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Tracheal implantation remains a major therapeutic challenge due to the unavailability of donors and the lack of biomimetic tubular grafts. Fabrication of biomimetic tracheal scaffolds of suitable materials with matched rigidity, enhanced flexibility and biocompatibility has been a major challenge in the field of tracheal reconstruction. In this study, customized tubular grafts made up of FDA-approved polycaprolactone (

Purpose This paper aims to discuss the successful 3D printing of styrene–ethylene–butylene–styrene (SEBS) block copolymers using solvent-cast 3D printing (SC-3DP) technique. Design/methodology/approach Three different Kraton grade SEBS block copolymers were used to prepare viscous polymer solutions (ink) in three different solvents, namely, toluene, cyclopentane and tetrahydrofuran. Hansen solubility parameters (HSPs) were taken into account to understand the solvent–polymer interactions. Ultraviolet–visible spectroscopy was used to analyze transmittance behavior of different inks. Printability of ink samples was compared in terms of shape retention capability, solvent evaporation and shear viscosity. Dimensional deviations in 3D-printed parts were evaluated in terms of percentage shrinkage. Surface morphology of 3D-printed parts was investigated by scanning electron microscope. In addition, mechanical properties and rheology of the SC-3D-printed SEBS samples were also investigated. Findings HSP analysis revealed toluene to be the most suitable solvent for SC-3DP. Cyclopentane showed a strong preferential solubility toward the ethylene–butylene block. Microscopic surface cracks were present on tetrahydrofuran ink-based 3D-printed samples. SC-3D-printed samples exhibited high elongation at break (up to 2,200%) and low tension set (up to 9%). Practical implications SC-3DP proves to be an effective fabrication route for complex SEBS parts overcoming the challenges associated with fused deposition modeling. Originality/value To the best of authors’ knowledge, this is the first report investigating the effect of different solvents on physicomechanical properties of SC-3D-printed SEBS block copolymer samples.

Purpose The purpose of this paper is to fabricate pre-existing geometries of the stents using solvent cast 3D printing (SC3P) and encapsulation of each stent with heparin drug by using aminolysis reaction. Design/methodology/approach The iron pentacarbonyl powder and poly-ɛ-caprolactone blend (PCIP) were used to print stent designs of Art18z, Palmaz-Schatz and Abbott Bvs1.1. The properties of antithrombosis, anticoagulation and blood compatibility were introduced in the stents by conjugation of heparin drug via the aminolysis process. The aminolysis process was confirmed by energy dispersive X-ray spectroscopy and Fourier transform infrared spectroscopy due to presence of amide group and nitrogen peak in the respective analysis. Biological studies were performed to depict the cell viability, hemocompatibility and antithrombotic properties. Besides, mechanical behaviors were analyzed to study the behavior of the stents under radial compression load and bending load. Findings The amount of heparin immobilized on the Art18z, Palmaz-Schatz and Abbott Bvs1.1 stents were 255 ± 27, 222 ± 30 and 212 ± 13 µg, respectively. The cell viability studies using L929 fibroblast cells confirmed the cytocompatibility of the stents. The heparinized SC3P printed stents displayed excellent thrombo-resistance, anticoagulation properties and hemocompatibility as confirmed by blood coagulation analysis, platelet adhesion test and hemolysis analysis. Besides, mechanical behavior was found in context of the real-life stents. All these assessments confirmed that the developed stents have the potential to be used in the real environment of coronary arteries. Originality/value Various customized shaped biodegradable stents were fabricated using 3D printing technique and encapsulated with heparin drug using aminolysis process.

Biodegradable zinc (Zn) has shown great potential in the area of biomedical applications. Though, the mechanical properties are decisive for the use of Zn for orthopedic and cardiovascular applications. Consequently, one needs to focus on improving the mechanical properties of Zn for its suitability in biomedical applications. Alloying of essential elements of the human body resulted in enhancement of Zn’s mechanical properties in recent years. The corrosion rate of pure Zn is ideal; however, the addition of other elements has resulted in a loss of its ideal corrosion rate. The inclusion of hydroxyapatite (HA) and iron (Fe) in Zn has also been reported in improving the mechanical properties. Hence, a need is raised for the development of a model which can predict the corrosion rate after adding HA along with Fe in Zn. In this research work, empirical based modeling is proposed to predict the corrosion rate, which incorporates the outcome of addition of Fe and HA in Zn. The Zn based materials were fabricated with the help of microwave sintering for developing the empirical model. The corrosion properties of the materials were assessed through a potentiodynamic polarization test in a simulated body fluid solution. The enhanced corrosion rate was attained with the rise in HA (wt%) and Fe (wt%) in Zn. An empirical correlation was established between the influencing controlling parameters (i.e., corrosion current, equivalent weight, and material density) of corrosion rate. Confirmation experiments were conducted to validate the developed model, and the highest error of 6.12% was obtained between the experimental and predicted values exhibiting the efficaciousness of the proposed model.

