Quantum dot-assembled nanoparticles with polydiacetylene supramolecule toward label-free, multiplexed optical...

Area of Science:

• Nanotechnology
• Biomolecular detection
• Materials Science

Background:

• Developing sensitive and specific methods for detecting biological molecules is crucial in diagnostics and research.
• Existing methods often require labels, increasing complexity and cost.
• Quantum dots (QDs) offer bright, tunable fluorescence, while polydiacetylenes (PDAs) exhibit responsive colorimetric and fluorescent changes.

Purpose of the Study:

• To create novel core-shell nanoparticles for label-free and multiplexed detection of biological molecules.
• To integrate quantum dots for encoding and polydiacetylene for sensing within a single nanoparticle system.
• To demonstrate the capability of these nanoparticles for simultaneous detection and imaging.

Main Methods:

• Synthesized silica nanoparticles (SiO(2)) embedded with blue or green quantum dots (QDs).
• Coated the SiO(2)@QDs nanoparticles with polydiacetylene (PDA) supramolecules via photo-induced polymerization of 10,12-pentacosadiynoic acid.
• Utilized QD photoluminescence for encoding and PDA fluorescence changes (blue to red upon heating) for sensing.
• Employed fluorescence microscopy for imaging and distinguishing multiplexed nanoparticle signals.

Main Results:

• Developed SiO(2)@QDs@PDA nanoparticles with distinct QD photoluminescence for encoding and responsive PDA fluorescence for sensing.
• Demonstrated that PDA fluorescence could be switched from blue to red under thermal stress, enabling signal activation.
• Successfully imaged and distinguished mixtures of blue-QD encoded nanoparticles (with inactive PDA) and red-QD encoded nanoparticles (with activated PDA) via fluorescence microscopy.
• Observed no interference or overlap between QD encoding fluorescence and PDA sensing fluorescence.

Conclusions:

• The developed SiO(2)@QDs@PDA nanoparticles are promising for label-free and multiplexed detection of biological molecules.
• The combination of QD encoding and PDA sensing offers a robust platform for simultaneous molecular identification.
• The system's ability to be imaged and distinguished via fluorescence microscopy highlights its potential in advanced diagnostic applications.