title: Application of paper-supported printed gold electrodes for impedimetric immunosensor development.
abstract: In this article, we report on the formation and mode-of-operation of an affinity biosensor, where alternate layers of biotin/streptavidin/biotinylated-CRP-antigen/anti-CRP antibody are grown on printed gold electrodes on disposable paper-substrates. We have successfully demonstrated and detected the formation of consecutive layers of supra-molecular protein assembly using an electrical (impedimetric) technique. The formation process is also supplemented and verified using conventional surface plasmon resonance (SPR) measurements and surface sensitive characterization techniques, such as X-ray photoelectron spectroscopy (XPS) and atomic force microscopy (AFM). The article provides a possible biosensor development scheme, where-(1) fabrication of paper substrate (2) synthesis of gold nanoparticle inks (3) inkjet printing of gold electrodes on paper (4) formation of the biorecognition layers on the gold electrodes and (5) electrical (impedimetric) analysis of growth-all are coupled together to form a test-structure for a recyclable and inexpensive point-of-care diagnostic platform.
authors.affiliation: Center of Excellence for Functional Materials and Laboratory of Physical Chemistry, Department of Natural Sciences, Åbo Akademi University, Turku, Finland; E-Mails: bjorn.torngren@abo.fi (B.T.); anni.maattanen@abo.fi (A.M.); jawad.sarfraz@abo.fi (J.S.); jouko.peltonen@abo.fi (J.P.).
authors.forename: Petri
authors.initials: P
authors.lastname: Ihalainen
authors.affiliation: Center of Excellence for Functional Materials and Physics, Department of Natural Sciences, Åbo Akademi University, Turku, Finland; E-Mail: ronald.osterbacka@abo.fi.
authors.forename: Himadri
authors.initials: H
authors.lastname: Majumdar
authors.affiliation: Division of Biopharmaceutics and Pharmacokinetics, Faculty of Pharmacy, University of Helsinki, Helsinki, Finland; E-Mails: tapani.viitala@helsinki.fi (T.V.); ylipertt@mappi.helsinki.fi (M.Y.).
authors.forename: Tapani
authors.initials: T
authors.lastname: Viitala
authors.affiliation: Center of Excellence for Functional Materials and Laboratory of Physical Chemistry, Department of Natural Sciences, Åbo Akademi University, Turku, Finland; E-Mails: bjorn.torngren@abo.fi (B.T.); anni.maattanen@abo.fi (A.M.); jawad.sarfraz@abo.fi (J.S.); jouko.peltonen@abo.fi (J.P.).
authors.forename: Björn
authors.initials: B
authors.lastname: Törngren
authors.affiliation: Laboratory of Biophysics, Institute of Biomedicine and Medicity Research Laboratories, University of Turku, Turku, Finland; E-Mails: tuonar@utu.fi (T.N.); harri.harma@utu.fi (H.H.).
authors.forename: Tuomas
authors.initials: T
authors.lastname: Närjeoja
authors.affiliation: Center of Excellence for Functional Materials and Laboratory of Physical Chemistry, Department of Natural Sciences, Åbo Akademi University, Turku, Finland; E-Mails: bjorn.torngren@abo.fi (B.T.); anni.maattanen@abo.fi (A.M.); jawad.sarfraz@abo.fi (J.S.); jouko.peltonen@abo.fi (J.P.).
authors.forename: Anni
authors.initials: A
authors.lastname: Määttänen
authors.affiliation: Center of Excellence for Functional Materials and Laboratory of Physical Chemistry, Department of Natural Sciences, Åbo Akademi University, Turku, Finland; E-Mails: bjorn.torngren@abo.fi (B.T.); anni.maattanen@abo.fi (A.M.); jawad.sarfraz@abo.fi (J.S.); jouko.peltonen@abo.fi (J.P.).
authors.forename: Jawad
authors.initials: J
authors.lastname: Sarfraz
authors.affiliation: Laboratory of Biophysics, Institute of Biomedicine and Medicity Research Laboratories, University of Turku, Turku, Finland; E-Mails: tuonar@utu.fi (T.N.); harri.harma@utu.fi (H.H.).
authors.forename: Harri
authors.initials: H
authors.lastname: Härmä
authors.affiliation: Division of Biopharmaceutics and Pharmacokinetics, Faculty of Pharmacy, University of Helsinki, Helsinki, Finland; E-Mails: tapani.viitala@helsinki.fi (T.V.); ylipertt@mappi.helsinki.fi (M.Y.).
authors.forename: Marjo
authors.initials: M
authors.lastname: Yliperttula
authors.affiliation: Center of Excellence for Functional Materials and Physics, Department of Natural Sciences, Åbo Akademi University, Turku, Finland; E-Mail: ronald.osterbacka@abo.fi.
authors.forename: Ronald
authors.initials: R
authors.lastname: Österbacka
authors.affiliation: Center of Excellence for Functional Materials and Laboratory of Physical Chemistry, Department of Natural Sciences, Åbo Akademi University, Turku, Finland; E-Mails: bjorn.torngren@abo.fi (B.T.); anni.maattanen@abo.fi (A.M.); jawad.sarfraz@abo.fi (J.S.); jouko.peltonen@abo.fi (J.P.).
authors.forename: Jouko
authors.initials: J
authors.lastname: Peltonen
keywords: immunoassays; impedance spectroscopy; inkjet printing; nanoparticles; paper electronics