High-Sensitivity Magnetic Levitation Reveals Intrinsic Protein Corona Heterogeneity on Identical Nanoparticles

Area of Science:

• Nanotechnology and Materials Science
• Biomolecular Interactions
• Proteomics and Analytical Chemistry

Background:

• The protein corona (PC) on nanoparticles (NPs) is crucial for their biological identity and function.
• Conventional analysis of PC-coated NPs often uses pooled measurements, masking subtle compositional heterogeneity.
• This lack of resolution limits understanding of NP-biomolecule interactions and nanomaterial performance.

Purpose of the Study:

• To develop and utilize a high-sensitivity magnetic levitation (MagLev) platform for resolving protein corona heterogeneity.
• To enable fractionation of nominally identical PC-coated NPs based on minute density variations.
• To provide a label-free analytical framework for detailed NP-biomolecule interaction studies.

Main Methods:

• Employed a high-sensitivity magnetic levitation (MagLev) platform with enhanced density resolution (10^-5 g/cm^3).
• Separated PC-coated NPs into multiple fractions along the MagLev column based on density differences.
• Conducted proteomic analysis on extracted fractions to identify and characterize protein composition.

Main Results:

• Successfully fractionated PC-coated NPs into distinct density populations, revealing intrinsic heterogeneity.
• Identified over 500 proteins, demonstrating a structured, continuous redistribution of protein composition across fractions.
• Observed fraction-dependent differences in protein abundance, overlap, and biological signatures, with upper fractions enriched in plasma proteins and lower fractions in structural/metabolic proteins.

Conclusions:

• Protein corona formation is inherently heterogeneous even on identical nanoparticles, a complexity missed by conventional pooled analyses.
• High-sensitivity MagLev offers a powerful, label-free method for resolving PC heterogeneity and studying NP-biomolecule interactions.
• This approach has significant implications for nanomedicine design, biomarker discovery, and the clinical translation of nanoparticle systems.