Mechanical Properties of Sub-Microbubbles with a Nanoparticle-Decorated Polymer Shell.

Nanoparticle-decorated polymer-coated sub-microbubbles (NP-P-coated SMBs), as proved, have shown promising application prospects in ultrasound imaging, magnetic resonance imaging, drug delivery, and so forth. However, the quantitative evaluation of the stability and mechanical properties of single NP-P-coated SMB is absent. Here, we first reported the stiffness and Young's modulus of single NP-P-coated SMB obtained by the PeakForce mode of atomic force microscopy. Such NP-P-coated SMBs could maintain perfect spherical shapes and have a thinner shell thickness (about 10 nm), as determined by characterization using a transmission electron microscope. Young's modulus of NP-P-coated SMBs is about 4.6 ± 1.2 GPa, and their stiffness is about 15.0 ± 3.1 N/m. Both modulus and stiffness are obtained from the linear region in the force-deformation curve and are nearly independent of their sizes. These results should be very useful to evaluate their stability, which plays a key role in maintaining the shell drug loading and acoustic capabilities.

His18 promotes reactive oxidative stress production in copper-ion mediated human islet amyloid polypeptide aggregation.

Copper ions play a critical role in human islet amyloid polypeptide (hIAPP) aggregation, which has been found in more than 90% of patients with type-2 diabetes (T2D). The role of Cu(ii) in the cell cytotoxicity with hIAPP has been explored in two aspects: inhibiting the formation of fibrillar structures and stimulating the generation of reactive oxygen species (ROS). In this work, we carried out spectroscopic studies of Cu(ii) interacting with several hIAPP fragments and their variants as well. Electron paramagnetic resonance (EPR) measurements and Amplex Red analysis showed that the amount of H2O2 generated in hIAPP(11-28) solution co-incubated with Cu(ii) was remarkably more than hIAPP(1-11) and hIAPP(28-37). Furthermore, the H2O2 level was seriously reduced when His18 of hIAPP(11-28) was replaced by Arg(R) or Ser(S), indicating that His18 is the key residue of Cu(ii) binding to hIAPP(11-28) to promote H2O2 generation. This is likely because the donation of electrons from the peptide to Cu(ii) ions would result in the formation of the redox-active complexes, which could stimulate the formation of H2O2. Overall, this study provides further insight into the molecular mechanism of Cu(ii) induced ROS generation.

[Construction of DNA vaccines containing C3d-P29 against Newcastle disease].

After cloning the C3d cDNA of AA broilers using the liver mRNA source, a pair of primers were designed to subclone the P29 gene to the pUC19 plasmid. Several tandems of P29 were constructed in the pUC19 plasmid using a pair of isoschizomers-BamH I and Bgl II. The pUC- P29.n was igested to get the gene of P29.n that was then cloned to pCDNA3.1 (+) plasmid. After this, the F Gene of Newcastle Disease Virus was cloned through RT-PCR and inserted into the upstream of the P29.n that was in the pCDNA-P29.n, and the DNA vaccines containing F gene against NDV with C3d-P29 as molecular adjuvant were constructed. Several groups of Specefic Pathogen Free chickens were injected with these recombinant plasmids. The pCDNA-F-P29.4 and pCDNA-F-P29.6 group had higher HI antibody titers than the pCDNA-F group. The pCDNA-F-P29.4 and pCDNA-F-P29.6 group's HI antibody titers did not achieve titers as high as the inactive vaccine group. However, they all provided protection against the lethal F48E9 virus challenge.