Biotech, Biomaterials and Biomedical: TechConnect Briefs 2015Biotech, Biomaterials and Biomedical TechConnect Briefs 2015

Sensors, Diagnostics & Imaging Chapter 3

Sensing voltage change across a lipid bilayer

Y. Chen, A.J. Makinen, T.J. O’Shaughnessy, A.L. Efros, A. Huston, K. Susumu, M.H. Stewart, J.B. Delehanty
Naval Research Laboratory, United States

pp. 118 - 120

Keywords: quantum dots, voltage sensing, nanoparticles, bilayer

Developing nanoscale probes capable of real-time sensing and imaging of neuronal action potentials would be useful in understanding neuronal communication. However, current available tools for imaging action potentials lack either the spatial or temporal sensitivity to understand neuronal networks with single cell resolution. Taking advantage of the inherent photophysical and electronic properties of various nanoparticle (NP) and NP-peptide hybrid constructs that allow for specific localization to cell plasma membrane, voltage changes due to action potentials can be directly detected. QDs can be engineered such that their spectral properties can be discretely tied to changes in a surrounding electric field and their nanoscale size and do not require genetic manipulation of the cell for function. This latter attribute makes them attractive alternatives to fluorescent methods such as genetic encoded calcium indicators (GECI) which uses calcium signaling as a proxy for action potentials. Two methods were used here to determine how the nanoparticles’ emission spectrum changes in a plasma membrane. Voltage applied to an artificial bilayer loaded with quantum dots simulates an action potential across a plasma membrane of a neuron. Coupled this with fluorescent microscopy and changes to the quantum dot emission spectrum were detected. The second application is loading of the QDs into cultured cells coupled with the induction of action potentials in.