Futuristic Three-Dimensional Printing and Personalized Neurosurgery

Abstract

Figure 1. Continuous liquid interface production apparatus. From Tumbleston JR, Shirvanyants D, Ermoshkin N, Janusziewicz R, Johnson AR, Kelly D, Chen K, Pinschmidt R, Rolland JP, Ermoshkin A, Samulski ET, DeSimone JM: Additive manufacturing. Continuous liquid interface production of 3D objects. Science 347:1349-1352, 2015. Reprinted with permission from AAAS. Disruptive technologies are rare phenomena. However, when they do come about, they have the potential to change the course of entire industries. Such is the case with the new three-dimensional (3D) printing technology from Carbon3D Inc. (Redwood City, California, USA), dubbed Continuous Liquid Interface Production (CLIP). With its innovative approach to additive manufacturing, CLIP has the potential to usurp and revolutionize 3D printing, with reverberations into several fields, including neurologic surgery. Conventional additive manufacturing, like Polyjet, Fused Deposition Modeling (FDM), Stereolithography (SLA) and Laser Sintering technology (SLS), function by adding materials layer by layer. For these techniques, two-dimensional printing is repeated over and over again until a 3D physical rendering is produced. Consequently, such a process takes several hours and in most cases results in an unfinished and “pixelated-like” end product. A post-processing interval adds further time to the process. CLIP technology, as described by Tumbleston et al., prints 3D physical models in a continuous fashion as opposed to layer by layer in conventional machines. This approach capitalizes on 2 opposing forces: ultraviolet (UV) light that promotes polymerization of resin, in contrast to oxygen (O2), which inhibits the polymerization of resin. The apparatus itself consists of a bath filled with resin, an O2-permeable and UVpermeable membrane, a build support plate, and a UV imaging unit (Figure 1). Polymerization of the intended part begins when a continuous sequence of UV images is projected through the O2permeable, UV-transparent window below the resin bath; this creates a layering, whereby directly above the window a liquid dead zone rich in O2 exists, where no polymerization occurs. Directly above the dead zone, O2 concentration decreases, and polymerization of the resin and construction of the 3D model occur, guided by the projected UV images. Simultaneously, the 3D part is elevated out of the resin bath by a continuously elevating build support plate (Video I). This process can speed up 3D printing up to 100-fold, producing a high-resolution finished or near-finished product without the layerings of 3D printing. A job that used to take hours now takes only minutes to complete. Moreover, the spectrum of