Study Enhanced Enzyme Diffusion with High-Speed Single Nanoparticle Rotational and Translational Tracking

Area of Science:

• Biochemistry
• Physical Chemistry
• Nanotechnology

Background:

• Catalytic enzymes with enhanced motion are of significant interest.
• However, the environmental impact of enzyme activity remains poorly understood.

Purpose of the Study:

• To investigate the environmental effects of active enzymes using a model urease system.
• To simultaneously monitor the diffusion of single anisotropic gold nanorods (AuNRs) to probe these effects.

Main Methods:

• Utilized high-speed dark-field imaging to track the diffusion of individual AuNRs.
• Applied the Stokes-Einstein equation to analyze diffusion coefficients and infer environmental changes.
• Varied substrate concentration to observe effects on AuNR diffusion heterogeneity.

Main Results:

• Observed enhanced translational and rotational diffusion of AuNRs, with inconsistent degrees.
• Found increased spatial but decreased temporal heterogeneity in AuNR diffusion with rising substrate concentration.
• Detected intermittent ballistic motion in AuNRs, suggesting localized environmental disturbances.

Conclusions:

• The catalytic reaction of urease induces localized, inhomogeneous distributions of enzymes in solution.
• These enzymatic reactions subtly affect the local physicochemical environment, influencing particle dynamics.
• High-speed imaging of nanorods provides a sensitive method for studying enzyme-induced environmental heterogeneity.