Label-free evaluation of protein aggregation by a point-of-care fluorometric device

Area of Science:

• Biophysics
• Analytical Chemistry
• Biotechnology

Background:

• Protein aggregation is a key indicator in neurological disorders.
• Current monitoring methods are often complex and require labels.
• Need for rapid, sensitive, and label-free detection platforms.

Purpose of the Study:

• Develop a cost-effective, portable, point-of-care fluorometric device.
• Utilize intrinsic protein fluorescence for label-free detection.
• Monitor protein structural alterations and aggregation.

Main Methods:

• Designed a light-emitting diode-based fluorometric device operating at 285 nm.
• Employed orthogonal optical configuration and metal-coated cuvettes (aluminum-coated) for enhanced fluorescence collection.
• Used thermally induced protein unfolding (bovine serum albumin, human serum albumin) as a model.
• Validated results with UV-Vis spectroscopy, microscopy, X-ray diffraction, CD spectroscopy, DLS, and FTIR.

Main Results:

• The device achieved nanomolar-level detection sensitivity.
• Detected concentration-dependent and thermally induced changes in intrinsic fluorescence (tryptophan, tyrosine residues).
• Observed intensity variations and red shifts, indicating protein unfolding and aggregation.
• Complementary techniques confirmed heterogeneous aggregates with amorphous and beta-sheet features.

Conclusions:

• The developed device reliably tracks protein structural destabilization and aggregation.
• Intrinsic fluorescence measurements strongly agree with established biophysical methods.
• The platform is a practical, label-free alternative for monitoring protein stability in point-of-care settings.