Wireless Nanobioelectronics for Electrical Intracellular Sensing

Abstract

In order for the field of bioelectronics to make an impact on healthcare, there is an urgent requirement for the development of "wireless" electronic systems to both sense and actuate cell behaviour. Herein we report the first example of an innovative intracellular wireless electronic communication system. We demonstrate that chemistry can be electrically modulated in a "wireless" manner on the nanoscale at the surface of conductive nanoparticles uptaken by cells at unreported low potentials. The system is made functional by modifying gold nanoparticles incorporating a Zn-porphyrin, which are taken up by cells and are shown to be biocompatible. It is demonstrated the redox state of Zn-porphyrin modified gold nanoparticles is modulated and reported on fluorescently when applying an external electrical potential. This provides an attractive new "wireless" approach to develop novel bioelectronic devices for modulating and sensing cellular behaviour using intracellular monitoring. The field of bioelectronic medicine offers a new paradigm in therapeutic intervention 1, 2. The technology is in its infancy, but relies on the ability to merge electronic devices with biology to then be used to sense and actuate cell/tissue and organ behaviour 3. The key challenge in advancing the field further is to develop new non-invasive methods to both electrically sense and actuate cell 3 behaviour. Our group 4-6 and others 7-10 have pioneered new methods for electrically communicating with the internal environment of a cell via use of nanowire electrodes. However, these methods tend to be invasive in nature as they necessarily have to pierce the plasma membrane which can lead to cell perturbations 11, 12. In addition, these electrodes require physical electrical connectivity from inside of the cells to the outside, thus hindering their use in more complex biological environments. Therefore, an approach to addressing these issues is to develop novel wireless electronic systems for the development of intracellular sensors and actuators. The development of novel bioelectronics using such a wireless-electronic approach may subsequently enable significant advancements in the ability to use intracellular electronics to facilitate cell communication and actuation. Therefore, the aim of this work was to develop a new bioelectronic approach for sensing electrical changes in response to the application of an externally applied voltage inside biological cells, thereby offering the first example of a wireless electronic tool to modulate redox inside of cells 13-14. The work undertaken was inspired by the fields of bipolar electrochemistry and drug delivery. Bipolar electrochemistry (also known as wireless electrochemistry) relies on placing a conductive particle between feeder electrodes which have potential difference placed across them. This causes the conductive particle to polarise and in doing so, causes a potential difference between the electrolyte and poles of the particle, consequently providing the thermodyamic driving force required ...

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