We designed gold nanoparticles (AuNPs) capped with iodine and polyethylene glycol (PEG) to provide effective enhancement for X‐ray CT imaging. The methoxy PEG‐iodine‐capped AuNPs were prepared through the chemisorption of iodine and substitution of methoxy PEG‐SH onto the surface of gold nanoparticles, and severe aggregation in TEM was not observed. The binding energies of Au 4f_7/2 and I 3d_5/2 of the methoxy PEG‐iodine‐capped AuNPs were obtained as 84.1 eV and 619.3 eV, respectively. The binding energy shift of methoxy PEG‐iodine‐capped AuNPs would be resulted from the chemisorption between gold nanoparticles and iodine atoms. The methoxy PEG‐iodine‐capped AuNPs have higher enhancement compared to PEG‐capped gold nanoparicles in the same amount of gold in vitro. After postinjection of methoxy PEG‐iodine‐capped AuNPs into the mice, dramatic contrast enhancement at the heart, aorta, liver, and kidney was observed, this was maintained up to 5 days, and there was no evidence of apparent toxicity. In conclusion, methoxy PEG‐iodine‐capped AuNPs might be a good candidate as a CT contrast agent for blood pool imaging, and this will also contribute to the prolongation of a blood circulation time for X‐ray CT imaging.

Background: Heat generation in a drug delivery carrier by exposure to near-infrared (NIR) light with excellent tissue transmittance is an effective strategy for drug release and tumor therapy. Because liposomes have amphiphilic properties, they are useful as drug carriers. Liposomes are also very suitable for drug delivery strategies using heat generation by NIR laser because lipid bilayers are easily broken by heat. Thermally generated bubbles from liposomes not only induce drug release, but also enable ultrasound imaging. Methods: Melanin, perfluorohexane (PFH), and 5-fluorouracil (5-FU)-loaded liposomes (melanin@PFH@5-FU-liposomes) that can generate heat and bubble by NIR laser irradiation were prepared by a thin film method. Conversion of light to heat and bubble generation of melanin@PFH@5-FU-liposomes were evaluated using an infrared (IR) thermal imaging camera and an ultrasound imaging system both in vitro and in vivo . To investigate tumor therapeutic effect, NIR laser of 808 nm was used to irradiate tumor site for 10 min after injecting melanin@PFH@5-FU-liposome into tail veins of CT26-bearing mice. Results: Melanin@PFH@5-FU-liposomes showed a spherical shape with a size of 209.6 ± 4.3 nm. Upon NIR laser irradiation, melanin@PFH@5-FU-liposomes exhibited effective temperature increase both in vitro and in vivo . In this regard, temperature increase caused a phase transition of PFH to induce bubble generation dramatically, resulting in effective drug release behavior and ultrasound imaging. The temperature of the tumor site was increased to 52 t and contrast was greatly enhanced during ultrasound imaging due to the generation of bubble. More importantly, tumor growth was effectively inhibited by injection of melanin@PFH@5-FU-liposomes with laser irradiation. Conclusions: Based on intrinsic photothermal properties of melanin and phase transition properties of PFH, melanin@PFH@5-FU-liposomes exhibited effective heat and bubble generation upon NIR laser irradiation. The elevated temperature induced bubble generation, resulting in contrast enhancement of ultrasound imaging. Melanin@PFH@5-FU-liposomes under NIR laser irradiation induced the death of cancer cells, thereby effectively inhibiting tumor growth. These results suggest that melanin@PFH@5-FU-liposomes can be utilized as a promising agent for photothermal tumor therapy and ultrasound imaging.

Solanum nigrum L., which has anti-inflammatory and antibacterial properties, has been used for disease prevention and treatment. Although the various effects of Solanum nigrum L. are well known, studies on the application of Solanum nigrum L. are insufficient. Herein, we analyzed the active constituents of Solanum nigrum L. extract, and evaluated the anti-inflammatory effect on an acute ear edema mouse model. It was confirmed that Solanum nigrum L. fruit extract contained more polyphenol and flavonoid contents than the whole plant extract. In addition, the evaluation of nitric oxide (NO) production inhibition showed the concentration-dependent inhibitory effect of Solanum nigrum L. extract. Moreover, Solanum nigrum L. fruit extract in 80% ethanol on 12-O-tetradecanoylphorbol 13-acetate (TPA)-induced acute ear edema mouse model showed less edema and greater suppression of inflammation than indomethacin, an inflammation inhibitor. These results show that the fruit extract of Solanum nigrum L. has anti-inflammatory activity, and can be used as an anti-inflammatory substance.