Service no. | Service scope | Service description | Reference fee | Turnaround |
1 | Purity assessment (lysis method) | Assess changes in particle concentration before and after Triton treatment as a preparation-quality indicator. | 500 CNY/sample | 3 business days |
2 | Purity assessment (dye method) | Label membranes with EVmembrane Green Stains and assess preparation quality using the assay readout. | 500CNY/sample | 3 business days |
3 | Zeta potential (ZetaView) | Measure zeta potential using the ZetaView platform. | 300 CNY/sample | 3 business days |
4 | Osmolality (SMC 30D) | Measure EV-preparation osmolality using the SMC 30D. | 200CNY/sample | 3 business days |
5 | Microbial culture test | Use a 24-hour shaking-culture assay to check for microbial contamination. | 200 CNY/sample | 3 business days |
6 | Mycoplasma test (qPCR) | Test for mycoplasma contamination by qPCR. | 200CNY/sample | 3 business days |
7 | Endotoxin test (LAL) | Measure endotoxin using a limulus amebocyte lysate assay kit. | 200 CNY/sample | 3 business days |
8 | Heavy-metal test (atomic absorption) | Atomic absorption testing for five elements in EV samples: lead, cadmium, chromium, mercury and arsenic. | 600CNY/sample | 5 business days |
Quality control is an important part of EV research and supports the accuracy and reliability of experimental results. EV purity, microbial content and endotoxin levels can affect downstream omics, cell and animal experiments. Testing should therefore be selected according to the intended downstream use to assess isolation quality.
1. Purity assessment
There is currently no single standardized method for characterizing EV purity. Approaches described in the literature include particle-to-protein ratio, negative protein markers, RNA fragment distribution and HPLC. Based on the reported in-house tests, two approaches were considered more reliable for purity characterization: (1) compare particle size and counts before and after Triton X-100 lysis to estimate the proportion of particles with lipid membranes; and (2) label membrane components with a membrane dye and use nano-flow cytometry to measure the proportion of fluorescently labelled particles. The latter is currently described as applicable only to EVs from animal cells.
2. Contaminant analysis
During EV preparation, the sample or environment may introduce bacterial or mycoplasma contamination or elevated endotoxin levels. These can bias downstream results or prevent experiments from proceeding. In addition to maintaining aseptic conditions during preparation, the resulting EVs should be tested as appropriate and meet the relevant requirements before downstream testing or use.
Lifeint provides EV research and application services from sample preparation, isolation and characterization to omics, functional studies, modification and scale-up. It jointly established a biomedical technology centre with Xiamen University School of Pharmaceutical Sciences, built process-development laboratories to GMP standards, and contributed to an EV expert consensus. Its service records cover more than 300 plant species.
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