Polyaniline-grafted nanodiamonds for efficient photothermal tumor therapy.

Polyaniline-grafted nanodiamond (PAN-ND) nanoparticles were fabricated by polymerizing aniline at the surface of amine-modified NDs for efficient photothermal therapy (PTT). A series of PAN from different aniline concentrations were also prepared to compare the properties and the efficiency of PTT. The polymerization rate of aniline was faster in the presence of NDs than that of aniline alone. Compared to PAN nanoparticles, PAN-ND has a spherical shape, smaller size, and ultimately higher cellular uptake efficiency. The temperature of aqueous PAN-ND dispersion increased to 44.4 °C after laser irradiation for 5 min. In addition, the UV absorbance intensity of PAN-ND increased at the lower pH at the near infrared (NIR) region, resulting in an enhanced photothermal effect at a tumor site. Notably, the viability of HeLa cells treated with PAN-ND decreased by less than 20%, suggesting the high efficiency of PTT. The PAN-ND can be a potential candidate for efficient photothermal tumor therapy.

Enhanced production of asiaticoside from hairy root cultures of Centella asiatica (L.) Urban elicited by methyl jasmonate.

Transformed root ("hairy root") cultures have been shown to be a good model for the study of many secondary metabolites. However, economically important compounds such as asiaticoside and madecassoside are produced in insignificant amounts in the root of Centella asiatica (L.) Urban. To overcome this problem, C. asiatica was transformed using Agrobacterium rhizogenes strain R1000 that harbors pCAMBIA1302 encoding the hygromycin phosphotransferase (hpt) and green fluorescence protein (mgfp5) genes and the hairy culture was coupled with elicitation technique. Hairy roots were obtained at a frequency of up to 14.1% from a tissue junction between the leaf and petiole. Abundant hairy roots were observed when co-cultivation of the plant with A. rhizogenes was done for 7 days (36.1%). Transformation was confirmed by PCR and Southern blot analyses. Five weeks after inoculation, no asiaticoside was detected in the hairy root samples. However, when 0.1 mM methyl jasmonate (MJ) was applied as an elicitor to the culture medium for 3 weeks, a large quantity of asiaticoside was generated (7.12 mg/g, dry wt). In the case of gene expression, 12 h after MJ treatment the expression of the CabAS (C. asiatica putative beta-amyrin synthase) gene in the hairy roots is significantly different from that of the control and this level of transcripts was maintained for 14 days. Our results showed that production of C. asiatica hairy roots could be optimized and the resulting cultures could be elicited with MJ treatment for enhanced production of asiaticoside.