| Abstract
| - We describe a simple and straightforward approach forhomogeneous and isothermal detection of individualrolling circle replication (RCR) products, which representindividual padlock probe circularization events. The RCRproducts constitute tens of kilobases long single-strandedtandem repeated copies of the probe sequence, and insolution, they fold into micrometer-sized random coils.The method is based on the local enrichment of fluorescence-labeled probes that hybridize to the coiled RCRproducts compared to the concentration of free probesin solution. We present a detailed characterization of thefluorescence-labeled products using a highly sensitive andfast microscopy setup. At a 104-fold excess of free label,we were able to detect and follow individual RCR productsat a signal-to-background noise ratio of 27. This highsignal-to-background noise ratio leaves room for analysisin a simple detection device at higher speeds or at lowerlabeling ratios.
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