UC vs. UF+SEC for EV Isolation from Conditioned Media

1. Overview

This note compares two mainstream EV extraction workflows: ultracentrifugation (UC) and ultrafiltration pre-concentration combined with size-exclusion chromatography (UF+SEC) using the ExoFaster-500 system. Conditioned media from three cell lines were tested via multi-dimensional characterization to provide method selection guidance.

2. Materials & Protocols

2.1 Sample Preparation

Conditioned media of ESC, HSC and NK cells in logarithmic phase were collected. Serial low-speed centrifugation (300 g, 3000 g, 10,000 g, 4 °C) removed cells, debris and large vesicles. Clarified supernatants were stored at −80 °C.

2.2 Isolation Workflows

1. Ultracentrifugation (UC)

   Samples underwent two ultracentrifugation steps (100,000 g, 2 h; 110,000 g, 2 h, 4 °C). Pellets were resuspended in pre-cooled PBS. Total runtime: 4–5 h; requires specialized ultracentrifuge.

2. UF preconcentration and SEC isolation on ExoFaster-500

   Samples were concentrated with 100 kDa ultrafiltration tubes (4,000 g, 10 min, 4 °C), then separated on the ExoFaster-500 SEC platform to collect EV fractions. Total runtime: ~1 h, suitable for high-throughput processing.

2.3 Characterization Methods

• TEM: Observe vesicle bilayer morphology and size

• Western Blot: Detect EV markers (CD63, TSG101) and contamination markers (GM130, Histone H3)

• NTA: Measure particle concentration and size distribution

• BCA assay: Quantify total protein; particle-to-protein ratio for purity evaluation

3. Core Results

1. Identical valid EV morphology and biomarkers

   Both methods produced intact cup-shaped bilayer EVs with peak sizes 130–170 nm. Positive EV markers CD63 and TSG101 were clearly detected, while no GM130 or Histone H3 signals were observed, confirming effective removal of cellular impurities.

   

   

2. UC delivers higher particle and protein yield

   NTA results showed significantly higher particle concentrations in UC extracts from HSC and NK supernatants. BCA testing also revealed higher total protein levels in UC preparations, meeting experimental demands for large EV quantities.

   

3. UF+SEC (ExoFaster-500) achieves superior purity

   Particle-to-protein ratio is a standard purity index. UF+SEC samples from all three cell types showed significantly higher ratios than UC groups, meaning less co-purified soluble non-vesicular proteins and purer EV products.

   

   
   

4. Performance Comparison & Suitable Applications

Parameter	Ultracentrifugation (UC)	UF+SEC (ExoFaster-500)
Total Time	4–5 h	~1 h
Operation	Complex, dedicated equipment required	Simple, automated, high-throughput compatible
EV Yield	High	Moderate
Purity	Low (more co-precipitated impurities)	High (effective impurity removal)
Vesicle Damage Risk	High shear force may disrupt membrane	Mild conditions preserve native structure
Recommended Use	Large-scale functional assays, bulk protein enrichment	Mass spectrometry, clinical sample testing, high-throughput biomarker screening

5. Conclusion

1. Choose UC for experiments requiring high EV concentration and abundant vesicle input.

2. Choose UF+SEC (ExoFaster-500) for assays prioritizing high purity, especially proteomic analysis, limited-volume clinical samples and batch screening.

3. The fast, gentle UF+SEC (ExoFaster-500) workflow is more suitable for clinical translation and high-throughput research.