Synthesis Of Functional Mesoporous Materials And Their Application In Proteins Separation

Protein,the primary component of organism,plays a crucial role in a variety of physical activities.Especially for low abundant proteins（LAP）,some of them are biomarkers in the clinical diagnosis.However,it is difficult to identify the LAP due to the enormous amount and dyamic concentration range of proteins in complex biological samples,which leads to the suppression of information on LAP by highly abundant proteins（HAP）.In response to this problem,specific capture and removal of HAP with large sample–handling capacities are in great demand to minimize the complexity of samples and improve the identification of LAP.In this dissertation,two sorts of functional mesoporous materials were designed and synthesized to specifically remove HAP based on the difference in isoelectric point and the number of their surface–exposed histidine（His）residues.（1）Diverse pH–sensitive functionalized Santa Barbara Amorphous–15（SBA–15）materials were synthesized by atom transfer radical polymerization（ATRP）with 2–（diethylamino）ethyl methacrylate and methacrylic acid units to separate proteins.The morphology and composition of the resulting functional materials were characterized by Fourier transform infrared spectroscopy,thermogravimetric analysis,X–ray diffraction,Zeta potential,elemental analysis,transmission electron microscopy and nitrogen gas adsorption–desorption isotherm test.The pH–sensitive SBA–15 became charged particles by protonation or deprotonation at different pH solutions.These materials adsorbed proteins by electrostatic interaction to separate acidic,neutral and basic proteins.In addition,the functional SBA–15 can be used to selectively separate HAP from egg white sample and human serum sample.The maximum removal efficiencies of ovalbumin and lysozyme from egg white sample were obtained as 99% and 95%,respectively,while the maximum removal efficiency of human serum abumin from human serum sample was about 80% by the proposed method.This treatment process dramatically reduced the complexity of real biological samples and facilitated the identification of LAP.（2）The Cu²⁺–immobilized functional mesoporous material was fabricated by thermally initiated free–radical polymerization of polyhedral oligomeric vinylsilsesquioxanes.It was used as adsorbent for highly specific separation of His–rich proteins in the extremely complex biological samples based on immobilized metal affinity chromatography.The functional mesoporous material was characterized and its ability for adsorption and separation of proteins was evaluated in detail.The measurements indicated that the resulting material exhibited large specific surface area and good selective adsorption ability.The maximum adsorption capacity for bovine hemoglobin（BHb）was 3150 mg/g.Moreover,the relative BHb adsorption capacity for the reused material remained almost unchanged after six cycles of reuse,suggesting that the porposed material had excellent recyclability.In addition,the material not only showed excellent performance for the removal of highly abundant serum albumin and hemoglobin in human blood,but also can be a good adsorbent for the enrichment of proteins in cell lysate.This approach can also be combined with other techniques to obtain more comprehensive data in proteomic analysis.