printability indicates that, due to the fluidity of PCL, the printability of blend becomes worse with the increase of PCL content, and the blend of 9PLA/1PCL possesses a relatively good printability. This work provides a practical guidance to the design of PLA/PCL blend filament for FDM printing bone scaffolds.

Currently, osteochondral (OC) tissue engineering has become a potential treatment strategy in repairing chondral lesions and early osteoarthritis due to the limited self-healing ability of cartilage. However, it is still challenging to ensure the integrity, physiological function and regeneration ability of stratified OC scaffolds in clinical application. Biomimetic OC scaffolds are attractive to overcome the above problems because of their similar biological and mechanical properties with native OC tissue. As a consequence, the researches on biomimetic design to achieve the tissue function of each layer, and additive manufacture (AM) to accomplish composition switch and ultrastructure of personalized OC scaffolds have made a remarkable progress. In this review, the design methods of biomaterial and structure as well as computer-aided design, and performance prediction of biopolymer-based OC scaffolds are presented; then, the characteristics and limitations of AM technologies and the integrated manufacture schemes in OC tissue engineering are summarized; finally, the novel biomaterials and techniques and the inevitable trends of multifunctional bio-manufacturing system are discussed for further optimizing production of tissue engineering OC scaffolds.

A rational molecular design approach was developed in our laboratory to guide the discovery of novel sterol biosynthesis inhibitors. Based on the application of bioactivities of heterocyclic rings and molecular docking targeting the sterol biosynthesis 14α-demethylase, a series of 4-chloropyrazole-based pyridine derivatives were rationally designed, synthesized, and characterized and their fungicidal activities were also evaluated. Bioassay results showed that

The selection of optimal process parameters has a decisive effect on the quality of 3D printing. In this work, the numerical and experimental methods were employed to investigate the FDM printing deposition process of PLA/GNPs nanocomposite. The effect of process parameters on cross-sectional morphology and dimension of the deposited filament, as well as the mechanical property of the FDM printed specimens were studied. The extrusion and the deposition process of the molten PLA/GNPs nanocomposite was simulated as a fluid flow by the paradigm of CFD, the effects of printing temperature and shear rate on thermal-physical properties, such as viscosity and surface tension, were considered in models. Under the assumptions of non-Newtonian fluid and creep laminar flow, the deposition flow was controlled by two key parameters: the nozzle temperature and the nozzle velocity. The numerical model was verified by experiments from four aspects of thickness, width, area, and compactness of the deposited PLA/GNPs nanocomposite filament cross-section. Both the numerical simulation and experiment results show that with the increase of nozzle temperature and nozzle velocity, the thickness, area, and compactness of the deposited filament decreases. While the width of deposited filament increased with the increase of nozzle temperature and decrease of nozzle velocity. The decrease in thickness and the increase in width caused by the change of process parameters reached 10.5% and 24.7%, respectively. The tensile strength of the printed PLA/GNPs specimen was about 61.8 MPa under the higher nozzle temperatures and velocity condition, an improvement of 18.6% compared to specimen with the tensile strength of 52.1 MPa under the lower nozzle temperatures and velocity condition. In addition, the experimental results indicated that under the low nozzle velocity and nozzle temperature condition, dimensional standard deviation of the printed specimens decreased by 52.2%, 62.7%, and 68.3% in X, Y, and Z direction, respectively.