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Continuous online microdialysis using microfluidic sensors: dynamic neurometabolic changes during spreading
Michelle L Rogers1, Delphine Feuerstein, Chi Leng Leong
1Department of Bioengineering, Imperial College, London, United Kingdom.
ACS Chemical Neuroscience
|April 12, 2013
Summary
This study used microfluidic biosensors to measure brain changes during spreading depolarizations (SD). Researchers found a significant delay between potassium increase and glucose decrease, revealing energy demands during brain injury.
Area of Science:
- Neuroscience
- Biomedical Engineering
- Sensor Technology
Background:
- Spreading depolarizations (SD) are detrimental to the injured brain.
- Understanding the neurochemical changes during SD is crucial for developing therapeutic strategies.
- Previous methods lacked the temporal resolution to capture rapid biochemical events during SD.
Purpose of the Study:
- To investigate the in vivo neurochemical effects of spreading depolarizations (SD) using microfluidic biosensors.
- To measure real-time changes in glucose and potassium concentrations in the brain cortex during SD.
- To elucidate the relationship between potassium ion flux and glucose metabolism during SD events.
Main Methods:
- Utilized in vivo microfluidic glucose biosensors and potassium ion selective electrodes implanted in rat cortex.
- Connected microdialysis probe to a polydimethylsiloxane (PDMS) microfluidic chip for real-time measurements.
- Validated sensor performance against the gold standard, rapid sampling microdialysis (rsMD).
Main Results:
- Microfluidic glucose biosensors accurately monitored glucose concentration changes (10-400 μM) with second-level temporal resolution.
- Demonstrated a novel time delay of 62 ± 24.8 seconds between potassium increase and glucose decrease during SD waves.
- High-temporal resolution of microfluidic sensors enabled the first-time demonstration of this delay at a single tissue site.
Conclusions:
- The observed delay indicates that glucose decrease during SD is driven by high energy demands for neuronal repolarization.
- Microfluidic biosensors offer unprecedented temporal resolution for studying dynamic neurochemical processes in vivo.
- This technology provides valuable insights into the pathophysiology of brain injury and potential therapeutic targets.
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