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Two different colors of water-soluble core-shell quantum dots CdTe/CdS (green and orange red) have been synthesized and characterized in this paper. The formation of core-shell quantum dots not only improves the fluorescence quantum yield, but also reduces the biological toxicity of quantum dots, and improves the fluorescence lifetime. Two novel fluorescent bioprobes, CdTe/CdS (λ em = 545 nm)-5-Fu and Bio-CdTe/CdS (λ em = 600 nm)-TAM, have been synthesized via the interaction of these two core-shell quantum dots with anticancer drugs (5-Fu) and P-gp inhibitors (TAM), respectively. These two fluorescent probes have been simultaneously used in fluorescence imaging of human breast cancer cells MDA-MB-231/MDR. It can be observed that under the action of P-gp inhibitors distributed on the cell membrane, anticancer drugs can be retained in cancer cells. According to the color of quantum dots on the probe, the visualization results of the action of anticancer drugs and P-gp inhibitors can be obtained. This study shows that to prepare functional bioprobes using core-shell quantum dots CdTe/CdS has great potential in the field of biomedical research such as anticancer drugs. Image 1 • CdTe/CdS core-shell QDs has higher fluorescence quantum yield and lower biological toxicity. • Simultaneous imaging of two bioprobes (CdTe/CdS-5-Fu, Bio-CdTe/CdS-TAM) in cancer cells. • Surface functionalization of quantum dots by anticancer drugs 5-Fu and P-gp inhibitors TAM. • Two colors bioprobes visualize the Interaction between Anticancer Drugs and P-gp Inhibitors. [ABSTRACT FROM AUTHOR]

Development of noninvasive bioimaging fluorescent probes for detecting particular enzyme activity is greatly recommendable for preclinical diagnosis of cancer. Given that the elevated β-gal activity is positively correlated with several tumors, developing a fluorescent probe for the sensing of β-gal is therefore highly desirable for cancer diagnosis. Herein, a new enzyme-activatable near-infrared (NIR) turn-on fluorescent probe (DMC-βgal) was developed for accurately detecting β-gal activity characterized by excellent selectivity, high sensitivity (LOD = 0.298 U/L), and low toxicity. More importantly, DMC-βgal qualifies remarkable NIR excitation (725 nm) and emission wavelength (770 nm), an ideal tool for restrained photodamage and suppressed autofluorescence. The above excellent performance of DMC-β-gal allowed for the accurate monitoring of endogenous β-gal in living cells. Moreover, the probe was successfully applied to detect intracellular β-gal activity in different types of cancer cells, verifying that SKOV-3 cells had a higher level of β-gal activity than those of A549, HCT-116, MCF-7, and HepG2 cells. Furthermore, DMC-βgal could real-time visualize endogenously β-gal in tumor-bearing nude mice with low auto-fluorescence interference. All results fully demonstrated that DMC-βgal has potential value as a promising strategy for diagnosis of β-gal-related diseases. [Display omitted] • A new near-infrared excited and emitted β-galactosidase (β-gal) fluorescent probe DMC-βgal was synthesized. • The probe DMC-βgal is characterized by excellent selectivity and high sensitivity (LOD = 0.298 U/L). • The probe is applied to prove that the β-gal activity in SKOV-3 cells is higher than HepG2, A549, HCT-116, MCF-7 cells. • DMC-βgal can real-time visualize the β-gal activity in tumor-bearing nude mice with low photodamage and autofluorescence. [ABSTRACT FROM AUTHOR]

Superoxide anion (O 2 •-) is an important biomarker for reactive oxygen species (ROS) generated through physiological and pathological processes. However, due to the short half-life of O 2 •- and high autofluorescence of cell tissues, in situ real-time tracking and monitoring of endogenous O 2 •- can be difficult. In this paper, a fluorescent probe IFP-O 2 was developed to detect endogenous O 2 •- in cells. The probe could instantaneously react with O 2 •- to produce fluorescence off-on effect; its detection limit was as low as 10 nM. Cell experiments also showed that the probe had low toxicity and mitochondrial targeting ability. The article presents, for the first time, a probe that can be employed to measure endogenous O 2 •- in oral cancer Cal-27 cells and is a promising tool for monitoring and evaluating apoptosis. Image 1 [ABSTRACT FROM AUTHOR]