The challenge

Viruses are produced in complex biological systems alongside process-related impurities — cell debris, proteins, and extracellular vesicles. Live titer assays take days and require susceptible cell lines. Indirect methods like ELISA and SP-IRIS don’t yield accurate particle concentration in mixed matrices.

With MRPS

MRPS detects each particle electrically as it transits a microfluidic constriction. Signal is proportional to particle volume regardless of refractive index or sample complexity. Results in minutes directly from cell culture supernatant — no dilution optimization, no reference standard.

The challenge

Viral vector preparations contain both genome-containing (full) and genome-free (empty) particles. Separating their quantification traditionally requires orthogonal assays on separate instruments — adding time, sample consumption, and opportunities for error.

With F-MRPS

The ARC adds fluorescence detection to MRPS. A membrane-permeable intercalating dye labels nucleic acid inside intact particles. Size, total concentration, and fluorescent (full) particle fraction are measured simultaneously — in a single 3 µL injection.

Example result — hAd5

Intact (full) hAd5 detected at 5.4 × 10&sup9; particles/mL — representing 64% of all particles in the measured size range.

Sample: hAd5 mixed with a broad extracellular vesicle background. Single measurement, no pre-processing.