Prellis Biologics, developer of a holographic organ printing system, has received an $8.7 million investment led by Khosla Ventures. The investment is a Series A and comes after Prellis announced major milestones in tissue engineering. Prellis structure transplanted alone is surrounded by single cell walled capillaries within two weeks of transplantation into immunocompetent mouse (left). Human tumor cells transplanted in Prellis structures grow rapidly, are highly vascularized, and demonstrate minimal hypoxia (right) (red = CD31, blue = DAPI, green = printed structure). Courtesy of Prellis Biologics. The company recently reported positive results from the first animal transplantation of its 3D tissue scaffolds — called Vascular Tissue Blanks — carried out at Stanford University. The transplanted structures were found to support human tumor growth rate at rates that are similar or better than typical tumor transplant methods, and with fewer cells. Typical tumor studies in animals require 2 million or more cells. With Prellis’ technology, full tumor engraftment and vascularization were achieved with just 200,000 cells, said Prellis co-founder and CEO Melanie Matheu. “A breakthrough like this opens the door to studying rare human tumors and complex human tumor immune system reactions,” Matheu said. “It has the potential to significantly reduce overall animal use and speed up drug discovery efforts.” Currently, more than 30 pharmaceutical and academic research labs, including groups at UC San Francisco, Johns Hopkins, UC Irvine, and Memorial Sloan Kettering, are experimenting with the technology. The company’s original seed round investors include True Ventures and Indie Bio, and have joined Khosla in the round. Total invested capital in Prellis is currently at $10.5 million.