Circular specimens for mechanical strength evaluation.Rectangular specimens for analysis of micro-porosity and cell viability.It featured a build envelope of 60 × 75 × 120 mm. The scientific team used a customized Formiga 3D printer for fabricating a patient-specific implant demonstrator. “As the melt viscosity strongly increases with polymer chain length or molecular weight, we hypothesize that a careful selection of the inherent viscosity (which is a measure for the molecular weight) can improve processability.” Viscosity is another issue the researchers had to tackle: “Therefore, upscaling and medical approval are complicated,” state the researchers. There is a major challenge however, because PLA only becomes soluble in organic solvents like dichloromethane (DCM) or chloroform (CHCl 3) that are toxic. Some intact CC spherulites are marked by white circles to show that they were present in each composite.PLA particles can either be prepared with solvent evaporation or mechanical milling. The PLLA-1.0 with the lowest inherent viscosity of 1 dl/g could be ground to the smallest particle size. Scanning electron microscope images of the polylactide (PLA)/calcium carbonate (CC) composite powder particles. However, it should be noted that the high strength comes at the expense of a low elongation at break of 2–10%, which shows that PLA is quite brittle.” “Thus, PLA is of particular interest for bone tissue engineering.
50–70 MPa, tensile modulus of 3000–4000 MPa, flexural strength of 100 MPa, and flexural modulus of 4000–5000 MPa,” state the researchers in their paper. “Among the biodegradable polymers, polylactide (PLA) has the highest mechanical strength (i.e., tensile strength of approx.
The team experimented with four different composite powders, and four different grades of polylactide. There are biodegradable & biocompatible options available though, and here the researchers learned more about them, along with creating a polylactide/calcium carbonate composite powder for SLS. This could cause problems later, and especially due to any exposure to chemicals. The obstacle is, however, that such implants stay in the patient’s body. The technology is suitable for creating complex structures to encourage bone growth, and there are methods already being used with both titanium and polyetherketoneketone (PEKK) implants. Scientists are often enticed by selective laser sintering (SLS) 3D printing for bioprinting, but solvents are often required. In ‘ Development of a solvent-free polylactide/calcium carbonate composite for selective laser sintering of bone tissue engineering scaffolds,’ researchers from all over Germany explore alternatives. With 3D printing, however, the use of solvents is often necessary. Healing large bone defects is an ongoing challenge, and scientists continue to look for ways to do so in tissue engineering. The PLLA-1.0-based composite had the smallest particle size (d50 = 53 μm), whereas the amorphous PDLLA-1.9-based composite had the largest particle size (d50 = 130 μm). Particle size distributions of the PLA/CC composite powders: (a) volumetric and (b) corresponding cumulative distributions as determined by laser diffraction analysis.
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