A New Role of Biological Macromolecules as Reference Materials for the
Sub-10 nm Calibration for the Real-time Electrophoretic ES-SMPS
Abstract
Electrospray scanning mobility particle sizer (ES-SMPS) is an
electrophoretic method for size characterization of nanoparticles (NPs)
and its population in biological samples such as macromolecules and
virus is growing. To ensure the measurement precision and accuracy,
especially for the sub-10 nm measurement, size calibration of ES-SMPS
system is necessary. Gold nanoparticles (AuNPs) are commonly chosen as
the reference materials (RMs) while the surfactants preventing NP
aggregate coat among NP surface lead to the measurement uncertainty in
ES-SMPS. In this paper, both AuNPs and self-disperse biological
macromolecules, bio-NPs, were selected for the evaluation of their
suitability as RMs for ES-SMPS. Two methods including centrifugation and
heating were used for the surfactant removal from AuNPs suspension while
the results showed little influence of the centrifugal and thermal
treatments on the accuracy improvement of AuNPs, where more than 22%
difference from the nominal diameter remained in AuNPs. In the case of
bio-NPs, bovine serum albumin (BSA), ubiquitin, low-density lipoprotein
(LDL) and high-density lipoprotein(HDL) were suspended in electrolyte.
BSA and ubiquitin presented good disperse and repeatable size compared
to literature, high stability at time intervals, and consequently were
suggested as ideal sub-10 nm RM for ES-SMPS calibration.