The Study On Novel Magnetic Molecularly Imprinted Nano-Composite System For Recognition Of Biomacromolecules

Protein molecular imprinting is an effective technique for the creation of specific recognition sites for template protein in a polymer network. It has only limited success and its progress has been slow due to some inherent limitations of protein template. Therefore, more investigations are required to further improve selectivity, stability, accessibility to recognition site and cost-effectiveness of the polymer, and the conventional preparation and analysis of molecular imprinted polymers (MIP) has to be modified to accommodate the physical properties of protein (e.g. size, complexity, flexibility and solubility).In this work, combining speediness of magnetic separation, selectivity of molecular imprinting technique and high surface-to-volume ratio and good mass transport of nano-structured materials, four kinds of novel core-shell magnetic molecularly imprinted nano-composite system with an average diameter of approximately 100～400 nm were synthesized for separation and recognition of biomacromolecules for the first time using surface imprinting technique. Four kinds of novel magnetic molecularly imprinted nano-composite system include:â‘ core-shell magnetic molecularly imprinted polymer nanoparticles for recognition of bovine hemoglobin. The magnetic nanoparticles were synthesized by the chemical coprecipitation of Fe²⁺ and Fe³⁺ in an ammonia solution. Subsequently, silica was coated on the Fe₃O₄ nanoparticles using a sol-gel method to obtain silica shell magnetic nanoparticles. Subsequently, 3-aminophenylboronic acid (APBA), which is the functional and cross-linking monomer, and poly(APBA) thin films were coated onto the silica-modified Fe₃O₄ surface through oxidation with ammonium persulfate in an aqueous solution in the presence or absence of protein. (2) novel nano-imprinted polymer using covalently bonded template method. Fe₃O₄ magnetic nanoparticles synthesized by chemical coprecipitation were surface modified. Aminopropylsilanzed magnetic nanoparticles was first aldehyde functionalized with glutaradehyde and then reacted with BHb by a covalently bond through imine groups. Core-shell superparamagnetic nano-polymer nanospheres were synthesized by poly(APBA)-coated thin film;â‘¢novel bovine hemoglobin surface-imprinted polystyrene nanoparticles with magnetic susceptibility. polystyrene was grafted on the the surface of silica-coated magnetic iron oxide nanoparticles through silylation reagent. The larger particle size of superparamagnetic surface-imprinted polystyrene nanoparticles with the special surface morphology were prepared through surface imprinting technique;â‘£superparamagnetic molecularly imprinted polystyrene nanoparticles with high dispersion. Surface-modified Fe₃O₄ magnetic nanoparticles were synthesized using oleic acid and sodium dodecylbenzenesulfonate (SDBS) as double-surface surfactant, which can prepare nano-sized Fe₃O₄ magnetic fluid with a stable aqueous dispersion. The magnetic polymer nanospheres were prepared by emulsion polymerization by using styrene and methylacrylic acid as the monomer with the existence of magnetic fluid and then imprinted thin layer of poly(APBA) was coated on their surface.The morphology, adsorption, and recognition properties of the magnetic molecularly imprinted nanomaterial were investigated by transmission electron microscopy (TEM), X-ray diffraction (XRD), thermogravimetric analysis (TGA), and vibrating sample magnetometer (VSM), and the recognition mechanism of template protein identification was discussed. The protein adsorption results showed that poly(APBA) MlP-coated magnetic nanoparticles have high adsorption capacity for template protein and comparatively low non-specific adsorption. Due to specific recognition sites for template protein on the imprinted shell make this nanoparticles with specific selectivity and high stability, the imprinted magnetic nanoparticles could easily reach the adsorption equilibrium and magnetic separation under an external magnetic field, thus overcoming the drawback of monolith materials of hindering protein molecules from diffusion. All these results demonstrate that the the imprinted polymer coated magnetic nanoparticles can be one of the most promising candidates for various applications, which include chemical and biochemical separation, cell sorting, recognition elements in biosensors, and drug delivery and has potential applications in the separation and detection of biomacromolecules so as to enable high abundance of protein to be removed and low abundance of protein to be enriched in proteomics. Based on the above, combining the advantages of magnetic nanotechnology, molecular imprinting technology, electromagnetics, analytical chemistry and so forth, this work provides new research ideas for the study of novel versatile molecularly imprinted polymer. In this work, the application of magnetic molecularly imprinted nanoparticles in the field of protein separation and enrichment were initially attempted.