If a recipe existed for creating the kinds of synthetic body parts once confined to the imaginations of TV scriptwriters, the instructions might include: Open your mind. Talk to strangers. Be patient. And collaborate across scientific specialties.

On a shuttle bus at a mechanical engineering convention one morning at 6:45 a.m., Jack Ricci, PhD, a UMDNJ-New Jersey Dental School (NJDS) professor of restorative dentistry, struck up a conversation with the only other passenger. The aerospace engineer explained that his company was feeding powdered titanium into a laser system to produce complex three-dimensional (3-D) parts, layer by layer, all of one piece. The idea of using computerized printing and technology to fabricate implants for biomedical applications may never have crossed the engineer's mind but it suddenly opened a puzzling window for Ricci. Could the same process that turns out turbine blades and filters be used for cheekbones, knees, or the broken thighs of people like New Jersey Governor James E. McGreevey? Sure.

For years, a UMDNJ team that includes Ricci had been collaborating with others, looking for a way to build biomaterial structures that would coax bones to regrow themselves. The encounter on the bus is typical of their serendipitous quest. Drawing on experts from cell biology, chemistry, physiology, anatomy, engineering and material science at NJDS, New Jersey Medical School (NJMS), New York University College of Dentistry, Integra LifeSciences Corporation in Plainsboro, Therics, Inc. in Princeton, and the New Jersey Center for Biomaterials (NJCB), this "Program for Engineered Tissue Response" has taken a stepping stone route toward the goal of making surgically implantable body parts. They've been on the road for more than six years. Now, with $2.15 million from the New Jersey Commission on Science and Technology and other grants as well as federal funds, the team is not quite ready to market a complete set of parts for the "bionic" man or woman, but as one investigator says, "You have to have a proving ground and that proving ground is bone." Another member of the team, Russell Parsons, PhD, NJMS professor of orthopedics and director of the Laboratory for Orthopedic Research, admits, "I've been replacing bones with all sorts of things for 25 years and this is the most exciting thing I've seen."

Bone tissue lost through aging, accidents or missing as a result of birth defects has always been a problem for surgeons who've had to chisel pieces from other places on the patient's own body or take it from cadavers.

The objective is to actually create natural bone, the researchers explain. Using a class of polymers called tyrosine polycarbonates and printers fashioned to deliver 3-D parts, the team has found a product that the human body won't reject, that doesn't make nearby bone brittle after implantation, that provides comfortable growing spaces for all kinds of cells as well as healthy blood flow, and that is eventually absorbed, disappearing and leaving real bone in its place. Meanwhile, architecture turns out to be critically important for all this to take place. Yes, architecture.

On a conference table at NJDS, inside a small plastic bag are several pale blue, aspirin-sized prototypes. They are spilled out and with a touch, it becomes apparent that no two are exactly alike. Referred to as "scaffolds" (temporary platforms or frameworks), under a microscope, the different weaves, dimensions and subtle shifts of micro-textural design are even clearer. These variations in architecture are not cosmetically inspired. "Something about the architecture encourages different kinds of cells to grow," according to Ricci. For instance, the smooth side of the scaffold, once implanted inside the body, will allow soft tissue to attach and grow. Meanwhile, muscle, bone, and ligaments all demand different properties in order to flourish. "It's as if the cell looks around and says, 'OK, this is the right curvature or the right combination of smooth versus rough.' We've suspected that some porosities would probably work better for soft tissue attachment and some structures would work better for bone. Now we know that if you control the architecture, you control the type of tissue that grows," Ricci says.

Laser printing the 3-D pieces makes many combinations possible. "You can dial in different surfaces wherever you want. We have one implant with a surface for epithelial attachment, a surface for soft tissue attachment and another one for bone." Inside a jaw ravaged by tooth and subsequent bone loss, this insert could promote gum as well as bone growth. Ordinarily, when you lose teeth, the bone eventually diminishes as well.

The team's favorite material, the tyrosine polycarbonate polymer, was pioneered by polymer chemist Joachim Kohn, PhD, director of NJCB, and is so unusual that the longer it remains in the body, the better the surrounding tissue reacts. "Normally, when we look at bone response to polymers, we get a blah result or find that the surrounding bone actually degrades," Ricci explains. This new resorbable polymer can even be laced with additives like proteins, growth factors or drugs. For example, a cancer patient with an implant might fare better if the piece contained anti-cancer medication. The researchers foresee the manufacture of standard implantable parts surgeons can pluck right off the shelf, along with custom-designed pieces created on the basis of patients' CT scans or magnetic resonance images.

Clinical trials of microstructured dental implants are ongoing here in the United States, Italy and South America. In fact, Ricci, who once questioned the wisdom of a bone biologist wandering into dental territory, met the doctor from Rome, who is now testing the laser machined parts, at a periodontal meeting. None of this might have been possible if they had all stayed in their traditional scientific arenas. Thinking out of the box led them into a bionic world.