Silver cations fold i-motif at neutral pHElectronic supplementary information (ESI) available: Experimental procedures, FRET melting curves and additional CD spectra. See DOI: 10.1039/c3cc43495h

i-Motif DNA structures have previously been utilised for many different nanotechnological applications, but all have used acidic conditions to fold the DNA. Herein we describe the use of silver cations to fold an i-motif forming DNA sequence at physiological pH. Subsequent DNA unfolding can be achieved by chelation with cysteine. Reversible folding of human telomeric DNA at room temperature and physiological pH using Ag + .