The combination of force and flexibility is at the core of biomechanics and enables virtually all body movements in living organisms. In sharp contrast, presently used machines are based on rigid, linear (cylinders) or circular (rotator in an electrical engine) geometries. As a potential bioinspired alternative, magnetic elastomers can be realized through dispersion of micro- or nanoparticles in polymer matrices and have attracted significant interest as soft actuators in artificial organs, implants, and devices for controlled drug delivery. At present, magnetic particle loss and limited actuator strength have restricted the use of such materials to niche applications. We describe the direct incorporation of metal nanoparticles into the backbone of a hydrogel and application as an ultra-flexible, yet strong magnetic actuator. Covalent bonding of the particles prevents metal loss or leaching. Since metals have a far higher saturation magnetization and higher density than oxides, the resulting increased force/volume ratio afforded significantly stronger magnetic actuators with high mechanical stability, elasticity, and shape memory effect.

Nucleic acids are the information carriers of all known life forms and can store more information per volume space than magnetic domain or floating gate based technologies (Flash drives < 1 TBcm À3 ; DNA > 10 8 TB cm À3 ). Besides future applications in information storage [1] and DNAbased computing, [2] DNA ismost suited for nanobiotechnology, [3] steganographic messaging, [4] encrypted barcoding, and as an anti-counterfeit tag for consumer goods. [5] However, nucleic acids are sensitive to harsh environmental conditions and elevated temperatures, and biological systems have had to develop elaborate repair mechanisms to maintain information integrity over time (more than 10 000 DNA lesions are repaired daily in each human cell).[6] The vulnerability of nucleic acids to hydrolysis (depurination and depyrimidination), [7] oxidation (formation of free radicals mediated by heavy metal ions), and alkylation requires well-controlled DNA storage conditions, ideally dry and at low temperatures.[8] Similarly, ancient DNA (a-DNA) is best recovered from permafrost samples, [9] or in dessicated form from amber [10] and from avian eggshell fossils.[11] Within these fossils a dense diffusion layer (polymerized terpenes or calcium carbonate) separates the desiccated DNA specimen from the environment, water, and reactive oxygen species.Here we show how the simple encapsulation of DNA in silica particles mimics these fossils and protects DNA from aggressive environmental conditions (Scheme 1). The procedure makes DNA processable at conditions well beyond its biological origin. We demonstrate that silicate and hydrofluoric acid chemistry is compatible with nucleic acid analysis by means of quantitative real-time polymerase chain reaction (qPCR). We also show how silica-protected DNA can be made compatible with injection molding at 200 8C such that polymers and consumer goods can be barcoded.

The combination of force and flexibility enables controlled and soft movements. In sharp contrast, presently used machines are solid and mostly based on stiff driveshafts or cog wheels. Magnetic elastomers are realized through dispersion of small particles in polymer matrices and have attracted significant interest as soft actuators for controlled movement or conveying and are particularly attractive candidates for magnetic pump applications. At present, low magnetic particle loading and thus limited actuator strength have restricted the application of such materials. Here, the direct incorporation of metal microparticles into a very soft and flexible silicone and its application as an ultra‐flexible, yet strong magnetic tube, is described. Because metals have a far higher saturation magnetization and higher density than oxides, the resulting increased force/volume ratio afforded significantly stronger magnetic actuators with high mechanical stability, flexibility, and shape memory. Elliptical inner diameter shape of the tubing allowed a very efficient contraction of the tube by applying an external magnetic field. The combination of magnetic silicone tubes and a magnetic field generating device results in a magnetic peristaltic pump.

Semiconducting polymer based X-ray detectors doped with high-Z nanoparticles hold the promise to combine mechanical flexibility and large-area processing with a high X-ray stopping power and sensitivity. Currently, a lack of understanding of how nanoparticle doping impacts the detector dynamics impedes the optimization of such detectors. Here, we study direct X-ray radiation detectors based on the semiconducting polymer poly(9,9-dioctyfluorene) blended with Bismuth(III)oxide (Bi2O3) nanoparticles (NPs). Pure polymer diodes show a high mobility of 1.3 × 10−5 cm2/V s, a low leakage current of 200 nA/cm2 at −80 V, and a high rectifying factor up to 3 × 105 that allow us to compare the X-ray response of a polymer detector in charge-injection conditions (forward bias) and in charge-collection conditions (reverse bias), together with the impact of NP-loading in the two operation regimes. When operated in reverse bias, the detectors reach the state of the art sensitivity of 24 μC/Gy cm2, providing a fast photoresponse. In forward operation, a slower detection dynamics but improved sensitivity (up to 450 ± 150 nC/Gy) due to conductive gain is observed. High-Z NP doping increases the X-ray absorption, but higher NP loadings lead to a strong reduction of charge-carrier injection and transport due to a strong impact on the semiconductor morphology. Finally, the time response of optimized detectors showed a cut-off frequency up to 200 Hz. Taking advantage of such a fast dynamic response, we demonstrate an X-ray based velocity tracking system.

