Polydopamine Nanoparticles for Deep Brain Ablation via Near-Infrared Irradiation.

Local resection or ablation remains an important approach to treat drug-resistant central neurological disease. Conventional surgical approaches are designed to resect the diseased tissues. The emergence of photothermal therapy (PTT) offers a minimally invasive alternative. However, their poor penetration and potential off-target effect limit their clinical application. Here, polydopamine nanoparticles (PDA-NPs) were prepared and characterized. Studies were performed to evaluate whether PDA-NPs combined with near-infrared (NIR) light can be used to ablate deep brain structures in vitro and in vivo. PDA-NPs were prepared with a mean diameter of ∼150 nm. The particles show excellent photothermal conversion efficiency. PDA-NPs did not show remarkable cytotoxicity against neuronal-like SH-SY5Y cell lines. However, it can cause significant cell death when combined with NIR irradiation. Transcranial NIR irradiation after PDA-NPs administration induced enhanced local hyperthermia as compared with NIR alone. Local temperature exceeded 60 °C after 6 min of irradiation plus PDA while it can only reach 48 °C with NIR alone. PTT with PDA (10 mg/mL, 3 µL) and NIR (1.5 W/cm2) can ablate deep brain structures precisely with an ablation volume of ∼6.5 mm3. Histological analysis confirmed necrosis and apoptosis in the targeted area. These results demonstrate the potential of NP-assisted PTT for the treatment against nontumorous central neurological diseases.

Metabolic profiling investigation of Fritillaria thunbergii Miq. by gas chromatography-mass spectrometry.

Thunberg fritillary bulb (the dry bulbs of Fritillaria thunbergii Miq.), a traditional Chinese Medicine, is widely applied as an expectorant and antitussive. In this investigation, the primary metabolites of bulbs, flowers, leaves, and stems of F. thunbergii were analyzed by gas chromatography-mass spectrometry. Principal component analysis, partial least squares-discriminate analysis, orthogonal projection to latent structures-discriminate analysis, and heat map analysis showed that there were dissimilar metabolites, and a negative correlation between amino acids and saccharides in different analytes. Furthermore, carbodiimide, tryptophan, glucose-6-phosphate, xylose, 2-piperidinecarboxylic acid, monoamidomalonic acid, phenylalanine, and histidine were found to play an important role in the plant metabolism net of F. thunbergii.

[Optimization of Supercritical Fluid Extraction of Total Flavonoids and Monomer Compositions from Taxus Remainder Extracts Free of Taxoids].

Objective: To optimize the supercritical fluid extraction technology of flavonoids from taxus remainder extracts free of taxoids( TREFT) by response surface methodology( RSM). Methods: By using a central composite design( CCD) in four factors and five levels to optimize the extraction parameters. The effects of extraction time, temperature, pressure and different concentration of ethanol and their interaction on the extraction rate of total flavonoids, amentoflavone, quercetin and ginkgetin which extracted from TREFT by supercritical fluid CO2 were investigated. Results: Under optimal conditions of extraction time for 2. 2 h,and the extraction temperature was 46. 4 ℃,the extraction pressure was 22. 6 MPa, and 80. 7% ethanol, the index experimental of total flavonoids and monomer compositions was 98. 75. Conclusion: The process of flavonoids extraction from TREFT is stable and feasible, which can provide technical support for the resource utilization of TREFT.

A label-free assay for T4 polynucleotide kinase/phosphatase activity and its inhibitors based on poly(thymine)-templated copper nanoparticles.

DNA 3'-phosphatase takes an important role in DNA damage repair, replication and recombination. Here, we present a novel label-free fluorescent assay for T4 polynucleotide kinase/phosphatase (T4 PNKP) activity and its inhibitor screening by using poly(thymine)-templated fluorescent copper nanoparticles (CuNPs) as a fluorescent indicator. In this assay, we designed a simple T-rich hairpin primer with a 3'-phosphoryl end, which can serve as both the substrate for T4 PNKP and DNA template for the formation of fluorescent CuNPs. Once the phosphorylated hairpin primer was hydrolyzed by T4 PNKP, the resulting hairpin primer with a 3'-hydroxyl end was immediately elongated to form a long double-strand product by DNA polymerase, which prohibited the formation of fluorescent CuNPs due to the lack of poly T single-stranded DNA template. This new strategy provides a sensitive, selective, and cost-effective manner for T4 PNKP analysis, which holds a great potential in the study of DNA damage repair mechanisms.

Autotoxicity and allelopathy of 3,4-dihydroxyacetophenone isolated from Picea schrenkiana needles.

Bioassay-guided fractionation of the diethyl ether fraction of a water extract of Picea schrenkiana needles led to the isolation of the phenolic compound 3,4-dihydroxy- acetophenone (DHAP). The allelopathic effects of DHAP were evaluated under laboratory conditions on P. schrenkiana, rice (Oryza sativa L.), wheat (Triticum aestivum L.), radish (Raphanus sativus L.), lettuce (Latuca sativa L.), cucumber (Cucumis sativus L.) and mung bean (Phaseolus radiatus L.). DHAP significantly inhibited seed germination and seedling growth of P. schrenkiana at concentrations of 2.5 mM and 0.5 mM (p < 0.05). Soil analysis revealed that P. schrenkiana forest soils contained exceptionally high DHAP concentrations (mean = 0.51 ± 0.03 mg/g dry soil), sufficient to inhibit natural P. schrenkiana recruitment. DHAP also exhibited strong allelopathic potential. It significantly inhibited wheat and lettuce seed germination at concentrations of 1 mM and 0.5 mM (p < 0.05). The active compound also completely inhibited root growth of the six test species at high concentrations. Our results suggest a dual role of DHAP, both as an allelochemical and as an autotoxicant. The potential for a single plant needle-leached compound to influence both inter- and intra-specific interactions emphasized the complex effects that plant secondary metabolites might have on plant population and community structure.