Optimization of 3D Printing Parameters of Polylactic-Co-Glycolic Acid-Based Biodegradable Antibacterial Materials Using Fused Deposition Modeling

A comprehensive review of emerging 3D-printing materials against bacterial biofilm growth on the surface of healthcare settings

A significant burden on the healthcare system, microbial contamination of biomedical surfaces can result in hospital-acquired illnesses. Bacteria, viruses, and fungi may live on surfaces for days or months and spread to patients and medical personnel. This article describes the 3D printing technologies, such as fused deposition modeling, bioprinting, binder jetting/inkjet, poly-jet, electron beam manufacturing, stereolithography, selective laser sintering, and laminated object manufacturing used for manufacturing the healthcare setting's surface to reduce bacterial contamination with exploring anti-biofilm activity against different bacterial species responsible for infections, based on the critical evaluation of published reports. This strategy has immense potential to become an upcoming approach for advancing the coating concept on the material's surface in healthcare settings. Our literature evaluation identifies beneficial 3D printing materials and associated technologies against microorganisms' growth, mainly bacteria involved in implant-based infection, emphasizing the development of anti-biofilm 3D-printed surfaces. Additionally, the authors have identified a few key areas where research and development are critically required to advance 3D-printing technology in healthcare settings.

Numerical Homogenization Calculation of Effective Stiffness of Fused Deposition Modeling Printing Carbon Fiber Reinforced Polylactic Acid Composites

The varied material and the inherent complex microstructure make predicting the effective stiffness of fused deposition modeling (FDM) printed polylactic acid (PLA)/carbon fiber (CF) composite a troublesome problem. This article proposes a microstructure scanning electron microscope (SEM) mapping modeling and numerical mean procedure to calculate the effective stiffness of FDM printing PLA/CF laminates. The printed PLA/CF parts were modeled as a continuum of 3D uniform linear elasticity with orthotropic anisotropy, and their elastic behavior was characterized by orthotropic constitutive relations. Micromechanical models of two typical deposition configurations, 0° unidirectional aligned configuration and 0°/90° angle-ply configuration of the printed parts were established based on the periodic representative volume element (RVE) technique. The elastic constants of the RVE models were estimated by volume average method in the finite element stress analysis, and the effects of deposition configurations, CF length, and content on the effective stiffness were also investigated. The results show that the effective stiffness of FDM printing PLA/CF composite is closely related to CF length, content, and the deposition configuration. With the increase of CF length and content, the Young's modulus and shear modulus of printed PLA/CF parts increase, whereas Poisson's ratio decreases. The printed PLA/CF parts with 0° unidirectional aligned configuration exhibits orthotropic characteristics, and the maximum Young's modulus appears along the first axis. The 0°/90° angle-ply FDM PLA/CF composite exhibits transverse isotropic characteristics and the lowest Young's modulus is found along the thickness direction.

Degradation behavior of 2D auxetic structure with biodegradable polymer under mechanical stress

Coronary heart disease is serious harm to human health. Vascular scaffold implantation is the main treatment. Biodegradable polymers are widely used in vascular scaffolds for good biodegradability and biocompatibility. However, whether the mechanical properties and radial expansion ability can successfully implant the scaffold without acute elastic retraction remains to be further studied. Because of the unique deformation mechanism, shear resistance, and resilience, auxetic structures can effectively avoid the restenosis of degraded vascular scaffolds. Firstly, the plane isotropic and plane anisotropic auxetic structural scaffolds were designed. The control structures (traditional structures) scaffolds were taken as the contrast. PCL was used to prepare the vascular auxetic by 3D printing. The printing parameters of fused deposition 3D printing, such as printing temperature, printing speed, and printing pressure, were studied to determine the optimal printing parameters of PCL. A self-assembled cyclic tensile stress loading device was used to investigate the degradation behavior of different scaffolds under different sizes of cyclic tensile stress, such as surface morphology, pH changes, mass loss rate, and mechanical properties. The increase of stress, surface roughness, and mass loss rate of the scaffolds all showed an increasing trend. pH gradually decreased from the fifth week, and the decrease was proportional to the stress. A large level of stress loading intensifies the decline of elastic modulus and the ultimate strength of the scaffold. In conclusion, the increase of periodic tensile stress will accelerate the degradation of scaffolds, and the degradation behavior of scaffolds with different configurations is different. The degradation rate of dilatant scaffolds was higher than that of control scaffolds, and the degradation rate of anisotropic auxetic scaffolds was higher than that of isotropic auxetic scaffolds, which provides a theoretical reference for the application of auxetic structure in the degradation of vascular scaffolds.