Genex Corp. has been sued by a Connecticut company, Biopolymers Inc., which alleges that the Gaithersburg biotechnology company infringed on its patent for a powerful glue based on secretions that mussels use to attach themselves to rocks.

The lawsuit was filed in federal district court in Baltimore last week after technology-licensing negotiations broke down. Genex officials said they broke off the year-long talks when they became convinced they could win the fight in court.

"The more we looked at their patent situation, the more questions we had," said Ruth Greenstein, a Genex executive. "We've had the matter looked at, and each time our counsel has said we're not infringing."

Both Biopolymers and Genex have developed synthetic versions of the mussel glue, a powerful, nontoxic, water-resistant adhesive that has potentially huge applications in medical and dental surgery. But Genex officials say their product, which is created through genetic engineering, isn't covered by Biopolymers' patents, which are for a naturally produced product.

The claims made in the Biopolymers suit are not unusual in the burgeoning field of biotechnology, where recombinant DNA has offered companies an easy and cost-effective way to manufacture existing natural substances.

"Biotechnology means that there are now two different ways to manufacture the same product," said Gerry Elman, a patent lawyer in Philadelphia and editor in chief of Biotech Law Report. "So you're likely to have two different inventors, and there's almost naturally going to be conflicts between them."

The Biopolymers version is naturally synthesized, made by grinding up mussels and extracting the glue from them using standard chemical techniques. The company has held a patent on its product since 1986. Genex's version is bioengineered, made by cloning the genetic makeup of the glue, and then growing it in bacteria.

"Our position is that ... {our} patent covers the synthetic adhesive composition whether it is produced by genetically engineered methods or by chemical synthesis," said Thomas Benedict, president of Biopolymers.

Lawyers for both sides said the Biopolymers suit will turn on the question of whether the language of Biopolymers' original patent claim is broad enough to cover mussel glue that is made by entirely different technology and that may have certain small differences in chemistry and structure.

If Genex were to lose the lawsuit, the company would still have the option of manufacturing the adhesive abroad, since Biopolymers has not filed for patent protection overseas.

Genex officials say they are negotiating a possible joint venture with a major adhesives manufacturer to produce the glue, which company officials say has a potential market of $500 million by 1992.

In another development yesterday, Genex announced that it had completed the acquisition of Xydex Corp., which makes sample preparation equipment for industrial and medical applications.