四級銨鹽與聚乙二醇接合於矯正用聚甲基丙烯酸甲酯表面之製備、特性及抗菌功能探討

Quaternary ammonium salt and polyethylene glycol grafted orthodontic PMMA surfaces – preparation, characterization, and anti-bacterial function

李忠遠(Chung-Yuan Lee)

指導教授 ： 張哲政

國立臺灣大學/理學院/化學研究所/碩士(2015年)

https://doi.org/10.6342/NTU.2015.02639

摘要

牙齒矯正活動維持器(Retainer)使用者中，有較高的風險被口腔中的細菌感染，而在細菌感染過程中，容易以產生生物膜的形式貼附在維持器表面上，使維持器保存不易且增加細菌感染風險，產生各種口腔疾病。
生醫材料的研究中，許多研究團隊致力於研究高分子表面修飾，藉由改變表面性質，如:官能基、親疏水性和生物活性分子等，使材料表面降低細菌存活的機率，達到抗菌材料的功效。
在本研究將探討使用牙醫臨床上使用的維持器基材聚甲基丙烯酸甲酯(PMMA)藉由表面修飾的方法使聚甲基丙烯酸甲酯的表面性質改變，接上具有抗菌能力的分子，並進行材料表面的各種分析，達到抗菌效果。
在本論文中，以反射式傅立葉轉換紅外線光譜儀(ATR-FTIR)、接觸角(CA)、化學分析能譜儀(XPS)對樣品進行表面分析，了解抗菌活性分子是否有接在聚甲基丙烯酸甲酯表面上。接著進一步進行抗菌實驗測試，並藉由掃描式電子顯微鏡(SEM)觀察表面細菌分布情形。結果呈現出四級銨鹽活性分子接在基材表面上後，具有良好的抗菌能力，此材料在未來應具有不錯的發展性。

關鍵字

四級銨鹽 ； 聚乙二醇 ； 表面修飾 ； 表面分析 ； 抗菌

並列摘要

Bacterial infections on biomedical devices have caused dental caries, periodontal disease, and osteomyelitis. Bacteria can easily colonize on the surface of the synthetic material and substance such as acrylic resin that is often used in removable appliances and retainers for orthodontic treatment. The growing bacteria colonies encapsulate themselves in a bacteria-produced matrix (called biofilm) of extracellular polysaccharides, proteins, and lipids, which protects the bacteria from purgation. The biofilm on the orthodontic resin surface causes the users to risk the possibility of oral infections.
In this thesis research, a facile method via acid treatment was developed to chemically modify surfaces for inhibition of bacterial colonization on biomedical devices. The modification was performed on an exemplified device of poly (methyl methacrylate) (PMMA) using antibacterial adhesion compounds such as poly (ethylene glycol) (PEG) and quaternary ammonium salt (QAS). PMMA was made via a pressurized process, which is a typical clinical fabrication method. Two synthesis routes were adopted for antibacterial adhesion. The PEG route treated the PMMA surface with PEG and sodium methoxide in methanol to yield the PEG-grafted PMMA (called PEG-g-PMMA). The QAS route treated the PMMA surface with acid first and then with QAS to obtain the QAS-grafted PMMA (called QAS-PMMA). To characterize the treated surface, the PEG-g-PMMA and QAS-PMMA samples were examined by attenuated total reflectance Fourier transform infrared spectroscopy (FTIR), contact angle (CA) measurements, X-ray photoelectron spectroscopy (XPS), and bacterial tests. Compared with the spectra obtained from pristine PMMA, the decrease in peak intensity at ~289.0 eV and increase in intensity at ~286.4 eV of the XPS C1s spectra obtained from PEG-g-PMMA, the increases in FTIR absorption at ~1096 cm-1 and ~3400 cm-1 due to the C-O-C stretching and O-H stretching vibrations, respectively, and the increased wettability confirmed the success in PEG grafting on the PMMA surface. The large increase in the C/O ratio of XPS survey spectra and the appearance of chloride and quaternary nitrogen signals in the XPS spectra obtained from QAS-g-PMMA confirmed the grafting of QAS on PMMA. The antibacterial function of the pristine or grafted PMMA material was tested via dropping human saliva on the material surface before the surface was brought to get in contact with the bacteria. After removing the bacteria, the materials sample was incubated in a bacteria-free solution and the O.D. value of the solution was measured at the wavelength of 600 nm. PEG-g-PMMA exhibited similar O.D. values with that of pristine PMMA. However, QAS-PMMA exhibited lower O.D. values than that of pristine PMMA. The PEG-g-PMMA gave a measured O.D. value close to that of pristine PMMA, and the QAS-g-PMMA showed a distinctively lower O.D. values. The O.D. value of S. mutans on PEG-g-PMMA was about 1.604 and pristine PMMA was 1.731. Both two high O.D. values expressed that the bacteria could develop on their surfaces. The O.D. value of S. mutans on QAS-g-PMMA was 0.020 which was significantly lower than the other two trials. The O.D. values of E. coli on the three types of PMMA showed the same trend as those of S. mutans. SEM studies of PEG-g-PMMA showed aggregation of PEG on PMMA and PEG-free areas. After antimicrobial tests, SEM images showed more bacteria colonized on PEG-g-PMMA and pristine PMMA than on QAS-g-PMMA. The presence of the PEG-free areas in the synthesized PEG-g-PMMA surface may thus contribute to its poor antimicrobial activity. Compared with the SEM images of PEG-g-PMMA, the images of QAS-g-PMMA showed the QAS grafting molecules to be relatively more evenly distributed in the QAS-g-PMMA surface than the PEG molecules in the PEG-g-PMMA surface. The disruption of bacteria membrane was also observed in the SEM images of QAS-g-PMMA. It indicated that the QAS-g-PMMA surfaces possessed antibacterial ability and would become prospective biomaterial on inhibiting bacteria. The possible antibacterial mechanism of QAS-g-PMMA is discussed.
In conclusion, the fabricated method of QAS-g-PMMA we used is relatively low-cost and easy way to fabricate antibacterial material in wet chemistry without plasma instrument. The QAS-g-PMMA was done by only using acid modified PMMA surface and QAS treated to form grafted antibacterial material.

並列關鍵字

QAS ； PEG ； surface modification ； surface analysis ； antibacterial ability

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