Fouladi Farnaz, Steffen Kristine J, Mallik Sanku
Department of Pharmaceutical Sciences, North Dakota State University , Fargo, North Dakota 58108, United States.
Bioconjug Chem. 2017 Apr 19;28(4):857-868. doi: 10.1021/acs.bioconjchem.6b00736. Epub 2017 Mar 8.
Liposomes are nanocarriers that deliver the payloads at the target site, leading to therapeutic drug concentrations at the diseased site and reduced toxic effects in healthy tissues. Several approaches have been used to enhance the ability of the nanocarrier to target the specific tissues, including ligand-targeted liposomes and stimuli-responsive liposomes. Ligand-targeted liposomes exhibit higher uptake by the target tissue due to the targeting ligand attached to the surface, while the stimuli-responsive liposomes do not release their cargo unless they expose to an endogenous or exogenous stimulant at the target site. In this review, we mainly focus on the liposomes that are responsive to pathologically increased levels of enzymes at the target site. Enzyme-responsive liposomes release their cargo upon contact with the enzyme through several destabilization mechanisms: (1) structural perturbation in the lipid bilayer, (2) removal of a shielding polymer from the surface and increased cellular uptake, (3) cleavage of a lipopeptide or lipopolymer incorporated in the bilayer, and (4) activation of a prodrug in the liposomes.
脂质体是一种纳米载体,可将所载物质递送至靶位点,从而在病变部位达到治疗药物浓度,并降低对健康组织的毒性作用。已经采用了几种方法来增强纳米载体靶向特定组织的能力,包括配体靶向脂质体和刺激响应脂质体。由于表面连接有靶向配体,配体靶向脂质体在靶组织中的摄取率更高,而刺激响应脂质体除非在靶位点暴露于内源性或外源性刺激物,否则不会释放其所载物质。在本综述中,我们主要关注对靶位点酶水平病理性升高有响应的脂质体。酶响应脂质体通过几种去稳定机制在与酶接触时释放其所载物质:(1)脂质双层中的结构扰动;(2)从表面去除屏蔽聚合物并增加细胞摄取;(3)切割掺入双层中的脂肽或脂聚合物;(4)激活脂质体中的前药。