Impedimetric Characterization of Bipolar Nanoelectrodes with Cancer Cells

Merging of electronics with biology, defined as bioelectronics, at the nanoscale holds considerable promise for sensing and modulating cellular behavior. Advancing our understanding of nanobioelectronics will facilitate development and enable applications in biosensing, tissue engineering, and bioelectronic medicine. However, studies investigating the electrical effects when merging wireless conductive nanoelectrodes with biology are lacking. Consequently, a tool is required to develop a greater understanding of merging conductive nanoparticles with cells. Herein, this challenge is addressed by developing an impedimetric method to evaluate bipolar electrode (BPE) systems that could report on electrical input. A theoretical framework is provided, using impedance to determine if conductive nanoparticles can be polarized and used to drive current. It is then demonstrated that 125 nm of gold nanoparticle (AuNP) bipolar electrodes (BPEs) could be sensed in the presence of cells when incorporated intracellularly at 500 μg/mL using water and phosphate-buffered saline (PBS) as electrolytes. These results highlight how nanoscale BPEs act within biological systems. This research will impact the rational design of using BPE systems in cells for both sensing and actuating applications

Towards in-vivo grown bioelectronics: utilising bipolar electrochemistry

Bipolar electrochemistry brings exciting possibilities to be able to grow electronics in situ within biological systems, thus creating electronics that seamlessly merge with biology and are on a similar scale to cellular components. This could allow the development of novel applications to tackle some of the world’s greatest health burdens, such as cancer. Therefore, the aim of this thesis is to develop bioelectronic systems, utilising bipolar electrochemistry, for possible applications in cancer treatment. State of the art bioelectronic treatment of cancer includes tumour treating fields: a novel therapy whereby high frequency electric fields are used to halt the growth of tumours. Electric fields are currently applied to target sites using external electrodes, hence the development of in-situ grown electrodes for this application could improve therapy outcomes and lower timeframes and costs. Working towards this application, this thesis has three main objectives: the development of wirelessly in situ grown microwires (MWs) in the presence of cells, the development of bipolar electrodes (BPEs) suitable for use in biological systems, and the development of a method to characterise nano-BPEs in order to better understand bipolar electrochemistry in the presence of biological systems. Ag MWs are grown using a wireless, bipolar electrochemical method. We build on previous literature by optimising the electrode setup required to grow Ag MWs. Alternating current (AC) is then used to grow Ag MWs for the first time and proofs of concept for growing MWs in the presence of 3D cell cultures and from the addition of a metal salt are presented. Nano-BPEs are developed using conductive metallic and polymeric nanoparticles. Bipolar electrochemical reactions are confirmed at the nanoscale BPEs using dynamic light scattering (DLS) and transmission electron microscopy (TEM) with energy dispersive X-ray spectroscopy (EDS). These BPEs are then introduced to a tumour treating fields (TTFs) research device and show promise in potentiating the cytotoxic effects of TTFs. Finally, an impedimetric method for the characterisation of nano-BPEs is developed. This method is then used to characterise nano-BPEs in the presence of biological systems. Au Nano-BPEs are shown to be sensed when placed intracellularly, therefore showing great promise for applications in bioelectronics. Overall, these developments will help advance the field of wireless bioelectronics and aid in the understanding of how bipolar electrochemistry performs at the nanoscale. This will have broad reaching impact in bioelectronic medicine, biosensing and nanoelectronics

Towards in-vivo grown bioelectronics: utilising bipolar electrochemistry

Bipolar electrochemistry brings exciting possibilities to be able to grow electronics in situ within biological systems, thus creating electronics that seamlessly merge with biology and are on a similar scale to cellular components. This could allow the development of novel applications to tackle some of the world’s greatest health burdens, such as cancer. Therefore, the aim of this thesis is to develop bioelectronic systems, utilising bipolar electrochemistry, for possible applications in cancer treatment. State of the art bioelectronic treatment of cancer includes tumour treating fields: a novel therapy whereby high frequency electric fields are used to halt the growth of tumours. Electric fields are currently applied to target sites using external electrodes, hence the development of in-situ grown electrodes for this application could improve therapy outcomes and lower timeframes and costs. Working towards this application, this thesis has three main objectives: the development of wirelessly in situ grown microwires (MWs) in the presence of cells, the development of bipolar electrodes (BPEs) suitable for use in biological systems, and the development of a method to characterise nano-BPEs in order to better understand bipolar electrochemistry in the presence of biological systems. Ag MWs are grown using a wireless, bipolar electrochemical method. We build on previous literature by optimising the electrode setup required to grow Ag MWs. Alternating current (AC) is then used to grow Ag MWs for the first time and proofs of concept for growing MWs in the presence of 3D cell cultures and from the addition of a metal salt are presented. Nano-BPEs are developed using conductive metallic and polymeric nanoparticles. Bipolar electrochemical reactions are confirmed at the nanoscale BPEs using dynamic light scattering (DLS) and transmission electron microscopy (TEM) with energy dispersive X-ray spectroscopy (EDS). These BPEs are then introduced to a tumour treating fields (TTFs) research device and show promise in potentiating the cytotoxic effects of TTFs. Finally, an impedimetric method for the characterisation of nano-BPEs is developed. This method is then used to characterise nano-BPEs in the presence of biological systems. Au Nano-BPEs are shown to be sensed when placed intracellularly, therefore showing great promise for applications in bioelectronics. Overall, these developments will help advance the field of wireless bioelectronics and aid in the understanding of how bipolar electrochemistry performs at the nanoscale. This will have broad reaching impact in bioelectronic medicine, biosensing and nanoelectronics

Impedimetric Characterization of Bioelectronic Nano-Antennae

The merging of electronics with biology at the nanoscale holds considerable promise for sensing and modulating cellular behavior. Advancing our understanding of nano-bioelectronics will facilitate development and enable applications in biosensing, tissue engineering and bioelectronic medicine. However, studies investigating the electrical effects when merging wireless conductive nanoelectrodes with biology are lacking. Consequently, a new tool is required to develop a greater understanding of the bioelectrical effects of merging conductive nanoparticles with biology. Herein, this challenge is addressed by developing an impedimetric method to evaluate bipolar electrochemical systems (BESs) that could act as nano-antennas. A theoretical framework is provided, using impedance to determine if conductive nanoparticles can be polarized and used to drive current. It is then demonstrated that 125 nm Au nanoparticle bipolar electrodes (BPEs) could be sensed in the presence of biology when incorporated intracellularly at 500 mg/ml, using water and PBS as electrolytes. These results highlight how nanoscale BPEs act within biological systems and characterize their behavior in electric fields. This research will impact on the rational design of using BPE systems in biology for both sensing and actuating applications.</p

Ivan Vladislavić and the possible city

The article explores the literary significance of Johannesburg in the writing of Ivan Vladislavić in the context of recent debates about how to read the African city. In his most recent work, Portrait with Keys: The City of Johannesburg Unlocked (2006), Vladislavić opens his personal archive of everyday life in the city to imaginative reinterpretation by readers. To read Vladislavić's “portrait” is to imagine the city as a space that might be written, read and experienced differently - to imagine it as a possible city. The self-reflexive nature of this project throws into critical relief recent calls to read Johannesburg as an “aesthetic project” rather than a “space of division” (Mbembe and Nuttall 353)