Multi-modal, Label-free, Optical Mapping of Cellular Metabolic Function and Oxidative Stress in 3D Engineered Brain...

Area of Science:

• Neuroscience
• Biophysics
• Cellular Metabolism

Background:

• Established brain imaging methods lack cellular resolution for metabolic studies.
• Understanding cellular metabolism is crucial for brain function and disease.
• Label-free imaging offers a non-invasive approach for dynamic metabolic assessment.

Purpose of the Study:

• To develop label-free imaging protocols for assessing metabolic function in engineered brain tissue.
• To investigate metabolic interactions between different brain cell types (neurons, astrocytes, microglia).
• To utilize spectral imaging to differentiate endogenous fluorophores for accurate metabolic metrics.

Main Methods:

• Developed label-free, two-photon excited fluorescence imaging protocols.
• Employed multi-wavelength spectral imaging to identify and differentiate key cellular fluorophores (NAD(P)H, FAD, lipofuscin).
• Quantified fluorescence intensity and lifetime metrics to assess cellular redox state and metabolic activity in 3D brain tissue models.

Main Results:

• Successfully mitigated spectral overlap from lipofuscin for reliable NAD(P)H and flavin autofluorescence measurements.
• Demonstrated significant metabolic differences between neurons and glial cells.
• Identified distinct metabolic pathway utilization (e.g., OXPHOS, glycolysis, glutathione pathway) in different cell types.

Conclusions:

• Established a label-free, non-destructive imaging approach for assessing brain cell metabolic function and interactions.
• Highlighted the complementary information gained from combining intensity and lifetime imaging metrics.
• This method advances the understanding of physiological and pathological brain processes at the cellular level.