High-Throughput Platform for Optoacoustic Probing of Genetically Encoded Calcium Ion Indicators
Urs A T Hofmann1, Arne Fabritius2, Johannes Rebling1
1Institute of Pharmacology and Toxicology and Faculty of Medicine, University of Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland; Institute for Biomedical Engineering and Department of Information Technology and Electrical Engineering, ETH Zurich, Gloriastrasse 35, 8092 Zurich, Switzerland.
Iscience
|December 9, 2019
Summary
A new imaging platform rapidly screens genetically encoded calcium ion indicators (GECIs) for optoacoustic (OA) imaging. This system accelerates the development of improved GECIs for deep-brain neuronal activity monitoring.
Area of Science:
- Neuroscience
- Biomedical Imaging
- Molecular Biology
Background:
- Optoacoustic (OA) imaging with genetically encoded calcium ion indicators (GECIs) offers potential for deep-brain neuronal activity mapping.
- Existing GECIs, optimized for fluorescence (FL) imaging, have limitations in contrast and wavelength penetration for effective OA applications.
Purpose of the Study:
- To develop and validate a novel imaging platform for rapid assessment and cross-validation of sensor protein responses for OA imaging.
- To facilitate the directed evolution of improved GECIs tailored for optoacoustic applications.
Main Methods:
- A high-throughput screening system was engineered for simultaneous optoacoustic and fluorescence evaluation of sensor proteins in Escherichia coli.
- The platform utilizes optimized pulsed light excitation and ultrasensitive ultrasound detection to minimize photobleaching and enable millisecond-precision calcium response characterization.
- The system allows for rapid, targeted probing of multiple bacterial colonies under varying calcium conditions.
Main Results:
- The platform enables efficient, cross-validated assessment of sensor protein performance for both OA and FL imaging modalities.
- Dynamic calcium ion responses can be characterized with millisecond temporal resolution, overcoming limitations of current methods.
- The system successfully screened sensor proteins, demonstrating its utility in optimizing absorption-based labels for OA GECIs.
Conclusions:
- The developed imaging platform significantly advances the screening process for optoacoustic genetically encoded calcium ion indicators.
- This technology is crucial for the directed evolution of novel GECIs with enhanced performance for deep-tissue neuronal imaging.
- The findings pave the way for next-generation optoacoustic neuroimaging tools.
