Compact and blinking-suppressed quantum dots for single-particle tracking in live cells

Area of Science:

• Nanotechnology
• Biomedical Imaging
• Materials Science

Background:

• Quantum dots (QDs) are advantageous for biological imaging due to their brightness, photostability, and tunable optical properties.
• A significant limitation of QDs is intermittent fluorescence intermittency, known as blinking, which hinders continuous observation.

Purpose of the Study:

• To develop blinking-suppressed quantum dots with maintained optical properties in aqueous solutions.
• To investigate the efficacy of a novel shell growth strategy for mitigating QD blinking.

Main Methods:

• Synthesized cadmium selenide (CdSe) core quantum dots with a precisely controlled, layer-by-layer grown, linearly graded alloy shell.
• Evaluated QD blinking suppression in organic solvents and aqueous solutions.
• Assessed the impact of polyethylene glycol (PEG)-based and multidentate ligand surface coatings on optical properties.
• Conducted live-cell receptor tracking studies using blinking-suppressed QDs.

Main Results:

• A linearly graded alloy shell dramatically suppressed QD blinking, with over 25% of QDs exhibiting no blinking ( >99% on-time).
• Theoretical modeling suggests the graded shell minimizes surface trap access and reduces lattice defects, key factors in blinking.
• Optical properties remained stable across different surface coatings and aqueous environments.
• Blinking-suppressed QDs enabled continuous trajectories in live-cell tracking.

Conclusions:

• Linearly graded alloy shells effectively suppress quantum dot blinking while preserving desirable optical characteristics.
• These improved QDs are suitable for biological applications, offering enhanced performance in aqueous media and facilitating long-term cellular imaging.
• The developed QDs represent a significant advancement for high-resolution, continuous live-cell imaging.