具抗污與抗菌特性之兩性離子型多巴胺甲基丙烯醯胺共聚物修飾牙釉質保護塗層

Abstract

齲齒為全球盛行率最高的口腔疾病之一，其發生與唾液蛋白吸附、細菌初始黏附及生物膜形成息息相關。現行臨床主要仰賴含氟製劑 (Duraphat)預防齲齒，雖可促進牙齒再礦化，然而仍存在需定期至診所施作、作用時間有限及缺乏抑制蛋白吸附與生物膜形成能力等限制。因此，本研究結合具仿生黏附能力之多巴胺甲基丙烯酸酯Dopamine methacrylate（DOPMA）與具高度抗污特性之兩性離子單體 2-methacryloyloxyethyl phosphorylcholine（MPC），並導入交聯劑 N,N′-methylenebisacrylamide（MBAA），開發兼具高附著性、抗蛋白吸附、抗菌及抗生物膜能力之 p(DOPMA-co-MPC) 共聚物塗層，期望作為新一代無氟牙釉質保護材料。 本研究利用自由基聚合合成不同 DOPMA與MPC 莫耳比之 p(DOPMA-co-MPC) 共聚物，並以¹H NMR、¹³C NMR、凝膠滲透層析（GPC）、動態光散射（DLS）、Zeta potential、接觸角（Water Contact Angle, WCA）及 UV–Vis 等分析材料特性，再將聚合物塗佈於牛牙牙釉質表面，評估其表面親水性、刷牙耐磨耗性、抗唾液蛋白吸附、抗細菌貼附、抗生物膜形成能力及細胞相容性。 研究結果顯示，各組別 p(DOPMA-co-MPC) 共聚物均成功合成，具有良好的分子量分布及穩定性；加入 MBAA 後可形成粒徑均勻且穩定之微膠結構，有效提升聚合物於牙釉質表面的附著能力及耐磨耗性。WCA 分析結果顯示，隨 MPC 含量增加，材料表面親水性顯著提升，其中 pMPC 因具有超親水特性，水滴接觸後立即鋪展而無法量測接觸角。抗蛋白吸附試驗顯示，所有交聯組均可降低唾液蛋白附著，其中 D1M1/MBAA 組別具有最佳抗蛋白吸附效果。細菌貼附與生物膜分析進一步證實，D1M1/MBAA 能最有效抑制 Streptococcus mutans 與 Escherichia coli 的附著及生物膜形成，整體抗污效果優於其他配方及商用氟漆 Duraphat。刷牙模擬試驗亦顯示，D1M1/MBAA 在機械磨耗後仍能維持良好的塗層完整性與抗污功能，顯示其具有優異的界面穩定性。CCK-8 細胞毒性試驗結果則證實，D1M1和D1M1/MBAA材料均維持良好的細胞存活率，顯示所開發之共聚物具有良好的生物相容性。 綜合以上結果，本研究成功合成兼具高附著性、高親水性、抗蛋白吸附、抗菌貼附、抗生物膜形成及良好生物相容性之 p(DOPMA-co-MPC) 兩性離子共聚物塗層。其中 D1M1/MBAA 展現最佳整體性能，不僅可有效降低牙釉質表面蛋白質與細菌附著，亦能提升塗層於口腔環境中的穩定性，具備作為新世代無氟牙齒防護塗層及長效口腔抗污生醫材料之應用潛力。

Dental caries is one of the most prevalent chronic oral diseases worldwide and is closely associated with salivary protein adsorption, bacterial adhesion, and subsequent biofilm formation. Although fluoride-based agents remain the primary strategy for caries prevention by promoting enamel remineralization, their clinical efficacy is limited by the need for repeated professional application and their inability to effectively inhibit protein adsorption and biofilm development. Therefore, this study aimed to develop a fluoride-free antifouling coating by combining dopamine methacrylate (DOPMA), a mussel-inspired adhesive monomer, with the zwitterionic monomer 2-methacryloyloxyethyl phosphorylcholine (MPC). The resulting p(DOPMA-co-MPC) copolymer was further crosslinked with N,N′-methylenebisacrylamide (MBAA) to improve coating stability and adhesion on enamel surfaces. A series of p(DOPMA-co-MPC) copolymers with different DOPMA/MPC molar ratios were synthesized via free radical polymerization and characterized by 1H NMR, 13C NMR, gel permeation chromatography (GPC), dynamic light scattering (DLS), zeta potential, water contact angle (WCA), and UV–Vis spectroscopy. The copolymer coatings were subsequently applied to bovine enamel surfaces to evaluate their surface wettability, toothbrushing durability, resistance to salivary protein adsorption, antibacterial adhesion, antibiofilm performance, and cytocompatibility. The results demonstrated that all copolymers were successfully synthesized with desirable molecular characteristics. Incorporation of MBAA produced stable microgel structures with uniform particle size distribution, significantly enhancing coating stability and adhesion on enamel surfaces. Increasing the MPC content markedly improved surface hydrophilicity, while pure pMPC exhibited superhydrophilic behavior, resulting in instantaneous water spreading that prevented WCA measurement. Among all formulations, the D1M1/MBAA group exhibited the best overall performance. This formulation showed the lowest salivary protein adsorption, effectively inhibited the adhesion of Streptococcus mutans and Escherichia coli, and significantly suppressed biofilm formation. Furthermore, the D1M1/MBAA coating maintained excellent surface integrity and antifouling performance after simulated toothbrushing, indicating superior mechanical durability and interfacial stability. Cytocompatibility evaluation using the CCK-8 assay confirmed high cell viability for all experimental groups, demonstrating favorable biocompatibility. In conclusion, a mussel-inspired zwitterionic p(DOPMA-co-MPC) coating with excellent adhesion, antifouling capability, antibacterial activity, antibiofilm performance, and biocompatibility was successfully developed. Among the tested formulations, D1M1/MBAA demonstrated the most balanced overall properties, suggesting its promising potential as a durable fluoride-free enamel coating for long-term prevention of dental biofilm formation and dental caries.