Methylene blue-loaded liposomes for enhanced photodynamic therapy

Photodynamic therapy is currently presented as a promising alternative to treat various pathologies. This technique is based on the use of a non-toxic photosensitizer, which can absorb energy from a light source with specific wavelength and irradiance characteristics. This process allows the photosensitizer to reach a higher energy state, triggering photochemical reactions that, in the presence of oxygen, generate reactive oxygen species capable of eliminating microorganisms.

Methylene blue, a compound derived from phenothiazine, has demonstrated analgesic, antibacterial and antitumor properties. In addition, compared to other photosensitizers, such as aminolevulinic acid, it offers the advantage of being less expensive.

Nonetheless, this photosensitizer presents some limitations, including limited tissue penetration and low stability in biological environments. To address these challenges, one possible solution is the utilization of nanometric vesicles to encapsulate and deliver the photosensitizer.

This work focuses on the design of liposomes containing methylene blue, which were coated with a hydrophilic polymer to prolong their permanence time at the application site.

光动力疗法现被视为治疗多种病理状态的有前景的替代疗法。该技术基于使用一种非毒性光敏剂，该光敏剂能够吸收具有特定波长和辐照度特性的光源能量。此过程使光敏剂达到更高的能量状态，从而触发光化学反应，在氧气存在的情况下，生成能够消除微生物的活性氧种。亚甲蓝，一种由苯噻嗪衍生的化合物，已显示出镇痛、抗菌和抗癌的特性。此外，与氨基卟啉酸等其他光敏剂相比，它还具有成本较低的优点。然而，这种光敏剂存在一些局限性，包括组织渗透性有限和在生物环境中的稳定性低。为了解决这些挑战，一个可能的解决方案是利用纳米级囊泡封装和递送光敏剂。本研究聚焦于设计含有亚甲蓝的脂质体，并使用亲水性聚合物对其进行涂层，以延长其在应用部位的停留时间。