【公開日：2023.07.28】【最終更新日：2023.05.21】
課題データ / Project Data
課題番号 / Project Issue Number
22HK0040
利用課題名 / Title
Photoreactive materials for enamel remineralization
利用した実施機関 / Support Institute
北海道大学 / Hokkaido Univ.
機関外・機関内の利用 / External or Internal Use
外部利用/External Use
技術領域 / Technology Area
【横断技術領域 / Cross-Technology Area】（主 / Main）計測・分析/Advanced Characterization（副 / Sub）-
【重要技術領域 / Important Technology Area】（主 / Main）量子・電子制御により革新的な機能を発現するマテリアル/Materials using quantum and electronic control to perform innovative functions（副 / Sub）-
キーワード / Keywords
電子顕微鏡/Electron microscopy,核磁気共鳴/Nuclear magnetic resonance,電子分光,表面・界面・粒界制御/ Surface/interface/grain boundary control
利用者と利用形態 / User and Support Type
利用者名（課題申請者）/ User Name (Project Applicant)
Zuniga Enrique
所属名 / Affiliation
北海道医療大学大学院歯学研究科
共同利用者氏名 / Names of Collaborators in Other Institutes Than Hub and Spoke Institutes
ARIM実施機関支援担当者 / Names of Collaborators in The Hub and Spoke Institutes
吉田すずか,鈴木啓太
利用形態 / Support Type
（主 / Main）技術代行/Technology Substitution（副 / Sub）-
利用した主な設備 / Equipment Used in This Project
報告書データ / Report
概要（目的・用途・実施内容）/ Abstract (Aim, Use Applications and Contents)
Orthodontic treatments are associated with an increased incidence of enamel demineralization, emphasizing the need for novel materials that can effectively control the release of calcium ions (Ca2+) and prevent this condition. One promising approach to achieve this goal is through the surface modification of Bioactive glass, which allows for the attachment of molecules capable of regulating Ca2+ release via different stimuli. In recent times, Photoreactive materials have gained attention due to their ability to provide precise and localized control over drug delivery, as well as optimize therapeutic formulations and regimens. These advantages are particularly important in the development of materials for enamel remineralization.
The aim of this study is to investigate the effectiveness of a photoreactive macrocyclic structure attached to the Bioactive glass surface in regulating Ca2+ uptake and release. Through the evaluation of changes in Ca2+ concentration in the medium, we aim to gain insights into the efficacy of this approach and its potential applications in orthodontics. This research has the potential to lead to the development of innovative therapeutic strategies to address enamel demineralization and improve orthodontic treatments.
実験 / Experimental
Bioactive glass was synthesized using the sol-gel method and subsequently characterized using scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), and transmission electron microscopy (TEM). The photoreactive macrocyclic structure, containing a pyridine group, was synthesized using traditional liquid synthesis and characterized using nuclear magnetic resonance (NMR) to evaluate the phase switch. For the immobilization of the photoreactive structure, the surface of the bioactive glass was functionalized using (3-aminopropyl)triethoxysilane (APTES). The macrocyclic structure was then immobilized onto the bioactive glass surface. The resulting material was characterized using SEM, TEM, EDX, and X-ray photoelectron spectroscopy (XPS). The XPS analysis indicated an increase in nitrogen groups as the content of the macrocyclic structure increased, confirming successful immobilization of the material.
The samples immersed in artificial saliva were exposed to UV light for 15 minutes followed by LED light for 15 minutes, with the light source being switched alternately until a total irradiation time of 1 hour was reached. During this time, changes in the calcium concentration were detected and measured using a sensor.
結果と考察 / Results and Discussion
The microscopy evaluation of the bioactive glass nanoparticles after immobilization revealed that the bioactive glass nanoparticles have an irregular shape with a particle size of 20nm. The X-ray photoelectron spectroscopy (XPS) analysis further showed that the nitrogen content increased due to the immobilization of the macrocyclic structure, with a direct proportional relationship to the amount of macrocyclic structure mixed with bioactive glass (Fig 1).
Additionally, the BG samples containing 5mg and 10mg of the organic compound displayed the presence of nanoribbons. These findings suggest that bioactive glass nanoparticles have potential for various applications. However, it is important to conduct further research and analysis to fully understand the significance and implications of these results (Fig 2).
The calcium release assay revealed that with UV light, calcium was released, while with LED light, calcium was taken from the medium. A statistically significant difference was observed with the unmodified bioactive glass nanoparticles (Figure 3 ).
In conclusion, this study successfully synthesized and immobilized a photoreactive macrocyclic structure to control calcium in the medium. These findings suggest the potential for a new series of materials for enamel remineralization.
図・表・数式 / Figures, Tables and Equations
Figure １ XPS spectra of the ether ligand (EL1) immobilized on the surface of the bioactive glass (BG) at different concentrations. (a) 5mg (EL1-5), (b) 10mg (EL1-10), (c) 30mg (EL1-30).
Figure 2 displays FE-SEM (field emission scanning electron microscopy) images of the ether ligand (EL1) immobilized on the surface of the bioactive glass (BG) at different concentrations. (a) 5mg (EL1-5), (b) 10mg (EL1-10), (c) 30mg (EL1-30). All SEM images were taken at a magnification of ×6,500.
Figure 3 Changes in Ca2+ concentration were observed for the ether ligand (30 mg; EL1-30) with switch on/off every 30 min, The change in irradiation source at 30 min reflects the capture and release of Ca2+
その他・特記事項（参考文献・謝辞等） / Remarks(References and Acknowledgements)
成果発表・成果利用 / Publication and Patents
論文・プロシーディング（DOIのあるもの） / DOI (Publication and Proceedings)
口頭発表、ポスター発表および、その他の論文 / Oral Presentations etc.
- (1) Zuniga-Heredia EE, Arteaga Arteaga F, Iijima M, Sawamura M. Bioactive glass surface functionalization for Ca2+ control. International Symposium of Porous Materials, Tokyo, Japan, 2021/11/4-5.
- (2) Zuniga-Heredia EE, Arteaga Arteaga F, Iijima M, Sawamura M. Photoswitchable azopyridine macrocyclic structure on bioactive glass for controlled release of Ca2+. The 102nd annual meeting of the Chemical society of Japan, Kobe, Japan, 2022/03/23-26.
特許 / Patents
特許出願件数 / Number of Patent Applications：0件
特許登録件数 / Number of Registered Patents：0件