Nano ES GEMMA and PDMA, new tools for the analysis of nanobioparticles—Protein complexes, lipoparticles, and viruses

Abstract

Differential mobility analysis (DMA) is a technique suited for size analysis as well as preparative collection of airborne nanosized airborne particles. In the recent decade, the analysis of intact viruses, proteins, DNA fragments, polymers, and inorganic nanoparticles was possible when combining this method with a nano-electrospray charge-reduction source for producing aerosols from a sample solution/suspensions. Mass analysis of high molecular weight noncovalent complexes is also possible with this methodology due to the linear correlation of the electrophoretic mobility diameter and the molecular mass. In this work, we present the analysis (size and molecular mass) of high molecular weight multimers (noncovalent functional homocomplex) of Jack bean urease in a mass range from 275 kDa up to 2.5 MDa, with mainly present tri-and hexamers but also higher oligomers of the 91 kDa monomer subunit. In a second experiment, the size analysis of intact very-low-density (ϳ35 nm), low-density (ϳ22 nm) and high-density lipoparticles (ϳ10 nm), which are heterocomplexes consisting of cholesterol, lipids, and proteins in different ratios, is presented. Results from mobility analysis were in excellent agreement with particle diameters found in literature. The last presented experiment demonstrates size analysis of a rod-like virus and selective sampling of a selected size fraction of electrosprayed, singly-charged tobacco mosaic virus particles. Sampling and subsequent transmission electron microscopic investigations of a specific size fraction (40 nm electrophoretic mobility diameter) revealed the folding of virus particles during the electrospray and charge reduction (electrical stress) as well as solvent evaporation (mechanical stress) process, leading to an observed geometry of 150 (length) ϫ 35 (width) nm (average cylindrical geometry of unsprayed intact virus 300 ϫ 18 nm). and viruses. Analysis of the formation process, stoichiometry, and molecular weight of those complexes can be very challenging as noncovalent interactions can easily be destroyed or biased when leaving specific native conditions [5], and as their molecular mass can easily exceed the working range of modern mass spectrometry. For these reasons, a demand for new analytical techniques, which preserve noncovalent interactions, deliver molecular mass and/or size related information (in contrast to capillary electrophoresis and native gel electrophoresis) and which have a working range that exceed conventional mass spectrometry, exists.Differential mobility analysis (DMA) is a technique developed to classify charged aerosolized particles under ambient pressure according to their electrophoretic mobility diameter [6]. In the recent decade, its working range was extended from m down to the nm size range [7], or in terms of molecular mass, into the kDa to GDa molecular mass range, thus closing the gap between classic aerosol particle technology (low m into mm range) and mass spectrometry (sub-nm to 10 nm). The size range of 10 to 200 nm is therefore of great in...

Analytical Approaches for Size and Mass Analysis of Large Protein Assemblies

“…The GEMMA analyzer has an extended size range and has been successfully used for particles of sizes ranging from 3 nm to 100 nm, which covers a mass range of a few kDa (small proteins) to 100 MDa (whole viruses or even cell organelles and DNA) (113). Applications of the GEMMA analyzer have ranged from analyzing antibody aggregation, macromolecular protein complexes (114), synthetic polymers (115), intact viruses (116), and lipoparticles (117). GEMMA analysis was successfully applied, for instance, on the 4.6-MDa cowpea chlorotic mottle virus (CCMV) (116) and the tobacco mosaic virus (117).…”

“…Applications of the GEMMA analyzer have ranged from analyzing antibody aggregation, macromolecular protein complexes (114), synthetic polymers (115), intact viruses (116), and lipoparticles (117). GEMMA analysis was successfully applied, for instance, on the 4.6-MDa cowpea chlorotic mottle virus (CCMV) (116) and the tobacco mosaic virus (117). Although the mass resolution of the GEMMA instrument is still too low to enable accurate mass measurement, GEMMA does provide parallel information about the electrophoretic mobility diameter of the analyzed particle.…”

Electrospray–differential mobility analysis of bionanoparticles

“…Here ρ is the density of the polymer (or protein), MW is the molecular weight, N avg is the Avagadro's number and d DMA is the analyte diameter determined by DMA [46,50]. It should be pointed out that for a known gas phase density of a particle, equation…”

Penetration of Monodisperse, Singly Charged Nanoparticles through Polydisperse Fibrous Filters

“…In order to obtain well-defined nanoaerosols for filter performance investigation, an arrangement containing an electrospray particle generator with a subsequent electrostatic size classification was used as described previously (Allmaier et al 2008). Suspensions holding a given type of nanoparticle were prepared in 20 mM aqueous ammonium acetate buffer solutions.…”

“…The PDMA is an advanced DMA system (Austrian patent no. 502207A1, 2007), which can be used to simultaneously monitor the size distribution of the nanoaerosol particles in question and to select one specific size fraction (Allmaier et al 2008). The PDMA consists of two in-house built nano-DMAs working in parallel ( Figure 5).…”