Dual Optical Response Strategy for the Detection of Cytochrome c Using Highly Luminescent Lanthanide-Based...

Area of Science:

• Nanomaterials Science
• Biochemical Sensing
• Analytical Chemistry

Background:

• Cytochrome c (Cyt c) is a crucial biomarker in cellular processes and disease.
• Accurate and sensitive detection of Cyt c is vital for biological and clinical research.
• Existing detection methods often require labels or suffer from background interference.

Purpose of the Study:

• To develop a novel label-free sensing strategy for ultrahigh-sensitivity detection of cytochrome c (Cyt c).
• To utilize inorganic-organic hybrid nanotubular sensor arrays incorporating lanthanides for enhanced detection.
• To establish a dual optical response mechanism for reliable Cyt c quantification.

Main Methods:

• Fabrication of nanotubular sensor arrays using sodium lithocholate (NaLC) templates.
• Sequential incorporation of photosensitizers (DHN or Phen) and terbium ions (Tb³⁺).
• Utilizing dual photoluminescence quenching responses (sensitized Tb³⁺ emission and DHN fluorescence) upon Cyt c binding.
• Employing time-gated measurements to eliminate background noise in cellular environments.

Main Results:

• Demonstrated a significant quenching of sensitized Tb³⁺ emission due to photosensitizer binding to Cyt c.
• Observed a unique spectral valley splitting with quantized quenching dip in DHN fluorescence, indicating efficient FRET with Cyt c's heme group.
• Achieved sensitive and selective detection of Cyt c in the concentration range of 0-30 μM with a low detection limit of approximately 20 nM.

Conclusions:

• The developed label-free dual optical response strategy offers ultrahigh sensitivity for Cyt c detection.
• The nanotubular sensor arrays provide a robust platform for Cyt c quantification, especially in complex biological matrices.
• Time-gated measurements enable advantageous detection of Cyt c within cellular environments by overcoming background interference.