The tangled highway of blood vessels that twists and turns inside our bodies, delivering essential nutrients and disposing of hazardous waste to keep our organs working properly has been a conundrum for scientists trying to make artificial vessels from scratch. Now a team from Brigham and Women's Hospital (BWH) has made headway in fabricating blood vessels using a three-dimensional (3D) bioprinting technique. The study is published online this month in Lab on a Chip. "Engineers have made incredible strides in making complex artificial tissues such as those of the heart, liver and lungs," said senior study author, Ali Khademhosseini, PhD, biomedical engineer, and director of the BWH Biomaterials Innovation Research Center. "However, creating artificial blood vessels remains a critical challenge in tissue engineering."