Method development to Estimate the Purity of Vesicle Preparations using Nanoparticle Tracking Analysis at the Cardiff University School of Medicine

NanoSight reports on how Nanoparticle Tracking Analysis, NTA, is being used in the development of a method to estimate the purity of vesicle preparations by comparing the ratio of nano-vesicle counts to protein concentration. This work is reported by Dr Aled Clayton of the School of Medicine at Cardiff University in an original research article published in the Journal of Extracellular Vesicles.

The School of Medicine at Cardiff University is one of the largest medical schools in the United Kingdom, home to over 3000 students and staff. It is a major international center for teaching and research providing a vibrant community of medical endeavor. The School is based at the University Hospital of Wales in Cardiff, but is also embedded at other hospital sites in Cardiff including Velindre Cancer Centre.

Dr Aled Clayton and his team are researching the roles of exosomes in modulating tumor immunity and the cancer microenvironment in prostate cancer. Exosomes are nanometer sized vesicles, produced in abundance by malignant cells but much of their physiological functions are incompletely understood.

Among Dr Clayton's interests are exosomes as possible disease markers, and has been using the NanoSight nanoparticle characterization system as a reliable tool to help develop projects in this field through the analysis of urine/serum from patients. He is keen to develop fluorescent methods with this platform in the future.

Describing his work, Dr Clayton says "as well as our own interests in cancer, we also collaborate with local colleagues interested in diverse conditions (Alzheimer's, cardiac disease, renal disease and others) in which vesicles may play a role. NanoSight's nanoparticle tracking analysis system has been a versatile platform aiding all of these studies."

Continuing, he said "prior to using NTA, there were few other options available. We had made use of electron microscopy but, we have come to rely on NTA as it is a very sensitive and versatile platform, well-suited to daily use."

The work of Dr Clayton and his postdoc, Dr Jason Webber, has recently been published in the Journal of Extracellular Vesicles where they posed the question "How pure are your vesicles?" In this paper, they proposed a straightforward method to estimate the purity of vesicle preparations by comparing the ratio of nanovesicle counts to protein concentration, using tools including the NanoSight NTA platform and a colorimetric protein assay such as the BCA-assay. They show this approach is simple enough to apply to every vesicle preparation within a given laboratory, assisting researchers as a routine quality control step. The paper also proposes that the approach may aid in comparing/standardizing vesicle purity across diverse studies, and may be of particular importance in evaluating vesicular biomarkers.

Paper: Webber. J. and Clayton. A. (2013) How pure are your vesicles? Journal of Extracellular Vesicles 2: 19861