Phthalocyanine Dimerization-based Molecular Beacons Using Near-irfluorescence

摘要

Since their 1996 inception by Tyagi and Kramer, molecular beacons (MBs) have become powerful tools for a variety of applications in DNA/RNA detection (e.g., real-time PCR, SNP detection, in vivo cellular imaging, cancer imaging, etc.). MB-based detection systems are separation-free and highly specific; however, their sensitivity (defined as the ratio of the fluorescence in the open versus closed form; signal-to-background, SB) is limited due to incomplete quenching of the closed form while signal in an open form is confined to one fluorophore. Various approaches for SB enhancement have been pursued including introduction of multiple fluorophores and/or quenchers, eximer emission, FRET, con-jugated-polymers, electrochemiluminescence, or quantum dots. The quest for more sensitive probes is still necessary along with the need to increase the MB reporting fluorophore's photostability to prolong observation times in imaging applications and conducting assays in the near-IR, where significant autofluorescence can be avoided.