Light Response In Curing Water Gel Type Of Organic Molecules Coating And Single-layer Membrane Surface Modification In The Design And Research

With the development of the biological sciences, photo-lithography technology has been greatly applied to the biological field, especially for the combination with hydrogel curing and surface modification of self-assembled monolayer (SAM). However, most of the reported works have their inherent defects and problems so far. To solve these problems, we expanded our work as described as follows:(1) The non-radical-type photo-cured hydrogel system. Photo-crosslinked hydrogel was defined as the hydrogel with the three-dimensional network structure formed by crosslinking polymerization upon visible or ultraviolet light irradiation. This kind of hydrogel has several advantages:photo-crosslinking in situ in water; easy to form photo-pattern; short curing time; lower heat of reaction. Light far prepared crosslinked hydrogel, however, in the photolithography process, up to date, most of the photo-crosslinked hydrogel often need photoinitiator agent to realize th crosslinking by radical polymerization, which greatly limited its application in the field of biological cells. Therefore, the invention of new biocompatible photo-linked hydrogel system is of great significance for the promotion of the hydrogel applications in biomedicine and other fields. To address this problem, in the first part of this paper, a new non-radical-type photo-cured hydrogel was designed and prepared. This polymer system includes three units:the unit the photo-caged mercapto unit; maleic imide unit that can occure Michael addition reaction with mercapto groups; and a hydrophilic polyethylene glycol (PEG) unit. These three units were copolymerized by radical polymerization with a certain molar ratio to obtain the amphiphilic linear macromolecules. Then, after the separation and purification, the linear polymer was dissolved in water, which was irradiated with ultraviolet light. Upon irradiation, the phototrigger photocut the chemical bond and free mercapto groups were released, which immediately reacted with the maleimide to generate photo-responsive self-crosslinking. thereby to form hydrogel in the irradiated area. Due to its low toxicity,photo-regulated micro-pattern, non-radical type photo-crosslinking, and without any addition of initiator, such kind of photo-crosslinked hydrogel would have broad application prospects in drug delivery, controlled growth of cells, tissue engineering scaffolds, and some other biomedical fields.(2) The photoresponsive monolayer system with twice charge transformation. We put forward a self-assembled monolayer system which can occur charge quadratic transformation in the second part of the thesis. We used two different phototrigger which was responsive to different wavelengths to connect the carboxyl group and the amino group in a single molecule. Then triethoxy silane was introduced at one end of the molecule to grafted on the quartz surface. In order to improve the water solubility of the monolayer film, we introduced polyethylene glycol at the other end of the molecule. Upon the irradiation of365nm light, the nitrobenzene protected amino group will be released in the monolayer film, which formed positively charged surface; In the same way, the p-hydroxyphenacyl protected carboxyl group will be released after irradiation with a Hg lamp, and the surface charge will changed from positive to negative. Combining with the photo-lithography techniques, this monolayer film with two kinds of charge modification upon regulated light irradaition endowed to fix different electrical materials on the membrane surface.