Label-Free Molecular Characterization of Protein Aggregates in Differentiated Astrocytes

Area of Science:

• Neuroscience
• Biophysics
• Cell Biology

Background:

• Astrocyte differentiation is crucial for brain function but is poorly understood in pathological conditions and cell cultures.
• Label-free analysis of astrocyte molecular composition and function at high resolution is needed to understand brain physio-pathology.
• Simultaneous analysis of structural, molecular, and functional features in undifferentiated astrocytes without exogenous tags is limited.

Purpose of the Study:

• To develop and apply a label-free, multi-parameter characterization method for analyzing astrocyte differentiation.
• To investigate the molecular and functional differences between differentiated and non-differentiated astrocytes.
• To establish a method for detecting astrocyte signatures in both healthy and pathological states.

Main Methods:

• Utilizing mid-infrared photothermal imaging for label-free analysis of astrocytes.
• Employing time-resolved photothermal diffusion measurements to assess thermal properties.
• Correlating protein structural signatures (α-helical and β-sheet content) with thermal relaxation dynamics.

Main Results:

• Differentiated astrocytes on nanomaterials interfaces show accumulated α-helical signatures in their processes.
• Non-differentiated astrocytes exhibit more diverse protein content, rich in β-sheets.
• Higher interfacial thermal resistance was observed at astrocyte processes, linking protein structure to thermal dynamics.

Conclusions:

• Mid-infrared photothermal imaging provides unique insights into the chemical and functional determinants of healthy astrocytes.
• This multi-parameter approach deepens the understanding of astrocyte differentiation mechanisms.
• The method enables the detection of molecular, morphological, and functional signatures of pathological astrocyte states ex-vivo.