FORM OF SECURITIES PURCHASE AGREEMENT Please submit a separate Securities Purchase Agreement for each individual fund/entity that will hold the SecuritiesSecurities Purchase Agreement • September 22nd, 2003 • Nanogen Inc • Laboratory analytical instruments • California
purchase one share of Common Stock for every four shares of Common Stock purchased by the Investor, having an exercise price of $4.75 per share, pursuant to the Terms and Conditions for Purchase of Securities attached hereto as Annex I and incorporated herein by reference as if fully set forth herein (the “Terms and Conditions”). Unless otherwise requested by the Investor, certificates representing the Securities purchased by the Investor will be registered in the Investor’s name and address as set forth below.
