Direct Immobilization of Coagulation Factor VIII on Au/Fe3O4 Shell/Core Magnetic Nanoparticles for Analytical Application (original) (raw)
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Synthesis of magnetic core–shell Fe3O4–Au nanoparticle for biomolecule immobilization and detection
Journal of Nanoparticle Research, 2009
The production of monodispersed magnetic nanoparticles with appropriate surface modification has attracted increasing attention in biomedical applications including drug delivery, separation, and purification of biomolecules from the matrices. In the present study, we report rapid and room temperature reaction synthesis of gold-coated iron nanoparticles in aqueous solution using the borohydride reduction of HAuCl 4 under sonication for the first time. The resulting nanoparticles were characterized with transmission electron microscopy (TEM), electron spectroscopy for chemical analysis (ESCA), ultraviolet visible spectroscopy (UV-Vis), and X-ray diffraction (XRD). Surface charges and magnetic properties of the nanoparticles were also examined. The pattern of Fe 3 O 4 nanoparticles is face centered cubic with an average diameter of 9.5 nm and the initial reduction of gold on the surface of Fe 3 O 4 particles exhibits uniform Fe 3 O 4-Au nanoparticles with an average diameter of 12.5 nm. The saturation magnetization values for the uncoated and gold-coated Fe 3 O 4 nanoparticles were found to be 30 and 4.5 emu/g, respectively, at 300 K. The progression of binding events between boronic acid terminated ligand shell and fructose based on the covalent bonding interaction was measured by absorbance spectral changes. Immunomagnetic separation was also performed at different E. coli concentration to evaluate capturing efficiency of resulting nanoparticles. Immunomagnetic separation percentages were varied in a range of 52.1 and 21.9% depend on the initial bacteria counts. Keywords Magnetic nanoparticles Á Gold-iron oxide nanoparticle Á Immunomagnetic separation Á Boronic acid Á E. coli Á Composite nanomaterials Á Nanomedicine
Biotechnology Progress, 2007
This article reports the chemical synthesis and functionalization of magnetic and gold-coated magnetic nanoparticles. The binding characteristics of streptavidin-conjugated nanoparticles were studied using prion protein as a target to a specific biotinylated aptamer. The size and structure of the particles were determined by transmission electron microscopy, and the binding of the prion to the particle was confirmed by Fourier transform infrared spectroscopy. The rate of prion binding to the aptamer was dose-dependent, and prion immobilization was more effective on L-aspartic acid-functionalized magnetic nanoparticles compared to the carboxyl-functionalized gold-coated magnetic nanoparticles. This study sets the stage for the development of prion detection platforms as well as our long-term goals in structure elucidation at the binding interface.
Bioconjugate chemistry, 2010
A new diagnostic system for the enrichment and detection of protein biomarkers from human plasma is presented. Gold nanoparticles (AuNPs) were surface-modified with a diblock copolymer synthesized using reversible addition-fragmentation chain transfer (RAFT) polymerization. The diblock copolymer contained a thermally responsive poly(N-isopropylacrylamide) (pNIPAAm) block, a cationic amine-containing block, and a semi-telechelic PEG₂-biotin end group. When a mixed suspension of 23 nm pNIPAAm-modified AuNPs was heated with pNIPAAm-coated 10 nm iron oxide magnetic nanoparticles (mNPs) in human plasma, the thermally responsive pNIPAAm directed the formation of mixed AuNP/mNP aggregates that could be separated efficiently with a magnet. Model studies showed that this mixed nanoparticle system could efficiently purify and strongly enrich the model biomarker protein streptavidin in spiked human plasma. A 10 ng/mL streptavidin sample was mixed with the biotinylated pNIPAAm-modified AuNPs an...
