At Vanderbilt University researchers are using cotton candy machines to spin capillary networks that may one day be used to help grow artificial organs. There not being laboratory cotton candy machines, the team is using the same devices you can have at home, but using different ingredients.
The investigators are employing hydrogels, already widely used to produce tissue-like constructs, that are able to produce entire bunches of capillaries between three and 55 microns in diameter. The technique takes cue from electrospinning, a manufacturing technique for creating fibers and different materials. The challenge was finding a hydrogel that would be compatible with the cotton candy machine approach and that would also maintain its structure at body temperatures.
Here are some details on the material and how it’s used:
The researchers experimented with a number of different materials before they discovered one that worked. The key material is PNIPAM, Poly (N-isopropylacrylamide), a polymer with the unusual property of being insoluble at temperatures above 32 degrees Celsius and soluble below that temperature. In addition, the material has been used in other medical applications and has proven to be rather cell-friendly.
The researchers first spin out a network of PNIPAM threads using a machine closely resembling a cotton candy machine. Then they mix up a solution of gelatin in water (a liquid at 37 degrees) and add human cells, like adding grapes to jello. Adding an enzyme commonly used in the food industry (transglutaminase, nicknamed “meat glue”) causes the gelatin to irreversibly gel. This warm mixture is poured over the PNIPAM structure and allowed to gel in an incubator at 37 degrees. Finally, the gel containing cells and fibers is removed from the incubator and allowed to cool to room temperature, at which point the embedded fibers dissolve, leaving behind an intricate network of microscale channels. The researchers then attach pumps to the network and begin perfusing them with cell culture media containing necessary chemicals and oxygen.
Here’s a video report about the research from Vanderbilt:
Study in Advanced Healthcare Materials: Development of 3D Microvascular Networks Within Gelatin Hydrogels Using Thermoresponsive Sacrificial Microfibers…