Magnetic microparticles post-synthetically coated by hyaluronic acid as an enhanced carrier for microfluidic bioanalysis

Abstract

Iron oxide based particles functionalized by bioactive molecules have been utilized extensively in biotechnology and biomedicine. Despite their already proven advantages, instability under changing reaction conditions, non-specific sorption of biomolecules on the particles' surfaces, and iron oxide leakage from the naked particles can greatly limit their application. As confirmed many times, surface treatment with an appropriate stabilizer helps to minimize these disadvantages. In this work, we describe enhanced post-synthetic surface modification of superparamagnetic microparticles varying in materials and size using hyaluronic acid (HA) in various chain lengths. Scanning electron microscopy, atomic force microscopy, phase analysis light scattering and laser diffraction are the methods used for characterization of HA-coated particles. The zeta potential and thickness of HA-layer of HA-coated Dynabeads M270 Amine were -50 mV and 85 nm, respectively, and of HA-coated p(GMA-MOEAA)-NH2 were -38 mV and 140 nm, respectively. The electrochemical analysis confirmed the zero leakage of magnetic material and no reactivity of particles with hydrogen peroxide. The rate of non-specific sorption of bovine serum albumin was reduced up to 50% of naked ones. The coating efficiency and suitability of biopolymer-based microparticles for magnetically active microfluidic devices was confirmed. Highlights: Post-synthetic surface modification of magnetic microparticles by hyaluronic acid  Hyaluronic acid -polymer of unique physicochemical and biological characteristics ABSTRACTIron oxide based particles functionalized by bioactive molecules have been utilized extensively in biotechnology and biomedicine. Despite their already proven advantages, instability under changing reaction conditions, non-specific sorption of biomolecules on the particles' surfaces, and iron oxide leakage from the naked particles can greatly limit their application. As confirmed many times, surface treatment with an appropriate stabilizer helps to minimize these disadvantages.In this work, we describe enhanced post-synthetic surface modification of superparamagnetic microparticles varying in materials and size using hyaluronic acid (HA) in various chain lengths. Scanning electron microscopy, atomic force microscopy, phase analysis light scattering and laser diffraction are the methods used for characterization of HA-coated particles. The zeta potential and thickness of HA-layer of HA-coated Dynabeads M270Amine were -50 mV and 85 nm, respectively, and of HA-coated p(GMA-MOEAA)-NH 2 were -38 mV and 140 nm, respectively. The electrochemical analysis confirmed the zero leakage of magnetic material and no reactivity of particles with hydrogen peroxide. The rate of nonspecific sorption of bovine serum albumin was reduced up to 50% of naked ones. The coating efficiency and suitability of biopolymer-based microparticles for magnetically active microfluidic devices was confirmed.

Magnetic beads-based electrochemical immunosensor for monitoring allergenic food proteins

“…Such is the case of carboxylate-modified Sera-Mag particles. In view of these microparticles' other excellent characteristics, such as good response to the magnetic field and high binding capacity, we decided to perform post-synthetic surface coating using HA as described previously [36]. Surface coating with such a glycosaminoglycan improves colloidal stability, provides a compact layer covering the surface iron oxides, and (last but not least) inserts free carboxylic functional groups enough for effective binding of specific antibodies.…”

“…The two kinds of magnetic particles-p(GMA-MOEAA)-NH 2 coated with hyaluronic acid (HA) [36] and commercially available carboxylate-modified Sera-Mag magnetic particles-were exploited for covalent coupling of specific antibodies using a slightly modified two-step carbodiimide method and with EDC as zero-length cross-linker and sulfo-NHS according to Hermanson [37]. Here, 1 mg of magnetic particles was washed five times with 50 mM Mes buffer (pH 5.0).…”

Benefits of Immunomagnetic Separation for Epitope Identification in Clinically Important Protein Antigens: A Case Study Using Ovalbumin, Carbonic Anhydrase I and Tau Protein

“…To avoid such inaccurate interpretation of the results it is necessary to include in each experiment appropriate negative control and minimize the possibility of non-specific interactions. The most common ways to suppress non-specific sorption include: (i) low-molecular reagents blocking the remaining reactive groups on the MPs surface (e. g. D-glyceraldehyde for hydrazide functional groups [36][37][38], ethanolamine and Tris for carboxylate functional groups [45]), (ii) MPs surface modification by protein/polymer layer (e. g. BSA [46], PEG [47,48], hyaluronic acid [49]), (iii) adding low levels of salt, chaotropic reagent or detergent in the binding and/or washing buffer (e. g. NaCl, sodium thiocyanate, SDS, urea [45]). The specificity of binding can be confirmed also by capturing in the presence of a large excess of other proteins or peptides (e. g. tryptic fragments of 1% BSA [37]) or using another antibody (differing in specificity or non-specific [45]).…”

Microfluidic magnetic fluidized bed for DNA analysis in continuous flow mode

“…We evaluated the microfluidic fluidized bed for performing individual steps of the magnetic bead PLP/C2CA protocol for DNA analysis (Fig. 1b), and compared it to ChipGenie® edition P (Fig 3), a commercially available benchtop solution for magnetic bead handling (Holubova et al 2014;Julich et al 2016;Julich et al 2014;Kucerova et al 2014). This instrument is designed with a holder for microscope slide format microfluidic chips, possesses a heating element and a magnet placed underneath the chip, and can perform magnetic bead actuation for mixing and incubation by mechanical movement of the magnet along the length of the microchannel.…”