Surface Modification Of Light And Macromolecular Regulation And Its Application

In recent years, the fixing of functional molecules on the substrate surface has been widely used in biology, ecology and chemical engineering filed etc. Despite the emergence of the enormous relevant reports, the issue is still the research focus and hot topic. While a variety of materials such as polymers, met als, met alloids and oxides are widely used in transportation, energy, communications, medical,chemical industry and daily life. However, with regard to vast majority of material surface, due to its poor compatibility and single properties/structures, directly limit their application in a good deal of fields. In order to improve the surface properties of materials, and finally achieve special application needs, it is necessary for materials to proceed vital function.In view of the above research situation and the previous work of our group, this thesis based on the matureUV induced surface photografting and the first report of lysozyme phase transition by our group, achieved the modification of various substrates, and realized the brilliant application of its multiaspect.In the first section, we report an extremely simple and integrative bifunctional method that could efficiently tailor an organic material surface toward both bioactive and bioinert functions. This method is based on the use of an amides-initiated photochemical reaction in a confined space, which depending on the type of solutes used, results in the incorporation of primary amine groups or surface carbon radicals on an inert polymer surface. The grafted amine group could be used as a highly reactive site for biomolecule conjugation, and the surface carbon radical could be used to initiate radical graft polymerization of antifouling polymer brushes. We expect this simple but powerful method could provide a general resolution to solve the interfacial problem of organic substrate, offering a low-cost practical approach for real biomedical applications.In the second section, we found that when a thin layer of CeCl3/HCl aqueous solution was applied onto polymeric substrate, and under UV irradiation, Ce3+was firstly photooxidized into Ce4+ in the presence of H+, and then in situ formed Ce4+ could perform oxidation reaction on C-H bonds of polymer surface to form active surface carbon radical for further radical graft polymerization as well as functional group transformation, meanwhile reduced itself to Ce3+ status with releasing H+. This photoinduced cerium recycling redox (PCRR) actually behaved as a biomimetic system towards an artificial recycling reaction, leading to a sustainable chemical modification strategy for directly transforming alkyl C-H bond on polymer surfaces to small molecular group and polymer brushes. This method is expected to provide a green and economical tool for industrial applications of polymer surface modification.On account of the work in the first and second section, we further developed a universal surface modification method that is multipurpose and applicable to any substrate surface. In this part, which is the third section, we reported how to manipulate surface property by utilizing lysozyme phase transition occurred under quasi-physiological condition. The phase-transited lysozyme product consisting of amyloid-contained microfiber network could stably attach onto a variety of substrates including met als, oxides, semiconductors and polymers. Such priming process imparted moderate hydrophilicity and enhanced corrosion resistance to surfaces. The priming also afforded mild positive charges and enriched C-H bonds on surfaces, which consequently supported the growth of a series of functional building blocks including polymer brushes, colloids, small molecules and bio-macromolecules based on chemically specific interactions. The bio-related applications based on this strategy were further emphasized. First, a bioactive surface was conveniently obtained by this modification to specifically and sensitively detect tumor markers from buffer and undiluted serum. Second, a one-pot protein immobilization method was developed, which featured a high integration of all the protein immobilization steps in single incubation process. Third, a smart stimuli-responsive surface being capable of performing 100% reversible transition between bioactive and bioinert surface was constructed, based on the unique feature of lysozyme phase transition coating that endured various harsh reagents but selectively detached from the surface in guanidine solution. This work lays a foundation for the use of phase-transited proteins as a universal surface modification tool.