In recent years, photoacoustic imaging, as an emerging imaging mode, has become a hotspot. We also synthesized gold selleck nanoprisms and observed that gold nanoprisms could amplify the PA signal for SCH727965 mouse in vivo bioimaging of gastrointestinal cancers [39]. However, how to obtain clear PA imaging of in vivo tumors and PA imaging-directed therapy to service clinical theranostics has become a great challenge. Herein, we fully used the advantages of gold nanorods and multiwalled carbon nanotubes and developed a simple and effective strategy to prepare NIR absorption enhancer MWNTs through covalent interaction of carboxyl groups on the MWNTs with silica-coated gold nanorods

(sGNRs). GNRs were prepared by the seed-mediated template-assisted protocol, coated by silica, and modified with the amino silane coupling agent with the aim of eliminating their cytotoxicity and improving their biocompatibility. Then, RGD peptides were conjugated with the sGNR/MWNT hybrid structure; resultant RGD-conjugated sGNR/MWNT (RGD-GNR-MWNT) nanoprobes were used for photoacoustic imaging of in vivo gastric

cancer cells as shown in Figure  1. Our results showed that RGD-GNR-MWNT probes will own great potential in applications such as targeted PA imaging and photothermal therapy in the near future. Figure 1 RGD-conjugated sGNR/MWNT hybrid for photoacoustic P505-15 molecular weight imaging. Methods All animal experiments (no. SYXK2007-0025) were approved by the Institutional Animal Care and Use Committee of Shanghai Jiao Tong University. Material source Multiwalled carbon nanotubes (MWNTs)

were purchased from the Shenzhen Nanoport Company (Shenzhen, China), and their diameters were around 20 ~ 30 nm. Chloroauric acid (HAuCl4 · 3H2O), cetyltrimethylammonium bromide (CTAB), sodium borohydride (NaBH4), tetraethylorthosilicate (TEOS), 3-aminopropyltrimethoxysilane (APTS), 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide (EDC), N-hydroxysuccinimide Sorafenib clinical trial (NHS), and ascorbic acid were obtained from Aldrich Company (Wyoming, IL, USA). Anhydrous ethanol and ammonium hydroxide were obtained from Sinopharm Co. (Beijing, China). RGD peptides were from Aldrich Company. Preparation of MWNT-COOH from MWNT Crude MWNTs (0.523 g) were added to aqueous HNO3 (20.0 mL, 60%) (Figure  1). The mixture was placed in an ultrasonic bath (40 kHz) for 40 min and then stirred for 48 h while being boiled under reflux. The mixture was then vacuum-filtered through a 0.22-mm Millipore polycarbonate membrane (Millipore Co., Billerica, MA, USA) and subsequently washed with distilled water until the pH of the filtrate was ca. 7. The filtered solid was dried under vacuum for 24 h at 70°C, yielding MWNT-COOH (0.524 g) [46, 47]. Synthesis of silica-modified gold nanorods In a typical experiment, GNRs were synthesized according to the seed-mediated template-assisted protocol [11, 48]. Twenty milliliters of the GNR solution was centrifuged at 9,600 rpm for 15 min.