The first systematic analysis of 3D rapid prototyped poly(ε-caprolactone) scaffolds manufactured through BioCell printing: the effect of pore size and geometry on compressive mechanical behaviour andin vitrohMSC viability

Abstract

Novel additive manufacturing processes are increasingly recognized as ideal techniques to produce 3D biodegradable structures with optimal pore size and spatial distribution, providing an adequate mechanical support for tissue regeneration while shaping in-growing tissues. With regard to the mechanical and biological performances of 3D scaffolds, pore size and geometry play a crucial role. In this study, a novel integrated automated system for the production and in vitro culture of 3D constructs, known as BioCell Printing, was used only to manufacture poly(ε-caprolactone) scaffolds for tissue engineering; the influence of pore size and shape on their mechanical and biological performances was investigated. Imposing a single lay-down pattern of 0°/90° and varying the filament distance, it was possible to produce scaffolds with square interconnected pores with channel sizes falling in the range of 245-433 µm, porosity 49-57% and a constant road width. Three different lay-down patterns were also adopted (0°/90°, 0°/60/120° and 0°/45°/90°/135°), thus resulting in scaffolds with quadrangular, triangular and complex internal geometries, respectively. Mechanical compression tests revealed a decrease of scaffold stiffness with the increasing porosity and number of deposition angles (from 0°/90° to 0°/45°/90°/135°). Results from biological analysis, carried out using human mesenchymal stem cells, suggest a strong influence of pore size and geometry on cell viability. On the other hand, after 21 days of in vitro static culture, it was not possible to detect any significant variation in terms of cell morphology promoted by scaffold topology. As a first systematic analysis, the obtained results clearly demonstrate the potential of the BioCell Printing process to produce 3D scaffolds with reproducible well organized architectures and tailored mechanical properties.

Cellularized versus decellularized scaffolds for bone regeneration

“…In previous studies, we extensively investigated the design and fabrication of PCL scaffolds for tissue engineering [16][17][18]. The effect of processing conditions (temperature, deposition velocity, screwrotational velocity and slice thickness) on the morphological and mechanical properties of extruded scaffolds was investigated and optimal processing conditions determine [16].…”

“…Experimental results reveal that deposition velocity and screw-rotational velocity have the highest influence in terms of porosity and mechanical properties. The in vitro biological behaviour was also assessed using scaffolds with different architectures (0º/90º, 0º/60º/120º and 0º/45º/90º/135º) seeded with hMSCs [17,18]. After 21 days of static culture viability/proliferation appeared to be strongly influenced by the pore size and pore shape.…”

Design, construction and mechanical testing of digital 3D anatomical data-based PCL–HA bone tissue engineering scaffold

“…Three different lay-down patterns were also adopted (0°/90°, 0°/60°/120°and 0°/45°/90°/135°), thus resulting in the orthogonal scaffold (0°/90°fiber orientation with quadrangular internal geometry), Pozi hole scaffold (0°/45°/90°/135° fiber orientation with 45°rotation for the fibers between each two floor in geometry), and triangular hole scaffold (0°/60°/ 120°fiber orientation with triangular internal geometry), respectively [17].…”

Additive manufacturing: From implants to organs

“…Autografts are associated with long recovery periods, donor site morbidity and a complex graft-shaping process to achieve biomechanical coupling; allografts and xenografts carry the possibility of immuno-rejection, inflammation and disease transmission, as well as poor mechanical performance. [7] For these reasons, tissue regeneration or engineering approaches are being explored. AM has been used as a tool in tissue regeneration through the production of biocompatible or biodegradable scaffolds -structures that serve as a platform to guide the growth of new tissues to replace damaged or defective ones.…”

“…[5] Scaffolds act not only as passive matrices to support cell adhesion or proliferation, but also as vehicles for the delivery of bioactive molecules, nutrients and waste products. [7] Their functional specifications translate into fabrication requirements for spatially varying structures with high geometric complexity coupled with different biomaterials. Such 'biofabrication' can be accommodated by AM techniques in combination with CAD and medical imaging.…”