Ramírez-Herrera Doris E, Rodríguez-Velázquez Eustolia, Alatorre-Meda Manuel, Paraguay-Delgado Francisco, Tirado-Guízar Antonio, Taboada Pablo, Pina-Luis Georgina
Centro de Graduados e Investigación, Instituto Tecnológico de Tijuana, A.P. 1166, 22500 Tijuana, BC, Mexico.
Facultad de Odontología, Universidad Autónoma de Baja California, Calzada Universidad 14418, Parque Industrial Internacional, 22390 Tijuana, BC, Mexico.
Nanomaterials (Basel). 2018 Apr 11;8(4):231. doi: 10.3390/nano8040231.
In the present work, we synthesize Near Infrared (NIR)-emitting alloyed mercaptopropionic acid (MPA)-capped CdTeSe quantum dots (QDs) in a single-step one-hour process, without the use of an inert atmosphere or any pyrophoric ligands. The quantum dots are water soluble, non-toxic, and highly photostable and have high quantum yields (QYs) up to 84%. The alloyed MPA-capped CdTeSe QDs exhibit a red-shifted emission, whose color can be tuned between visible and NIR regions (608-750 nm) by controlling the Te:Se molar ratio in the precursor mixtures and/or changing the time reaction. The MPA-capped QDs were characterized by UV-visible absorption spectroscopy, fluorescence spectroscopy, transmission electron microscopy (TEM), energy dispersive X-ray spectroscopy (EDS), and zeta potential measurements. Photostability studies were performed by irradiating the QDs with a high-power xenon lamp. The ternary MPA-CdTeSe QDs showed greater photostability than the corresponding binary MPA-CdTe QDs. We report the Förster resonance energy transfer (FRET) from the MPA-capped CdTeSe QDs as energy donors and Cyanine5 NHS-ester (Cy5) dye as an energy acceptor with efficiency () up to 95%. The distance between the QDs and dye (), the Förster distance (₀), and the binding constant () are reported. Additionally, cytocompatibility and cell internalization experiments conducted on human cancer cells (HeLa) cells revealed that alloyed MPA-capped CdTeSe QDs are more cytocompatible than MPA-capped CdTe QDs and are capable of ordering homogeneously all over the cytoplasm, which allows their use as potential safe, green donors for biological FRET applications.
在本工作中，我们在一个小时的单步过程中合成了近红外（NIR）发射的巯基丙酸（MPA）包覆的CdTeSe量子点（QDs），无需使用惰性气氛或任何自燃性配体。这些量子点具有水溶性、无毒、高光稳定性且量子产率（QYs）高达84%。MPA包覆的合金化CdTeSe量子点表现出红移发射，通过控制前驱体混合物中的Te:Se摩尔比和/或改变反应时间，其颜色可在可见光和近红外区域（608 - 750 nm）之间调节。通过紫外-可见吸收光谱、荧光光谱、透射电子显微镜（TEM）、能量色散X射线光谱（EDS）和zeta电位测量对MPA包覆的量子点进行了表征。通过用高功率氙灯照射量子点进行光稳定性研究。三元MPA-CdTeSe量子点比相应的二元MPA-CdTe量子点表现出更高的光稳定性。我们报道了以MPA包覆的CdTeSe量子点作为能量供体和花菁5 NHS-酯（Cy5）染料作为能量受体的Förster共振能量转移（FRET），效率（）高达95%。报道了量子点与染料之间的距离（）、Förster距离（₀）和结合常数（）。此外，对人癌细胞（HeLa）进行的细胞相容性和细胞内化实验表明，MPA包覆的合金化CdTeSe量子点比MPA包覆的CdTe量子点具有更高的细胞相容性，并且能够均匀地分布在整个细胞质中，这使其能够作为生物FRET应用中潜在的安全、绿色供体。
