Comparative Evaluation of the Chemical Composition, Antioxidant and Antimicrobial Activities of the Volatile Oils of Hawk Tea from Six Botanical Origins.

In this study, volatile oils of six Hawk tea varieties were studied for their chemical composition, antioxidant and antimicrobial activities to screen the most suitable botanical origins of Hawk tea. A total of 72 components were separated and identified from the six oils. The major constituents of the volatile oils were: α-pinene, camphene, limonene, 1,8-cineole, linalool, cis-nerolidol, and germacrene B. Moreover, the volatile oils were evaluated for antioxidant potential and antimicrobial activities. The results showed that all volatile oils exhibited acceptable antioxidant and antimicrobial activities, which suggested that these volatile oils may serve as natural alternatives to synthetic antioxidants and preservatives to be applied in food and pharmaceutical industries. Principal component analysis results denoted that some major compounds may be closely related to the antioxidant and antimicrobial activities. It also showed that the volatile oils from Litsea coreana var. lanuginosa and Litsea pungens Hemsl. were characterized by positive values of first two principal components, indicating higher active chemical compounds and antioxidant and antimicrobial activities compared with other species. Thus, they were temporarily considered as good sources of Hawk tea.

Near-Infrared Light-Responsive Hydrogel for Specific Recognition and Photothermal Site-Release of Circulating Tumor Cells.

Isolation of single circulating tumor cells (CTCs) from patients is a very challenging technique that may promote the process of individualized antitumor therapies. However, there exist few systems capable of highly efficient capture and release of single CTCs with high viability for downstream analysis and culture. Herein, we designed a near-infrared (NIR) light-responsive substrate for highly efficient immunocapture and biocompatible site-release of CTCs by a combination of the photothermal effect of gold nanorods (GNRs) and a thermoresponsive hydrogel. The substrate was fabricated by imprinting target cancer cells on a GNR-pre-embedded gelatin hydrogel. Micro/nanostructures generated by cell imprinting produce artificial receptors for cancer cells to improve capture efficiency. Temperature-responsive gelatin dissolves rapidly at 37 °C; this allows bulk recovery of captured CTCs at physiological temperature or site-specific release of single CTCs by NIR-mediated photothermal activation of embedded GNRs. Furthermore, the system has been applied to capture, individually release, and genetically analyze CTCs from the whole blood of cancer patients. The multifunctional NIR-responsive platform demonstrates excellent performance in capture and site-release of CTCs with high viability, which provides a robust and versatile means toward individualized antitumor therapies and also shows promising potential for dynamically manipulating cell-substrate interactions in vitro.

Photoresponsive immunomagnetic nanocarrier for capture and release of rare circulating tumor cells.

Isolation, release and culture of rare circulating tumor cells (CTCs) may, if implemented, promote the progress of individualized anti-tumor therapies. To realize the release of CTCs without disruption of their viability for further culture and analysis, we designed an effective photocontrolled CTC capture/release system by combination of photochemistry and immunomagnetic separation. 7-Aminocoumarin was synthesized as the phototrigger to bridge the connection between the anti-EpCAM antibody and the magnetic beads. The coumarin moieties produced cleavage of a C-O bond under both ultraviolet (UV) and near-infrared (NIR) light illumination, breaking the bridge and releasing CTCs from the immunomagnetic beads. Compared with conventional immunomagnetic separation systems, the negative influence of absorbed immunomagnetic beads on further CTCs culture and analysis was effectively eliminated. The system can specifically recognize 102 MCF-7 cells in 1 mL of human whole blood samples with 90% efficiency and 85% purity. Under the irradiation of UV and NIR light, 73 ± 4% and 52 ± 6% of captured cells were released with a viability of 90% and 97%, respectively. Furthermore, this technique has been used to detect CTCs from whole blood of cancer patients with high purity. This study demonstrates that the photochemical-based immunomagnetic separation method for isolating, releasing and culturing CTCs from clinic patients may provide new opportunities for cancer diagnosis and personalized therapy.