Flame spray pyrolysis (FSP) was utilized to fabricate palladium in silica nanocomposites (core-shell structure) in a single step. The nanometer scale transformation of these materials to Pd dispersed on an amorphous silica matrix (oxide-supported noble metal) at elevated temperatures (500-900 °C) was investigated using transmission electron microscopy and CO chemisorption. A spatially resolved (1-D) population balance model was utilized to describe the transformation by diffusion and aggregation processes. The model describes the influence of temperature, matrix viscosity, particle sizes, and concentrations and enables a prediction of the morphology (core-shell vs supported) of metal/silica nanocomposites processed at elevated temperatures. The data are discussed in terms of aerosol formation mechanisms (consecutive vs simultaneous coagulation) and compared to literature data on the high-temperature formation of nanocomposites. To illustrate the validity of the physical model and mechanisms, a network modifier (CaO) was added to the glassy matrix of the composite (Pd/CaO/SiO 2 ), decreasing the matrix viscosity and resulting in the predicted morphology.

Inspired by the natural expansion and contraction mechanism, we present a combustion powered soft silicone monoblock pump lasting for over 10 000 pumping cycles.

Surface-modified magnetic nanoparticles can be used in extraction processes as they readily disperse in common solvents and combine high saturation magnetization with excellent accessibility. Reversible and recyclable adsorption and desorption through solvent changes and magnetic separation provide technically attractive alternatives to classical solvent extraction. Thin polymer layered carbon-coated cobalt nanoparticles were tagged with β-cyclodextrin. The resulting material reversibly adsorbed organic contaminants in water within minutes. Isolation of the immobilized inclusion complex was easily carried out within seconds by magnetic separation due to the strong magnetization of the nanomagnets (metal core instead of hitherto used iron oxide). The trapped molecules were fully and rapidly recovered by filling the cyclodextrin cavity with a microbiologically well accepted substitute, e.g., benzyl alcohol. Phenolphthalein was used as a model compound for organic contaminants such as polychlorinated dibenzodioxins (PCDDs) or bisphenol A (BPA). Fast regeneration of nanomagnets (compared to similar cyclodextrin-based systems) under mild conditions resulted in 16 repetitive cycles (adsorption/desorption) at full efficiency. The high removal and regeneration efficiency was examined by UV-vis measurements at chemical equilibrium conditions and under rapid cycling (5 min). Experiments at ultralow concentrations (160 ppb) underline the high potential of cyclodextrin modified nanomagnets as a fast, recyclable extraction method for organic contaminants in large water streams or as an enrichment tool for analytics.

Background:The purpose of this preliminary study was to assess the in vivo performance of synthetic, cotton wool-like nanocomposites consisting of a biodegradable poly(lactide-co-glycolide) fibrous matrix and containing either calcium phosphate nanoparticles (PLGA/CaP 60:40) or silver doped CaP nanoparticles (PLGA/Ag-CaP 60:40). Besides its extraordinary in vitro bioactivity the latter biomaterial (0.4 wt% total silver concentration) provides additional antimicrobial properties for treating bone defects exposed to microorganisms.Materials and Methods:Both flexible artificial bone substitutes were implanted into totally 16 epiphyseal and metaphyseal drill hole defects of long bone in sheep and followed for 8 weeks. Histological and histomorphological analyses were conducted to evaluate the biocompatibility and bone formation applying a score system. The influence of silver on the in vivo performance was further investigated.Results:Semi-quantitative evaluation of histology sections showed for both implant materials an excellent biocompatibility and bone healing with no resorption in the adjacent bone. No signs of inflammation were detectable, either macroscopically or microscopically, as was evident in 5 µm plastic sections by the minimal amount of inflammatory cells. The fibrous biomaterials enabled bone formation directly in the centre of the former defect. The area fraction of new bone formation as determined histomorphometrically after 8 weeks implantation was very similar with 20.5 ± 11.2 % and 22.5 ± 9.2 % for PLGA/CaP and PLGA/Ag-CaP, respectively.Conclusions:The cotton wool-like bone substitute material is easily applicable, biocompatible and might be beneficial in minimal invasive surgery for treating bone defects.