Technical ArticleRapid Histochemistry Using Slow Off-rate Modified Aptamers With Anionic CompetitionGupta, Shashi PhD*; Thirstrup, Derek MS†; Jarvis, Thale C. PhD*; Schneider, Daniel J. PhD*; Wilcox, Sheri K. PhD*; Carter, Jeff BSc*; Zhang, Chi PhD*; Gelinas, Amy PhD*; Weiss, Allison PhD*; Janjic, Nebojsa PhD*; Baird, Geoffrey S. MD, PhD† Author Information *SomaLogic, Inc, Boulder, CO †the Department of Laboratory Medicine, University of Washington, Seattle, WA Supported by University of Washington, Department of Laboratory Medicine and SomaLogic, Inc. The authors (D.T., G.S.B.) disclose research support from SomaLogic, Inc as a potential conflict of interest. The remaining authors are employees of SomaLogic, Inc. Supplemental Digital Content is available for this article. Direct URL citations appear in the printed text and are provided in the HTML and PDF versions of this article on the journal's Website, www.appliedimmunohist.com. Reprints: Geoffrey S. Baird, MD, PhD, Department of Laboratory Medicine, University of Washington, Harborview Medical Center, Box 359743, 325 9th Avenue, Seattle, WA 98105 (e-mail: [email protected]). Received August 11, 2010 Accepted October 7, 2010 Applied Immunohistochemistry & Molecular Morphology: May 2011 - Volume 19 - Issue 3 - p 273-278 doi: 10.1097/PAI.0b013e3182008c29 Buy SDC Metrics AbstractIn Brief Immunohistochemistry is used in both research and clinical settings to identify proteins in tissue samples. Despite the power and versatility of immunohistochemistry, limitations are imposed by the slow diffusion of antibodies through tissue and the need for secondary staining or signal amplification. Aptamers can circumvent these limitations, but their application has been hindered by nonspecific binding to cellular components, particularly in the nucleus. Here we describe unique slow off-rate modified aptamers that facilitate rapid and selective binding to target proteins in tissue. Specifically, we have developed a fluorescent aptamer that binds to the human epidermal growth factor receptor 2 (HER2) in breast carcinomas quickly and specifically, and we have shown that the slow off-rate of the aptamer from the HER2 protein contributes to its selectivity. These findings open the door to aptamer histochemistry applications in both research and clinical settings, including intraoperative diagnostics in which speed and accuracy are paramount. Supplemental Digital Content is available in the article. © 2011 Lippincott Williams & Wilkins, Inc.