May help ease the transplant shortage。
Artificial corneal research has finally made new progress. Recently, researchers at the University of Newels said in a paper published in Experimental Eye Research that they have successfully printed artificial corneas on 3D printers. The researchers mixed corneal stem cells extracted from healthy donors with sodium alginate (a sugar sometimes used for tissue regeneration) and collagen to form a printable "bio-ink". Solution, and then copy the artificial cornea through a 3D printer.
Che Connon, a professor of tissue engineering at Newcastle University, one of the creators of artificial corneas, says finding a suitable bio-ink is not easy, and every team is working hard. The bio-ink they use "can keep stem cells alive, but also produce materials that are strong enough to retain shape and are soft enough to fit into the nozzles of 3D printers."
Previously, the same team used a similar hydrogel to allow stem cells to survive for several weeks at room temperature, and the corneal cells printed this time remained 83% viable after one week. Conn said, “Now we are ready to use bio-ink containing stem cells so that users can start printing tissue without worrying about cell growth alone.”
To match the size and shape of the cornea to the patient, the researchers used a special camera to image the volunteer's eyeball and built a three-dimensional model of their cornea. The team then entered the template into a 3D printer, which sprayed bio-ink onto the gel to create a cornea that took less than 10 minutes to print before the stem cells continued to grow. The finished product looks like a contact lens.
This is the first time researchers have recreated the unique curved shape of the cornea, Connon said, which is the key to the success of artificial corneas. “Without (the corneal) shape, you are not making the cornea.”
The cornea plays an important role in focusing the line of sight and preventing eye contact with dirt and bacteria. However, because it is located at the outermost layer of the eye, it is also vulnerable to damage, and light vision is impaired and blindness is severe. Currently, corneal blindness is the third most common cause of blindness after cataracts and glaucoma worldwide, with approximately 10 million people suffering from corneal blindness.
According to a survey published in the JAMA Ophthalmology, between August 2012 and August 2013, researchers collected data from 157 countries with 99.8% of the world's population and found that There are 12.7 million people waiting for a corneal transplant. In China, this figure is 2 million. According to the 2006 National Statistical Survey of Persons with Disabilities, there are about 4 million blind patients with corneal disease in China, of which about 2 million can be recovered through corneal transplant surgery – this is the most recent survey.
However, the shortage of corneal transplants is very serious. According to the aforementioned American Journal of Medicine, this year, only 116 countries had performed approximately 180,000 corneal transplants, and approximately 53% of the world's population could not receive corneal transplants. There is no official organization in China to count the donation of corneas. The Corneal Transplantation Expert Consensus 2015 of the Chinese Medical Association Ophthalmology Branch of the Ophthalmology Branch mentioned that “the number of corneal transplants performed in the country is about 5,000 cases per year. ."
In recent years, laser eye surgery has become widespread, and people who have done this kind of surgery cannot donate corneas, and the supply of corneas is more serious.
The research team believes that the study of artificial corneas using 3D printing technology can help solve the problem of corneal transplant shortage worldwide. Connon said that now, enough stem cells can be cultured from a donated cornea to print 50 human corneas.
However, there is still a long way to go before this technology can be put into clinical use on a large scale. The research team will continue to fine-tune the printing process and also need to perform safety tests on animals. Professor Connon predicts that if clinical trials are successful, the technology can be applied within five years. “We are envisioning a situation where a doctor has a 3D printer in the corner while the surgeon is performing the surgery. The doctor can take the ink out of the shelf, put it in the printer and print it