Eyeworld

NOV 2018

EyeWorld is the official news magazine of the American Society of Cataract & Refractive Surgery.

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20 November 2018 EW NEWS & OPINION by Liz Hillman EyeWorld Senior Staff Writer a 3D printer in the corner of the room and there they have a range of inks containing cells that are sealed and can be stored for days or weeks, and the doctor takes the bio-ink off the shelf, plugs it in the printer, and immediately prints an eye, cornea, skin, or some other tissue," Dr. Con- non said. The hope in the future is that this technology could be used to print on-demand, customized cor- neas of the correct size and match- ing patient's refractive needs, but there are a number of challenges that remain. Dr. Connon said this paper pro- vides a proof-of-principle that you can take a topographical image of a patient's cornea, render it in 3D on a computer, and recreate the corneal shape on a 3D printer using corneal stromal stem cells in a bio-ink. "The challenges will be numer- ous but the first one would be, what needs to be done to that printed cornea to make it perhaps suturable, for example. How is it going to be transplanted directly into the eye, how will it stick in there? … Then there are safety and efficacy studies Human corneal stromal cells printed with a bio-ink that is shelf stable for more than 1 week F or more than 2 decades Che Connon, PhD, profes- sor of tissue engineering, Newcastle University, Tyne, U.K., has been working with corneal cells. Most recently, his work led to the development of the first 3D-printed cornea made with human cells. There are several conditions that might require corneal transplants. And while several procedures are available to address this need, for those that require a graft, there is a "world shortage" of donor tissue, Dr. Connon said, prompting the desire for an on-demand tissue source that's not reliant upon human donors but meets similar biocompat- ibility, safety, and efficacy standards. "Working toward the 3D-print- ed cornea is a good way of address- ing this need," Dr. Connon said. In the journal Experimental Eye Research, 1 Dr. Connon and core- searchers Steve Swioklo, PhD, and Abigail Isaacson, doctoral student, Institute of Genetic Medicine, New- castle University, describe how they used 3D "bio-printing" to create corneal structures that were similar to that of the human cornea with a "collagen-based bio-ink containing encapsulated corneal keratocytes." The keratocytes in this 3D-printed cornea showed high viability at day 1 and 1 week post-printing. The cornea printed by the team was a curved tissue. In separate research, Dr. Connon and his team discovered that the curvature of the cornea, in addition to being respon- sible for some refractive properties, actually affected the corneal cells (keratocytes). "The keratocytes respond to a curved surface and align in response to that curved surface. What we've taken from that is that the curvature of the eye is also important for the maintenance of keratocytes within it," Dr. Connon explained. "When we're looking at making an engi- neered cornea, we knew we wanted to create a curved tissue because this would be a cue for the cells within it to behave appropriately, given enough time." Dr. Connon said the print- er they used was relatively cheap (about $8,000), and that decision was made on purpose with the idea being that the technology could someday be accessible to doctors around the world. "We're thinking ahead, and also because we think that it's not nec- essary to create every single facet of the cornea. We don't need to print in the finest possible detail. We've previously shown cells can do that fine tuning, under the right condi- tions," Dr. Connon explained. The ink itself is composed of collagen and a polysaccharide extracted from seaweed that, as Dr. Connon put it, "gives it the right characteristics to keep cells alive." What's more, it's extrudable but also stable enough to hold its shape once printed. The keratocytes with the hydrogel encapsulation technology are shelf stable for several weeks in a sealed tube. "For printing, we're thinking ahead and imagining a situation in a doctor's surgery [where] they have Meet the first 3D-printed "human" cornea Dr. Connon (left) and Dr. Swioklo (right) watch a 3D cornea made of human corneal stromal cells being printed. Dr. Swioklo and Dr. Connon show a dyed, 3D-printed cornea. Source (all): Newcastle University

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