Invitrogen Gateway® Technology Invitrogen Gateway® Technology: please see Limited Use Label License No. 19: Gateway® Cloning Products. Nucleic acid-related materials DSN-related materials (also referred to as "Products") are intended for research use only. The Products are covered by U.S. Patents No. 7,435,794 and 7,803,922. By use of these Products, you accept the terms and conditions of the applicable Limited Use Label License #002. PCR PCR is the subject of patents issued in certain countries. The purchase of Evrogen kits does not include a license to perform PCR. However, many researchers may not be required to obtain a license. Other investigators may already have a license to perform PCR through use of a thermal cycler with the appropriate label license.