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Hemoglobin becomes electroactive upon interaction with surface-protected Au nanoparticles
Rafael Del Caño1, Lucia Mateus1, Guadalupe Sánchez-Obrero1
1Department of Physical Chemistry and Applied Thermodynamics, Institute of Fine Chemistry and Nanochemistry, University of Cordoba, Campus Rabanales, Ed. Marie Curie 2ª Planta, E-14014 Córdoba, Spain.
Talanta
|September 18, 2017
Summary
Gold nanoparticles (AuNP) bioconjugates with hemoglobin (Hb) exhibit electroactivity on electrodes. These AuNP-Hb bioconjugates show enhanced electrocatalytic activity for hydrogen peroxide and oxygen reduction.
Area of Science:
- Electrochemistry
- Nanobiotechnology
- Protein-Nanoparticle Interactions
Background:
- Hemoglobin (Hb) protein is typically electrochemically inactive on glassy carbon electrodes.
- Gold nanoparticles (AuNPs) can be functionalized with various molecular layers.
- Bioconjugation of proteins onto nanoparticles is a key strategy in biosensor development.
Purpose of the Study:
- To investigate the electrochemical behavior of hemoglobin (Hb) bioconjugated with gold nanoparticles (AuNPs).
- To assess the electrocatalytic activity of these bioconjugates for reduction reactions.
- To understand the role of the nanoparticle surface and capping agents on protein electroactivity.
Main Methods:
- Preparation of AuNP bioconjugates with Hb using three different capping agents: citrate, 6-mercaptopurine, and ω-mercaptoundecanoic acid.
- Electrochemical characterization using cyclic voltammetry on a glassy carbon electrode.
- pH-dependent electrochemical measurements to assess protein structural integrity.
- Evaluation of electrocatalytic activity towards hydrogen peroxide and oxygen reduction.
Main Results:
- AuNP-Hb bioconjugates displayed a pair of redox peaks at -0.37V, indicating electroactivity absent in free Hb.
- Electron transfer rate constants were determined for the different bioconjugates.
- Protein structural integrity was maintained upon bioconjugation, as evidenced by pH-dependent studies.
- The bioconjugates demonstrated significant electrocatalytic activity for the reduction of hydrogen peroxide and oxygen.
- Electrochemical activity was primarily localized to the first Hb layer around the AuNPs, with some contribution from the second layer.
Conclusions:
- Gold nanoparticles functionalized with hemoglobin exhibit robust electrochemical activity and electrocatalytic properties.
- The nature of the capping agent influences the electrochemical response of the AuNP-Hb bioconjugates.
- AuNP-Hb bioconjugates show promise for applications in electrochemical sensing and catalysis, particularly for oxygen and peroxide reduction.
