Personalized-medicine startup Nanosphere filed for a $100 million IPO Monday, but an analyst said the move could be a prelude to a merger with one of its larger rivals.

Nanosphere, based in Northbrook, Illinois, makes a system to perform molecular diagnostic tests. Earlier this year Nanosphere applied for U.S. Food and Drug Administration approval of tests to gauge a person’s risk of blood clots and how a patient metabolizes the anti-blood clot medicine warfarin, sold under the brand name Coumadin.

The company also is developing tests for cancer, cystic fibrosis gene mutation, herpes viral infection, and cardiovascular disease risk and diagnosis.

In a telephone interview from a Stockholm suburb, Mark Bunger, research director at Lux Research, said the IPO filing could push giant competitors like Roche, Abbott or Becton, Dickinson to consider acquiring the nearly eight-year-old company.

“It does make a lot of sense for an existing medical diagnostics company to acquire them,” he said.

Because Nanosphere is a medical-device company, the time to market is much shorter than that for a drug development company, Mr. Bunger noted. “You don’t have to wait 10 years to get through trials to see revenue trickle in,” he said.

Nanosphere’s chief executive, William Moffitt, is no stranger to both IPOs and acquisition deals. Before taking the reins at Nanosphere, he was president and chief executive of i-STAT when the diagnostic products maker staged an IPO in 1992 and was acquired by Abbott in 2003 for almost $400 million.

The IPO filing comes a week after NanoDynamics, the Buffalo, New York-based maker of materials used in the environmental and energy sectors, cited market conditions in shelving its own IPO. Markets stabilized on Monday after sub-prime lending fears triggered a liquidity crisis and a roller coaster ride in the major indexes.

Nanosphere, which lost $8.8 million in the quarter ended March 31 and had an accumulated deficit of $112.6 million, has attracted large chunks of venture capital. In May 2006, the company closed on a $57 million series D round from Bain Capital Ventures, Brookside Capital, Lurie Investments and Allen & Company and in February 2007, the company borrowed $12.5 million from Venture Lending & Leasing.

Allen & Company also is an underwriter for the IPO, along with Leerink Swann, Piper Jaffray and lead underwriter Credit Suisse.

The company plans to trade under the symbol “NSPH” on the Nasdaq National Market.

Nanosphere plans to use about $50 million of the IPO proceeds to finance research and development of its core Verigene System and about $40 million for sales and marketing.

The company was co-founded by Chad Mirkin, director of Northwestern University's Institute for Nanotechnology. Mr. Bunger said Mr. Mirkin is one of the world's top nanotechnology "gurus."