Syringe-injectable Mesh Electronics for Stable Chronic Rodent Electrophysiology
July 21st, 2018
24K views
Mesh electronics probes seamlessly integrate and provide stable, long-term, single-neuron level recording within the brain. This protocol uses mesh electronics for in vivo experiments, involving the fabrication of mesh electronics, loading into needles, stereotaxic injection, input/output interfacing, recording experiments, and histology of tissue containing mesh probes.
Overview
This protocol demonstrates the use of mesh electronics for stable, long-term, single-neuron level recording in the brain. It outlines the fabrication and implantation process, emphasizing the seamless integration with neural tissue.
Key Study Components
Area of Science
- Neuroscience
- Electrophysiology
- Neural Engineering
Background
- Mesh electronics probes allow for in vivo experiments.
- They do not elicit a chronic immune response in gliosis.
- This technique aids in understanding brain aging, development, and diseases.
- Stable recordings can enhance data collection in neuroscience research.
Purpose of Study
- To fabricate mesh electronics for brain implantation.
- To provide a detailed protocol for researchers.
- To demonstrate the advantages of mesh electronics in neural recording.
Methods Used
- Fabrication of mesh electronics using photolithography.
- Loading mesh electronics into needles for injection.
- Stereotaxic injection into mouse brains.
- Histological analysis of tissue post-implantation.
Main Results
- Successful integration of mesh electronics with neural tissue.
- Stable recordings from single neurons over extended periods.
- Demonstration of the procedure by trained researchers.
- Validation of the method through histological examination.
Conclusions
- Mesh electronics provide a promising tool for neuroscience research.
- The technique enhances the understanding of brain functions and diseases.
- Future applications may include studying various neurological conditions.
Frequently Asked Questions
What are mesh electronics?
Mesh electronics are probes designed for stable, long-term neural recordings.
How do mesh electronics integrate with brain tissue?
They seamlessly integrate without causing chronic immune responses.
What is the main advantage of using mesh electronics?
They allow for stable recordings at the single-neuron level.
Who demonstrated the procedure in the study?
Tao Zhou and Jung Min Lee from the Lieber Group.
What methods are used in the fabrication of mesh electronics?
Photolithography, thermal evaporation, and spin coating are key methods.
What type of experiments can mesh electronics be used for?
They can be used for in vivo experiments to study brain functions.
Executive Industry Relevance
Syringe-injectable mesh electronics address a critical challenge in neuroscience R&D: achieving stable, long-term neural recordings without chronic immune response or signal degradation. This technology enables predictive de-risking of target validation studies by providing reliable single-neuron tracking over extended periods, supporting translational continuity from discovery through preclinical validation. The seamless tissue integration reduces biological variability, enhancing data reproducibility for target confidence and portfolio triage in neurodegenerative disease research.
Strategic Applications in Biopharma R&D
Early Discovery & Target Validation
- Scientific Value: Enables interrogation of therapeutic hypotheses through stable single-unit spiking activity detection across multiple brain regions over months.
- Operational Value: Supports biological de-risking by minimizing gliosis-induced signal instability, reducing variability in longitudinal target engagement studies.
- Predictive Value: Facilitates mechanistic de-risking of targets involved in aging, development, and pathogenesis by correlating electrophysiology with histological analysis.
Screening & Assay Development
- Assay Readiness: Provides a standardized, reusable platform for quantitative neural activity measurement, enabling reliable compound evaluation in freely moving models.
- Scalability: Mesh electronics can be fabricated via standard photolithography, allowing adaptation across multiple target validation pipelines.
- Output Standardization: Generates consistent local field potential and spike-sorted data, supporting cross-functional comparison of pharmacological interventions.
Translational & Preclinical Research
- Disease Relevance: Directly supports studies of aging processes, brain development, and disease pathogenesis through chronic, gliosis-free interfacing.
- Translational Continuity: Enables precise correlation of electrophysiology data with immunohistochemical analysis, strengthening biomarker alignment.
