Harvard Engineers Make Custom Blood Vessel Grafts in Minutes With 3D Printing

Harvard bioengineers have demonstrated a 3D printing process that can produce custom synthetic blood vessel grafts in minutes. The work, led by Michael Peters at the John A. Paulson School of Engineering and Applied Sciences, addresses a long-standing gap in vascular medicine: there are no clinically approved synthetic implants for blood vessels smaller than 6 millimeters in diameter.

How the process works

The team used Focused Rotary Jet Spinning, an additive platform originally developed to build in vitro heart models. The system turns liquid polymer solutions into ultra-thin fibers using high-speed spinning and focused air streams. Those fibers collect on a rotating mandrel to form tubular scaffolds that resemble natural blood vessels.

The grafts are made from a synthetic copolymer of polylactic acid and polycaprolactone. Over time, the scaffold degrades as the patient's own cells rebuild the tissue. The structure is designed to limit clotting, a common complication with existing synthetic grafts.

Intraoperative manufacturing

The researchers call the approach intraoperative manufacturing. The printing speeds and customizability mean a graft could theoretically be produced for a specific injury or patient during surgery. Dentists are already using 3D printing for same-day restorations. The Harvard team believes vascular surgery could be next.

Kevin Kit Parker, whose lab created the platform, said the goal is to move manufacturing into the operating suite. If FDA manufacturing requirements can be met while the patient is on the table, the technology could serve limb salvage, congenital heart repair, and trauma cases where waiting days for a standard implant is not an option.

The research context

The study joins a wave of point-of-care 3D printing developments in medicine. Earlier this year, the Defense Health Agency and Walter Reed's 3D Medical Applications Center received FDA clearance for a titanium cranial plate system, the first cleared implant granted to a point-of-care institution. At Rambam Health Care Campus in Israel, EOS and PTC opened a digital implant engineering center that combines metal AM with hospital-based design. The Harvard graft work adds tissue engineering to the same trend.

The research is published in Advanced Materials. It does not replace existing clinical products tomorrow, but it shows the direction: faster customization, fewer supply-chain dependencies, and implants made for the patient in front of you rather than for an average population.