Extended Data Fig. 2: Characterization of microorganism enrichment in a clinical-grade biopharmaceutical product using synthetic β2GPI nanoparticles.
From: One-day rapid sterility test for human-derived biopharmaceuticals
a-c, The capture efficiency of β2GPI nanoparticles was re-evaluated in clinical-grade MSC products, containing 5 × 106 MSCs/mL. In all experiments, microorganisms were spiked into 5 mL of clinical-grade MSC products and subjected to microbial capture, followed by colony enumeration via agar plating. a, Capture efficiency for six microbial species at a concentration of 10 CFU/mL (N = 10). Compared to pure MSC culture medium (grey bar), similar capture efficiency was observed regardless of MSC presence, suggesting minimal impact on enrichment performance. b, Capture efficiency of multi-drug resistant (MDR) strains. Reference strains and MDR strains of S. aureus and P. aeruginosa were tested at a concentration of 10 CFU/mL (N = 5). The average capture efficiency between MDR and reference strains differed by less than 3% within each species. c, Microbial suspensions of S. aureus and P. aeruginosa were prepared using Bioball® products at 1 CFU/μL, and 3 μL (equivalent to 3 CFU) were spiked into 5 mL of clinical-grade MSC products to achieve a theoretical concentration of 0.6 CFU/mL (N = 10), followed by microbial capture. An identical 3 μL aliquot of the same microbial suspension was directly streaked onto agar plates (N = 10) to validate the precision of ultra-low inoculation. This approach yielded mean colony counts of 1.8 ± 1.17 CFU for S. aureus and 1.9 ± 1.14 CFU for P. aeruginosa, with one sample per species showing no colony formation. Samples with average colony counts deviating by more than ±2 CFU from the expected 3 CFU were excluded from analysis. Under these validated conditions, positivity rates following microbial capture were 80% and 90% for S. aureus and P. aeruginosa, respectively, supporting reliable microbial detection by NEST even at ultra-low inoculum levels. Bar plots display the mean, with SD shown as an upper error bar. All data points represent biologically independent experimental replicates.
