Probing nanoparticle--protein interaction by capillary electrophoresis

Area of Science:

• Biophysical Chemistry
• Nanotechnology
• Biomedical Engineering

Background:

• Understanding nanoparticle-protein interactions is crucial for biomedical applications and mitigating adverse biological effects.
• Quantitative biophysical parameter measurement is key to this understanding.
• Capillary electrophoresis (CE) offers a versatile platform for such measurements.

Purpose of the Study:

• To demonstrate the utility of capillary electrophoresis (CE) for quantitative analysis of nanoparticle-protein interactions.
• To differentiate between stable and transient nanoparticle-protein complexes.
• To investigate the influence of nanoparticle physicochemical properties on interaction dynamics.

Main Methods:

• Capillary Zone Electrophoresis (CZE) for resolving stable complexes.
• Affinity Capillary Electrophoresis (ACE) for analyzing fast-binding kinetics.
• Utilizing the Hill equation to calculate dissociation constants (K(D)) and cooperativity coefficients (n).

Main Results:

• CZE successfully separated stable nanoparticle-protein complexes from free components.
• ACE identified transient complexes through distinct mobility shifts.
• Interactions of bovine serum albumin (BSA) with Fe(3)O(4) and Au nanoparticles showed varying binding kinetics (slow and fast, respectively).
• Dissociation constants and cooperativity coefficients were determined, allowing evaluation of nanoparticle properties and buffer impacts on interactions.

Conclusions:

• CE is a simple, flexible technique for probing protein interactions with diverse nanoparticles.
• The separation capabilities of CE can be extended to complex multicomponent systems, including protein-protein and protein-small molecule interactions influenced by nanoparticle adsorption.