Absolute Quantification of Bionanoparticles by Electrospray Differential Mobility Analysis: An Application to Lipoprotein Particle Concentration Measurements

Abstract

This study presents an upgraded electrospray differential mobility analysis (ES-DMA) setup for the absolute quantification of bionanoparticle concentrations in biological samples, with a special focus on non-high-density-lipoprotein particle concentrations (non-HDL-P). Metrological characterization of the system's analytical performances for concentration measurements shows that the mean intermediate precision relative standard deviation is 14% for biological samples, 6% for silica nanoparticles, and less than 1% for diameter measurements. This study also demonstrates that the most accurate method for non-HDL-P quantification in native serum samples implies daily calculation of the electrospray transmission efficiency (E) of the system with the WHO SP3-08 reference material. The establishment of the uncertainty budget reveals that the main contribution to particle concentration measurement uncertainties is the electrospray transmission efficiency. This data additionally shows that E is not only low (approximately 15-20%) but also highly variable over time and strongly affected by sample composition. This work suggests that absolute enumeration of bionanoparticles is achievable with ES-DMA but provided that a special care is taken to quantifying E with a calibrator of nature and matrix highly similar to the samples ones.

Establishing SI-Traceability of Nanoparticle Enumeration Techniques: A Case Study on Electrospray Differential Mobility Analysis

“…However, as mentioned before, such material is not commercially available. Our study additionally highlighted the fact that E probably depends on the physico-chemical characteristics of the particles and on the conductivity of the analyzed samples [23] Either way, it appears that E is specific for a given sample and that its value may not be transferable to any sample regardless of sample composition and of the entity being measured. These observations thus indicate that using a reference material made of inorganic monodisperse particles with certified number concentration may not be suitable to measure E for lipoproteins in biological samples due to the physico-chemical differences of biological and inorganic matrices.…”

“…Analyses being performed at ambient pressure and temperature, small variations of these parameters may also induce small variations of the gas viscosity, then impacting flow-rates in the system and again, number size distribution measurements [17]. However, we demonstrated that the major parameter contributing to the uncertainty budget associated to absolute lipoprotein quantification by ES-DMA was the ES transmission efficiency E, i.e., the percentage of aerosolized particles that are actually detected and counted by the system compared to the initial particle number concentration in the colloidal suspension [23,24].…”

“…These particles are in charge of lipid transportation in blood and have notably been causally related to cardiovascular diseases [22]. In this study, we presented a metrologically improved procedure to measure lipoprotein number concentrations in liquid biological matrices, based on number size distribution measurements in aerosol phase with ES-DMA [23]. We however evidenced some limitations making ES-DMA unsuitable as a primary reference procedure in the current state-of-the-art.…”

Advanced lipoprotein testing for cardiovascular diseases risk assessment: a review of the novel approaches in lipoprotein profiling

“…the concentration in the initial sample. Various approaches have been reported, but to date, debates remain concerning the most adapted method and harmonization of the process have not yet been achieved [86,89,90].…”

“…Contrary to most methods reported for lipoprotein profiling and quantification, ES-DMA is the only one for which the measurand is the full intact lipoprotein [91]. However, it was demonstrated that calibration with appropriate standards is necessary to achieve accurate quantification and a study of results comparability with IN revealed important variability depending on the calibration material chosen [90]. As for diameter measurement accuracy, ES-DMA systems are generally calibrated with CRMs of inorganic nanoparticles and provide highly precise measurements [90,92].…”