Generic High-Capacity Electrochemical Capture and Release of Proteins by Polyelectrolyte Brushes

We present a polyelectrolyte brush electrode with high-capacity for protein immobilization that captures and releases proteins by an electrochemical potential. Central to our concept is the use of polyelectrolyte brushes that switch reversibly by electrochemistry. Our electrode enables high-fidelity control of protein species in space and time. We predict several application areas for this technology; for instance in protein separation and in biomedical devices.</p

Redox chemistry of nickelocene-based monomers and polymers

The oxidation of [n]nickelocenophanes [Ni(η5-C5H4)2(CH2)3] (3), [Ni(η5-C5H4)2(SiMe2)2] (10), [Ni(η5-C5H4)2(SiMe2)2O] (11), [Ni(η5-C5H4)2(CH2)4] (12), and poly(nickelocenylpropylene) [Ni(η5-C5H4)2(CH2)3]n (4) to both the monocationic and dicationic species was investigated in dichloromethane by cyclic voltammetry (CV) and square-wave voltammetry. The presence of acetonitrile on the oxidation potentials of 3 in dichloromethane was also investigated by CV. The [n]nickelocenophanes 3 and 10–12 exhibited two single-electron Nernstian redox processes, and the monocations [3]+, [10]+, [11]+, and [12]+ were isolable as [B(C6F5)4]− salts after chemical oxidation, and were structurally characterized. Ni–Cpcent distances in all four monomers decreased upon oxidation, with a structural distortion manifested in the ring-tilt angle, α, among other angles. CV studies of the reversible first oxidation process to the polyelectrolyte {[Ni(η5-C5H4)2(CH2)3]+}n ([4]n+) were used to estimate the molecular weight of the polymeric material (Mw = 5300 g mol–1) by comparing its diffusion coefficient with that of a monomeric analogue, and the second electrochemical oxidation of polymer 4 was found to be only partially chemically reversible