MPQ-cytometry: a magnetism-based method for quantification of nanoparticle–cell interactions

Abstract

Precise quantification of interactions between nanoparticles and living cells is among the imperative tasks for research in nanobiotechnology, nanotoxicology and biomedicine. To meet the challenge, a rapid method called MPQ-cytometry is developed, which measures the integral non-linear response produced by magnetically labeled nanoparticles in a cell sample with an original magnetic particle quantification (MPQ) technique. MPQ-cytometry provides a sensitivity limit 0.33 ng of nanoparticles and is devoid of a background signal present in many label-based assays. Each measurement takes only a few seconds, and no complicated sample preparation or data processing is required. The capabilities of the method have been demonstrated by quantification of interactions of iron oxide nanoparticles with eukaryotic cells. The total amount of targeted nanoparticles that specifically recognized the HER2/neu oncomarker on the human cancer cell surface was successfully measured, the specificity of interaction permitting the detection of HER2/neu positive cells in a cell mixture. Moreover, it has been shown that MPQ-cytometry analysis of a HER2/neu-specific iron oxide nanoparticle interaction with six cell lines of different tissue origins quantitatively reflects the HER2/neu status of the cells. High correlation of MPQ-cytometry data with those obtained by three other commonly used in molecular and cell biology methods supports consideration of this method as a prospective alternative for both quantifying cell-bound nanoparticles and estimating the expression level of cell surface antigens. The proposed method does not require expensive sophisticated equipment or highly skilled personnel and it can be easily applied for rapid diagnostics, especially under field conditions. † Electronic supplementary information (ESI) available. See

Recent Advances in Magnetic Microfluidic Biosensors

“…Another rapid method for studying the surface of cells using biomolecules on MNPs using the MPQ technique, called MPQ-cytometry, was demonstrated in [ 38 ]. Specifically, it is the integral non-linear response produced by magnetically labeled biomolecules in a cell sample that is measured with the MPQ technique (see Figure 4 ).…”

“…The unbound nanoparticles are then removed from the sample by centrifugation. The amount of nanoparticles bound to the cells is measured using the magnetic particle quantification (MPQ) technique at combinatorial frequencies (Reproduced with permission from [ 38 ]. The Royal Society of Chemistry, 2016.).…”

Synthesis and Characterization of Hybrid Core-Shell Fe3 O4 /SiO2 Nanoparticles for Biomedical Applications

“…The cells removed from the culture plastic surface (0.7 × 10 6 ) were washed twice with PBS, incubated with nanoparticles at a concentration of 0.01 g/L at room temperature for 2 h, and washed from unbound particles under constant stirring. The number of cell-bound particles was determined by MPQ-cytometry [18].…”

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“…Small size and reliable detectability make nanoparticles extremely attractive for the development of in situ biosensors that perform non-invasive analysis directly in cell culture or tissue slices (Shipunova et al 2016;Lee et al 2007;Gandra et al 2016). In situ monitoring of changes of biomolecule concentration in the natural or physiological environment is highly demanded in many fields of biology and medicine for efficient analysis of various biological processes.…”