Size and surface charge characterization of nanoparticles with a salt gradient

Area of Science:

• Biotechnology
• Nanotechnology
• Biomarker Discovery

Background:

• Exosomes are crucial biomarkers for diseases like cancer and Alzheimer's, found in liquid biopsies.
• Accurate exosome purification, size, and surface characterization are vital for diagnostics.
• Current purification methods are time-consuming, potentially damaging, and lack simultaneous size/zeta potential measurement.

Purpose of the Study:

• To develop a rapid, one-step method for exosome concentration and simultaneous size and zeta potential measurement.
• To overcome limitations of existing exosome purification and characterization techniques.

Main Methods:

• Utilized a salt gradient within a capillary channel to concentrate exosomes from dilute solutions.
• Employed a single-step measurement combining particle and fluid transport for trapping.
• Applied fitting to the spatial distribution of exosomes to determine size and surface charge (zeta potential).

Main Results:

• Achieved over a two-orders-of-magnitude increase in particle concentration within minutes.
• Successfully measured both size and zeta potential from a single exosome measurement.
• Demonstrated applicability to other nanoparticle types.

Conclusions:

• The developed method offers a fast, efficient, and non-damaging approach for exosome characterization.
• This technique has potential applications in exosome-based diagnostics and nanoparticle analysis.
• The low-cost polymer device fabrication enhances accessibility for research and clinical use.