A highly sensitive luminescent lectin sensor based on an α-D-mannose substituted Tb3+ antenna complex

Area of Science:

• Biochemistry
• Biophysical Chemistry
• Chemical Biology

Background:

• Lectin-carbohydrate interactions are crucial for intercellular communication and cell surface changes in health and disease.
• Optical techniques using luminescent lanthanoid complexes offer potential for ratiometric biosensing and disease detection.
• Investigating these interactions is key to understanding biological processes and developing diagnostic tools.

Purpose of the Study:

• To synthesize a novel terbium (Tb3+) complex with an alpha-D-mannose residue.
• To investigate the binding affinity of this complex with rhodamine-B-isothiocyanate labeled concanavalin A (RITC-Con A).
• To explore the potential of luminescence resonance energy transfer (LRET) for studying carbohydrate-protein interactions.

Main Methods:

• Synthesis of a Tb(3+)-DO3A complex functionalized with an alpha-D-mannose residue.
• Luminescence spectroscopy and dynamic studies to analyze spectral changes.
• Measurement of binding constants using LRET between the lanthanoid complex and labeled Concanavalin A.

Main Results:

• Successful synthesis of the Tb(3+)-DO3A-mannose complex.
• Observation of luminescence spectral changes indicative of LRET from the Tb complex to RITC-Con A.
• Determination of a binding constant one order of magnitude higher than previously reported values for similar interactions.

Conclusions:

• The study demonstrates the first use of a pre-organized luminescent lanthanoid complex for studying carbohydrate-protein interactions via LRET.
• The developed system shows enhanced binding affinity, suggesting improved sensitivity for biosensing applications.
• This approach holds promise for advancing ratiometric biosensing and disease detection technologies.