Good old ink jet printers are really versatile machines. Last week, I told you they will be used to print organic transistors. Now, Canadian and German researchers are using a slightly modified version of the printer that sits on your desk to build three-dimensional bioceramic bones. They took "advantage of the ink-jet printer's ability to print layer upon layer to produce three-dimensional porous materials using the same building blocks as real bone." The key is that their new process works at room temperature and also is able to produce a great variety of shapes. Anyway, this method will certainly be not used by surgeons and hospitals before many years.
Before going further, below is a picture showing several examples of complex 3D shapes made in dicalcium phosphate dihydrate (DCPD or brushite): a disc with 32 1.5 mm diameter holes, and human skulls made by reducing the scale of CT [computed tomography] data by a factor of 4, one skull is sectioned to show internal detail (Credit: Jake Barralet/McGill University).
"Rather than printing on paper, we’re printing on a bed of cement powder using an acid instead of ink, which reacts with the cement to print whatever pattern we want," explained Dr. Barralet. "It’s similar to a CT scan, in that the image is created one layer at a time. The result is three-dimensional."
Printers are already used for modeling purposes, said Dr. Barralet, but this is the first time anyone has used a modified printer to produce artificial bone made of calcium phosphate at room temperature using the minerals brushite and hydroxyapatite. Because the process takes place at room temperature, the researchers are able to make custom-shaped grafts from materials that decompose at low temperatures.
This research work has been published by Advanced Materials under the name "Direct Printing of Bioceramic Implants with Spatially Localized Angiogenic Factors" (Volume 19, Issue 6, Pages 795-800). Here is a link to the article -- if you're a subscriber. You also can read some supporting information to this paper, from which the above figure has been extracted (PDF format, 5 pages, 324 KB).
Finally, will this process be used anytime soon by reconstructive surgeons? Apparently not. "We're a long way from seeing this method used in a hospital setting, but it's an important first step toward a revolutionary change in bone-grafting technology," said Dr. Barralet.
Sources: McGill University news release, Montreal, Quebec, March 5, 2007; and various websites
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