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- ItemHuman spermbots for patient-representative 3D ovarian cancer cell treatment(Cambridge : RSC Publ., 2020) Xu, Haifeng; Medina-Sánchez, Mariana; Zhang, Wunan; Seaton, Melanie P. H.; Brison, Daniel R.; Edmondson, Richard J.; Taylor, Stephen S.; Nelson, Louisa; Zeng, Kang; Bagley, Steven; Ribeiro, Carla; Restrepo, Lina P.; Lucena, Elkin; Schmidt, Christine K.; Schmidt, Oliver G.Cellular micromotors are attractive for locally delivering high concentrations of drug, and targeting hard-to-reach disease sites such as cervical cancer and early ovarian cancer lesions by non-invasive means. Spermatozoa are highly efficient micromotors perfectly adapted to traveling up the female reproductive system. Indeed, bovine sperm-based micromotors have shown potential to carry drugs toward gynecological cancers. However, due to major differences in the molecular make-up of bovine and human sperm, a key translational bottleneck for bringing this technology closer to the clinic is to transfer this concept to human material. Here, we successfully load human sperm with Doxorubicin (DOX) and perform treatment of 3D cervical cancer and patient-representative ovarian cancer cell cultures, resulting in strong anticancer cell effects. Additionally, we define the subcellular localization of the chemotherapeutic drug within human sperm, using high-resolution optical microscopy. We also assess drug effects on sperm motility and viability over time, employing sperm samples from healthy donors as well as assisted reproduction patients. Finally, we demonstrate guidance and release of human drug-loaded sperm onto cancer tissues using magnetic microcaps, and show the sperm microcap loaded with a second anticancer drug, camptothecin (CPT), which unlike DOX is not suitable for directly loading into sperm due to its hydrophobic nature. This co-drug delivery approach opens up novel targeted combinatorial drug therapies for future applications. © 2020 The Royal Society of Chemistry.
- ItemHigh-rate amorphous SnO2 nanomembrane anodes for Li-ion batteries with a long cycling life(Cambridge : RSC Publ., 2014) Liu, Xianghong; Zhang, Jun; Si, Wenping; Xi, Lixia; Oswald, Steffen; Yan, Chenglin; Schmidt, Oliver G.Amorphous SnO2 nanomembranes as anodes for lithium ion batteries demonstrate a long cycling life of 1000 cycles at 1600 mA g−1 with a high reversible capacity of 854 mA h g−1 and high rate capability up to 40 A g−1. The superior performance is because of the structural features of the amorphous SnO2 nanomembranes. The nanoscale thickness provides considerably reduced diffusion paths for Li+. The amorphous structure can accommodate the strain of lithiation/delithiation, especially during the initial lithiation. More importantly, the mechanical feature of deformation can buffer the strain of repeated lithiation/delithiation, thus putting off pulverization. In addition, the two-dimensional transport pathways in between nanomembranes make the pseudo-capacitance more prominent. The encouraging results demonstrate the significant potential of nanomembranes for high power batteries.
- ItemUltrasmall SnO₂ nanocrystals: hot-bubbling synthesis, encapsulation in carbon layers and applications in high capacity Li-ion storage([London] : Macmillan Publishers Limited, part of Springer Nature, 2014) Ding, Liping; He, Shulian; Miao, Shiding; Jorgensen, Matthew R.; Leubner, Susanne; Yan, Chenglin; Hickey, Stephen G.; Eychmüller, Alexander; Xu, Jinzhang; Schmidt, Oliver G.Ultrasmall SnO2 nanocrystals as anode materials for lithium-ion batteries (LIBs) have been synthesized by bubbling an oxidizing gas into hot surfactant solutions containing Sn-oleate complexes. Annealing of the particles in N2 carbonifies the densely packed surface capping ligands resulting in carbon encapsulated SnO2 nanoparticles (SnO2/C). Carbon encapsulation can effectively buffer the volume changes during the lithiation/delithiation process. The assembled SnO2/C thus deliver extraordinarily high reversible capacity of 908 mA·h·g−1 at 0.5 C as well as excellent cycling performance in the LIBs. This method demonstrates the great potential of SnO2/C nanoparticles for the design of high power LIBs.
- ItemManipulating topological states by imprinting non-collinear spin textures([London] : Macmillan Publishers Limited, part of Springer Nature, 2015) Streubel, Robert; Han, Luyang; Im, Mi-Young; Kronast, Florian; Rößler, Ulrich K.; Radu, Florin; Abrudan, Radu; Lin, Gungun; Schmidt, Oliver G.; Fischer, Peter; Makarov, DenysTopological magnetic states, such as chiral skyrmions, are of great scientific interest and show huge potential for novel spintronics applications, provided their topological charges can be fully controlled. So far skyrmionic textures have been observed in noncentrosymmetric crystalline materials with low symmetry and at low temperatures. We propose theoretically and demonstrate experimentally the design of spin textures with topological charge densities that can be tailored at ambient temperatures. Tuning the interlayer coupling in vertically stacked nanopatterned magnetic heterostructures, such as a model system of a Co/Pd multilayer coupled to Permalloy, the in-plane non-collinear spin texture of one layer can be imprinted into the out-of-plane magnetised material. We observe distinct spin textures, e.g. vortices, magnetic swirls with tunable opening angle, donut states and skyrmion core configurations. We show that applying a small magnetic field, a reliable switching between topologically distinct textures can be achieved at remanence.