Effect of buffer at nanoscale molecular recognition interfaces – electrostatic binding of biological polyanions

We investigate the impact of an over-looked component on molecular recognition in water–buffer. The binding of a cationic dye to biological polyanion heparin is shown by isothermal calorimetry to depend on buffer (Tris–HCl 4 HEPES 4 PBS). The heparin binding of selfassembled multivalent (SAMul) cationic micelles is even more buffer dependent. Multivalent electrostatic molecular recognition is buffer dependent as a result of competitive interactions between the cationic binding interface and anions present in the buffer.