Specific G-quadruplex-probing is crucial for both biological sciences and biosensing applications. Most reported probes are focused on fluorescent or colorimetric recognition of G-quadruplexes. Herein, for the first time, we reported a new specific G-quadruplex-probing technique—resonance light scattering (RLS)-based ratiometric recognition. To achieve the RLS probing of G-quadruplexes in the important physiological pH range of 7.4-6.0, four water soluble cationic porphyrin derivatives, including an unreported octa-cationic porphyrin, with large side arm substituents were synthesized and developed as RLS probes. These RLS probes were demonstrated to work well for ratiometric recognition of G-quadruplexes with high specificity against single- and double-stranded DNAs, including long double-stranded ones. The working mechanism was speculated to be based on the RLS signal changes caused by porphyrin protonation that was promoted by the end-stacking of porphyrins on Gquadruplexes. This work adds an important member in G-quadruplex probe family, thus providing a useful tool for studies on G-quadruplex-related events concerning G-quadruplex formation, destruction and changes in size, shape and aggregation. As a proofof-concept example of applications, the RLS probes were demonstrated to work well for label-free and sequence-specific sensing of microRNA. This work also provides a simple and useful way for the preparation of cationic porphyrins with high charges.
Digital Commons Citation
Zhang, Li-Ming; Cui, Yun-xi; Zhu, Li-Na; Chu, Jun-Qing; and Kong, De-Ming, "Cationic Porphyrins with Large Side Arm Substituents as Resonance Light Scattering Ratiometric Probes for Specific Recognition of Nucleic Acid G-quadruplexes" (2019). Faculty & Staff Scholarship. 2136.
Zhang, L.-M., Cui, Y.-X., Zhu, L.-N., Chu, J.-Q., & Kong, D.-M. (2019). Cationic porphyrins with large side arm substituents as resonance light scattering ratiometric probes for specific recognition of nucleic acid G-quadruplexes. Nucleic Acids Research, 47(6), 2727–2738. https://doi.org/10.1093/nar/gkz064