What are dendrimers good for? Dow Chemical is eager to find out

MIDLAND, Mich., Nov. 12, 2001 — Officials at Dow Chemical Co. say they are poised for a marketing push that will attempt to finally make a commercial success of an intriguing form of plastics known as dendrimers.

Touted for their potential for a wide variety of industrial and medical applications, dendrimers have had limited commercial success since they were discovered by Dow researcher Donald Tomalia in 1979.

The one company spun off to capitalize on their discovery, Dendritech Inc. of Midland has struggled since its founding in 1992, and last year sold the patent rights back to Dow.

“There’s 15 years of literature out there, and its always said, ‘Hey, success is just around the corner.’ Fifteen years, and there’s still no big commercial application, despite everyone and their brother, particularly in academia, doing research,” said Jeff Lackey, senior technology manager at Dow and the person in charge of reinvigorating commerce in dendrimers.

“If we can’t make this a commercial success, no one can.”

Meanwhile, Dendritech, founded by Tomalia in 1992 after Dow chose then not to pursue commercial development of dendrimers, has repositioned itself since selling its technology portfolio back to Dow for an undisclosed sum in March 2000.

Dendritech used the money to retire debt, has dropped the heavy expense of research and development and is solidly in the black as a Dow-licensed manufacturer and supplier of dendrimers to researchers worldwide, said Emery Scheibert, Dendritech’s president. Its 32 different dendrimers are marketed by Sigma-Aldrich Inc. through its Handbook of Fine Chemicals.

Dendritech has also begun seeking out federally funded Small Business Innovation Research (SBIR) grants. Its first two grants, for $65,000 each, came from the U.S. Department of Defense’s Ballistic Missile Defense Organization — one for using dendrimers to make a copper-nano composite for coating wires in microelectronics and the other to see if nanoscale voids in dendrimer coatings can improve performance in future generations of integrated circuits.

Unlike other plastics, which are made of haphazard, long strands, dendrimers are precisely constructed molecules built on the nanoscale. They have branching ends, which reminded Tomalia of a tree, hence the Greek root word “dendra,” for tree.

Dendrimers are grown in a multistep process through up to 10 generations. Each step doubles the complexity at the branching end. Since their discovery, thousands of papers have been published in scientific journals, describing a myriad of applications.

Drugs can be attached to their ends or placed inside cavities within them, and they may one day provide targeted drug delivery to fight cancer. Researchers say they can be used to bind antibodies to substrates in diagnostic devices of the future. Depending on their structure and what they are combined with, they can be insulators or conductors.

Dendrimers are very sticky. One of the few commercial applications over the years has been for commercial ink makers, who use the dendrimers to bind inks to wet surfaces.

Dendrimers are versatile. Like buckyballs, they have a symmetry that is both eye-catching and intriguing. They are also so costly that most of the 1,000 pounds or so a year produced by Dendritech goes to academic researchers in tiny quantities, and not toward commercial applications.

According to Robert Nowak, Dendritech’s chief executive officer, a 10th-generation dendrimer goes through 22 different chemical reactions, which take three months in the lab. The result is that a 10th-generation dendrimer lists for $1,500 for 100 milligrams on Dendritech’s Web site. A sixth-generation dendrimer is $660 per gram. The cheapest and simplest dendrimer is $21 a gram.

“The biggest drawback to dendrimers is cost,” said Lackey. “You’re not going to make trash liners out of them. Or car fenders, not at the current price. The cost keeps it out of a lot of mainstream applications.”

Dow bought the patents back 19 months ago, and has been active since in organizing a market push, said Lackey, whose dendrimer team includes a research and development staff, marketers, licensing experts and patent specialists.

His team has begun approaching its huge base of commercial customers and partners. “One advantage we have is close access to many companies around the world. We just go talk to them and show them what dendrimers can do. It’s a market-focused approach — see what the problems are that our customers say dendrimers will solve.”

Today, Dow officials say Dendritech is the only licensed maker and seller of dendrimers in the world. It won’t have that niche to itself for long.

Tomalia, who invented dendrimers 22 years ago, left Dendritech’s board of directors when the Dow negotiations were completed. He gave up royalty claims on the patents in exchange for a non-exclusive license to manufacture and sell dendrimers.

In August, it was announced that he had formed a new company, Dendritic Nanotechnologies Ltd., with $2.2 million (U.S.) in funding over three years from two Australian firms, Starpharma Pooled Development Ltd. and PanBio Ltd.

Dendritic Nanotechnologies will have its official headquarters in Australia, but R&D will be conducted at its U.S. offices at a new tech park being built in Mt. Pleasant, Mich., in conjunction with Central Michigan University and the state of Michigan.

Tomalia said he expects to move into his new offices by April, and that the company will focus on applications for coatings in microelectronics, medical diagnostics, drug delivery and using a form of dendrimers to kill such viruses as Ebola, hepatitis and HIV.

He made it clear he is taking dead aim at his old company.

“We intend to have the premier dendritic company in the world,” he said.


Related Story: Dendrimer’s dad thinks he’s finally tamed the money-munching molecule

Tom Henderson at [email protected] or call 734-528-6292.


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