Design and fabrication of 3D-printed anatomically shaped lumbar cage for intervertebra disc (IVD) degeneration treatment

Spinal fusion is the gold standard surgical procedure for degenerative spinal conditions when conservative therapies have been unsuccessful in rehabilitation of patients. Novel strategies are required to improve biocompatibility and osseointegration of traditionally used materials for lumbar cages. Furthermore, new design and technologies are needed to bridge the gap due to the shortage of optimal implant sizes to fill the intervertebral disc defect. Within this context, additive manufacturing technology presents an excellent opportunity to fabricate ergonomic shape medical implants. The goal of this study is to design and manufacture a 3D-printed lumbar cage for lumbar interbody fusion. Optimisations of the proposed implant design and its printing parameters were achieved via in silico analysis. The final construct was characterised via scanning electron microscopy, contact angle, x-ray micro computed tomography (μCT), atomic force microscopy, and compressive test. Preliminary in vitro cell culture tests such as morphological assessment and metabolic activities were performed to access biocompatibility of 3D-printed constructs. Results of in silico analysis provided a useful platform to test preliminary cage design and to find an optimal value of filling density for 3D printing process. Surface characterisation confirmed a uniform coating of nHAp with nanoscale topography. Mechanical evaluation showed mechanical properties of final cage design similar to that of trabecular bone. Preliminary cell culture results showed promising results in terms of cell growth and activity confirming biocompatibility of constructs. Thus for the first time, design optimisation based on computational and experimental analysis combined with the 3D-printing technique for intervertebral fusion cage has been reported in a single study. 3D-printing is a promising technique for medical applications and this study paves the way for future development of customised implants in spinal surgical applications

A novel technique for the production of electrospun scaffolds with tailored three-dimensional micro-patterns employing additive manufacturing

Electrospinning is a common technique used to fabricate fibrous scaffolds for tissue engineering applications. There is now growing interest in assessing the ability of collector plate design to influence the patterning of the fibres during the electrospinning process. In this study, we investigate a novel method to generate hybrid electrospun scaffolds consisting of both random fibres and a defined three-dimensional (3D) micro-topography at the surface, using patterned resin formers produced by rapid prototyping (RP). Poly(D,L-lactide-co-glycolide) was electrospun onto the engineered RP surfaces and the ability of these formers to influence microfibre patterning in the resulting scaffolds visualized by scanning electron microscopy. Electrospun scaffolds with patterns mirroring the microstructures of the formers were successfully fabricated. The effect of the resulting fibre patterns and 3D geometries on mammalian cell adhesion and proliferation was investigated by seeding enhanced green fluorescent protein labelled 3T3 fibroblasts onto the scaffolds. Following 24 h and four days of culture, the seeded scaffolds were visually assessed by confocal macro- and microscopy. The patterning of the fibres guided initial cell adhesion to the scaffold with subsequent proliferation over the geometry resulting in the cells being held in a 3D micro-topography. Such patterning could be designed to replicate a specific in vivo structure; we use the dermal papillae as an exemplar here. In conclusion, a novel, versatile and scalable method to produce hybrid electrospun scaffolds has been developed. The 3D directional cues of the patterned fibres have been shown to influence cell behaviour and could be used to culture cells within a similar 3D micro-topography as experienced in vivo

Physical and Biological characterization of composite scaffolds for cartilage replacement

The following data files are provided: Physical characterization - Raw indentation curves for the composite materials and the two single components, as well as an Excel file containing the numerical results obtained from mechanical testing and swelling analysis. Biological characterization - Excel files containing raw data and numerical results for the number of cells over time in 2D and 3D, cell morphology in 2D, metabolic activity in 3D, and cell migration in 3D