Controlled Anchoring of Iron-Oxide Nanoparticles on Polymeric Nanofibers: Easy Access to Core@Shell Organic-Inorganic Nanocomposites for Magneto-Scaffolds

Composites combining superparamagnetic iron oxide nanoparticles (SPIONs) and polymers are largely present in modern (bio)materials. However, while SPIONs embedded in polymer matrices are classically reported, the mechanical and degradation properties of the polymer scaffold are impacted by the SPIONs. Therefore, the controlled anchoring of SPIONs onto polymer surfaces is still a major challenge. Herein, we propose an efficient strategy for the direct and uniform anchoring of SPIONs on the surface of functionalized-polylactide (PLA) nanofibers via a simple free ligand exchange procedure to design PLA@SPIONs core@shell nanocomposites. The resulting PLA@SPIONs hybrid biomaterials are characterized by electron microscopy (SEM and TEM) and EDXS analysis, to probe the morphology and detect elements present at the organic/inorganic interface, respectively. A monolayer of SPIONs with a complete and homogeneous coverage is observed on the surface of PLA nanofibers. Magnetization experiments show that magnetic properties of the nanoparticles are well-preserved after their grafting on the PLA fibers and that the size of the nanoparticles does not change. The absence of cytotoxicity, combined with a high sensitivity of detection in MRI both in vitro and in vivo make these hybrid nanocomposites attractive for the development of magnetic biomaterials for biomedical applications

Electrical Properties of Boron-Doped P-SiGeC Grown on N(-)-Si Substrate

Electrical properties of fully strained boron-doped Si0.90−yGe0.10Cy/n−–Si grown by low pressure chemical vapor deposition have been investigated as a function of carbon content (0.2%–1.5%), using the variable temperature (25–650 K) Hall-effect technique. The results of Hall-effect measurements show that the Si substrate and the SiGeC/Si interfacial layer affect significantly the electrical properties of the SiGeC epitaxial layer. Thus, a three-layer conducting model has been used to extract the carrier concentration and mobility of the SiGeC layer alone. At room temperature, the hole carrier concentration decreases from 6.8×1017 to 2.4×1017 cm−3 and the mobility decreases from 488 to 348 cm2/V  s as the carbon concentration increases from 0.2% to 1.5%. The boron activation energy increases from 20 to 50 meV as C increases from 0.2% to 1.5% with an increment of 23 meV per atomic % of C

Electrical Properties of Boron-Doped P-SiGeC Grown on N(-)-Si Substrate

Electrical properties of fully strained boron-doped Si0.90−yGe0.10Cy/n−–Si grown by low pressure chemical vapor deposition have been investigated as a function of carbon content (0.2%–1.5%), using the variable temperature (25–650 K) Hall-effect technique. The results of Hall-effect measurements show that the Si substrate and the SiGeC/Si interfacial layer affect significantly the electrical properties of the SiGeC epitaxial layer. Thus, a three-layer conducting model has been used to extract the carrier concentration and mobility of the SiGeC layer alone. At room temperature, the hole carrier concentration decreases from 6.8×1017 to 2.4×1017 cm−3 and the mobility decreases from 488 to 348 cm2/V  s as the carbon concentration increases from 0.2% to 1.5%. The boron activation energy increases from 20 to 50 meV as C increases from 0.2% to 1.5% with an increment of 23 meV per atomic % of C