From singly charged exosomes to vaccine particles and viruses – what can electrospray ionization with different analyzers provide?

For the detailed characterization of nature-made (non-covalent bio specific protein complexes, intact viruses, virus-antibody complexes and exosomes) and engineered (virus-like-particles (VLPs), liposomes and gold NPs) nanoparticles (NP) besides immunological and functional parameters usually methods as transmission electron microscopy (TEM), scanning electron microscopy (SEM) as well as atomic force microscopy (AFM), analytical ultracentrifugation, size exclusion chromatography (SEC), asymmetric flow field-flow fractionation (AF4), multiangle light scattering (MALS) or dynamic light scattering (DLS) are used.

The use of nano electrospray ionization (nESI) for desorption and ionization of the above mentioned kinds of NPs is a relative new development. Now it is possible to generate ions with multiple charges as well as a single charge fixed on such spherical nanoparticles. How this is done in different ways (charge reduction by means of Po210, corona discharge or soft X-rays) will be discussed briefly.
Here, we want to present analytical data (size, molecular mass and particle number/mass concentrations) with two nESI-based devices (32K quadrupole reflectron, QRTOF and nano differential mobility analyzer, nDMA) which open up new avenues for the detailed analysis of the above mentioned different kinds of nano-objects. Furthermore the collection of size-separated NPs (by means of a commercial nDMA and a home-built parallel nDMA) will be shown allowing further investigations of such NP fractions as DotBlot, AFM or TEM analysis.