Department of Biochemistry, Laboratory for Intelligence Modeling & Neurophysics, Boston University School of Medicine, 650 Albany St., X-140, Boston, Massachusetts 02118, United States.
Langmuir. 2013 Feb 5;29(5):1490-7. doi: 10.1021/la303526k. Epub 2013 Jan 18.
Liposomes offer a method to encapsulate high concentrations of a drug, protecting the therapeutic upon in vivo administration. With an appropriate mechanism to manipulate lipid bilayer permeability, liposomes have the potential to deliver encapsulated drugs in a spatially and temporally controlled manner. In this investigation, the photosensitizer aluminum phthalocyanine disulfonic acid (AlPcS(2)) is identified as a modulator of the colloidal properties of liposomes. AlPcS(2) adsorption to liposomes stabilizes lipid bilayers and reduces permeability. Spectroscopic data suggests that AlPcS(2) interacts with the phospholipid to increase lipid bilayer stability. In the presence of AlPcS(2), the liposome permeability was five times lower than that without the photosensitizer. This results in more stable liposome systems that contain higher doses of the encapsulated material for longer. Then, upon irradiation of the AlPcS(2)-liposome system with tissue penetrating red light, lipid bilayer permeability increases 10-fold over the baseline. The release is shown to be a singlet oxygen mediated process, due to the type II photodynamic action of AlPcS(2). It is concluded that this activity provides a novel photorelease mechanism for liposome mediated drug delivery.
脂质体提供了一种封装高浓度药物的方法，在体内给药时可保护治疗药物。通过适当的机制来操纵脂质双层的通透性，脂质体有可能以时空可控的方式输送封装的药物。在这项研究中，光敏剂铝酞菁二磺酸钠（AlPcS(2)）被鉴定为脂质体胶体性质的调节剂。AlPcS(2)吸附到脂质体上稳定了脂质双层并降低了通透性。光谱数据表明，AlPcS(2)与磷脂相互作用以增加脂质双层的稳定性。在 AlPcS(2)存在的情况下，脂质体的通透性比没有光敏剂时低五倍。这导致含有更高剂量封装材料的更稳定的脂质体系统可以维持更长时间。然后，在用组织穿透红光照射 AlPcS(2)-脂质体系统时，脂质双层的通透性比基线增加了 10 倍。释放被证明是一种单线态氧介导的过程，这是由于 AlPcS(2)的 II 型光动力作用。研究结论认为，这种活性为脂质体介导的药物输送提供了一种新的光释放机制。
