Peptide Functionalized Gold Nanoparticles as a Stimuli Responsive Contrast Medium in Multiphoton Microscopy

Area of Science:

• Biomedical Engineering
• Nanotechnology
• Optical Imaging

Background:

• Need for high signal-to-noise ratio contrast agents for noninvasive biomedical sensing.
• Challenge in developing biocompatible contrast agents that avoid increasing background signals.
• Existing methods lack sensitivity for detecting specific biochemical interactions.

Purpose of the Study:

• To present a concept utilizing gold nanoparticles (AuNPs) as stimuli-responsive contrast agents for multiphoton microscopy (MPM).
• To demonstrate the potential of AuNPs for noninvasive biochemical sensing.
• To develop a method for enhanced optical biosensing with high biochemical contrast.

Main Methods:

• Functionalization of gold nanoparticles (AuNPs) with peptides sensitive to specific biochemical triggers.
• Utilizing multiphoton laser scanning microscopy (MPM) to detect changes in AuNP luminescence.
• Inducing AuNP aggregation via zinc ions (Zn2+) or matrix metalloproteinase-7 (MMP-7) to trigger multiphoton-induced luminescence (MIL).

Main Results:

• Peptide-functionalized AuNPs exhibited minimal luminescence until aggregation induced by Zn2+ or MMP-7.
• Aggregation caused a significant increase in MIL signal, enabling detection of biochemical stimuli.
• The process was reversible upon removal of Zn2+, demonstrating tunable sensing capabilities.

Conclusions:

• Gold nanoparticles can be engineered as stimuli-responsive contrast agents for MPM-based biosensing.
• This approach allows for noninvasive detection of specific biochemicals through aggregation-induced luminescence.
• The developed method offers a promising future tool for advanced optical biosensing applications.