Fluorescent titration

Calf thymus dsDNA, purchased from Sigma-Aldrich Co, and RNA from torula yeast, purchased from Wako Pure Chemical Industries, were used in the fluorescence titration^40,41. DNA/RNA selectivity of PC1 was compared with commercialized nucleus markers (Pico-Green, Hoechst 33342; ThermoFisher Scientific). All chemicals are used without additional treatment or further purifications. UV/Vis absorption spectra were recorded on a Shimadzu UV-3510 spectrometer with a resolution of 0.5 nm and emission spectra were measured with an FP-6600 Hitachi spectrometer with a resolution of 0.2 nm. CD spectra were measured with a JASCO FT/IR6100. 1.0 cm square quartz cell was used for all optical measurements. About 1.0 g/L dsDNA solution (1.0 mL) or 2.0 g/L RNA solution (1.0 mL) were added to dye solutions (2.0 mL) with absorbance around 0.2 at each maximum wavelength at room temperature by using a micro pipet. After titration, the combined solution was gently shaken several times to stabilize the absorbance and fluorescence intensities of all samples. (see detailed results in the supporting information)