Magnetic nanoparticles (MNPs) have great potential in biomedical applications because of their magnetic response offers the possibility to direct them to specific areas and target biological entities. Magnetic separation of biomolecules is one of the most important applications of MNPs because their versatility in detecting cancer biomarkers. However, the effectiveness of this method depends on many factors, including the type of functionalization onto MNPs. Therefore, in this study, magnetite nanoparticles have been developed in order to separate the 5-nucleotidase enzyme (5eNT). The 5eNT is used as a bio-indicator for diagnosing diseases such as hepatic ischaemia, liver tumor, and hepatotoxic drugs damage. Magnetic nanoparticles were covered in a core/shell type with silica, aminosilane, and a double shell of silica-aminosilane. A ScFv (fragment antibody) and anti-CD73 antibody were attached to the coated nanoparticles in order to separate the enzyme. The magnetic separation of this enzyme with fragment antibody was found to be 28% higher than anti-CD73 antibody and the enzyme adsorption was improved with the double shell due to the increased length of the polymeric chain. Magnetite nanoparticles with a double shell (silica-aminosilane) were also found to be more sensitive than magnetite with a single shell in the detection of biomarkers.
Development of Antibody-Coated Magnetite Nanoparticles for Biomarker Immobilization
Magnetic nanoparticles (MNPs) have great potential in biomedical applications because of their magnetic response offers the possibility to direct them to specific areas and target biological entities. Magnetic separation of biomolecules is one of the most important applications of MNPs because their versatility in detecting cancer biomarkers. However, the effectiveness of this method depends on many factors, including the type of functionalization onto MNPs. Therefore, in this study, magnetite nanoparticles have been developed in order to separate the 5 -nucleotidase enzyme (5eNT). The 5eNT is used as a bio-indicator for diagnosing diseases such as hepatic ischaemia, liver tumor, and hepatotoxic drugs damage. Magnetic nanoparticles were covered in a core/shell type with silica, aminosilane, and a double shell of silica-aminosilane. A ScFv (fragment antibody) and anti-CD73 antibody were attached to the coated nanoparticles in order to separate the enzyme. The magnetic separation of this enzyme with fragment antibody was found to be 28% higher than anti-CD73 antibody and the enzyme adsorption was improved with the double shell due to the increased length of the polymeric chain. Magnetite nanoparticles with a double shell (silica-aminosilane) were also found to be more sensitive than magnetite with a single shell in the detection of biomarkers.
Biomedicines, 2020
Aptamer-based approaches are very promising tools in nanomedicine. These small single-stranded DNA or RNA molecules are often used for the effective delivery and increasing biocompatibility of various therapeutic agents. Recently, magnetic nanoparticles (MNPs) have begun to be successfully applied in various fields of biomedicine. The use of MNPs is limited by their potential toxicity, which depends on their biocompatibility. The functionalization of MNPs by ligands increases biocompatibility by changing the charge and shape of MNPs, preventing opsonization, increasing the circulation time of MNPs in the blood, thus shielding iron ions and leading to the accumulation of MNPs only in the necessary organs. Among various ligands, aptamers, which are synthetic analogs of antibodies, turned out to be the most promising for the functionalization of MNPs. This review describes the factors that determine MNPs’ biocompatibility and affect their circulation time in the bloodstream, biodistribution in organs and tissues, and biodegradation. The work also covers the role of the aptamers in increasing MNPs’ biocompatibility and reducing toxicity.
Protein-Coated Magnetic Nanoparticles: Creation and Investigation
A novel universal approach to cross-linking of protein macromolecules on the surface of magnetite na-noparticles has been developed. The approach is based on protein liability to free radical modification, leading to the formation of intermolecular covalent cross links. Free radicals are locally generated on the surface of nanoparticles. Using a set of physicochemical methods, it has been proven that stable coatings composed of protein macromolecules are formed around individual nanoparticles. The proteins fixed on nanoparticles do not lose their activity as a result of adsorption and free radical modification. Fluorescent probe approach for evaluation of the native functional properties of serum albumin as a part of coating is suggested.
