Meanwhile, the MGC803 and GES-1 cells treated with the prepared probes were used as the control group. Afterward, the cells were rinsed with phosphate buffered saline (PBS) three times and then fixed with 2.5% glutaraldehyde solution for 30 min. For nuclear counterstaining, MGC803 cells were incubated with 1 mM Hoechst 33258 in PBS for 5 min. The cells were observed and imaged using a fluorescence microscope (Nikon

TS100-F, Nikon Co., Tokyo, Japan). Preparation of gastric cancer-bearing nude mice model Pathogen-free athymic nude (nu/nu) BALB/c mice were housed in an accredited vivarium, maintained at 22°C ± 0.5°C with a 12-h light/dark cycle and were allowed to access food and water. Male athymic nude mice (4 to 6 weeks old) were used to establish subcutaneous gastric cancer models; 2 × 106 MGC803 cells suspended in 100 μL of pure DMEM were subcutaneously injected into the right anterior PI3K inhibitor flank area of each MK-8669 clinical trial mouse. Four weeks later, tumors were observed to grow to approximately 5 mm

in diameter. RGD-conjugated sGNR/MWNT nanoprobes for photoacoustic imaging Photoacoustic imaging of the study in vitro and in vivo was accomplished by a PA system (Endra Nexus 128, Endra Life Sciences, Ann Arbor, MI, USA). The excitation laser (Opotek, Carlsbad, CA, USA) is irradiated from the bottom of a hemispherical bowl, whose wavelength is tunable from 680 to 950 nm. PA characteristics of prepared nanoprobes in vitro were firstly investigated before in vivo imaging. PA intensity corresponding to different concentrations and wavelengths were studied by setting the probe in the tube. Subsequently, gastric cancer-bearing

nude mice were treated with 500 μg of prepared nanoprobes. Animal orientation and tumor position should be kept constant in the bowl during experiments to make sure that each Montelukast Sodium scan was in the same position in favor of comparison and imaging alignment. Filling the slot with distilled water provided acoustic coupling with the animal. Then, pre-injection scans and post-injection scans were both acquired when the tumor site was irradiated by the laser. The PA signals, which were received by the ultrasonic transducers, were spirally distributed on the surface of the bowl and then directed to a computer. Reconstruction of the 2D and 3D PA image was performed using Osirix imaging software (OsiriX Foundation, Geneva, Switzerland). Results and discussion Preparation and characterization of sGNR/MWNT hybrid Figure  2 showed typical transmission electron microscopy (TEM) images and high-resolution TEM (HR-TEM) images of (a, b) MWNTs, (c, d) sGNRs, and (e, f) MWNTs/sGNRs. As shown in Figure  2a, MWNTs are very pure and did not contain amorphous carbon particles, metal catalysts, etc. The average diameter of MWNTs was around 20 nm.