A Biotinylated Conducting Polypyrrole for the Spatially Controlled Construction of an Amperometric Biosensor

Abstract

A new biotin derivative functionalized by an electropolymerizable pyrrole group has been synthesized. The electrooxidation of this biotin pyrrole has allowed the formation of biotinylated conducting polypyrrole films in organic electrolyte. Gravimetric measurements based on a quartz crystal microbalance, modified by the biotinylated polymer, revealed an avidin-biotin-specific binding at the interface of polymer-solution. The estimated mass increase corresponded to the anchoring of 1.5 avidin monolayers on the polypyrrole surface. In addition, the subsequent grafting of biotinylated glucose oxidase was corroborated by electrochemical permeation studies. Enzyme multilayers composed of glucose oxidase or polyphenol oxidase were elaborated on the electrode surface modified by the biotinylated polypyrrole film. The amperometric response of the resulting biosensors to glucose or catechol has been studied at +0.6 or -0.2 V vs SCE, respectively.

Biosensors from conjugated polyelectrolyte complexes

“…The coupling of a recognition event to photoinduced electron transfer or a change in the electronic structure of the conjugated polymer produces changes in the luminescence, UV-visible absorption, or redox potential of the polymer (4, 5). Extensive research has been carried out by using conjugated polymers (derivatives of polydiacetylene, electrochemically polymerized polypyrrole, or polythiophene) as chromic (16)(17)(18)(19) or electrochemical (20)(21)(22)(23)(24)(25)(28)(29)(30)(31) biosensors. However, the relatively low sensitivity of UV-visible absorption measurements, the complex electrochemical instrumentation required, and the nonspecific interactions between biomolecules and conjugated polymers have prevented practical and general use.…”

“…As a result of this sensitivity, conjugated polymers are promising as sensory materials (4,5); sensing may be accomplished by transducing and͞or amplifying physical or chemical changes into electrical, optical, or electrochemical signals. Conjugated polymers have been used to detect chemical species (chemosensors) (6), such as ions (7)(8)(9)(10)(11), gases (for example, trinitrotoluene) (6,(12)(13)(14), and other chemicals (15), or biomolecules such as proteins, antibodies (16)(17)(18)(19)(20)(21)(22)(23)(24)(25)(26)(27), and DNA (28-31), using electrical (13,15), chromic (7,8,(16)(17)(18)(19), electrochemical (7-9, 20-25, 28-31), photoluminescent (11,26), chemoluminescent (27), or gravimetric (14) responses.…”

“…Biosensors based on conjugated polymers as sensory materials exhibit real-time response [electrochemical (20)(21)(22)(23)(24)(25) or optical (16)(17)(18)(19)26)] to the ligand-receptor recognition event. The coupling of a recognition event to photoinduced electron transfer or a change in the electronic structure of the conjugated polymer produces changes in the luminescence, UV-visible absorption, or redox potential of the polymer (4,5).…”

Recent Developments, Characteristics, and Potential Applications of Electrochemical Biosensors

“…49,[64][65][66][67]72,73 Such analytical tools exhibited lower sensitivity than the biosensors based on the same enzyme in aqueous media, because of the organic media ability to reduce the rate of enzymatic reaction. 73 Lactitol, an uncharged polyhydroxyl, was reported to constitute an efficient additive for the improvement of the analytical characteristics of amperometric biosensors since it had highly hydrophilic properties and the capacity to replace bound water via hydrogen bonding with the enzyme.…”

“…The polymer film did operate in aqueous and organic media. 72,73 The electrochemical technique involved a sequential procedure of electro-polymerization. Covalent binding was observed to affect the catalytic activity or the recognition properties of biomolecules.…”