Biofunctionalized Polymer Surfaces Exhibiting Minimal Interaction towards Immobilized Proteins

An invisible surface: Single protein molecules were immobilized on a cross-linked polymer surface (see cartoon), and imaged using fluorescence resonance energy transfer (FRET). The surface not only maintained the correct conformation of the protein molecules, but also allowed them to be unfolded and refolded fifty times consecutively. Moreover, the measured δG, cooperativity and the transition midpoint in guanidinium chloride of the unfolding-folding transition on the surface was identical to the protein in solution. Thus, the surface is energetically ‘invisible’ to the folding protein.