title: Rapid histochemistry using slow off-rate modified aptamers with anionic competition.
abstract: 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.
authors.affiliation: SomaLogic, Inc, Boulder, CO, USA.
authors.forename: Shashi
authors.initials: S
authors.lastname: Gupta
authors.forename: Derek
authors.initials: D
authors.lastname: Thirstrup
authors.forename: Thale C
authors.initials: TC
authors.lastname: Jarvis
authors.forename: Daniel J
authors.initials: DJ
authors.lastname: Schneider
authors.forename: Sheri K
authors.initials: SK
authors.lastname: Wilcox
authors.forename: Jeff
authors.initials: J
authors.lastname: Carter
authors.forename: Chi
authors.initials: C
authors.lastname: Zhang
authors.forename: Amy
authors.initials: A
authors.lastname: Gelinas
authors.forename: Allison
authors.initials: A
authors.lastname: Weiss
authors.forename: Nebojsa
authors.initials: N
authors.lastname: Janjic
authors.forename: Geoffrey S
authors.initials: GS
authors.lastname: Baird
mesh_terms: D052158:Aptamers, Peptide / Q000737:chemistry / Q000378:metabolism*; D001943:Breast Neoplasms / Q000175:diagnosis* / Q000378:metabolism / Q000473:pathology; D002277:Carcinoma / Q000175:diagnosis* / Q000378:metabolism / Q000473:pathology; D004815:Epidermal Growth Factor / Q000378:metabolism; D005260:Female; D005456:Fluorescent Dyes / Q000737:chemistry / Q000378:metabolism*; D006801:Humans; D025202:Molecular Diagnostic Techniques; D011485:Protein Binding; D012680:Sensitivity and Specificity
chemical_list: D052158:Aptamers, Peptide; D005456:Fluorescent Dyes; D004815:Epidermal Growth Factor