생체 분자 말단기를 가지는 브러쉬 고분자의 합성 및 분석 연구
- 생체 분자 말단기를 가지는 브러쉬 고분자의 합성 및 분석 연구
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- Polymeric materials of any dimensions, including miniaturized and multilayer structure, can easily be processed at low cost and have high flexibility, high mechanical strength, and good scalability. Furthermore, their properties can easily be tailored through chemical synthesis. Through chemical bonding of specific molecules to the polymer backbone or side chain, the function of polymer can be changed. With such advantages, there has been significant research effort in recent years in the field of brush polymer.
Brush polymers were first reported in the 1940s with the synthesis of a polyvinyl polymer with n-alkyl side groups. Brush polymers have since received significant attention from both academia and industry because their numerous end groups permit high loading of desirable functional groups onto the polymer. Research efforts developed synthetic routes to new functional brush polymers, and the structures and properties of these new polymers have been investigated. Several interesting brush polymer systems have been described as potential candidate materials for applications in a range of fields, such as biomaterials, microelectronics, flat panel displays, optics and optoelectronics, solar cells, adhesives, and gas separation techniques.
In the area of biomaterials, biomolecule-mimicking brush polymers may be useful in a variety of solid forms as biocompatible coating materials, tissue culture materials, biomedical sensor materials, protein separation membranes, and gene delivery carriers. Most of these applications require formation of nanoscale thin films with control over the nanostructures.
In Chapter II, New DNA-mimicking brush polymers were synthesized: poly[oxy(11-(3-(9-adeninyl)propionato)-undecanyl-1-thiomethyl)ethylene] (PECH-A), poly[oxy(11-(thyminyl- 1-aceto)-undecanyl-1-thiomethyl)ethylene] (PECH-T), poly[oxy(11-(3-(9-guanyl)propionato)-undecanyl-1-thiomethyl)ethylene] (PECH-G), poly[oxy(11-(N4-acetylcytosinyl-1-aceto)-undecanyl-1-thiomethyl)ethylene] (PECH-C), and poly[oxy(11-(urasilyl-1-aceto)-undecanyl-1-thiomethyl)ethylene] (PECH-U). These polymers were found to be thermally stable up to 220 C and could be applied easily by conventional coating processes to produce good quality films. Interestingly, brush polymers formed molecular layer structures to provide nucleobase-rich surfaces. The nucleobase-rich surfaces of the polymer films demonstrated selective protein adsorption, suppressed bacterial adherence, facilitated HEp-2 cell adhesion, and exhibited good biocompatibility in mice.
In Chapter III, We synthesized two new DNA-mimicking brush polymers: poly[oxy(11-(3-(9-adeninyl)propionato)-undecanyl-1-thiomethyl)ethylene] (PECH-AP) and poly[oxy(11-(5-(9-adenylethyloxy)-4-oxopentanoato)undecanyl-1-thiomethyl)ethylene] (PECH-AS). These polymers were found to be thermally stable up to 220 C and could be applied easily by conventional coating processes to produce good quality films. Interestingly, both brush polymers formed molecular multi-bilayer structures to provide an adenine-rich surface. Despite the structural similarities, PECH-AS surprisingly exhibited higher hydrophilicity and better water sorption properties than PECH-AP. These differences were attributed to the chemical structures in the bristles of the polymers. The adenine-rich surfaces of the polymer films demonstrated selective protein adsorption, suppressed bacterial adherence, facilitated HEp-2 cell adhesion, and exhibited good biocompatibility in mice. However, the high hydrophilicity and good water sorption characteristics of the PECH-AS film suggest that this brush polymer is better suited to applications requiring good biocompatibility and reduced chance of bacterial infection compared with the PECH-AP film.
In Chapter IV, we synthesized novel brush polymers bearing thymine moieties in which the chemical loading of thymine moieties is maximized and that self-assemble into molecular layer-by-layer structures (i.e., molecular lamellar structures) and provide thymine-rich surfaces: poly(oxy(11-thyminoacetyloxyundecylthiomethyl)ethylene) (PECH(S)-T) and poly(oxy(11-thyminoacetyloxyundecylsulfonylmethyl)ethylene) (PECH(SO2)-T). These brush polymers are thermally stable up to around 225C. PECH(S)-T exhibits relatively high water sorption whereas PECH(SO2)-T exhibits low water sorption. The synchrotron grazing incidence X-ray scattering (GIXS) analysis found that thin films of PECH(S)-T are amorphous but that it forms a molecular lamellar structure in water as well as in metal ion solutions, whereas thin films of PECH(SO2)-T always have molecular lamellar structures providing thymine-rich surfaces
this lamellar structure is retained in water and metal ion solutions. Surface plasmon resonance spectroscopy (SPRs) analysis was performed and it was found that PECH(SO2)-T exhibits excellent sensitivity, selectivity, and reversibility in sensing mercury ions in aqueous solutions, with properties that are superior to those of PECH(S)-T. We propose a strategy based on the control of morphological nanostructure for developing high performance polymers for the chemical monitoring of metal ions.
In Chapter V, we synthesized novel poly(ethylene oxide) based brush polymers with glucose bristle end. The brush polymers are thermally stable up to 200 °C and present excellent processability
nanometer-scale thin films of the polymers with smooth surfaces are easy to produce through simple spin-, roll- and dip-coating, and subsequent drying process. In thin film states, brush polymers exhibit molecular layer structures with stable glucose-rich surfaces. Surfaces of brush glycopolymers suppressed protein adsorption and promoted HEp-2 cell adhesion. Furthermore, the brush polymer revealed biocompatibility in mice.
In Chapter VI, A series of well-defined brush polymers, poly(oxy(11-(3-sulfonylpropyltrimethyl-glycinyl)undecylesterthiomethyl)ethylene-co-oxy(n-dodecylthio-methyl)ethylene)s (PECH-DMAPSm, where m is the mol% of DMAPS (sulfobetaine) end group) were synthesized. The thermal properties and phase transitions of these polymers were investigated. The polymers were thermally stable up to 185 C. The polymers were found to form favorably into multi-bilayer structures, always providing hydrophilic, zwitterionic sulfobetaine end groups at the film surface. Because of the sulfobetaine groups present at the surface, the polymer films promoted HEp-2 cell adhesion and revealed biocompatibility in mice but significantly suppressed protein adsorption. These results collectively indicate that the sulfobetaine-containing brush polymers are suitable for use in biomedical applications, including medical devices and biosensors that require biocompatibility.
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