Superconducting gap of overdoped Tl2Ba2CuO6+d observed by Raman scattering

We report Raman scattering spectra for single crystals of overdoped Tl2Ba2CuO6+d (Tl-2201) at low temperatures. It was observed that the pair-breaking peaks in A1g and B1g spectra radically shift to lower energy with carrier doping. We interpret it as s-wave component mixing into d-wave, although the crystal structure is tetragonal. Since similar phenomena were observed also in YBa2Cu3Oy and Bi2Sr2CaCu2Oz, we conclude that s-wave mixing is a common property for overdoped high-Tc superconductors.Comment: 8 pages, 3 figures, proceedings of SNS200

On properly integrating the electronic Raman and optical infra-red spectra of HTSC cuprate materials

New electronic Raman and I.R. spectroscopy results from optimally and overdoped high temperature superconducting (HTSC) cuprate systems are interpreted in terms of the negative-U, boson-fermion crossover model. Distinction is made between those features which follow the condensate gap, 2Delta(p), and those that are set by the local-pair binding energy, cursive U(p). The critical role of doping level psubc = 0.185 is highlighted in conjunction with the matter of developing quasiparticle incoherence, making connection here with recent transport and related results. E//c IR results in magnetic fields parallel and perpendicular to c prove particularly illuminating. The general scheme developed continues to embrace all experimental data very satisfactorily.Comment: 23 pages, 4 figure

Development of Functional Chimeric Nanoparticles by Membrane Fusion of Small Extracellular Vesicles and Drug-Encapsulated Liposomes

Since small extracellular vesicle (sEVs) are involved in cell-to-cell communication via transfer of certain bioactive molecules and have the capability to overcome biological barriers against drug transport, their use as a drug delivery system (DDS) has been demonstrated in treatment of a diverse range of diseases. However, some issues in drug encapsulation have been pointed out, including low encapsulation efficiency and poor reproducibility. It was previously reported that liposomes containing phosphatidylserine (PS) can fuse together in the presence of calcium ion, which allows for drug encapsulation into the resultant liposomes (i.e., calcium fusion method). On the other hand, PS is reportedly present in lipid membrane of sEVs as a distinct lipid composition. We therefore hypothesized that PS-mediated membrane fusion of sEVs with PS-liposomes encapsulating therapeutic agents via the calcium fusion method can be applied to convenient drug encapsulation into sEVs. Membrane fusion of PS-liposomes and sEVs derived from murine melanoma B16F1 cells (B16-sEVs) was firstly confirmed. The obtained nanoparticles, termed chimeric nanoparticles (CM-NP), showed comparable cellular uptake to B16-sEVs into B16F1 cells. Moreover, CM-NP encapsulating an anticancer drug doxorubicin (DOX) (CM-NP-DOX) could be prepared by membrane fusion of PS-liposomes encapsulating DOX (PS-Lipo-DOX) and B16-sEVs. CM-NP-DOX exhibited a superior anticancer effect on B16F1 cells in vitro compared with PS-Lipo-DOX. These findings suggest that the calcium fusion method could be applied for membrane fusion of sEVs and PS-liposomes, and that this approach would likely be useful for efficient drug encapsulation into sEVs, as well as increasing liposome functionality