Nanoparticles as fluorescence labels: is size all that matters?

Area of Science:

• Biochemistry
• Biophysics
• Materials Science

Background:

• Fluorescence-based detection is sensitive and accessible for bioassays.
• The impact of fluorescent labels, especially nanoparticles, on binding dynamics is often overlooked.
• Understanding label effects is crucial for accurate bioassay interpretation.

Purpose of the Study:

• To investigate the influence of nanoparticle fluorescent labels on ligand-receptor binding.
• To analyze the effects of quantum dots and polymer nanospheres on the streptavidin-biotin system.
• To determine if binding changes are predictable and explainable.

Main Methods:

• Utilizing fluorescence cross-correlation spectroscopy (FCCS).
• Examining the streptavidin-biotin binding system with nanoparticle labels.
• Quantifying changes in binding equilibrium and dynamics.

Main Results:

• Nanoparticle labels (quantum dots, polymer nanospheres) were found to alter binding equilibria.
• Despite alterations, the changes in binding were largely predictable.
• The mesoscopic size and surface tension of nanoparticles correlate with binding changes.

Conclusions:

• Nanoparticle fluorescent labels can perturb bioassay binding equilibria.
• The observed binding perturbations are largely predictable and quantifiable.
• Nanoparticle size and surface tension are key factors influencing binding dynamics in bioassays.