Synthesis And Application Of Functionalized Magnetic Nanomaterials And Porous Materials

Superparamagnetic nano materials with high specific surface area and mobility in an external magnetic field have received extensive attention in many fields.However,the existing properties of magnetic materials cannot fully meet the stringent conditions and higher requirements for functions in many application scenarios.Therefore,one of the major challenges in the research is concurrently improve the stability,adsorption capacity and adsorption selectivity and keep the superparamagnetism of nano materials by accurately construct the structure and modify with the proper functional groups.Due to the complexity of sample,separation analysis of biomolecules has been troubled with some problems such as low specificity and separation efficiency for a long time.Herein,we designed and prepared a series of superparamagnetic Fe₃O₄nanoparticles,molecularly imprinted nanoparticles and mesoporous silica nanoparticles based on boronate affinity,to the selective adsorption and separation of glycoproteins,adenosine and pyrocatechol.Moreover,an enantioselective potentiometric sensor modified with porous organic cages(POCs)material was prepared for the recognition of enantiomers.The main contents are summerized as follows:1.Superparamagnetic Fe₃O₄ nanoparticles are prepared with Fe Cl₃,sodium acetate,glycol and polyethylene glycol by a solvothermal method,then the 3-aminopropyl triethoxysilane(APTES)was condensation on the surface of nanoparticles to prepared Fe₃O₄@SiO₂-NH₂.The phenylboric acid functionalized was achieved by the ammonia condensation between 2,3-difluoro-4-formyl phenylboric acid(DFFPBA)and the-NH₂,and the Fe₃O₄@SiO₂-DFFPBA was used for selective adsorption of template molecules such as glycoproteins.Finally,a molecularly imprinted layer was covered on the surface nanoparticles by the condensation polymerization of tetraethyl orthosilicate(TEOS).Adsorption thermodynamics,kinetics and selective adsorption capacity of imprinted particles were investigated,and the control of imprinted layer thickness and its effect on adsorption capacity were discussed.The adsorption capacity of obtained MNPs@MIP-OVA and MNPs@MIP HRP to OVA or HRP was distinct higher than non-imprinted particles.Moreover,MNPs@MIP-OVA and MNPs@MIP HRP can selectively adsorb OVA and HRP to BSA and another glycoprotein respectively.2.A‘thiol-ene click chemistry'strategy was use to synthesis the phenylboronic acid functionalized magnetic Fe₃O₄ nanoparticles.Superparamagnetic Fe₃O₄nanoparticles are prepared by the same solvothermal method as chapter one,then the-SH and-alkenyl functionalized was achieved by the condensation of 3-mercaptopropyl trimethoxysilane(MPTES)and 3-(methacryloxide)propyl trimethoxy silane(MPS)respectively.Eventually,the 3-acryla Midophenylboronic acid(AAPBA),4-vinyl phenylboric acid(VPBA)and 4-mercaptophenylboronic acid(MPBA)was bonded onto the surface of particles by the‘thiol-ene click chemistry'.The obtained three phenylboronic acid functionalized magnetic Fe₃O₄ nanoparticles show favourable adsorption capacity and selectivity toward cis-diol-containing compounds such as glycoprotein,adenosine and pyrocatechol.3.A new strategy to prepare functionalized magnetic SBA-15 mesoporous silica by co-condensation and click chemistry was developed.Triblock copolymers P123 was used as template,3-mercaptopropyl trimethoxysilane(MPTES)or 3-(methacryloxide)propyl trimethoxy silane(MPS)was co-condensation with tetraethyl orthosilicate(TEOS)to obtained SBA-15 mesoporous silica on the surface of Fe₃O₄@n SiO₂nanoparticles.Then the 3-acryla Midophenylboronic acid(AAPBA)or 4-mercaptophenylboronic acid(MPBA)was bonded with Fe₃O₄@n SiO₂@m SiO₂-SH or Fe₃O₄@n SiO₂@m SiO₂-alkenyl by the‘thiol-ene click chemistry'respectively to synthesis phenylboronic acid functionalized magnetic SBA-15 mesoporous silica Fe₃O₄@n-SiO₂@m-SiO₂-AAPBA and Fe₃O₄@n-SiO₂@m-SiO₂-MPBA.The effects of additive amount of MPTES and MPS on the synthesis,and adsorption properties for adenosine,deoxyadenosine,dihydroxybenzene isomers,proteins(TRF,OVA,HRP and BSA)of the mesoporous materials were investigated.The results indicate that the specific surface area,pore volume and adsorption capacity of the mesoporous materials decreased with the increase of the amount of MPTES and MPS,but their adsorption selectivity of adenosine and catechol increased with the addition of MPTES and MPS.Furthermore,the experiment also proved the volume selection can be achieved through space exclusion effect of mesoporous channel.This characteristic makes the phenylboric acid modified magnetic mesoporous nanomaterials have the potential to selectively adsorb small biological molecules with cis-diol structure in complex biological samples such as blood samples.4.Tow versatile functional material,porous organic cages CC3-R and CC9-R with chiral interlinked tridimensional pore channel structures were applied as chiral selector in PVC membrane electrodes to fabricated the potentiometric sensor.Factors influencing the enantioselectivity of the modified membrane electrode,such as the content of CC3-R,the category of plasticiser and the p H value of analyte solutions,were systematically investigated.After optimisation,the CC3-R modified membrane electrodes shown good enantioselectivity toward S-2-amino-1-butanol(log,=-0.98)with acceptable sensitivity on a p H range of 6.0?9.0.The CC9-R modified membrane electrodes exhibited impressive discrimination toward D-malic acid over L-malic acid with a potentiometric enantioselectivity coefficient-1.36 at pH 8.0.