Du Pont Buys Stake in Small Biotech Firm

SAN DIEGO — Du Pont Co. agreed Tuesday to invest $2.5 million in Molecular Biosystems in return for an 8% stake in the small San Diego biotechnology company and exclusive license rights to Molecular Biosystems’ DNA-probe technology.

The agreement, in which the Wilmington, Del., chemical giant will get 450,000 shares of the San Diego company’s common stock, enlarges upon the companies’ existing relationship.

Molecular Biosystems is developing DNA probes--medical testing devices that use genetic materials to detect viruses, bacteria and genetic abnormalities. In May, the biotechnology company signed a $1.5-million research and development agreement with Du Pont linking Molecular Biosystems’ technologies with Du Pont’s marketing and research capabilities.

‘Growing Relationship’

Du Pont’s expanded involvement with the San Diego company “should be interpreted as . . . the next step in a deeper and growing relationship,” Molecular Biosystems Vice President Vincent A. Frank said. “They are pleased with the work we are doing.”

Frank said that, although Molecular Biosystems’ relationship with Du Pont so far has focused on research, the two companies expect to decide by mid-1986 which products they will develop first.

Molecular Biosystems reported a net loss of $105,000 for the fiscal first quarter ended June 30, compared to a $301,000 loss in the year-earlier period.