Mercury 400

¹ H and ¹³C NMR spectra were measured with Varian NMR spectrometers (Inova 300, Varian 400, and Mercury 400). For optical spectra, DNA-CAs were prepared as ∼1 μM solutions in water (Molecular Biology grade, Corning). Absorption spectra were measured with a Cary 100 Bio UV–vis spectrometer, fluorescence spectra obtained by a Jobin Yvon-Spex Fluorolog 3 spectrometer, and fluorescence lifetime measurements were made with a PTI EasyLife LS spectrometer. Mass spectra were obtained using ESI or MALDI-TOF ionization modes at the Stanford University Mass Spectrometry Facility. HPLC was performed with a Shimadzu LC-20AD equipped with an SPD-M20A diode array detector and a Phenomenex Jupiter reverse phase C5 column. Dynamic light scattering measurements were made with a Malvern Instruments Nanoseries ZS90 Zetasizer. Epifluorescence microscopy for cell bioimaging and library screening were conducted on a Nikon Eclipse 80i microscope equipped with a Nikon Plan Fluor 4–40× objective and a QIClick digital CCD camera, with a 100 W high-pressure mercury lamp as the excitation source (365 nm mercury plasma emission line), 340–380 nm excitation filter, and >420 nm long-pass emission filter. Photographs of aqueous phase DNA-CAs, DNA-CAs in hydrogel, and flexible DNA-CA display were captured with an iPhone 6S+ camera, with a 365 nm gel transilluminator UV source (VWR LM-20E) as backlight.

GCPN is synthesized according to the previously described method (Kim et al., 2018b (link)). In brief, GCA (300 mg) was dissolved in 3 mL dimethyl formamide. Then 173 mg dicyclohexylcarbodiimide (DCC) and 96 mg N-hydroxysuccinimide (NHS) were added to active the carboxyl group, and 2.1 mL ethylenediamine (EDA) was added and stirred at room temperature overnight. After the reaction, unreacted EDA was removed by vacuum evaporation at 80 °C. The mixture was filtered and precipitated in ethyl acetate. The pellet (GCA-EDA) was dissolved in 10 mL water and lyophilized. CPN (0.1 mL) was dispersed in 2 mL 2-(N-morpholino)ethanesulfonic acid buffer (0.1M, pH= 6.0). Then 5 mg 1-ethyl-3-(3-(dimethylamino)propyl)carbodiimide hydrochloride and 5 mg NHS were added and stirred for 0.5 h. The synthesized GCA-EDA (10 mg) was added and stirred overnight in dark. After the reaction, GCPN was collected by ultracentrifugation (M_w = 10 kD) at 3500 rpm for 10 min. The synthesis was confirmed by Nuclear magnetic resonance (NMR, Mercury 400, Varian, Palo Alto, CA, USA). The size and Zeta potential were measured by dynamic laser scattering (DLS) using Malvern Zetasizer Nano-ZS (Malvern, Worcestershire, UK). The morphology of CPN and GCPN was observed by JEOL JEM 2800 Scanning Transmission Electron Microscopes (JEOL, MA, USA).