Polymer fibers provide a mesh for tissue growth that can be monitored through near-infrared fluorescence imaging. Originally developed for solar cells, the material, called TQ1, exhibits fluorescent lifetimes in the subnanosecond range, which is optimal for in situ imaging, according to a team of Swedish researchers. TQ1 fibers (red) with live embryonic chicken heart muscle cells (green). Courtesy of Daniel Aili and Abeni Wickham/Linköping University. This could make the fibers valuable in regenerative medicine, where damaged organs and tissue are replaced with new tissue grown from the recipient's own body. The researchers tested TQ1 with chicken and mouse cells and found no toxic effects. In longer-term tests in rats, the material caused limited inflammation but also appeared to stimulate the growth of blood vessels necessary for tissue survival. "On top of that, the fibers are fluorescent and glow in a wavelength range where we can see and follow the implant in the tissue," said Daniel Aili, a senior lecturer at Linköping University. "Until now, there has been a problem with soft biomaterials, in that we have not been able to see how they integrate with living cells and tissue, and what happens with the material over time." The fluorescent properties of the material allow its interactions with the tissue to be imaged for up to 90 days. The research was published Advanced Functional Materials (doi: 10.1002/adfm.201500351). For more information, visit www.liu.se