Differentiating α-synuclein aggregates using charge-sensitive gold nanoclusters.

Area of Science:

• Biochemistry
• Nanotechnology
• Neuroscience

Background:

• Alpha-synuclein (α-syn) aggregation in the brain is a hallmark of Parkinson's disease (PD).
• Differentiating toxic α-syn oligomers from monomers is critical for understanding PD pathogenesis.
• Conformation-dependent toxicity of amyloidogenic proteins necessitates specific detection methods.

Purpose of the Study:

• To develop a label-free sensing approach using gold nanoclusters (AuNCs) to distinguish between α-syn monomers and amyloid aggregates.
• To leverage surface charge differences of AuNCs for selective detection of wild-type and mutant [A30P]-α-Syn conformations.
• To evaluate the sensitivity and specificity of AuNCs as potential biomarkers for Parkinson's disease.

Main Methods:

• Utilized label-free gold nanoclusters (AuNCs) with distinct surface charges (Pro-AuNCs and His-AuNCs).
• Employed fluorescence spectroscopy and electrochemical measurements (impedance spectroscopy) to analyze α-syn interactions.
• Conducted cell culture studies to validate in vitro findings and assess specificity.

Main Results:

• Pro-AuNCs showed higher sensitivity to monomeric wild-type and [A30P]-α-Syn.
• His-AuNCs demonstrated greater sensitivity towards amyloid forms of α-syn.
• Impedance spectroscopy achieved a picomolar (pM) detection limit, surpassing fluorescence sensitivity.
• Cell studies confirmed the specificity of AuNCs in detecting different α-syn conformations.

Conclusions:

• Developed AuNCs effectively distinguish aggregated and monomeric forms of α-syn based on charge.
• The developed probe exhibits high sensitivity and specificity for detecting α-syn conformations.
• This approach holds potential for creating novel sensors to investigate Parkinson's disease etiology.