Single-Particle Functionality Imaging of Antibody-Conjugated Nanoparticles in Complex Media

Area of Science:

• Nanotechnology
• Biomedical Engineering
• Surface Chemistry

Background:

• Nanoparticle (NP) properties change upon serum contact, forming a biomolecular corona.
• This corona can impair targeted NPs' specificity and selectivity, reducing therapeutic efficiency.
• Understanding corona effects on NP ligand functionality is crucial for effective nanoparticle design.

Purpose of the Study:

• To quantify the influence of serum exposure on antibody-functionalized NP functionality.
• To evaluate NP functionality and cell uptake in complex biological media.
• To compare covalent and noncovalent antibody conjugation methods regarding NP functionality after serum exposure.

Main Methods:

• Utilized straightforward total internal reflection fluorescence (TIRF) microscopy for single-particle analysis.
• Quantified NP functionality after incubation in full serum.
• Conducted cell uptake studies to evaluate NP targeting efficiency.

Main Results:

• Single-particle resolution revealed significant interparticle heterogeneity in NP functionality.
• Substantial differences in functionality were observed between covalently and noncovalently conjugated NPs.
• Only NPs with high amounts of covalent antibody conjugation retained some functionality, showing cell specificity.

Conclusions:

• Single-particle characterization of NPs in complex media is essential.
• Covalent conjugation with sufficient antibodies is key to maintaining NP targeting capabilities in serum.
• This study informs the design of targeted NPs for improved therapeutic applications in biological environments.