Abstract：
Nanomaterial-mediated antibacterial photodynamic therapy (aPDT) emerges as a promising treatment against antibiotic-resistant bacterial biofilms. Specifically, titanium dioxide nanoparticles (TiO2 NPs) are being investigated as photosensitizers in aPDT to address biofilm related diseases. To enhance their photocatalytic performance in the visible spectral range for biomedical applications, various strategies have been adopted, including reduction of TiO2 NPs. However, despite improvements in visible-light photoactivity, reduced TiO2 NPs have yet to reach their expected performance primarily due to the instability of oxygen vacancies and their tendency to reoxidize easily. To address this, we present a two-step approach to fabricate highly visible-light active and stable TiO2 NP photocatalysts, involving nitrogen doping followed by a magnesium-assisted reductive annealing process. X-ray photoelectron spectroscopy analysis of the synthesized reduced nitrogen-doped TiO2 NPs (H:Mg-N-TiO2 NPs) reveals that the presence of nitrogen stabilizes oxygen vacancies and reduced Ti species, leading to increased production of reactive oxygen species under visible-light excitation. The improved aPDT efficiency translates to a 3-fold enhancement in the antibiofilm activity of nitrogen-doped compared to undoped reduced TiO2 NPs against both Gram-positive (Streptococcus mutans) and Gram-negative (Porphyromonas gingivalis, Fusobacterium nucleatum) oral pathogens. These results underscore the potential of H:Mg-N-TiO2 NPs in aPDT for combating bacterial biofilms effectively.
摘要：
纳米材料介导的抗菌光动力疗法（aPDT）作为一种有前途的治疗抗生素抗性细菌生物膜。具体来说,二氧化钛纳米粒子（TiO2NP）作为光敏剂在aPDT中的研究，以解决生物膜相关的疾病。为了增强其在可见光谱范围内的光催化性能，用于生物医学应用，采取了各种策略，包括TiO2NP的还原。然而,尽管可见光活性有所改善，主要由于氧空位的不稳定性和它们容易再氧化的倾向,还原的TiO2NP尚未达到其预期性能。为了解决这个问题，我们提出了一种两步方法来制造高可见光活性和稳定的TiO2NP光催化剂，涉及氮掺杂，然后进行镁辅助还原退火工艺。合成的还原氮掺杂TiO2NP（H：Mg-N-TiO2NP）的X射线光电子能谱分析显示，氮的存在稳定了氧空位和还原的Ti物种，导致在可见光激发下活性氧的产生增加。与未掺杂的还原TiO2NP相比，提高的aPDT效率转化为氮掺杂的抗生物膜活性提高了3倍，对革兰氏阳性（变异链球菌）和革兰氏阴性（牙龈卟啉单胞菌，有核梭杆菌)口腔病原体。这些结果强调了aPDT中H:Mg-N-TiO2NP有效对抗细菌生物膜的潜力。