Analytical Methods, 2012
Target protein-magnetic nanoparticle (MNP) conjugates, i.e. α-glucosidase-MNP and protein tyrosine phosphatase 1B (PTP1B)-MNP, were prepared and evaluated for the first time for affinity extraction of the enzyme inhibitors from herbal extracts. Four ligands extracted from granati pericarpium were identified by ESI-MS analysis. In vitro tests indicated that they inhibited both α-glucosidase and PTP1B, two important target proteins for diabetic treatment. Screening for ligands binding to therapeutic target proteins is an effective approach to discover drug leads. 1-3 High throughput screening (HTS) based on colorimetric or fluorometric measurements on multiwell microplates is the most commonly used method for screening of enzyme inhibitors. 4-6 HTS works perfectly with large libraries of synthetic compounds, but not applicable sometimes to assay complex samples such as herbal extracts that may contain many UV-absorbing or fluorescent compounds. 7-8 In addition, since herbal medicines are characteristic of being complexes of many active constituents, identification of the therapeutic agents becomes even more challenging. 9-10 Studies on biological fingerprinting of herbal medicines by using deliberately devised chromatographic procedures were reported. 11-12 Over the past years, search for enzyme inhibitors present in medicinal plants has been one of the major interests in drug discovery and development. 13-14 To study these complex sample matrices, methods based on affinity chromatography (LC), mass spectrometry (MS), and capillary electrophoresis (CE) are used. 15-17 However, these methods are normally either tedious/time-consuming or require dedicated skills for sample pre-treatments. Use of nanometer sized materials in biological studies provides new avenues to probe biomolecular interactions. 18 Functionalized magnetic nanoparticles (MNPs), in particular, find wide applications not only in areas such as magnetic resonance imaging, drug delivery, and biosensing, but also in biological and chemical separations due to the convenience of magnetic solid-liquid separation. 19-21 Based on the theory of ligand-protein interaction, protein-MNP conjugates promise to be very useful for extraction of ligands from complex sample matrices. Antibody conjugated MNPs were used for separation of target biomarkers from human plasma. 22 Human serum albumin (HSA) functionalized MNPs (HSA-MNPs) were evaluated for ligand fishing from pharmaceutical formulations. 23 Extraction of low
Biocompatible magnetic nanocomposites of Fe-AuNPs and poly(2-hydroxylethyl methacrylate) (PHEMA) were employed as a strategic protein immobilization platform. The hybrid magnetic nanocomposites were prepared by applying a 'grafting to' ATRP protocol. Fe-AuNPs having Fe core and Au shell were initially prepared by the inverse micelle method. Disulfide-containing PHEMA (DT-PHEMA) was grafted to the Fe-AuNPs surface by taking the advantages of the thiol chemistry. The grafting of DT-PHEMA to the Fe-AuNPs was confirmed by relevant spectroscopic analyses. The superparamagnetic property, a basic requirement for facile protein immobilization, of the magnetic nanocomposites was measured by the SQUID analysis. Lysozyme, -globulins and bovine serum albumin (BSA) were immobilized onto magnetic nanocomposites via the adsorption strategy. The absorption intensity of lysozyme, -globulins and BSA on the PHEMA grafted Fe-AuNPs were observed to be higher than that of bare Fe-AuNPs.
ACS Applied Materials & Interfaces, 2019
Although the functionalization of magnetic nanoparticles (MNPs) with biomolecules has been widely explored for various biological applications, achieving efficient bio-conjugations with a wide range of biomolecules through a single, universal and versatile platform remains a challenge, which may significantly impact their applications' outcomes. Here, we report a novel MNP platform composed of Au@Fe core/satellite nanoparticles (CSNPs) for versatile and efficient bio-conjugations. The engineering of the CSNPs is facilely formed through the self-assembly of ultra-small gold nanoparticles (AuNPs, 2-3 nm in diameter) around MNPs with a polysiloxane-containing polymer coating. The formation of the hybrid magnetic nanostructure is revealed by absorption spectroscopy, dynamic light scattering (DLS), transmission electron microscopy (TEM), element analysis using atomic absorption spectroscopy, and vibrating sample magnetometer. The versatility of biomolecule loading to the CSNP is revealed through the bio-conjugation of a widerange of relevant biomolecules including streptavidin, antibodies, peptides and oligonucleotides. Characterizations including DLS, TEM, lateral flow strip assay, fluorescence assay, giant magnetoresistive (GMR) nanosensor array, highperformance liquid chromatography (HPLC), and absorption spectrum are performed to further confirm the efficiency of various bio-conjugations to the CSNP. In conclusion, this study demonstrates that the CSNP is a novel MNP-based platform that offers versatile and efficient surface functionalization with various biomolecules.