Using a cotton candy machine to make artificial tissues with an embedded vascular system and a skull base sealer to help surgeons repair holes in the base of the skull after surgery are two student-developed inventions that were awarded finalist status in the 2009 Collegiate Inventors Competition.

The finalists, a former graduate student and a senior engineering student, recently returned from the final judging in Chicago, Oct. 18-20.

Leon Bellan, a former graduate student and postdoctoral associate in applied and engineering physics, conceived the idea for using a cotton candy machine to make artificial tissues while he was a graduate student in Harold Craighead's lab and after hearing Weill Cornell Medical College surgeon Jason Spector speak at a symposium about the challenges of producing materials that mimic capillaries in living tissue.

Bellan made the artificial tissues by spinning a wad of cotton candy, covering it with a liquid polymer, letting the polymer solidify, then soaking it in water to dissolve the sugar. What was left was a material containing an interconnected network of tiny, capillary-size tubes.

Bellan's 3-D microchannel networks were the subject of a paper published in the Feb. 9 edition of the journal Soft Matter, co-authored by Spector, Craighead and others.

Mark Levatich, a senior majoring in biological engineering and biology with a concentration in neurobiology, was recognized for his skull base sealer. Advised by David Lipson, senior lecturer in biomedical engineering, he invented the device after shadowing doctors at Weill Cornell Medical College for part of an anthropology class. Specifically he watched neurosurgeons perform endoscopic procedures on the area around the pituitary gland, which sits near the base of the skull.

Doctors used forceps to place pieces of fat grafted from the patient and surgical foam into the hole in the skull. With luck, soft tissue grew over this foam and formed a seal. But often, the seal was imperfect, and cerebrospinal fluid leaked out, requiring later surgical repair.

Levatich's skull base sealer works with a trigger action that pushes pre-mixed bone cement into the hole. The cement is inserted directly into the skull to ensure a solid seal. Bone cement is pushed by a threaded screw-like plunger.

His prototype consists of a single tube packed to deploy a protective pad of foam against the brain, followed by a plastic self-sealing sheet as a mold. Bone cement is then injected between the pad and the mold. The mold holds the bone cement in place while it cures and also acts as a waterproof barrier to insulate the cement so that while it cures, cooling water can be circulated through the nasal area, thus protecting the brain and nasal tissues from heat produced during the curing process.