**5. 3D printing**

In addition to novel gene regulation techniques, there have also been advancements made in the promising area of three-dimensional (3D) printing for medical needs. 3D printing has revolutionised many aspects of our lives, with its uses and benefits still being tested in medicine. 3D printing has the potential to revolutionise the way we practice medicine and tissue regeneration and transplantation are two fields where opportunities are endless. It is a wellknown fact that the need and demand for organ and tissue replacement largely outweighs the supply, even with recently increasing numbers of deceased donors [50]. What if we could eliminate the need for donors and, at the same time, resolve a major issue associated with

**Figure 6.** Bone scaffolds generated by selective laser sintering, (A) image of the scaffold, (B) front view, (C) top view and (D) back view of bone scaffold parts, courtesy of Do et al. [50].

organ transplantation – the risk of immune rejection? Do et al. speaks about this in an article about 3D printed scaffolds and their potential applications [51]. The aim would be to create scaffolds that have properties of the native recipient microenvironment and the ability to promote angiogenesis and osteogenesis, and various tissue engineering techniques could be used in order to facilitate this process and this is still a work in progress, albeit an ever-expanding and promising field (see **Figure 6**). Other studies have suggested that 3D scaffolds could also exhibit bactericidal properties, and aid not only tissue regeneration, but also prevent the high risk of infection that comes with any foreign body or implant. Correiaa et al. have shown that silver nanoparticles could be a suitable way to achieve this [52]. The idea of 3D printing has attracted neuroscientists, too, and Zhu et al. hypothesised that the combination of 3D printed scaffolding and low-level light therapy could aid neural regeneration, and favourable results have been achieved in this in vitro neural stem cell study [53]. Further studies will be needed to assess how effective and useful the proposed 3D printing methods for tissue regeneration in humans will actually be.
