Abstract

It has been demonstrated an increase in resistance of Candida albicans to conventional therapies, probably, due the indiscriminate use of the conventional antifungal drugs. In this aspect, the nanotechnology generates the possibility of creating new therapeutic agents. Thus, the objective of this paper was to produce and characterize a bovine serum albumin (BSA) nanoparticle encapsulated with Methylene Blue (MB). In addition, the effect of BSA nanoparticles encapsulated with MB (BSA-MB) was evaluated on both growth and biofilm formation by C. albicans by Photodynamic Antimicrobial Chemotherapy (PACT) protocols. The BSA-MB nanoparticles were prepared by the desolvation process. The nanoparticulate system was studied by steady-state techniques, scanning electron microscopy and their biological activity was evaluated in vitro both growth and biofilm formation by C. albicans. The synthetized BSA-MB nanoparticles were spherical in shape exhibiting a 100–200 nm diameter with a low tendency to aggregate (PDI values < 0.2). MB photophysical properties were shown to be preserved after BSA encapsulation. A significant reduction in C. albicans growth, after PACT was observed, in a dependent manner on MB-loaded in BSA nanoparticles concentration used. It was observed an inhibition of 23, 65 and 83% in the presence of MB-loaded in BSA nanoparticles 0.1, 0.5 and 1.0 µg.mL⁻¹, respectively. In addition, MB-loaded BSA nanoparticles 0.5 µg.mL⁻¹ were able to reduce both biofilm formation (80%) and the transition from yeast to filamentous form by C. albicans. The results presented here demonstrated a potentiation of the phototoxic effect of MB after BSA encapsulation, since the concentrations of MB-loaded BSA nanoparticles necessary to inhibits ∼50% of C. albicans development was 10 times minor than that observed for free MB. Taken together, these results suggest the potential of PACT, using MB-loaded BSA nanoparticles in inhibiting C. albicans development. The synthesis and design of BSA nanoparticles can be successfully applied for MB encapsulation and offer the possibility to drive the toxicity effect to a specific target, as an evaluation on both growth and biofilm formation by Candida albicans.

摘要

已经证明白色念珠菌对常规疗法的抵抗力增加，这可能是由于不加区别地使用常规抗真菌药物所致。在这方面，纳米技术产生了创造新治疗剂的可能性。因此，本文的目的是生产和表征用亚甲蓝 (MB) 封装的牛血清白蛋白 (BSA) 纳米颗粒。此外，还评估了用 MB (BSA-MB) 封装的 BSA 纳米粒子对白色念珠菌的生长和生物膜形成的影响通过光动力抗菌化学疗法 (PACT) 协议。BSA-MB 纳米粒子是通过去溶剂化过程制备的。通过稳态技术、扫描电子显微镜研究纳米颗粒系统，并在体外评估了白色念珠菌的生长和生物膜形成的生物活性。合成的 BSA-MB 纳米颗粒呈球形，直径为 100-200 nm，具有低聚集趋势（PDI 值 < 0.2）。在 BSA 封装后，MB 光物理特性得以保留。白色念珠菌显着减少在观察到 PACT 后，生长以依赖于所用 BSA 纳米颗粒中 MB 负载的方式。在 BSA 纳米颗粒 0.1、0.5 和 1.0 µg.mL ^{-1 中}存在负载 MB 的情况下，观察到抑制分别为 23、65 和 83% 。此外，加载 MB 的 BSA 纳米粒子 0.5 µg.mL ^-1能够减少生物膜形成 (80%) 和白色念珠菌从酵母到丝状形式的转变。这里展示的结果证明了 BSA 封装后 MB 的光毒性作用增强，因为负载 MB 的 BSA 纳米粒子的浓度是抑制约 50%白色念珠菌所必需的发展比观察到的免费 MB 小 10 倍。总之，这些结果表明 PACT 的潜力，即使用载有 MB 的 BSA 纳米颗粒抑制白色念珠菌的发展。BSA 纳米粒子的合成和设计可以成功应用于 MB 封装, 并提供将毒性作用驱动到特定目标的可能性, 作为对白色念珠菌生长和生物膜形成的评估。