Nakamura Maki, Oyane Ayako, Shimizu Yoshiki, Miyata Saori, Saeki Ayumi, Miyaji Hirofumi
Nanomaterials Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), Central 5, 1-1-1, Higashi, Tsukuba, Ibaraki 305-8565, Japan.
Nanomaterials Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), Central 5, 1-1-1, Higashi, Tsukuba, Ibaraki 305-8565, Japan.
Acta Biomater. 2016 Dec;46:299-307. doi: 10.1016/j.actbio.2016.09.015. Epub 2016 Sep 15.
We achieved rapid, surfactant-free, and one-pot fabrication of antibacterial calcium phosphate (CaP) submicrospheres containing silver nanoparticles by combining physical laser and chemical coprecipitation processes. In this physicochemical process, weak pulsed laser irradiation (20min) was performed on a labile CaP reaction mixture supplemented with silver ions as a light-absorbing agent. The silver content in the submicrospheres was controlled for a wide range (Ag/P elemental ratio varied from 0.60 to 62.0) by tuning the initial concentration of silver ions (from 5 to 20mM) in the CaP reaction mixture. At the silver concentration of 5mM, we obtained unique nanocomposite particles: CaP submicrospheres (average diameter of approximately 500nm) containing metallic silver nanoparticles dispersed throughout, as a result of CaP and silver coprecipitation with simultaneous photoreduction of silver ions and spheroidization of the coprecipitates. These CaP submicrospheres containing silver nanoparticles (ca. 0.3mg silver per 1mg submicrospheres) exhibited antibacterial activity against major pathogenic oral bacteria, i.e., Streptococcus mutans, Aggregatibacter actinomycetemcomitans, and Porphyromonas gingivalis. Moreover, the CaP submicrospheres dissolved and neutralized the acidic environment generated by Streptococcus mutans, demonstrating their potential as acid-neutralizing and remineralizing agents. The present process and resulting antibacterial CaP-based submicrospheres are expected to be useful in dental healthcare and infection control.
Nano- and microsized spheres of calcium phosphate (CaP) containing silver nanoparticles have great potential in dental applications. Conventional fabrication processes were time-consuming or weak regarding the size/shape control of the spheres. In this study, we achieved a simple (one-pot), rapid (20-min irradiation), and surfactant-free fabrication of CaP submicrospheres containing silver nanoparticles by pulsed laser irradiation to a mixture of calcium, phosphate, and silver ion solutions. The resulting CaP submicrospheres contained metallic silver nanoparticles dispersed throughout in a sequence of reactions: CaP and silver coprecipitation, laser-induced melting and spheroidization of the coprecipitates, and photoreduction of silver ions. These submicrospheres showed antibacterial activity against oral bacteria and acid-neutralizing property in the bacterial suspension, and hence are worth considering for dental applications.
我们通过结合物理激光和化学共沉淀过程，实现了含银纳米颗粒的抗菌磷酸钙（CaP）亚微球的快速、无表面活性剂且一锅法制备。在这个物理化学过程中，对添加了作为光吸收剂的银离子的不稳定CaP反应混合物进行弱脉冲激光照射（20分钟）。通过调节CaP反应混合物中银离子的初始浓度（从5到20mM），可在很宽的范围内控制亚微球中的银含量（Ag/P元素比从0.60变化到62.0）。在银浓度为5mM时，我们获得了独特的纳米复合颗粒：CaP亚微球（平均直径约为500nm），其中分散着金属银纳米颗粒，这是由于CaP和银共沉淀，同时银离子光还原和共沉淀物球化的结果。这些含银纳米颗粒的CaP亚微球（每1mg亚微球约含0.3mg银）对主要致病性口腔细菌，即变形链球菌、伴放线聚集杆菌和牙龈卟啉单胞菌表现出抗菌活性。此外，CaP亚微球溶解并中和了变形链球菌产生的酸性环境，证明了它们作为酸中和和再矿化剂的潜力。目前的方法和所得的基于CaP的抗菌亚微球有望在牙科保健和感染控制中发挥作用。
含银纳米颗粒的磷酸钙（CaP）纳米和微米级球体在牙科应用中具有巨大潜力。传统的制备过程在球体的尺寸/形状控制方面耗时或效果不佳。在本研究中，我们通过对钙、磷酸盐和银离子溶液的混合物进行脉冲激光照射，实现了含银纳米颗粒的CaP亚微球的简单（一锅法）、快速（20分钟照射）且无表面活性剂的制备。所得的CaP亚微球包含分散在其中的金属银纳米颗粒，经历了一系列反应：CaP和银共沉淀、激光诱导共沉淀物的熔化和球化以及银离子的光还原。这些亚微球在细菌悬浮液中对口腔细菌表现出抗菌活性和酸中和特性，因此在牙科应用中值得考虑。
