Department of Chemistry, National Taiwan University, Taipei 10617, Taiwan.
Department of Bioscience and Biotechnology, National Taiwan Ocean University, Keelung 20224, Taiwan; Center of Excellence for the Oceans, National Taiwan Ocean University, Keelung 20224, Taiwan; College of Pharmacy, Kaohsiung Medical University, Kaohsiung 80708, Taiwan.
J Colloid Interface Sci. 2022 Dec 15;628(Pt A):717-725. doi: 10.1016/j.jcis.2022.08.003. Epub 2022 Aug 2.
Most biochemical reactions that occur in living organisms are catalyzed by a series of enzymes and proceed in a tightly controlled manner. The development of artificial enzyme cascades that resemble multienzyme complexes in nature is of current interest due to their potential in various applications. In this study, a nanozyme based on photoswitchable carbon-dot liposomes (CDsomes) was developed for use in programmable catalytic cascade reactions. These CDsomes prepared from triolein are amphiphilic and self-assemble into liposome-like structures in an aqueous environment. CDsomes feature excitation-dependent photoluminescence and, notably, can undergo reversible switching between a fluorescent on-state and nonfluorescent off-state under different wavelengths of light irradiation. This switching ability enables the CDsomes to exert photocatalytic oxidase- and peroxidase-like activities in their on- (bright) and off- (dark) states, respectively, resulting in the conversion of oxygen molecules into hydrogen peroxide (HO), followed by the generation of active hydroxyl radicals (OH). The two steps of oxygen activation can be precisely controlled in a sequential manner by photoirradiation at different wavelengths. Catalytic reversibility also enables the CDsomes to produce sufficient reactive oxygen species (ROS) to effectively kill tumor cells. Our results reveal that CDsomes is a promising photo-cycling nanozyme for precise tumor phototherapy through regulated programmable cascade reactions.
大多数发生在生物体中的生化反应都是由一系列酶催化的，并以严格控制的方式进行。由于其在各种应用中的潜力，目前人们对开发类似于天然多酶复合物的人工酶级联反应很感兴趣。在这项研究中，开发了一种基于光开关碳点脂质体（CDsomes）的纳米酶，用于可编程催化级联反应。这些由三油酸甘油酯制备的 CDsomes 具有两亲性，并在水相环境中自组装成类似脂质体的结构。CDsomes 具有激发依赖性的光致发光特性，值得注意的是，在不同波长的光照射下，它们可以在荧光开启态和非荧光关闭态之间进行可逆切换。这种切换能力使 CDsomes 在开启（明亮）和关闭（黑暗）状态下分别发挥类过氧化物酶和过氧化物酶的光催化活性，导致氧分子转化为过氧化氢（HO），随后产生活性羟基自由基（OH）。通过在不同波长下进行光照射，可以精确地顺序控制这两个氧激活步骤。催化可逆性还使 CDsomes 能够产生足够的活性氧物质（ROS），有效地杀死肿瘤细胞。我们的研究结果表明，CDsomes 是一种有前途的光循环纳米酶，可通过调节可编程级联反应进行精确的肿瘤光疗。
