University of Oulu

Peltola, E., Aarva, A., Sainio, S., Heikkinen, J. J., Wester, N., Jokinen, V., Koskinen, J., & Laurila, T. (2020). Biofouling affects the redox kinetics of outer and inner sphere probes on carbon surfaces drastically differently – implications to biosensing. Physical Chemistry Chemical Physics, 22(29), 16630–16640.

Biofouling affects the redox kinetics of outer and inner sphere probes on carbon surfaces drastically differently

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Author: Peltola, Emilia1; Aarva, Anja1; Sainio, Sami2,3;
Organizations: 1Department of Electrical Engineering and Automation, School of Electrical Engineering, Aalto University, Espoo, Finland
2Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, Menlo Park, CA 94025, USA
3Microelectronics Research Unit, Faculty of Information Technology and Electrical Engineering, University of Oulu, Oulu, Finland
4Department of Chemistry and Materials Science, School of Chemical Technology, Aalto University, Espoo, Finland
Format: article
Version: published version
Access: open
Online Access: PDF Full Text (PDF, 3.5 MB)
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Language: English
Published: Royal Society of Chemistry, 2020
Publish Date: 2020-09-22


Biofouling imposes a significant threat for sensing probes used in vivo. Antifouling strategies commonly utilize a protective layer on top of the electrode but this may compromise performance of the electrode. Here, we investigated the effect of surface topography and chemistry on fouling without additional protective layers. We have utilized two different carbon materials; tetrahedral amorphous carbon (ta-C) and SU-8 based pyrolytic carbon (PyC) in their typical smooth thin film structure as well as with a nanopillar topography templated from black silicon. The near edge X-ray absorption fine structure (NEXAFS) spectrum revealed striking differences in chemical functionalities of the surfaces. PyC contained equal amounts of ketone, hydroxyl and ether/epoxide groups, while ta-C contained significant amounts of carbonyl groups. Overall, oxygen functionalities were significantly increased on nanograss surfaces compared to the flat counterparts. Neither bovine serum albumin (BSA) or fetal bovine serum (FBS) fouling caused major effects on electron transfer kinetics of outer sphere redox (OSR) probe Ru(NH3)63+ on any of the materials. In contrast, negatively charged OSR probe IrCl62− kinetics were clearly affected by fouling, possibly due to the electrostatic repulsion between redox species and the anionically-charged proteins adsorbed on the electrode and/or stronger interaction of the proteins and positively charged surface. The OSR probe kinetics were less affected by fouling on PyC, probably due to conformational changes of proteins on the surface. Dopamine (DA) was tested as an inner sphere redox (ISR) probe and as expected, the kinetics were heavily dependent on the material; PyC had very fast electron transfer kinetics, while ta-C had sluggish kinetics. DA electron transfer kinetics were heavily affected on all surfaces by fouling (ΔEp increase 30—451%). The effect was stronger on PyC, possibly due to the more strongly adhered protein layer limiting the access of the probe to the inner sphere.

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Series: PCCP. Physical chemistry chemical physics
ISSN: 1463-9076
ISSN-E: 1463-9084
ISSN-L: 1463-9076
Volume: 22
Issue: 29
Pages: 16630 - 16640
DOI: 10.1039/d0cp02251a
Type of Publication: A1 Journal article – refereed
Field of Science: 114 Physical sciences
116 Chemical sciences
Funding: EP acknowledges funding from Academy of Finland (#321996 and #328854) and Jane and Aatos Erkko Foundation. NW acknowledges funding from Business Finland (grant number 2117731), the Orion Research Foundation sr and the Foundation for Aalto University Science and Technology. The authors acknowledge the provision of facilities by Aalto University OtaNano-Micronova Nanofabrication Center, OtaNano-Nanomicroscopy Center (Aalto-NMC) and RawMatters research infrastructure (RAMI). This project has received funding from the European Union’s Horizon 2020 research and innovation programme under the Marie Skłodowska-Curie grant agreement no. 841621. SLAC National Accelerator Laboratory, is supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences under contract no. DE-AC02-76SF00515. The authors wish to acknowledge CSC – IT Center for Science, Finland, for the computational resources provided for this work.
EU Grant Number: (841621) TACOMA - Towards Application specific tailoring of CarbOn nanoMAterials
Copyright information: © The Authors 2020. This article is licensed under a Creative Commons Attribution-NonCommercial 3.0 Unported Licence.