Department of Chemistry, Faculty of Science, University of Zanjan, Zanjan, Iran; Nanobiomaterials Group, Pharmaceutical Sciences Research Center, Tehran University of Medical Sciences, Tehran 1417614411, Iran.
Nanobiomaterials Group, Pharmaceutical Sciences Research Center, Tehran University of Medical Sciences, Tehran 1417614411, Iran.
J Photochem Photobiol B. 2018 Apr;181:14-22. doi: 10.1016/j.jphotobiol.2018.02.004. Epub 2018 Feb 9.
Antimicrobial photodynamic therapy (aPDT) has been emerged as a noninvasive strategy to remove bacterial contaminants such as S. mutans from the tooth surface. Photosensitizer (PS), like indocyanine green (ICG), plays a key role in this technique which mainly suffers from the poor stability and concentration-dependent aggregation. An appropriate nanocarrier (NC) with enhanced antibacterial effects could overcome these limitations and improve the efficiency of ICG as a PS. In this study, various ICG-loaded NCs including graphene oxide (GO), GO-carnosine (Car) and GO-Car/Hydroxyapatite (HAp) were synthesized and characterized by Fourier Transform Infrared Spectroscopy (FT-IR), X-ray Diffraction (XRD), Filed Emission Scanning Electron Microscopy (FE-SEM), Energy Dispersive Spectroscopy (EDS), Zeta Potential and Ultraviolet-Visible spectrometry (UV-Vis). The colony forming unit and crystal violet assays were performed to evaluate the antimicrobial and anti-biofilm properties of PSs against S. mutans. The quantitative real-time PCR approach was also applied to determine the expression ratio of the gtfB gene in S. mutans. The zeta potential analysis and UV-Vis spectrometry indicated successful loading of ICG onto/into NCs. GO-Car/HAp showed highest amount of ICG loading (57.52%) and also highest aqueous stability after one week (94%). UV-Vis spectrometry analyses disclosed a red shift from 780 to 800 nm for the characteristic peak of ICG-loaded NCs. In the lack of aPDT, GO-Car@ICG showed the highest decrease in bacterial survival (86.4%) which indicated that Car could significantly promote the antibacterial effect of GO. GO@ICG, GO-Car@ICG and GO-Car/HAp@ICG mediated aPDT, dramatically declined the count of S. mutans strains to 91.2%, 95.5% and 93.2%, respectively (P < 0.05). The GO@ICG, GO-Car@ICG, GO-Car/HAp@ICG significantly suppressed the S. mutans biofilm formation by 51.4%, 63.8%, and 56.8%, respectively (P < 0.05). The expression of gtfB gene was considerably reduced to 6.0, 9.0 and 7.9-fold after aPDT in the presence of GO@ICG, GO-Car@ICG, GO-Car/HAp@ICG, respectively (P < 0.05). It could be concluded that the multi-functionalized GO as a novel nanocarrier could significantly enhance the ICG loading, stability, and improve its inhibitory effects as a photosensitizer in aPDT against S. mutans. These findings might provide opportunity for efficient treatment of local dental infections.
抗菌光动力疗法 (aPDT) 已成为一种从牙齿表面去除细菌污染物（如变形链球菌）的非侵入性策略。光敏剂 (PS)，如吲哚菁绿 (ICG)，在该技术中起着关键作用，但主要受到稳定性差和浓度依赖性聚集的限制。适当的纳米载体 (NC) 具有增强的抗菌作用，可以克服这些限制并提高 ICG 作为 PS 的效率。在这项研究中，合成了各种负载 ICG 的 NC，包括氧化石墨烯 (GO)、GO-肌肽 (Car) 和 GO-Car/羟基磷灰石 (HAp)，并通过傅里叶变换红外光谱 (FT-IR)、X 射线衍射 (XRD)、场发射扫描电子显微镜 (FE-SEM)、能谱 (EDS)、Zeta 电位和紫外可见分光光度计 (UV-Vis) 进行了表征。通过平板菌落计数和结晶紫测定评估 PS 对变形链球菌的抗菌和抗生物膜特性。还应用实时定量 PCR 方法来确定变形链球菌 gtfB 基因的表达比率。Zeta 电位分析和 UV-Vis 光谱表明 ICG 成功加载到 NC 上/内。GO-Car/HAp 显示出最高的 ICG 载药量（57.52%），并且在一周后也具有最高的水稳定性（94%）。UV-Vis 光谱分析显示，负载 ICG 的 NC 的特征峰从 780nm 红移至 800nm。在缺乏 aPDT 的情况下，GO-Car@ICG 显示出最高的细菌存活率降低（86.4%），表明 Car 可以显著促进 GO 的抗菌作用。GO@ICG、GO-Car@ICG 和 GO-Car/HAp@ICG 介导的 aPDT 可使变形链球菌菌株的数量分别减少到 91.2%、95.5%和 93.2%（P<0.05）。GO@ICG、GO-Car@ICG、GO-Car/HAp@ICG 分别显著抑制变形链球菌生物膜形成 51.4%、63.8%和 56.8%（P<0.05）。GO@ICG、GO-Car@ICG、GO-Car/HAp@ICG 存在时，gtfB 基因的表达分别降低了 6.0、9.0 和 7.9 倍（P<0.05）。在 aPDT 后。结论：作为一种新型纳米载体的多功能化 GO 可以显著提高 ICG 的载药量、稳定性，并提高其作为 PS 在 aPDT 中对变形链球菌的抑制作用。这些发现可能为局部口腔感染的有效治疗提供机会。