With the benefit of offering hydrolysis breakdown and bio-resorption of its products, polylactic acid (PLA) is among the most frequently utilized polymers for many biomedical applications. Composites made of polylactic acid (PLA) and bioactive substances such as bioactive glass (BG) are developing as novel biomaterials because they comprise the mechanical properties and bioactivity of bioactive glass (BG) with the conformability and bio absorption of PLA. In this work, composites of PLA/BG were produced by employing the solvent-based three-dimensional printing process. To accomplish this, 0–2 wt% of BG particles (size ≤ 2 µm) were added to PLA. The resulting composite mix was then fed into a solvent-based 3D printer for the layer-by-layer construction of composites. According to the SEM/EDX investigation, BG particles were evenly dispersed throughout the polymer matrix which resulted in the interfacial bonding between them. FTIR and XRD analysis showed that PLA and BG did not interact chemically. All the composites were evaluated for cytocompatibility by in vitro cellular tests, which also proved their suitability as a substrate for NIH 3T3 cell adherence and growth. The composites were also found to be good in terms of hemocompatibility and platelet adhesion. In conclusion, additional studies on these materials were encouraged by the successful outcomes, which suggested that 3D-printed composite scaffolds consisting of PLA and BG particles might be useful in soft and hard tissue engineering.

This work focusses on fabrication of biodegradable iron-hydroxyapatite (Fe-HAp) composite using rapid tooling and pressureless microwave sintering. Carbonyl iron particles and hydroxyapatite powders were mixed in a planetary ball mill in varying proportions. Molds of phosphate-based investment material were filled (under ultrasonic action) with prepared powder mixer and then sintered in a microwave furnace. Fe-HAp composite samples were successfully fabricated using the developed methodology. Based on response surface methodology, planning of experimentation was done to evaluate the effect of process parameters namely sintering temperature, soaking time, HAp percentage and heating rate on shrinkage, sintered density, and compressive yield strength. It was revealed that out of all the factors, HAp percentage was the most influencing parameter. Scanning electron microscopy of prepared samples confirmed the proper bonding of particles without any application of pressure. It was also confirmed from X-ray diffraction analysis that no oxidation and contamination of samples from mold material took place. To find the optimum processing parameters, a multi-objective optimization based on genetic algorithm (GA) was done and results were verified using confirmatory experiments.

The fabrication of ordered pore topological structures (OPTS) with an improved biodegradation profile offers unique attributes required for bone reconstruction. These attributes consisted of fully interconnected porous structure, bone-mimicking mechanical properties, and the possibility of fully regenerating bony defects. Most of the biomaterials based on magnesium were associated with the problem of too fast degradation rate. Here, the present aim was based on the fabrication of ordered pore topological Fe structures (OPTFS) using micro-extrusion-based 3D printing followed by pressureless microwave sintering. Two different kinds of pore features namely randomly distributed interconnected micropores and designed interconnected macropores were investigated. Static in vitro degradation results inferred that the H-2 mm pore size of hexagonal based ordered pore topological Fe structures (H-OPTFS) exhibited the highest degradation rate of 6.45 mg cm

The significant advantage of using magnesium as a surgical implant is its ability to biodegrade in situ, eliminating the requirement for implant removal surgery. However, investigating biomedical implant fabrication processes required the study analyses from the perspective of the process plan and environmental impact for better sustainable solutions. In the present study, magnesium and hydroxyapatite-based composite material have been selected for fabricating the bio-medical implant. The real-time data has been observed in the production processes. The environmental impacts of the produced bio-implant material are compared with those of the bio-implant produced using friction-stir processing and laser-based powder metallurgy. It is observed from the analysis that conventional methods can be utilized for making bio-medical implants cost-effectively after careful modifications in the process sequence and parameters. The environmental impact analysis provided a detailed visualization of major hotspots and supported effective decision-making toward improving the production process. At the same time, the comparative analysis provides a clear picture of the hotspots in the bio-implant production processes. The study compared the environmental impact of two bio-implant production processes and provided valuable insights to reduce overall cost and improve environmental impact across the supply chain. A bio-implant prototype has been made with a cheaper alternative to additive manufacturing.

Supplemental material, supplementary_1 for Effects of rotary ultrasonic bone drilling on cutting force and temperature in the human bones by Ravinder Pal Singh, Pulak Mohan Pandey, Chittaranjan Behera and Asit Ranjan Mridha in Proceedings of the Institution of Mechanical Engineers, Part H: Journal of Engineering in Medicine

Supplemental material, Supplementary for Experimental investigations and statistical modeling of cutting force and torque in rotary ultrasonic bone drilling of human cadaver bone by Ravinder Pal Singh, Pulak Mohan Pandey, Asit Ranjan Mridha and Tanuj Joshi in Proceedings of the Institution of Mechanical Engineers, Part H: Journal of Engineering in Medicine