Functional Polymer Brushes on Diamond as a Platform for Immobilization and Electrical Wiring of Biomolecules

Abstract

For the biofunctionalization of electronic devices, polymer brushes can provide a route which allows combining the advantages of other commonly used approaches, such as immobilization of functional biomolecules via self assembled monolayers or coated polymer matrices: high stability and loading capacity, efficient electron transport, and excellent biocompatibility. In the work presented here, poly(methacrylic acid) brushes are prepared by self‐initiated photografting and photopolymerization on diamond electrodes. In this straightforward process no prior grafting of initiators is required since the initiation of the polymerization can be conveniently controlled by the hydrogen or oxygen termination of the diamond surface. Boron doped nanocrystalline diamond as an electrode material provides extreme chemical inertness and stability, inherent biocompatibility, and superior electrochemical properties, such as the large accessible potential window and low background currents. As a proof of concept we demonstrate the amperometric detection of glucose by polymer brushes covalently modified with the redox enzyme glucose oxidase and aminomethyl ferrocene as electron mediator. Characterization by X‐ray photoelectron spectroscopy and atomic force microscopy both indicate a high loading of the ferrocene mediator. Consistently, electrochemical cyclic voltammetry shows a multilayer equivalent loading of ferrocene and highly efficient electron transfer throughout the polymer film. Overall, functionalized polymer brushes can provide a promising platform for the immobilization and electrical wiring of biomolecules for bioelectronic and biosensing applications.

Functionalization of Boron-Doped Nanocrystalline Diamond with N3 Dye Molecules

“…The selection of an efficient catalytic system is of great importance to achieve high coupling yields in transition metal catalyzed cross-couplings. 32,33 Best results were obtained for a Pd(OAc) 2 -P(o-tol) 3 catalytic system compared to other systems using Pd(PPh 3 ) 4 or Pd(dppf)Cl 2 .…”

“…They have for instance been used as efficient transducers for sensors. [3][4][5][6][7] B:NCD thin film electrodes decorated with metal nanoparticles have shown catalytic effects in the reduction of CO 2 and alkenes, 8 the oxidation of methanol, 9 and the degradation of environmental pollutants. 10 Recently, boron-doped diamond nanoparticles have been produced from CVD diamond films.…”

Redox‐Switchable Supramolecular Graft Polymer Formation via Ferrocene–Cyclodextrin Assembly

“…Due to the above‐noted properties, Fc is a widely used component for the construction of redox‐switchable systems via host–guest interaction with CDs, e.g., for application in electrochemistry, biochemical‐sensors, and self healing materials . Numerous reports address “grafting‐from” or “grafting‐to” approaches for installing Fc‐containing polymer brushes on surfaces by ATRP and RAFT polymerization …”

Chain Extension of Stimuli‐Responsive Polymer Brushes: A General Strategy to Overcome the Drawbacks of the “Grafting‐To” Approach

“…[1][2][3][4][5][6][7] Polymer brushes are a specifi c example of stimuli-responsive thin fi lms and involve macromolecules that are grafted chemically to a surface at suffi ciently high grafting densities so that the polymer chains experience excluded volume repulsions and adopt a stretched conformation. The structural diversity of those smart materials have gained increased interest over the last decades and offers a variety of opportunities for the fabrication of bio-interactive and responsive interfaces.…”