Objectives

To functionalize novel chlorhexidine (CHX) particles with iron oxide (Fe₃O₄) nanoparticles and control their release kinetics in a dental resin using an external magnetic field.

Methods

Fe₃O₄ nanoparticles were synthesized and incorporated into spherical CHX particles and the powder was freeze dried. Resin disc specimens were produced using a UDMA-HEMA resin mixed with freeze dried spherical Fe₃O₄-CHX particles (5 wt.%), which were placed into a Teflon mould (10 mm diameter × 1 mm depth) and covered with a Mylar strip. A MACS magnet was left in contact for 0 min (Group 1), 5 min (Group 2) or 10 min (Group 3) and the resin discs subsequently light cured (Bluedent LED pen, Bulgaria) for 60 s per side. The resin discs were immersed in deionized water at various time points up to 650 h. UV–Vis absorbance was used to determine the CHX content. CHX released for each time point was determined. The functionalized CHX particles and resin discs were characterized using TEM, TGA, EDX and SEM.

Results

Fe₃O₄ nanoparticles (20 nm) incorporated into the spherical CHX particles led to a mean (SD) particle size reduction from 17.15 (1.99) μm to 10.39 (2.61) μm. The presence of Fe₃O₄ nanoparticles in the spherical CHX particles was confirmed with SEM, EDX, and TGA. SEM of Group 1 resin discs (no magnetic exposure) showed functionalized CHX spheres were homogeneously distributed within the resin discs. For resin discs which had magnetic exposure (5 or 10 min) the particles started to cluster nearer the surface (Group 2: 43.7%, Group 3: 57.3%), to a depth of 94 μm. UV–Vis absorbance revealed Group 1 resin discs had a cumulative CHX release of 4.4% compared to 5.9% for Group 2 and 7.4% for Group 3 resin discs, which had magnetic exposure (5, 10 min).

Significance

Fe₃O₄ nanoparticle functionalized CHX spheres demonstrated a magnetic field responsive property. A magnetic field responsive release of CHX may be useful in clinical situations where the drug can be directed to give a tailored release at the site of infection.

中文翻译：

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使用磁场控制氯己定从HEMA-UDMA树脂中释放

目标

若要使用氧化铁（Fe ₃ O ₄）纳米粒子功能化新型洗必太（CHX）粒子，并使用外部磁场控制其在牙科树脂中的释放动力学。

方法

合成Fe ₃ O ₄纳米颗粒，并将其掺入球形CHX颗粒中，并将粉末冷冻干燥。使用UDMA-HEMA树脂与冷冻干燥的球形Fe ₃ O ₄混合制备树脂圆盘样品将-CHX颗粒（5重量％）放入特氟隆模具（直径10mm×深度1mm）中并用聚酯薄膜带覆盖。使MACS磁体接触0分钟（第1组），5分钟（第2组）或10分钟（第3组），然后将树脂圆盘光固化（Bluedent LED笔，保加利亚），每边60 s。将树脂圆盘在长达650 h的不同时间点浸入去离子水中。UV-Vis吸光度用于确定CHX含量。确定每个时间点释放的CHX。使用TEM，TGA，EDX和SEM对功能化的CHX颗粒和树脂圆盘进行了表征。

结果

球形CHX颗粒中掺入的Fe ₃ O ₄纳米颗粒（20 nm）导致平均（SD）粒径从17.15（1.99）μm减小到10.39（2.61）μm。Fe ₃ O ₄的存在SEM，EDX和TGA证实了球形CHX颗粒中的纳米颗粒。第1组树脂盘的SEM（无磁暴露）显示，功能化的CHX球均匀地分布在树脂盘中。对于具有磁暴露（5或10分钟）的树脂圆盘，颗粒开始聚集在表面附近（组2：43.7％，组3：57.3％），深度达到94μm。UV-Vis吸光度显示，第1组树脂光盘的累积CHX释放为4.4％，而第2组树脂光盘的磁性暴露（5、10分钟）为5.9％，第3组树脂光盘的7.4％。

意义

Fe ₃ O ₄纳米粒子官能化的CHX球表现出磁场响应特性。CHX的磁场响应释放在临床情况下可能有用，在这种情况下，可以指导药物在感染部位进行定制释放。