Conducting Polymer-Coated Carbon Cloth Captures and Releases Extracellular Vesicles by a Rapid and Controlled Redox Process

Jesna Ashraf; Alireza Akbarinejad; Colin L Hisey; Devon T Bryant; Julie Wang; Bicheng Zhu; Clive W Evans; David E Williams; Lawrence W Chamley; David Barker; Lisa I Pilkington; Jadranka Travas-Sejdic

doi:10.1021/acsami.2c06481

Conducting Polymer-Coated Carbon Cloth Captures and Releases Extracellular Vesicles by a Rapid and Controlled Redox Process

ACS Appl Mater Interfaces. 2022 Jul 12. doi: 10.1021/acsami.2c06481. Online ahead of print.

Authors

Jesna Ashraf^{1

2}, Alireza Akbarinejad^{1

2}, Colin L Hisey³, Devon T Bryant¹, Julie Wang³, Bicheng Zhu^{1

2}, Clive W Evans^{1

4}, David E Williams^{1

2}, Lawrence W Chamley³, David Barker^{1

2}, Lisa I Pilkington¹, Jadranka Travas-Sejdic^{1

2}

Affiliations

¹ Polymer Biointerface Centre, School of Chemical Sciences, The University of Auckland, Auckland 1010, New Zealand.
² The MacDiarmid Institute of Advanced Materials and Nanotechnology, Wellington 6140, New Zealand.
³ Hub for Extracellular Vesicles Investigations (HEVI), Department of Obstetrics and Gynaecology, The University of Auckland, Auckland 1023, New Zealand.
⁴ School of Biological Sciences, The University of Auckland, Auckland 1010, New Zealand.

PMID: 35820023
DOI: 10.1021/acsami.2c06481

Abstract

Electrochemical techniques offer great opportunities for the capture of chemical and biological entities from complex mixtures and their subsequent release into clean buffers for analysis. Such methods are clean, robust, rapid, and compatible with a wide range of biological fluids. Here, we designed an electrochemically addressable system, based on a conducting terpolymer [P(EDOT-co-EDOTSAc-co-EDOTEG)] coated onto a carbon cloth substrate, to selectively capture and release biological entities using a simple electrochemical redox process. The conducting terpolymer composition was optimized and the terpolymer-coated carbon cloth was extensively characterized using electrochemical analysis, Raman and Fourier transform-infrared spectroscopy, water contact angle analysis, and scanning electron microscopy. The conductive terpolymer possesses a derivative of EDOT with an acetylthiomethyl moiety (EDOTSAc), which is converted into a "free" thiol that then undergoes reversible oxidation/reduction cycles at +1.0 V and -0.8 V (vs Ag/AgCl), respectively. That redox process enables electrochemical capture and on-demand release. We first demonstrated the successful electrochemical capture/release of a fluorescently labeled IgG antibody. The same capture/release procedure was then applied to release extracellular vesicles (EVs), originating from both MCF7 and SKBR3 breast cancer cell line bioreactors. EVs were captured using the substrate-conjugated HER2 antibody which was purified from commercially available trastuzumab. Capture and release of breast cancer EVs using a trastuzumab-derived HER2 antibody has not been reported before (to the best of our knowledge). A rapid (2 min) release at a low potential (-0.8 V) achieved a high release efficiency (>70%) of the captured, HER2^+ve, SKBR3 EVs. The developed system and the electrochemical method are efficient and straightforward and have vast potential for the isolation and concentration of various biological targets from large volumes of biological and other (e.g., environmental) samples.

Keywords: HER2; antibody; carbon cloth; conducting polymer; electrochemical release; electrochemically switchable; extracellular vesicles; trastuzumab.