No abstract

No abstract

Liposomal drug delivery systems (LDDSs) are promising tools used for the treatment of diseases where highly toxic pharmacological agents are administered. Currently, destabilising LDDSs by a specific stimulus at a target site remains a major challenge. The bacterial mechanosensitive channel of large conductance (MscL) presents an excellent candidate biomolecule that could be employed as a remotely controlled pore-forming nanovalve for triggered drug release from LDDSs. In this study, we developed superparamagnetic nanoparticles for activation of the MscL nanovalves by magnetic field. Synthesised CoFe2O4 nanoparticles with the radius less than 10 nm were labelled by SH groups for attachment to MscL. Activation of MscL by magnetic field with the nanoparticles attached was examined by the patch clamp technique showing that the number of activated channels under ramp pressure increased upon application of the magnetic field. In addition, we have not observed any cytotoxicity of the nanoparticles in human cultured cells. Our study suggests the possibility of using magnetic nanoparticles as a specific trigger for activation of MscL nanovalves for drug release in LDDSs.

No abstract

Iron-sheathed MgB2 wires doped with 0, 1.3 and 2.52 wt% carbon protected nickel superparamagnetic nanoparticles (the average diameter of the particles is 20 nm) and sintered at 650 °C were prepared. X-ray diffraction patterns and magnetization measurements showed that neither substitution of C for B nor substitution of Ni for Mg occurred during the synthesis process. Scanning electron microscopy imaging of the doped sample revealed a homogeneous distribution of nickel particles within the MgB2 matrix. Transport (magnetoresistivity R(T,B) and critical current density Jc(B) in the temperature range 1.5–40 K) and magnetic measurements (magnetic hysteresis loops at temperatures below and above the superconducting transition temperature) were performed on Fe-sheathed wires and the superconducting cores of these wires. A small enhancement of the irreversibility field Birr(t = Tirr(B)/Tirr(0)) of the doped wires was observed in the low field range. Significant enhancement of Jc(B), especially at low temperature (5 K), was observed: at 5 K and 10 T, for both doped wires, Jc is 2.5 times larger than that for the undoped wire.