Novel Functionalization of Boron-Doped Diamond by Microwave Pulsed-Plasma Polymerized Allylamine Film

We report the novel modification of a hydrogen-terminated polycrystalline boron-doped electrode with a microwave pulsed-plasma polymerized allylamine. Boron-doped diamond (BDD) was coated with a very thin layer of adherent cross-linked, pinhole- and additive-free allylamine plasma polymer (PPAAm) resistant to hydrolysis and delamination and characterized by a high density of positively charged amino groups. The pulsed microwave plasma was applied to improve the cross-linking degree and bonding of the plasma polymeric films to boron-doped diamond. The amine-treated BDD films were assessed by advanced surface analytical techniques, such as X-ray photoelectron spectroscopy (XPS), FT-IR, scanning electron microscopy (SEM), laser-induced fluorescence, and water contact angle measurements. The amine-modified Si/BDD surface was functionalized with selected organic molecules containing a carboxylic group in the presence of coupling agents such as diisopropylcarbodiimide (DIC). The anthraquinone derivatives Boc-Lys(AQ)-OH and peptide anthraquinone derivatives of dendrimers were used as electroactive agents for characterization by cyclic voltammetry (CV). The fluorescence reference standards Rhodamine 110 and Fmoc-Trp(Boc)-OH were selected for fluorescence studies.