Press Release March 22, 2007

Arrowhead Subsidiary, Unidym, to Merge with Carbon Nanotechnologies, Inc.

March 22, 2007 — Arrowhead Research Corporation (NASDAQ: ARWR) announced today that its majority-owned subsidiary, Unidym, Inc., has entered into a definitive agreement to merge with Carbon Nanotechnologies, Inc. (“CNI”).  CNI was co-founded by the late Nobel laureate and nanotube pioneer Richard Smalley. The combined company, which will operate under the Unidym name, will have exclusive licenses to all the intellectual property in CNI’s portfolio, for control of 59 U.S.-issued carbon nanotube-related patents. The transaction is expected to close in early April. 

Goodwin Procter attorneys Rachael Simonoff Wexler, Danielle M. Lauzon, Adam Ghander, and Kenda Stewart, as well as Mitch BloomJanet Andolina, Eric Willenbacher, Ann McGovern and Ellie Simon represented Arrowhead Research Corporation and its subsidiary, Unidym, in this transaction.