Recent trends in natural polysaccharide based bioinks for multiscale 3D printing in tissue regeneration: A review.

Biofabrication by three-dimensional (3D) printing has been an attractive technology in harnessing the possibility to print anatomical shaped native tissues with controlled architecture and resolution. 3D printing offers the possibility to reproduce complex microarchitecture of native tissues by printing live cells in a layer by layer deposition to provide a biomimetic structural environment for tissue formation and host tissue integration. Plant based biomaterials derived from green and sustainable sources have represented to emulate native physicochemical and biological cues in order to direct specific cellular response and formation of new tissues through biomolecular recognition patterns. This comprehensive review aims to analyze and identify the most commonly used plant based bioinks for 3D printing applications. An overview on the role of different plant based biomaterial of terrestrial origin (Starch, Nanocellulose and Pectin) and marine origin (Ulvan, Alginate, Fucoidan, Agarose and Carrageenan) used for 3D printing applications are discussed elaborately. Furthermore, this review will also emphasis in the functional aspects of different 3D printers, appropriate printing material, merits and demerits of numerous plant based bioinks in developing 3D printed tissue-like constructs. Additionally, the underlying potential benefits, limitations and future perspectives of plant based bioinks for tissue engineering (TE) applications are also discussed.

An alternative to plaster cast treatment in a pediatric trauma center using the CAD/CAM technology to manufacture customized three-dimensional-printed orthoses in a totally hospital context: a feasibility study.

The aim of this study is to implement the clinical use of the three-dimensional (3D) design and printing technology in pediatric pathologies requiring immobilization. We describe the manufacturing process of the 3D device in place of the plaster cast usually applied to a child 48/72 h after the access to the Trauma Center Traumatology Hub. This procedure had already been performed at Level II, Trauma Center, Campania Region, Orthopaedic Division of Santobono Children's Hospital, Naples, Italy. The operative phase was performed by two 3D printers and a scanner in the bioengineering laboratory of the hospital's outpatient area. The phase of software elaboration requires close cooperation among physicians and engineers. We decided to use a model with a double-shell design and holes varying in width to ensure complete ventilation and lightness of the device. We chose to treat nondisplaced metaphyseal distal fractures of the radius in 18 patients enrolled from January 2017 to November 2017. The flow chart includes clinical and radiological examinations of every enrolled child, collecting information required by the program and its elaboration by bioengineers, and then transfer of the results to 3D printers. The child, immobilized by a temporary splint, wore his 3D device after 12/24 h. Then, he underwent serial check-ups in which the effectiveness and appropriateness of the treatment were clinically monitored and evaluated using subjective scales: visual analogue scale and patient-rated wrist evaluation. All the fractures consolidated both radiologically and clinically after the treatment, with no complications reported. Only one partial breakage of the device happened because of an accidental fall. The statistical analysis of the visual analogue scale and patient-rated wrist evaluation data shows that children's activities of everyday life improved during the immobilization thanks to this treatment. This first study shows that using a 3D device instead of a traditional plaster cast can be an effective alternative approach in the treatment of pediatric nondisplaced metaphyseal distal radius fractures, with high overall patient satisfaction. We believe that 3D technology could be extended to the treatment of more complex fractures; this will be the subject of our second study.