RESUMEN
Novel hot electron-emitting working electrodes and conventional counter electrodes were created by screen printing. Thus, low-cost disposable electrode chips for bioaffinity assays were produced to replace our older expensive electrode chips manufactured by manufacturing techniques of electronics from silicon or on glass chips. The present chips were created by printing as follows: (i) silver lines provided the electronic contacts, counter electrode and the bottom of the working electrode and counter electrode, (ii) the composite layer was printed on appropriate parts of the silver layer, and (iii) finally a hydrophobic ring was added to produce the electrochemical cell boundaries. The applicability of these electrode chips in bioaffinity assays was demonstrated by an immunoassay of human C-reactive protein (i) using Tb(III) chelate label displaying long-lived hot electron-induced electrochemiluminescence (HECL) and (ii) now for the first time fluorescein isothiocyanate (FITC) was utilized as an a low-cost organic label displaying a short-lived HECL in a real-world bioaffinity assay.
Asunto(s)
Electroquímica/métodos , Electrones , Inmunoensayo/métodos , Mediciones Luminiscentes/métodos , Proteína C-Reactiva/metabolismo , Calibración , Electrodos , Humanos , Propiedades de SuperficieRESUMEN
Tb(III) chelates exhibit intense hot electron-induced electrogenerated chemiluminescence during cathodic polarization of metal/polystyrene-graphite (M/PG) electrodes in fully aqueous solutions. The M/PG working electrode provides a sensitive means for the determination of aromatic Tb(III) chelates at nanomolar concentration levels with a linear log-log calibration curve spanning more than five orders of magnitude. The charge transport and other properties of these novel electrodes were studied by electrochemiluminescence measurements and cyclic voltammetry. The present composite electrodes can by utilized both under pulse polarization and DC polarization unlike oxide-coated metal electrodes which do not tolerate cathodic DC polarization. The present cost-effective electrodes could be utilized e.g. in immunoassays where polystyrene is extensively used as a solid phase for various bioaffinity assays by using electrochemiluminescent Tb(III) chelates or e.g. Ru(bpy)32+as labels.