We are very pleased to see our recent work highlighted by the Royal Society of Chemistry at Chemistry World. To dot miss this enjoyable summary of our article “Farming thermoelectric paper”!
The beginning of 2019 has been fruitful in terms of publications for the N&N group! Last 22nd January 2019 the article “Farming thermoelectric paper” was published on Energy & Environmental Science. This study has been carried out in collaborations with the NanOpto group at ICMAB. Congratulations to all the authors for this multidisciplinary work!
The paper entitled “Nanoclusters of crystallographically aligned nanoparticles for magnetic thermotherapy: aqueous ferrofluid, agarose phantoms and ex vivo melanoma tumour assessment” has recently been published on the Nanoscale Journal. We congratulate Anna Roig and our collaborator Marcela Fernández for being authors of this nice study!
Abstract: Magnetic hyperthermia is an oncological therapy where magnetic nanostructures, under a radiofrequency field, act as heat transducers increasing tumour temperature and killing cancerous cells. Nanostructure heating efficiency depends both on the field conditions and on the nanostructure properties and mobility inside the tumour. Such nanostructures are often incorrectly bench-marketed in the colloidal state and using field settings far off from the recommended therapeutic values. Here, we prepared nanoclusters composed of iron oxide magnetite nanoparticles crystallographically aligned and their specific absorption rate (SAR) values were calorimetrically determined in physiological fluids, agarose-gel-phantoms and ex vivo tumours extracted from mice challenged with B16-F0 melanoma cells. A portable, multipurpose applicator using medical field settings; 100 kHz and 9.3 kA m−1, was developed and the results were fully analysed in terms of nanoclusters’ structural and magnetic properties. A careful evaluation of the nanoclusters’ heating capacity in the three milieus clearly indicates that the SAR values of fluid suspensions or agarose-gel-phantoms are not adequate to predict the real tissue temperature increase or the dosage needed to heat a tumour. Our results show that besides nanostructure mobility, perfusion and local thermoregulation, the nanostructure distribution inside the tumour plays a key role in effective heating. A suppression of the magnetic material effective heating efficiency appears in tumour tissue. In fact, dosage had to be increased considerably, from the SAR values predicted from fluid or agarose, to achieve the desired temperature increase. These results represent an important contribution towards the design of more efficient nanostructures and towards the clinical translation of hyperthermia.
We are happy to announce that last 1st of November 2018, the paper “Stability and nature of the volume collapse of ε-Fe2O3 under extreme conditions” was published on the journal Nature Communications. This study is co-authored by the permanent researcher at the N&N group Martí Gich.
Abstract: Iron oxides are among the major constituents of the deep Earth’s interior. Among them, the epsilon phase of Fe2O3 is one of the less studied polymorphs and there is a lack of information about its structural, electronic and magnetic transformations at extreme conditions. Here we report the precise determination of its equation of state and a deep analysis of the evolution of the polyhedral units under compression, thanks to the agreement between our experiments and ab-initio simulations. Our results indicate that this material, with remarkable magnetic properties, is stable at pressures up to 27 GPa. Above 27 GPa, a volume collapse has been observed and ascribed to a change of the local environment of the tetrahedrally coordinated iron towards an octahedral coordination, finding evidence for a different iron oxide polymorph. DOI: https://doi.org/10.1038/s41467-018-06966-9
Congratulations to the authors Martí Gich, Anna Roig (N&N group), Pengfei Niu (former member of the N&N group) and César Fernández‐Sánchez (N&N collaborator form the Barcelona Institute of Microelectronics) for their published paper “Metal Nanoparticle Carbon Gel Composites in Environment in Water Sensing Applications”. The manuscript was published in the journal Chemical Record in a special issue dedicated to Prof. Ruiz-Hitzky.
Abstract: The synthesis of organic‐inorganic nanocomposites that can interact with different environmental pollutants and can be mass‐produced are very promising materials for the fabrication of chemical sensor devices. Among them, metal (or metal oxide) nanoparticles doped conductive porous carbon composites can be readily applied to the production of electrochemical sensors and show enhanced sensitivity for the measurement of water pollutants, thanks to the abundant accessible and functional sites provided by the interconnected porosity and the metallic nanoparticles, respectively. In this personal account, an overview of several synthesis routes of porous carbon composites containing metallic nanoparticles is given, paying special attention to those based on sol‐gel techniques. These are very powerful to synthesize hybrid porous materials that can be easily processed into powders and thin films, so that they can be implemented in electrode fabrication processes based on screen‐printing and lithography techniques, respectively. We emphasize the sol‐gel routes developed in our group for the synthesis of bismuth or gold nanoparticle doped porous carbon composites applied to fabricate electrochemical sensors that can be scaled down to produce miniaturized on‐chip sensing devices for the sensitive detection of heavy metal pollutants in water. The trend towards the miniaturization of electrochemical sensors to be readily employed as analytical tools in environmental monitoring follow the market requirements of rapid and accurate on‐site analysis, small sample consumption and waste production, as well as potential for continuous or semi‐continuous in‐situ determination of a wide variety of target analytes.