Baicalin induces apoptosis in SW620 human colorectal carcinoma cells in vitro and suppresses tumor growth in vivo

In the United States, colorectal cancer (CRC) is the second most frequent malignancy and the fourth most common cause of cancer death. Baicalin, a flavone derivative isolated and purified from the dry root of Scutellaria, was assessed for its antitumor effects in human SW620 CRC cells. Baicalin (200 μM) inhibited proliferation of SW620 cells. Baicalin (200 μM) increased activities of caspase-3, -8, and -9 in SW620 cells. Furthermore, flow cytometric analysis of baicalin-treated SW620 cells showed an increase in sub-G1 cells, and the dihydroethidium assay showed significant enhancement of intracellular peroxide production in baicalin-treated cells. Addition of N-acetylcysteine prevented most of the baicalin-induced apoptosis, which in turn mediated cytotoxicity in human SW620 cells. In vivo, baicalin (50 mg/kg/day, i.p.) treatment inhibited 55% of tumor growth in xenografted nude mice by 4 weeks, compared to that of the vehicle control (p < 0.05). Baicalin had no noteworthy influence on body weight. Thus, we suggest the development of baicalin as a potential leading antitumor agent in CRC.     

Electrostatic assembly of gold colloidal nanoparticles on organosilane monolayers patterned by microcontact electrochemical conversion

A new approach is introduced for electrostatically guided adsorption of colloidal nanoparticles onto a patterned self-assembled monolayer (SAM) with feature sizes ranging from nm to mm. Patterning of the adsorption templates is realized by electric-field-induced anodic oxidation of aminosilane SAM using an ink-free method. In this versatile method, both "positive" and "negative" type pattern transfers are possible. The chemically converted patterns are induced by localized electrical fields on the microcontacted areas, and the patterning resolution is insensitive to the diffusion of oxidizing agents because of the self-limiting oxidation kinetics, thereby enabling high-resolution, large-scale parallel patterning.     

Surfactant-assisted hollowing of Cu nanoparticles involving halide-induced corrosion-oxidation processes

We have demonstrated a simple fabrication of hollow nanoparticles by halide-induced corrosion oxidation with the aid of surfactants. Cuprous oxide Cu2O nanoshells can be generated by simply mixing Cu nanoparticles with alkyltrimethylammonium halides at 55 degrees C for 16 min. The hollowing mechanism proposed is that absorption of surfactants onto the Cu surface facilitates the formation of the void interior through an oxidative etching process. Upon extending the reaction up to 4 h, fragmentation, oxidation, and self-assembly were observed and the CuO ellipsoidal structures were formed. The headgroup lengths of the surfactants influenced the degree of CuO ellipsoidal formation, whereby longer surfactants favored the generation of ellipsoids. Optical absorption measured by UV-visible spectroscopy was used to monitor both oxidation courses of Cu-->Cu2O and Cu2O-->CuO and to determine the band-gap energies as 2.4 eV for Cu2O nanoshells and 1.89 eV for CuO ellipsoids. For the contact-angle measurements, the wettability changed from hydrophilicity (18 degrees) to hydrophobicity (140 degrees) as the Cu2O nanoshells shifted to CuO ellipsoids.     

DNA-gold nanorod conjugates for remote control of localized gene expression by near infrared irradiation

Gold nanorods were attached to the gene of enhanced green fluorescence protein (EGFP) for the remote control of gene expression in living cells. The UV-vis spectroscopy, electrophoresis, and transmission electron microscopy (TEM) were used to study the optical and structural properties of the EGFP DNA and gold nanorod (EGFP-GNR) conjugates before and after femto-second near-infrared (NIR) laser irradiation. Upon NIR irradiation, the gold nanorods of EGFP-GNR conjugates underwent shape transformation that resulted in the release of EGFP DNA. When EGFP-GNR conjugates were delivered to cultured HeLa cells, induced GFP expression was specifically observed in cells that were locally exposed to NIR irradiation. Our results demonstrate the feasibility of using gold nanorods and NIR irradiation as means of remote control of gene expression in specific cells. This approach has potential applications in biological and medical studies.     

Simultaneous determination of adenosine and its metabolites by capillary electrophoresis as a rapid monitoring tool for 5'-nucleotidase activity

A simple and rapid capillary electrophoretic method was developed for the simultaneous determination of micro-molar adenosine, hypoxanthine and inosine in enzyme assays without using radioactive labeled substrates. Prior to electrophoretic separation, addition of acetonitrile and sodium chloride to the assay solution and brief centrifugation are recommended for the purpose of sample cleanup and sample stacking. Under the optimal condition, the good separation with high efficiency was achieved in 6 min. Using deoxyadenylate as an internal standard, the linear range of the method was 5-200 microM, and the concentration limits of detection of adenosine, hypoxanthine and inosine were 2.2, 3.6 and 1.4 microM, respectively. Application of the proposed method was demonstrated by the activity assay of 5'-nucleotidase from Hep G2 cells.     

Continuous dielectrophoretic separation of particles in a spiral microchannel

Particle separation is a fundamental operation in the areas of biology and physical chemistry. A variety of force fields have been used to separate particles in microfluidic devices, among which electric field may be the most popular one due to its general applicability and adaptability. So far, however, electrophoresis‐based separations have been limited primarily to batchwise processes. Dielectrophoresis (DEP)‐based separations require in‐channel micro‐electrodes or micro‐insulators to produce electric field gradients. This article introduces a novel particle separation technique in DC electrokinetic flow through a planar double‐spiral microchannel. The continuous separation arises from the cross‐stream dielectrophoretic motion of particles induced by the non‐uniform electric field inherent to curved channels. Specifically, particles are focused by DEP to one sidewall of the first spiral, and then dielectrophoretically deflected toward the other sidewall of the second spiral at a particle‐dependent rate, leading to focused particle streams along different flow paths. This DEP‐based particle separation technique is demonstrated in an asymmetric double‐spiral microchannel by continuously separating a mixture of 5/10 μm particles and 3/5 μm particles.     

Ameliorative Effect of Imperatorin on Dermatophagoides pteronyssinus-Induced Allergic Asthma by Suppressing the Th2 Response in Mice

Imperatorin is a furanocoumarin derivative and an effective ingredient in several Chinese medicinal herbs. It has favorable expectorant, analgesic, and anti-inflammatory effects. In this study, we investigated whether imperatorin has protective effects against Dermatophagoides pteronyssinus (Der p)-induced asthma in mice. Lung and bronchial tissues were histopathologically examined through hematoxylin–eosin staining. The concentrations of immunoglobin E (IgE), IgG1, IgG2a in serum and those of T helper 1 (Th1) and two cytokines and eosinophil-activated chemokines in bronchoalveolar lavage fluid (BALF) were detected using an enzyme immunoassay. Histological examination revealed that imperatorin reduced inflammatory cell infiltration, mucus hypersecretion, and endothelial cell hyperplasia. The examination also indicated that imperatorin could reduce the inflammatory cell count in BALF as well as IgE and IgG1 expression in serum, but IgG2a expression was significantly increased. Imperatorin reduced the production of interleukin (IL)-4, IL-5, and IL-13 by Th2, promoted the production of interferon-γ and IL-12 by Th1, and increased the production of IL-10 in bronchoalveolar lavage fluid. These findings suggest that imperatorin has a considerable anti-inflammatory effect on Der p-induced allergic asthma in mice.