Pittsburgh will host the state's third annual attempt to make something big of nanotechnology.

Nanotechnology is research and technology development at the atomic, molecular or macromolecular levels. The technology involves creating and manipulating materials so small that 100,000 of them are no bigger than the width of a human hair.

Dennis Yablonsky, the state's secretary for community and economic development, announced yesterday that the "Business of Nano: Pennsylvania Nanotechnology Conference 2005" would be held April 18 to 20 at the Westin Convention Center Hotel, Downtown. Previous conferences were held in Philadelphia and State College.

The hope is that nanotech will revolutionize everything from biopharmaceuticals and therapeutics to agriculture and energy, and that Pennsylvania will be a leader in the technology. The state has invested more than $42 million to build out facilities and jump-start nanotech programs.

"Nanotechnology is seen as the next big thing in the sciences," said Arthur Caplan, a bioethicist at the University of Pennsylvania, who is a conference organizer.

"This conference is both an effort to explain nanotechnology and to try [to] make sure that Pennsylvania gets a piece of that next big thing."

Conference topics will range from electronics to instrumentation. One session will consider novel strategies being used in Europe and Asia to develop nanotechnology. Another will help nanotech companies fight their way through a "patent thicket" that makes it difficult to launch a product.