- Risk-Adjusted Advancement: Stable recordings over year-long timescales improve confidence in preclinical target selection and lead identification decisions.
Pipeline & Workflow Integration
The method integrates into the discovery continuum from early target validation through preclinical research, enabling hypothesis testing, pathway clarification, and biological de-risking with high spatiotemporal resolution.
- Discovery Biology: Supports hypothesis interrogation and functional target validation by detecting single-unit spiking activity in 26 of 32 channels at both two and four months post-injection.
- Screening: Delivers assay-ready, reproducible neural recordings in freely moving mice, facilitating reliable compound screening and target engagement assessment.
- Analytics: Provides quantitative dependent variable measurements including local field potential amplitude and spike-sorted traces, enabling statistical comparison across conditions and timepoints.
- Translational Research: Connects discovery to preclinical validation by allowing histology to be performed on implanted tissue, precisely correlating electrophysiology with cellular environment.
- Enterprise Reuse: Fabrication uses standard photolithography, positioning the technology as a reusable capability across multiple neuroscience discovery programs.
Operational & Enterprise Impact
- Scientific Value: Predictive confidence in target validation through chronic, stable single-neuron tracking without immune-mediated signal loss.
- Operational Value: Standardization and scalability via photolithography-based fabrication and stereotaxic injection using standard capillary needles.
- Strategic Value: Improved go/no-go decisions by reducing late-stage biological risk associated with target engagement variability in chronic models.
- Portfolio Impact: Risk-adjusted prioritization of targets in neurodegenerative and neurodevelopmental programs through reliable longitudinal data collection.
Implementation Considerations
- Requires expertise in neural engineering, photolithography, and stereotaxic surgery for successful fabrication and implantation.
- Depends on access to thermal evaporators, mask aligners, and stereotaxic frames with syringe pumps for precise mesh electronics delivery.
- Necessitates cross-team standardization between fabrication, surgery, and electrophysiology teams to ensure consistent probe handling and interfacing.
- Adaptation considerations include adjusting mesh dimensions and electrode density for different brain regions and model systems while maintaining ultraflexibility.
- Practical limitations include the need for careful handling during needle loading and injection to prevent probe damage, as noted in the procedural steps for retracting the needle at matched flow rates.
Biopharma FAQs
Why does impedance testing matter for target validation with mesh electronics?
Impedance testing confirms successful electrical interfacing between mesh electronics and instrumentation, which is critical for validating target engagement signals; high impedance indicates connection issues that must be resolved before recording to ensure data reliability in longitudinal studies.
How does independent variable isolation enable mechanistic de-risking in neural target studies?
By enabling stable, chronic recordings in freely moving mice, mesh electronics allow researchers to isolate the effects of genetic or pharmacological manipulations on neural activity over time, reducing confounding variables and improving confidence in target mechanism validation.
What quantitative dependent variable measurements enable predictive confidence in target selection?
Local field potential amplitude and spike-sorted single-unit activity provide quantitative, reproducible readouts that support statistical comparison of neural responses across conditions, enhancing predictive confidence in target validation and lead identification.
Why do replication requirements matter for cross-functional collaboration in mesh electronics studies?
Replication across multiple recording sessions and timepoints (e.g., two and four months post-injection) ensures consistent signal stability and reduces biological variability, which is essential for aligning discovery, translational, and preclinical teams on target validation outcomes.
What statistical analysis capabilities are required before implementing mesh electronics in preclinical workflows?
The ability to compare local field potential and spike-sorted data across experimental groups and timepoints using standard neurophysiological statistical methods is required to assess target modulation effects and support go/no-go decisions in therapeutic development.
Chapters in this video
0:04
Title
0:41
Fabrication of Mesh Electronics
3:59
Loading of Mesh Electronics into Needles
4:32
Stereotaxis Injection of Mesh Electronics into Live Mouse Brain
6:16
Input/output Interfacing
8:06
Neural Recording Experiments
8:25
Results: Representative Neural Recording Results
9:17
Conclusion
