Label-free Catalytic and Molecular Beacon Containing an Abasic Site for Sensitive Fluorescent Detection of Small Inorganic and Organic Molecules

摘要

In this work, two methods with complementary features, catalytic and molecular beacon (CAMB) and label-free fluorescent sensors using abasic site, have been combined into new label-free CAMB sensors that possess advantages of each method. The label-free method using dSpacer-containing molecular beacon makes CAMB more cost-effective and less interfering to the catalytic activity, while the CAMB allows the label-free method to use true catalytic turnovers for signal amplifications, resulting in a new label-free CAMB sensor for Pb²⁺ ion, with a detection limit of 3.8 nM while maintaining the same selectivity. Furthermore, by using CAMB to overcome the label-free method’s limitation of the requiring excess enzyme strand, a new label-free CAMB sensor using aptazyme is also designed to detect adenosine down to 1.4 μM, with excellent selectivity over other nucleosides.