The application of fluorescent II-VI semiconductor quantum dots (QDs) as active photosensitizers in photodymanic inactivation (PDI) is still being evaluated. In the present study, we prepared 3 nm size CdTe QDs coated with mercaptosuccinic acid and conjugated them electrostatically with Zn(II) meso-tetrakis (N-ethyl-2-pyridinium-2-yl) porphyrin (ZnTE-2-PyP or ZnP), thus producing QDs-ZnP conjugates. We evaluated the capability of the systems, bare QDs and conjugates, to produce reactive oxygen species (ROS) and applied them in photodynamic inactivation in cultures of Candida albicans by irradiating the QDs and testing the hypothesis of a possible combined contribution of the PDI action. Tests of in vitro cytotoxicity and phototoxicity in fibroblasts were also performed in the presence and absence of light irradiation. The overall results showed an efficient ROS production for all tested systems and a low cytotoxicity (cell viability >90%) in the absence of radiation. Fibroblasts incubated with the QDs-ZnP and subjected to irradiation showed a higher cytotoxicity (cell viability <90%) depending on QD concentration compared to the bare groups. The PDI effects of bare CdTe QD on Candida albicans demonstrated a lower reduction of the cell viability (~1 log10) compared to bare ZnP which showed a high microbicidal activity (~3 log10) when photoactivated. The QD-ZnP conjugates also showed reduced photodynamic activity against C. albicans compared to bare ZnP and we suggest that the conjugation with QDs prevents the transmembrane cellular uptake of the ZnP molecules, reducing their photoactivity.
荧光 II-VI 半导体量子点(QDs)作为活性光敏剂在光致失活(PDI)中的应用仍在评估之中。在本研究中,我们制备了涂有
巯基丁二酸的 3 nm 大小的
碲化镉量子点,并将其与 Zn(II) 介四(N-乙基-2-
吡啶-2-基)
卟啉(ZnTE-2-PyP 或 ZnP)进行静电共轭,从而产生了 QDs-ZnP 共轭物。我们评估了裸 QDs 和共轭物系统产生活性氧(ROS)的能力,并通过照射 QDs 将其应用于白色念珠菌培养物的光动力灭活,同时测试了 PDI 作用可能共同发挥作用的假设。在有光照射和无光照射的情况下,还对成纤维细胞的体外细胞毒性和光毒性进行了测试。总体结果显示,所有测试系统都能有效产生 ROS,在无辐射的情况下,细胞毒性较低(细胞存活率大于 90%)。与裸露组相比,用 QDs-ZnP 培养并接受辐照的成纤维细胞显示出更高的细胞毒性(细胞存活率<90%),这取决于 QDs 的浓度。裸 CdTe QD 对白色念珠菌的 PDI 效应表明,与裸 ZnP 相比,细胞存活率的降低率较低(约为 1 log10),而裸 ZnP 在光激活时具有较高的杀微
生物活性(约为 3 log10)。与裸 ZnP 相比,QD-ZnP 共轭物对白念珠菌的光动力活性也有所降低,我们认为与 QD 的共轭阻止了细胞对 ZnP 分子的跨膜吸收,从而降低了它们的光活性。