Biosynthesized Silver Nanoparticles for Cancer Therapy and In Vivo Bioimaging.

In the current communication, a simple, environmentally compatible, non-toxic green chemistry process is used for the development of silver nanoparticles (AgZE) by the reaction between silver nitrate (AgNO3) and the ethanolic leaf extract of Zinnia elegans (ZE). The optimization of AgZE is carried out using a series of experiments. Various physico-chemical techniques are utilized to characterize the nanomaterials. The cell viability assay of AgZE in normal cells (CHO, HEK-293T, EA.hy926, and H9c2) shows their biocompatible nature, which is supported by hemolytic assay using mouse RBC. Interestingly, the nanoparticles exhibited cytotoxicity towards different cancer cell lines (U-87, MCF-7, HeLa, PANC-1 and B16F10). The detailed anticancer activity of AgZE on human glioblastoma cell line (U-87) is exhibited through various in vitro assays. In vivo the AgZE illustrates anticancer activity by inhibiting blood vessel formation through CAM assay. Furthermore, the AgZE nanoparticles when intraperitoneally injected in C57BL6/J mice (with and without tumor) exhibit fluorescence properties in the NIR region (excitation: 710 nm, emission: 820 nm) evidenced by bioimaging studies. The AgZE biodistribution through ICPOES analysis illustrates the presence of silver in different vital organs. Considering all the results, AgZE could be useful as a potential cancer therapeutic agent, as well as an NIR based non-invasive imaging tool in near future.

L-noradrenaline functionalized near-infrared fluorescence CdSeTe probe for the determination of urea and bioimaging of HepG2 Cells.

In this paper, near-infrared (NIR) light emitting L-noradrenaline functionalized CdSeTe QDs (NA-CdSeTe) were synthesized and applied to the biosensing of urea. When the pH value of NA-CdSeTe solution was adjusted from neutral to alkalinity, the noradrenaline on the surface of QDs would turn to quinone, which triggered the fluorescence quenching of NA-CdSeTe probe due to the charge transfer interactions between QDs and the proximal quinone. Based on the fact that the hydrolysis of urea in the presence of urease would release OH- and slightly change the pH value of the solution, the fluorescence intensity of NA-CdSeTe QDs could be linked to the enzymatic degradation of urea. The novel urea-biosensing system could effectively determinate urea in the dynamic concentration range from 0.057 to 13mmol/L. Furthermore, NA-CdSeTe probe could serve as an "optical window" for the bioimaging of urea with high selectivity in the serum samples and HepG2 cells. The urea-bioimaging system could effectively probe urea in the dynamic concentration range from 0.2 to 5mmol/L. This NIR probe was excellent candidate not only for its sensitive with urea but also its real-time bioimaging. We expected that this NIR probe based strategy could pave the way for developing simple, no enzyme immobilization required and good sensitive method related detections for further medical applications.

In vivo near-infrared imaging and phototherapy of tumors using a cathepsin B-activated fluorescent probe.

The development of multifunctional reagents for simultaneous specific near-infrared (NIR) imaging and phototherapy of tumors is of great significance. This work describes the design of a cathepsin B-activated fluorescent probe (CyA-P-CyB) and its applications as an NIR imaging probe for tumor cells and as a phototherapy reagent for tumors. In vitro experiments demonstrated that CyA-P-CyB was activated via the cleavage of a peptide linker by cathepsin B in tumor cells to produce fluorescence in the NIR region based on a FRET mechanism. MTT assays showed that the phototoxicity of CyA-P-CyB toward cells depended on the activity of cathepsin B, and the probe exhibited specific phototoxicity toward tumor cells. CyA-P-CyB was also successfully applied to the in vivo imaging and phototherapy of tumors. Histological analysis indicated that CyA-P-CyB had no cytotoxic effects on seven mouse tissues (lung, liver, heart, kidney, pancreas, spleen and brain) after the CyA-P-CyB treatment and laser irradiation.

Chitosan-based core-shell nanomaterials for pH-triggered release of anticancer drug and near-infrared bioimaging.

As a naturally-abundant biopolymer, chitosan (CS) exhibit pH-sensitive structural transformation within a narrow pH range. Integrating hydrophobic groups to CS molecules gives modified CS polymers with more adjustable pH responsiveness. In this paper, near-infrared (NIR) photoluminescent Ag2S QDs capped by long-chain carboxylic acid were synthesized and then conjugated with CS via esterification reaction. The anticancer drug doxorubicin (DOX) has an affinity for the hydrophobic oleoyl groups and was entrapped by them to produce Ag2S(DOX)@CS nanospheres. A variety of experiments were performed to characterize the nanospheres. In vitro and in vivo experiments showed that the nanospheres can release DOX at lowered pH in tumor cells and have high antitumor efficacy. In addition, the strong NIR signal derived from the encapsulated Ag2S QDs makes real-time monitoring of the nanosphere distribution in a body possible. This study provides a new CS-based nanocomposite drug carrier for efficient cancer therapy.