Extension of the fluidics NTF-Biobank of polytraumatized patients with extracellular vesicles: improved vesicle...

Extracellular vesicles (EVs) show diagnostic relevance in trauma, prompting the development of the NTF‑EV‑Biobank as an extension of the established Network Trauma Research (NTF) plasma/serum biobank. After optimizing the EV isolation and characterization standard operating procedure (SOP) at a single center, this multicenter study evaluates its transferability and examines how sample transport affects EV quality before large‑scale implementation in a nationwide biobank setting.

Plasma and serum from polytrauma patients and healthy controls (n=10) were processed under the standardized NTF‑Biobank protocol and distributed to three centers. EVs were isolated using the unified NTF‑EV‑Biobank workflow, exchanged between centers, and analyzed for protein markers, particle size and concentration (NTA), total protein content, and morphology (TEM) to compare EV quality across sites.

Implementation of the EV biobank protocol across participating centers, as well as inter-center transport on dry ice, was successfully performed without complications. All samples arrived at the analyzing centers in a frozen state. EVs exhibited typical vesicular morphology as confirmed by transmission electron microscopy and remained positive for CD9 and CD81, indicating that transportation did not affect morphology or surface marker expression. However, transportation did reduce EV yield as assessed by NTA, while total protein content remained unchanged.

Transport of isolated EVs between centers resulted in a significant reduction in EV yield, accompanied by a partial increase in particle size. Based on these findings, the storage and distribution of EVs in isolated form within the NTF-EV-Biobank were deemed unsuitable. Instead, samples should be stored and transported as plasma/serum, with EV isolation performed at the destination site.