Researchers at Harvard University have developed a technique that lets them create biomaterial heart valves in a matter of minutes. The approach, called ‘Focused Rotary Jet Spinning’, has been described by the researchers as ‘a cotton-candy machine with a hair dryer behind it.’ Essentially, the technique involves using jets of air to direct polymer strands onto a heart valve shaped frame. This results in a porous scaffold that allows cardiac cells to enter and grow. The formed constructs also have the mechanical properties to function as a one-way valve within the heart. The scaffolds contain nanoscale cues that encourage cells to enter and proliferate, with the ultimate goal that the biomaterial scaffold will be progressively replaced by cells, eventually resulting in a regenerated heart valve.
Regenerative medicine is progressing, with the ultimate goal of replacing diseased, damaged, or missing parts of the body. To achieve this, scientists are getting more advanced in their use of biomaterials which can support living cells and potentially turn into complex tissues if their biochemical and mechanical properties are correct. However, the devil is in the detail, and designing materials that can appeal to cells, which explore and react to their world at the nanoscale, is challenging.
In terms of complex tissues, heart valves certainly fit the bill. These structures consist of three overlapping leaflets that prevent backflow of blood. However, this new technique has allowed these researchers to create a proxy valve in just minutes in a manner that appears to encourage cells into the scaffold. “Cells operate at the nanometer scale, and 3D printing can’t reach down to that level, but focused rotary jet spinning can put nanometer-scale spatial cues in there so that when cells crawl up into that scaffold, they feel like they’re in a heart valve, not a synthetic scaffold,” said Kit Parker, one of the leaders of the Harvard team. “There’s a certain trickery that’s involved.”
The approach also allows the researchers to create the valves in mere minutes, which is much faster than many approaches traditionally used to create biomaterial scaffolds. “The two big advantages of our method are speed and spatial fidelity,” said Michael Peters, another researcher involved in the study. “We can create really small fibers — on the nanoscale — that mimic the extracellular matrix that heart valve cells are used to living and growing inside, and we can spin full valves in a matter of minutes, in contrast to currently available technologies that can take weeks or months to make.”
So far, the researchers have implanted the valves into sheep. In this very preliminary study, which ran for just one hour, the valves successfully controlled blood flow in the heart, did not cause tears or thrombus formation, and allowed the infiltration of nearby cells.
Study in journal Matter: On-demand heart valve manufacturing using focused rotary jet spinning
Via: Harvard University