Nanogen, Inc., developer of advanced diagnostic products, announced today that it was issued U.S. Patent No. 6,864,071, "Multiplex amplification and separation of nucleic acid sequences using ligation-dependent strand displacement amplification and bioelectronic chip technology," by the U.S. Patent and Trademark Office. The '071 patent relates to amplifying and analyzing multiple samples of nucleic acid using ligation-based strand displacement amplification (SDA) technologies. The intellectual property pertains to research Nanogen conducted in collaboration with Becton Dickinson and increases Nanogen's portfolio of technologies for multiplex amplification on a chip.