Title : Integrating planar and non-planar layers for optimized bioprinted scaffold structures with controlled porosity
Abstract:
Bioprinting has emerged as an attractive technology to treat tissue injuries. The most common approach in 3D printing is performed based on plane layering. When the bioprinted implant slides over other tissue (e.g. when the injury is in a joint), the stair-step effect of a typical planar layering may introduce additional friction and wear the contact surface. Therefore, non-planar layering methods could be useful to improve the tissue interactions. However, most of the methods in the literature are not adequate to achieve a desired internal porosity of the implant. Hence, our methodology is based on the planar and non-planar layers integration to ensure a smoother implant finish while preserving an adequate internal structure with controlled porosity, allowing oxygen and nutrients transmission, as well as cells proliferation. For this purpose, our approach consists of dividing a given lesion according to the curvature of the surface: planar trajectories are applied to the bottom part, while non-planar trajectories are used in the surface. The Poisson method is employed to reconstruct the surface of the model, then the parametrization of the surface, which consists of an area-preserving mapping, is utilized to generate non-planar trajectories. The developed algorithm can be used on conventional 3D bioprinters and has been evaluated on a model representing a bone defect, showing robust results. In addition, since there are no gold standard metrics to compare non-planar algorithms performance and usually their evaluation is based on qualitative aspects, in this study different metrics are proposed to evaluate the resulting trajectories of our methodology and a similar work in the context of bioprinting: number of interruptions when printing the model and number of collisions detected when printing non-planar layers. The comparison between this method and an existing non-planar trajectory method has revealed advantages, since it allows an improved control in collisions and to lessen the waste of material and path interruptions, therefore, reducing the number of fabrication defects. Thereby, this approach presents a novel method for generating non-planar layers capable of optimizing scaffold structure with a controlled internal porosity to ensure that adequate requirements for tissue regeneration are fulfilled.
Audience Take Away Notes:
- Our apn adproach gives new insights into the development of non-planar bioprinting methodologies
- This work achieves reducing the stair-step effect and improving mechanical properties of models while preserving aequate scaffold configuration for the targeted application
- Our research could be used as a starting point to develop an extensive quantitative evaluation when developing non-planar bioprinting algorithms
