Antibody-conjugated paramagnetic nanobeads: kinetics of bead-cell binding.

Shahid Waseem,Sebastian Bhakdi,Stefan Schreier,Michael Allen,Rachanee Udomsangpetch

doi:10.3390/ijms15058821

Abstract

Specific labelling of target cell surfaces using antibody-conjugated paramagnetic nanobeads is essential for efficient magnetic cell separation. However, studies examining parameters determining the kinetics of bead-cell binding are scarce. The present study determines the binding rates for specific and unspecific binding of 150 nm paramagnetic nanobeads to highly purified target and non-target cells. Beads bound to cells were enumerated spectrophotometrically. Results show that the initial bead-cell binding rate and saturation levels depend on initial bead concentration and fit curves of the form A(1 − exp(−kt)). Unspecific binding within conventional experimental time-spans (up to 60 min) was not detectable photometrically. For CD3-positive cells, the probability of specific binding was found to be around 80 times larger than that of unspecific binding.

Highlights

Magnetic labelling of cells with paramagnetic nanoparticles is widely used in biomedical sciences.Labelled cells are used in research as well as in clinical diagnostics and therapy, facilitating a range of applications from magnetic cell separation [1] and clinical imaging to targeted drug delivery [2].The present paper focuses on labelling of cells for magnetic separation of target cells from heterogeneous cell suspensions
The efficiency of magnetic separation is influenced by factors related to the hardware of the magnetic separation system used and factors determined by the quality of the magnetic labelling of cells which depend on the properties or quality of the magnetic nanobeads employed [11]
X-ray diffraction (XRD) confirmed that the iron oxide crystals consist of pure magnetite (Fe3O4)

Summary

Introduction

Magnetic labelling of cells with paramagnetic nanoparticles is widely used in biomedical sciences.Labelled cells are used in research as well as in clinical diagnostics and therapy, facilitating a range of applications from magnetic cell separation [1] and clinical imaging to targeted drug delivery [2].The present paper focuses on labelling of cells for magnetic separation of target cells from heterogeneous cell suspensions. Magnetic labelling of cells with paramagnetic nanoparticles is widely used in biomedical sciences. Labelled cells are used in research as well as in clinical diagnostics and therapy, facilitating a range of applications from magnetic cell separation [1] and clinical imaging to targeted drug delivery [2]. The present paper focuses on labelling of cells for magnetic separation of target cells from heterogeneous cell suspensions. For magnetic cell separation in biomedical sciences, high gradient magnetic separation (HGMS) is the most widely used technique, with over 12,000 studies published [3]. In most magnetic cell separation protocols, target cells are labelled with magnetic nanobeads that are conjugated to specific antibodies [10]. An ideal magnetic nanobead-based cell labelling system would offer completely specific binding of beads to target cells while completely avoiding binding of beads to non-target cells [12]. To optimize a nanobead-based magnetic separation system, it is crucial to understand the kinetics of specific and unspecific binding of beads to cells

Results

Discussion

Conclusion