ROLLA, Mo. -- Finding new ways to use glass -- in everything from paving roads to treating cancer -- has been a long-term goal for Dr. Delbert E. Day, Curators' Professor Emeritus of ceramic engineering at the University of Missouri-Rolla. Recently, Day's method of treating inoperable liver cancer with radiation contained in microscopic glass beads was approved by the U.S. Food and Drug Administration for use in the United States.
FDA approval for the treatment occurred in February. The first patients to be treated with radioactive glass beads, now marketed under the name TheraSphere by MDS Nordion, will take place later this year at the Mayo Clinic in Rochester, Minn., and at the University of Pittsburgh School of Medicine.
The treatment consists of injecting millions of tiny, radioactive glass beads into the main artery supplying blood to the liver. The blood carries the beads into the liver, where they deliver localized radiation to malignant cells in liver tumors.
"Healthy tissue is virtually unaffected, the radiation can be safely delivered, and side effects are minimal," Day says.
"The beads, or microspheres, are 15 to 35 microns in diameter, or about half the thickness of a human hair," Day adds. The beads are made from a special aluminosilicate glass that contains yttrium oxide, a rare-earth element.
When the glass beads are placed inside a nuclear reactor for serval days, the yttrium becomes radioactive. The radioactive beads are then injected into the liver, where they irradiate the liver for a period of 3-4 weeks, after which they are no longer radioactive but remain in the liver indefinitely.
Day, who joined the UMR faculty in 1961, and co-inventor, Dr. Gary J. Ehrhardt of the University of Missouri-Columbia, started their research on the glass beads in 1982. Their first patent was granted in 1988, and since that time they have been granted a total of six U.S. patents and eight foreign patents.
More recently, Day has turned his research efforts toward finding new ways for doctors to treat severely broken bones by using glass pins and surgical sutures to treat those breaks. Day and Dr. David Westenberg, a UMR assistant professor of biological sciences, have discovered that, in addition to promoting bone strength, the glass pins and sutures could help prevent infection better than metal pins.
"Glass is a good alternative to metal because it can be incorporated with silver, which is known to fight bacteria," Day says. "Doctors could eventually speed up recovery times and strengthen bone mass by using infection fighting glass pins and surgical sutures to treat breaks."
In addition to finding medical uses for glass, Day was instrumental in developing "glasphalt," which consists of mixing crushed waste glass with the sand and stone of asphalt to form a paving material. Glasphalt, which originated at UMR in the late 1960s, has been used to construct roads, parking lots, sidewalks and airport runways. "Significant amounts of products made from any type and color of glass have been used to pave roads and parking lots across the United States," Day says.
Several parking lots on the UMR campus as well as a stretch of highway near Rolla have been paved with glasphalt. In November 1996, glasphalt was used to pave the runway, parking apron and taxiway at a general aviation airport in Rolla.
Glass may also be the answer to the safe disposal of large quantities of nuclear waste now stored in steel tanks at many sites in the United States, Day says. He received a U.S. patent in 1997 for his research into ways to dispose of excess uranium and plutonium from dismantled nuclear weapons. The method involves the use of a special iron phosphate glass to chemically dissolve the nuclear waste.
"That special family of glasses holds promise as the means to safely dispose of many types of nuclear waste," Day says.
Day also worked with NASA for more than 15 years conducting experiments to prepare high purity glass by using the weightlessness of space. Two UMR glass-melting experiments were conducted on the space shuttle Challenger in 1983 and 1985. More recent research has been conducted on the ground as well as below ground, in a former mine shaft in Japan that is used to simulate the low-gravity conditions of space.
NASA has chosen Day to conduct at least two additional glass melting and crystallization experiments on the International Space Station, which is now being constructed. Those experiments are scheduled for 2002 or 2003.
"Space is an excellent laboratory for investigating glass melting procedures," Day says. "In an orbiting space vehicle, gravity is at least 10,000 times less than it is on Earth, so it is possible to experiment with glass or high-temperature melts without the use of containers, which normally contaminate melts on Earth."
Day became interested in glass and its countless uses while a student in ceramic engineering at UMR. "I became interested in the properties and many uses of glass as an undergraduate student at UMR," he says. "I took a course in glass and as a result of that class I prepared a paper and presented it in a student speaking contest at an American Ceramic Society meeting. From then on I had an interest in glass research."