Water-soluble peptide-coated nanoparticles: control of the helix structure and enhanced differential binding to immune cells

The stabilizing action of C(α)-tetrasubstituted α-amino acids inserted into a sequence of short peptides allowed for the first time the preparation of water-soluble nanoparticles of different materials coated with a helix-structured undecapeptide. This peptide coating strongly favors nanoparticle uptake by human immune system cells.     

Surface binding vs. sequestration; the uptake of benzohydroxamic acid at iron(iii) oxide surfaces

Benzohydroxamic acid is shown to be an unexpectedly good ligand for iron(iii) oxides, favouring surface attachment to the formation of trisbenzohydroxamato complexes, which are known to have very high thermodynamic stability in solution.     

XRF mapping and TEM analysis of coated and uncoated silica nanoparticles in A549 cells and human monocytes

The evaluation of nanomaterials intracellular distribution still remains a challenge in nanomedicine applications and toxicological studies. Synchrotron radiation X-ray microscopy combined with X-ray fluorescence (XRF) microspectroscopy provides unique information that has pushed the frontiers of biological research, particularly when investigating intracellular mechanisms. In this work, the presence of silica nanoparticles in in vitro cultured human lung epithelial cell line and freshly extract human monocytes has been investigated. For the uptake and intracellular distribution of NPs, cells were cultured on polymeric substrates (Mylar). The SiO₂–NPs have been synthesized at JRC and characterized by dynamic light scattering, centrifugal liquid sedimentation, and transmission electron microscopy (TEM), whereas their interaction with cells was investigated with TEM and XRF. For the latter, we used TwinMic in scanning transmission mode coupled with low-energy XRF spectroscopy, paying particular attention to the distribution of different elements, namely, Fe, O, C, Si, and Mg. Si XRF signals recorded on cells exposed to uncoated silica and epoxy-coated silica nanoparticles are comparable, indicating low difference in cellular uptake and suggesting a similar interaction between nanoparticles and cells. However, the TEM analysis indicates a better affinity of the coated nanoparticles for the cell membrane. Moreover, the TEM analysis shows also the presence of nanoparticles in endosomes.     

相对论平均场理论对Pb同位素位移的研究

运用变形的相对论平均场理论研究了Pb同位素链的基态性质. 对关联的处理采用了BCS方法, 不成对核子的处理运用了“阻塞”法. 计算的结果很好地符合了实验上Pb的平均结合能, 中子分离能, 同位素位移. 接着从原子核的微观结构出发, 比较详细地研究了Pb链同位素位移出现反常扭折这一重要性质的物理机制.