Sialic acid-engineered mesoporous polydopamine dual loaded with ferritin gene and SPIO for achieving endogenous and exogenous synergistic T2-weighted magnetic resonance imaging of HCC.

BACKGROUND: Hepatocellular carcinoma (HCC) is a common malignant tumor with poor prognosis. Magnetic resonance imaging (MRI) is one of the most effective imaging methods for the early diagnosis of HCC. However, the current MR contrast agents are still facing challenges in the early diagnosis of HCC due to their relatively low sensitivity and biosafety. Thus, the development of effective MR agents is highly needed for the early diagnosis of HCC. RESULTS: Herein, we fabricated an HCC-targeted nanocomplexes containing SPIO-loaded mesoporous polydopamine (MPDA@SPIO), sialic acid (SA)-modified polyethyleneimine (SA-PEI), and alpha-fetoprotein regulated ferritin gene (AFP-Fth) which was developed for the early diagnosis of HCC. It was found that the prepared nanocomplexes (MPDA@SPIO/SA-PEI/AFP-Fth) has an excellent biocompatibility towards the liver cells. In vivo and in vivo studies revealed that the transfection of AFP-Fth gene in hepatic cells significantly upregulated the expression level of ferritin, thereby resulting in an enhanced contrast on T2-weighted images via the formed endogenous MR contrast. CONCLUSIONS: The results suggested that MPDA@SPIO/SA-PEI/AFP-Fth had a superior ability to enhance the MR contrast of T2-weighted images of tumor region than the other preparations, which was due to its HCC-targeted ability and the combined T2 contrast effect of endogenous ferritin and exogenous SPIO. Our study proved that MPDA@SPIO/SA-PEI/AFP-Fth nanocomplexes could be used as an effective MR contrast agent to detect HCC in the early stage.

Study of the photodegradation kinetics and pathways of hexaflumuron in liquid media.

Hexaflumuron, one of the benzoylphenylurea insect growth regulators, can be leached into surface water and thus having a potential impact on aquatic organisms. In this study, the photodegradation processes of hexaflumuron under high-pressure mercury lamp irradiation were assessed. The photodegradation kinetics were studied, as were the effects of pH, different light sources, organic solvents and environmental substances, including nitrate ions (NO3(-)), nitrite ions (NO2(-)), ferrous ions (Fe(2+)), ferric ions (Fe(3+)), humic acid, sodium dodecyl sulfate (SDS) and hydrogen peroxide (H2O2). Three photodegradation products in methanol were identified by gas chromatography-mass spectrometry (GC-MS). In general, the degradation of hexaflumuron followed first-order kinetics. In the four media studied, the photodegradation rate order was n-hexane > methanol > ultrapure water > acetone. Faster degradation was observed under high-pressure mercury lamp irradiation than under xenon lamp irradiation. The pH had a considerable effect, with the most rapid degradation occurring at pH 5.0. The photodegradation rate of hexaflumuron was promoted in the presence of NO3(-), NO2(-), Fe(2+), humic acid, SDS and H2O2, but inhibited by Fe(3+). Moreover, the presumed photodegradation pathway was proposed to be the cleavage of the urea linkage.

The synthesis route and the growth mechanism of aligned GaN nanobelts.

Crystallographically aligned GaN nanobelt arrays were synthesized through a hybrid process of Au-assisted nucleation followed by non-Au-assisted anisotropy vapor-solid growth on a (100) γ-LiAlO2 substrate. To the best of our knowledge, this is the first report on aligned GaN nanobelts.

[Spectral determination of the contents of mineral elements in polygonum cuspidatum].

The present paper reports the determination of mineral elements by FAAS, including K, Ca, Na, Mg, Fe, Zn, Mn and Cu. The best condition for the determination was investigated. The best ionization inhibitor and acidity media were confirmed. The experiment used CsCl to prevent ionization interference, and the concentration of HCl was controlled below 2%. At the same time SrCl prevented interference of P to Ca. So the value of absorbance was stable. The results were obtained by calibration curve method. The analysis method is simple, rapid, accurate and fitting to the determination of mineral elements in plants. The recoveries of the method are 90.5%-108.2%. The relative standard deviations are 0.3%-0.7%. The result show that large amounts of mineral elements are embodied in polygonum cuspidatum. The contents of K and Ca are in conformation with the medical effects of polygonum cuspidatum, and each element is related closely to its growing.