Hybrid helical magnetic microrobots are achieved by sequential electrodeposition of a CoNi alloy and PPy inside a photoresist template patterned by 3D laser lithography. A controlled actuation of the microrobots by a rotating magnetic field is demonstrated in a fluidic environment.

Magnetic tubular implantable micro-robots are batch fabricated by electroforming. These microdevices can be used in targeted drug delivery and minimally invasive surgery for ophthalmologic applications. These tubular shapes are fitted into a 23-gauge needle enabling sutureless injections. Using a 5-degree-of-freedom magnetic manipulation system, the microimplants are conveniently maneuvered in biological environments. To increase their functionality, the tubes are coated with biocompatible films and can be successfully filled with drugs.

A method to functionalize steerable magnetic microdevices through the co-electrodeposition of drug loaded chitosan hydrogels is presented. The characteristics of the polymer matrix have been investigated in terms of fabrication, morphology, drug release and response to different environmental conditions. Modifications of the matrix behavior could be achieved by simple chemical post processing. The system is able to load and deliver 40-80 μg cm(-2) of a model drug (Brilliant Green) in a sustained manner with different profiles. Chitosan allows a pH responsive behavior with faster and more efficient release under slightly acidic conditions as can be present in tumor or inflamed tissue. A prototype of a microrobot functionalized with the hydrogel is presented and proposed for the treatment of posterior eye diseases.

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The surface properties of electrodeposited poly(pyrrole) (Ppy) doped with sodium dodecylbenzenesulphonate (NaDBS) are modified by two methods: addition of poly(ethylene glycol) (PEG) during the electrodeposition and through redox cycling post electrodeposition. X-ray photoelectron spectroscopy (XPS) was used to ascertain PEG incorporation and to analyze the change in the oxidation state of the polymer. Anodic cycling resulted in the formation of micrometer-sized surface cracks which increased the amount of Rhodamine-B dye adsorbed onto the surface, and played a role in decreasing the wettability of the surface. The change in surface wettability caused by these cracks was mitigated by the presence of PEG in the Ppy matrix. Compared to the incorporation of PEG, redox cycling was more effective in passively modulating the adhesion of NIH 3T3 fibroblast cells on the Ppy surface. Based on the attenuation of surface polarity of the Ppy surfaces by the incorporated PEG, a mechanism is proposed to explain the observed cell adhesion behavior.

In spite of these outstanding properties, nc metals typically 42 show relatively poor thermal stability. 8,9 Grain growth occurs in 43 these materials at relatively low homologous temperatures (often 44 less than 50% of the melting temperature), mainly because of the 45 large amounts of metastable grain boundaries and defects, where 46 enhanced atomic diffusivity is promoted. As a result, the use of nc aries. 1,8,9 Alloying with certain specific elements can have a . Indicated with the symbols 0, 2, and * are the XRD peaks corresponding to the Cu seed layer, the Ni 1Àx Cu x film and a Cu-rich phase that forms during annealing. Shown in the insets are enlargements of the (111) XRD peaks of the as-deposited films (in black) and the films annealed at T ANN = 625 K (in blue). Note that pronounced XRD peak narrowing (i.e., grain growth and microstrain release) occurs in pure Ni and Ni 0.88 Cu 0.12 films already at T ANN = 575 K. Conversely, for the films containing larger Cu percentages, a clear decrease in the peak width is only observed at higher temperatures (T ANN = 625 K). Remarkably, the FFT analyses corresponding to grain 1 (G1) and grain (G2) feature single spots located at the {111} interplanar distance (d 111 ≈ 0.2038 nm). Conversely, double-spots are clearly observed in FFT images GB1 and GB2, which correspond to the grain boundary region and include portions of grains 1 and 2. In particular, the emerging small inner spots in FFT(GB1) and FFT(GB2) correspond to a slightly larger interplanar distance, d 111 ≈ 0.2085 nm, indicating that the grain boundary region is enriched in Cu. Figure 6. (a) Bright-field scanning transmission electron microscopy image of the Ni 0.56 Cu 0.44 film annealed at T ANN = 625 K; (b) elemental quantification (at% Ni and Cu), using electron energy loss spectroscopy EELS, following the white arrow highlighted in a, which traverses a grain boundary (GB) region. The EELS analysis reveals that the GB region is a Cu-rich NiÀCu solid solution, whereas the composition of the surrounding grains is concurrently depleted in Cu, indicating Cu grain boundary segregation. ACS Applied Materials & Interfaces

Porous nanostructures of polypyrrole (Ppy) were fabricated using colloidal lithography and electrochemical techniques for potential applications in drug delivery. A sequential fabrication method was developed and optimized to maximize the coverage of the Ppy nanostructures and to obtain a homogeneous layer over the substrate. This was realized by masking with electrophoretically-assembled polystyrene (PS) nanospheres and then electroplating. Drug/biomolecule adsorption and the release characteristics for the porous nanostructures of Ppy were investigated using rhodamine B (Rh-B). Rh-B is an easily detectable small hydrophobic molecule that is used as a model for many drugs or biological substances. The porous Ppy nanostructures with an enhanced surface area exhibited higher Rh-B loading capacity than bulk planar films of Ppy. Moreover, tunability of surface morphology for further applications (e.g., sensing, cell adhesion) was demonstrated.

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