Colorful neurons firing during voltage imaging.

See Your Cells in Action: Voltage Imaging Unveiled

"Discover how genetically encoded voltage indicators (GEVIs) light up cellular communication, offering new insights into brain activity and beyond."


Imagine being able to watch the electrical conversations happening inside your cells. That's the promise of voltage imaging, a revolutionary technique that allows scientists to visualize changes in membrane potential—the driving force behind cellular communication. This article explores how genetically encoded voltage indicators (GEVIs) are making this possible, opening new doors in neuroscience and beyond.

Traditional methods for studying electrical activity in cells have limitations. Organic voltage-sensitive dyes, used for decades, lack specificity and can be difficult to apply to certain cell types. GEVIs offer a more targeted approach. By genetically engineering cells to express fluorescent proteins that respond to voltage changes, researchers can observe activity in specific cell populations with unprecedented precision.

This article will guide you through the principles of voltage imaging using GEVIs, highlighting the different types of sensors available and the experimental setup required. Whether you're a seasoned researcher or just curious about the inner workings of cells, this overview will provide a solid foundation for understanding this exciting field.

What are Genetically Encoded Voltage Indicators (GEVIs)?

Colorful neurons firing during voltage imaging.

GEVIs are essentially fluorescent reporters that change their brightness or color in response to changes in the electrical potential across a cell's membrane. They consist of a voltage-sensing domain linked to one or more fluorescent proteins. When the membrane potential changes, the voltage-sensing domain shifts, altering the fluorescent protein's properties. This allows researchers to 'see' the electrical activity of the cell.

There are three primary classes of GEVIs:

  • Single Fluorescent Protein (FP) GEVIs: These use a single fluorescent protein that changes its fluorescence intensity in response to voltage changes.
  • Förster Resonance Energy Transfer (FRET)-based GEVIs: These use two fluorescent proteins, a donor and an acceptor. Voltage changes alter the distance or orientation between the proteins, affecting the efficiency of energy transfer (FRET) and changing the relative fluorescence of the donor and acceptor.
  • Hybrid GEVIs: These combine a membrane-anchored fluorescent protein with a separate quenching molecule that responds to voltage.
While all three classes have their uses, single FP and FRET-based GEVIs are currently the most widely used, particularly for in vivo (live organism) imaging. FRET-based GEVIs offer the advantage of ratiometric measurements, which can reduce artifacts caused by variations in probe concentration or illumination.

The Future of Seeing Electricity

Voltage imaging with GEVIs is a rapidly evolving field with immense potential. As new and improved GEVIs are developed, and imaging techniques become more sophisticated, we can expect even more detailed insights into the electrical dynamics of cells and circuits. This will not only advance our understanding of fundamental biological processes but also pave the way for new diagnostic and therapeutic strategies for a wide range of neurological and other disorders.

About this Article -

This article was crafted using a human-AI hybrid and collaborative approach. AI assisted our team with initial drafting, research insights, identifying key questions, and image generation. Our human editors guided topic selection, defined the angle, structured the content, ensured factual accuracy and relevance, refined the tone, and conducted thorough editing to deliver helpful, high-quality information.See our About page for more information.

This article is based on research published under:

DOI-LINK: 10.3791/53566, Alternate LINK

Title: Imaging Membrane Potential With Two Types Of Genetically Encoded Fluorescent Voltage Sensors

Subject: General Immunology and Microbiology

Journal: Journal of Visualized Experiments

Publisher: MyJove Corporation

Authors: Sungmoo Lee, Hong Hua Piao, Masoud Sepheri-Rad, Arong Jung, Uhna Sung, Yoon-Kyu Song, Bradley J. Baker

Published: 2016-02-04

Everything You Need To Know

1

What are Genetically Encoded Voltage Indicators (GEVIs)?

Genetically Encoded Voltage Indicators (GEVIs) are fluorescent reporters designed to visualize the electrical activity within cells. These indicators are engineered to change their fluorescent properties in response to alterations in the membrane potential, which is the electrical difference across a cell's membrane. This allows researchers to observe and study the cellular communication process.

2

Why is voltage imaging with GEVIs important?

Voltage imaging with Genetically Encoded Voltage Indicators (GEVIs) is significant because it provides a non-invasive method to observe electrical activity in cells with high specificity. Unlike traditional methods, such as using organic voltage-sensitive dyes, GEVIs allow scientists to target specific cell populations, offering unprecedented precision in observing cellular behavior. This is crucial for understanding the complex dynamics of neural circuits and other cellular processes.

3

What are the different types of GEVIs?

There are three main classes of Genetically Encoded Voltage Indicators (GEVIs). Single Fluorescent Protein (FP) GEVIs use a single fluorescent protein that changes its intensity. FRET-based GEVIs use two fluorescent proteins, a donor and an acceptor, and voltage changes affect the efficiency of energy transfer. Hybrid GEVIs combine a membrane-anchored fluorescent protein with a separate quenching molecule. Single FP and FRET-based GEVIs are currently the most widely used, particularly for *in vivo* imaging.

4

How does voltage imaging with GEVIs work?

The process involves genetically engineering cells to express Genetically Encoded Voltage Indicators (GEVIs). These indicators contain a voltage-sensing domain linked to a fluorescent protein. As the membrane potential changes, the voltage-sensing domain shifts, altering the fluorescent protein's properties. Researchers then use specialized microscopy techniques to detect the changes in fluorescence, allowing them to 'see' the electrical activity within the cells. This method facilitates the study of complex biological processes.

5

What are the implications of using GEVIs?

The implications of voltage imaging using Genetically Encoded Voltage Indicators (GEVIs) are vast. It holds the potential to advance our understanding of fundamental biological processes by providing detailed insights into the electrical dynamics of cells and circuits. This understanding could pave the way for new diagnostic and therapeutic strategies for neurological disorders and other diseases by allowing researchers to visualize and understand the underlying mechanisms of these conditions at a cellular level.

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