Effects of surface modification of quantum dots on viability and migration of triple-negative breast cancer cells

Triple-negative breast cancer (BC) shows strong metastasis and has a bad prognosis. There are few effective approaches until date to detect BC cells at an early stage. Quantum dots (QDs) are one of the most promising nanomaterials for the detection of BC cells. QDs are usually modified with some functional molecules, such as PEG and BSA, to decrease or possibly eliminate their toxicity. Although a large number of studies have investigated the cytotoxicity of QDs, the effects of surface modification of QDs on biological behaviors of triple-negative BC cells remain unclear. In this work, QDs were prepared using the hydrothermal method and chemically modified with PEG and BSA. The optical performance of QDs was recorded with a digital camera. Their absorption and fluorescence (FL) properties were analyzed by UV-Vis spectrometer and FL spectrophotometer, respectively. The effects of QDs and surface modification on viability and migration were principally investigated. The possible mechanism was primarily analyzed. The results show that QDs exhibit excellent optical performance under ultraviolet irradiation. Surface modification slightly reduces the photon count reaching the QDs surface. Moreover, surface modification results in a blue-shift of FL peak of QDs, which is ascribed to the change in surface chemical environment because of PEG and BSA modifications. In addition, QDs, PEG coated QDs (PEG@CdTe) and BSA coated QDs (BSA@CdTe) can reduce viability and inhibit migration of BC cells. The inhibition effects are time- and concentration-dependent. In addition, PEG and BSA modified QDs exhibit lower inhibition effects on BC cells, as compared with unmodified QDs. In this process, Reactive oxygen species (ROS) does not appear to play an important role, and other pathways should be considered. This work provides experimental support and useful clinical guidance for QDs-applications in BC detection.