A multifunctional architecture for biomedical applications has been developed by deliberately combining the useful functions of superparamagnetism, luminescence, and surface functionality into one material. Good control of the core-shell architecture has been achieved by employing a sol-gel synthesis. Superparamagnetic iron oxide nanoparticles are first coated with silica to isolate the magnetic core from the surrounding. Subsequently, the dye molecules are doped inside a second silica shell to improve photostability and allow for versatile surface functionalities. The architecture has been characterized by transmission electron microscopy, UV-vis absorption and emission spectroscopy, energy-dispersive X-ray spectroscopy, X-ray diffraction, and magnetometry. The hybrid nanoparticles exhibit improved superparamagnetic behavior over the as-received nanoparticles with a significant decrease in the blocking temperature. The architecture shows emission properties similar to those of the free dye molecules, suggesting that the first silica shell successfully prevents luminescence quenching by minimizing dyemagnetic core interactions.

We report the structural and physical properties of epitaxial Bi 2 FeCrO 6 thin films on epitaxial SrRuO 3 grown on (100)-oriented SrTiO 3 substrates by pulsed laser ablation.The 300 nm thick films exhibit both ferroelectricity and magnetism at room temperature with a maximum dielectric polarization of 2.8 µC/cm 2 at E max = 82 kV/cm and a saturated magnetization of 20 emu/cc (corresponding to ~ 0.26 µ B per rhombohedral unit cell), with coercive fields below 100 Oe. Our results confirm the predictions made using ab-initio calculations about the existence of multiferroic properties in Bi 2 FeCrO 6 .

A novel method combining wet chemistry for synthesis of an Fe core, 532 nm laser irradiation of Fe nanoparticles and Au powder in liquid medium for deposition of an Au shell, and sequential magnetic extraction/ acid washing for purification has been developed to fabricate oxidation-resistant Fe@Au magnetic coreshell nanoparticles. The nanoparticles have been extensively characterized at various stages during and up to several months after completion of the synthesis by a suite of electron microscopy techniques (HRTEM, HAADF STEM, EDX), X-ray diffraction (XRD), UV-vis spectroscopy, inductively coupled plasma atomic emission spectroscopy, and magnetometry. The surface plasmon resonance of the Fe@Au nanoparticles is red shifted and much broadened as compared with that of pure colloidal nano-gold, which is explained to be predominantly a shell-thickness effect. The Au shell consists of partially fused ∼3-nm-diameter fcc Au nanoparticles (lattice interplanar distance, d ) 2.36 Å). The 18-nm-diameter magnetic core is bcc Fe single domain (d ) 2.03 Å). The nanoparticles are superparamagnetic at room temperature (300 K) with a blocking temperature, T b , of ≈170 K. After 4 months of shelf storage in normal laboratory conditions, their mass magnetization per Fe content was measured to be 210 emu/g, ∼96% of the Fe bulk value.

Dynamic spatial control of MOF position is obtained by incorporating carbon‐coated cobalt nanoparticles within metal organic framework (MOF)‐5 crystals. The cobalt framework composite obtained responds efficiently to magnetic stimuli. A luminescent functionality is added, showing that multifunctional MOF devices can be prepared. This new generation of adaptive material is tested as a position‐controlled molecular sensor.

Digital microfluidics based on electrowetting-on-dielectric (EWOD) has recently emerged as one of the most promising technologies to realize integrated and highly flexible lab-on-a-chip systems. In such EWOD-based digital microfluidic devices, the aqueous droplets have traditionally been manipulated either directly in air or in an immiscible fluid such as silicone oil. However, both transporting mediums have important limitations and neither offers the flexibility required to fulfil the needs of several applications. In this paper, we report on an alternative mode of operation for EWOD-based devices in which droplets enclosed in a thin layer of oil are manipulated in air. We demonstrate the possibility to perform on-chip the fundamental fluidic operations by using such water-oil core-shell droplets and compare systematically the results with the traditional approach where the aqueous droplets are manipulated directly in air or oil. We show that the core-shell configuration combines several advantages of both the air and oil mediums. In particular, this configuration not only reduces the operation voltage of EWOD-based devices but also leads to higher transport velocities when compared with the manipulation of droplets directly in air or oil.