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International audience; Hybrid nanocomposites containing Carbon nanotubes (CNT) and inorganic nanoparticles produce new properties due to interfacial effectsabsent in the individual nanomaterials. ZnO is a well-known semiconductor. Conversely, HfO2 is a wide bandgap dielectric. When reduced to nanoparticles with average sizes of 2.6nm, they emanate in the blue-green part of the visible spectrum. This is attributed to surface defects generated due to size reduction, which in turn create luminescent defect states within the band gap of HfO2. In both cases, i.e. ZnO and HfO2, the oxygen vacancy related emission is between 2.3 and 2.5eV. Both materials also emit at approximately 3.3eV. In ZnO, the emission at 3.27eV corresponds to the near band edge emission (NBE), while as in HfO2 it corresponds to the Hf3+ defects states. When combined with CNT, changes in the emission spectra are observed producing new phenomena. In the case of HfO2-CNT, both visible and UV photoexcitations are capable of producing a photocurrent at zero bias. This advocates its applicability as an active layer in photovoltaic cells. Depending on the photoexcitation, different defectstates participate in the generation of photocurrents. Furthermore, Ag nanoparticles can act as nano-antennas owing to their plasmonic effect and the addition of Ag nanoparticles to ZnO-CNT demonstrates that the optical bandgap of the nanocomposites increases due to the Burnstein-Moss effect. Thus,conjoining Ag to ZnO-CNT not only enhances the UV emission but also suppresses the visible emission. For highly defective ZnO, addition of Ag nanoparticles allows visiblelight activation of ZnO-CNT-Ag nanohybrids. This talk will cover the synthesis and optical properties of the nanohybrids.In addition, a modified common multimeter capable of measuring nanocurrents from HfO2-CNT will be briefly presented.

Erwan Rauwel1 ,* Siham Al-Arag2 ,* Hamideh Salehi,2 Carlos O Amorim,3 Frédéric Cuisinier,2 Mithu Guha,4 Maria S Rosario,5 Protima Rauwel1 1Institute of Technology, Estonian University of Life Sciences, Tartu, Estonia; 2LBN, University of Montpellier, Montpellier, France; 3Dpt. Of Physics & CICECO – Aveiro Institute of Materials, University of Aveiro, Aveiro, Portugal; 4Dpt. Of General & Molecular Pathology, Faculty of Medicine, University of Tartu, Tartu, Estonia; 5CICECO – Aveiro Institute of Materials, University of Aveiro, Aveiro, Portugal*These authors contributed equally to this workCorrespondence: Erwan Rauwel Email erwan.rauwel@emu.eePurpose: Nanotechnology applied to cancer treatment is a growing area of research in nanomedicine with magnetic nanoparticle-mediated anti-cancer drug delivery systems offering least possible side effects. To that end, both structural and chemical properties of commercial cobalt metal nanoparticles were studied using label-free confocal Raman spectroscopy.Materials and Methods: Crystal structure and morphology of cobalt nanoparticles were studied by XRD and TEM. Magnetic properties were studied with SQUID and PPMS. Confocal Raman microscopy has high spatial resolution and compositional sensitivity. It, therefore, serves as a label-free tool to trace nanoparticles within cells and investigate the interaction between coating-free cobalt metal nanoparticles and cancer cells. The toxicity of cobalt nanoparticles against human cells was assessed by MTT assay.Results: Superparamagnetic Co metal nanoparticle uptake by MCF7 and HCT116 cancer cells and DPSC mesenchymal stem cells was investigated by confocal Raman microscopy. The Raman nanoparticle signature also allowed accurate detection of the nanoparticle within the cell without labelling. A rapid uptake of the cobalt nanoparticles followed by rapid apoptosis was observed. Their low cytotoxicity, assessed by means of MTT assay against human embryonic kidney (HEK) cells, makes them promising candidates for the development of targeted therapies. Moreover, under a laser irradiation of 20mW with a wavelength of 532nm, it is possible to bring about local heating leading to combustion of the cobalt metal nanoparticles within cells, whereupon opening new routes for cancer phototherapy.Conclusion: Label-free confocal Raman spectroscopy enables accurately localizing the Co metal nanoparticles in cellular environments. The interaction between the surfactant-free cobalt metal nanoparticles and cancer cells was investigated. The facile endocytosis in cancer cells shows that these nanoparticles have potential in engendering their apoptosis. This preliminary study demonstrates the feasibility and relevance of cobalt nanomaterials for applications in nanomedicine such as phototherapy, hyperthermia or stem cell delivery.Keywords: Raman spectroscopy, cobalt nanoparticles, cancer cells, stem cells, cellular uptake, apoptosis, label-free tool

International audience

Atomic layer deposition (ALD), a gas-phase thin film deposition technique based on repeated, self-terminating gas-solid reactions, has become the method of choice in semiconductor manufacturing and many other technological areas for depositing thin conformal inorganic material layers for various applications. ALD has been discovered and developed independently, at least twice, under different names: atomic layer epitaxy (ALE) and molecular layering. ALE, dating back to 1974 in Finland, has been commonly known as the origin of ALD, while work done since the 1960s in the Soviet Union under the name "molecular layering" (and sometimes other names) has remained much less known. The virtual project on the history of ALD (VPHA) is a volunteer-based effort with open participation, set up to make the early days of ALD more transparent. In VPHA, started in July 2013, the target is to list, read and comment on all early ALD academic and patent literature up to 1986. VPHA has resulted in two essays and several presentations at international conferences. This paper, based on a poster presentation at the 16th International Conference on Atomic Layer Deposition in Dublin, Ireland, 2016, presents a recommended reading list of early ALD publications, created collectively by the VPHA participants through voting. The list contains 22 publications from Finland, Japan, Soviet Union, United Kingdom, and United States. Up to now, a balanced overview regarding the early history of ALD has been missing; the current list is an attempt to remedy this deficiency. (C) 2016 Author(s).

International audience

Photoluminescent ZnO carbon nanomaterials are an emerging class of nanomaterials with unique optical properties. They each, ZnO and carbon nanomaterials, have an advantage of being nontoxic and environmentally friendly. Their cost-effective production methods along with simple synthesis routes are also of interest. Moreover, ZnO presents photoluminescence emission in the UV and visible region depending on the synthesis routes, shape, size, deep level, and surface defects. When combined with carbon nanomaterials, modification of surface defects in ZnO allows tuning of these photoluminescence properties to produce, for example, white light. Moreover, efficient energy transfer from the ZnO to carbon nanostructures makes them suitable candidates not only in energy harvesting applications but also in biosensors, photodetectors, and low temperature thermal imaging. This work reviews the synthesis and photoluminescence properties of 3 carbon allotropes: carbon quantum or nanodots, graphene, and carbon nanotubes when hybridized with ZnO nanostructures. Various synthesis routes for the hybrid materials with different morphologies of ZnO are presented. Moreover, differences in photoluminescence emission when combining ZnO with each of the three different allotropes are analysed.

Silver has been recognized as a nontoxic, safe inorganic antibacterial/antifungal agent used for centuries. Silver demonstrates a very high potential in a wide range of biological applications, more particularly in the form of nanoparticles. Environmentally friendly synthesis methods are becoming more and more popular in chemistry and chemical technologies and the need for ecological methods of synthesis is increasing; the aim is to reduce polluting reaction by-products. Another important advantage of green synthesis methods lies in its cost-effectiveness and in the abundance of raw materials. During the last five years, many efforts were put into developing new greener and cheaper methods for the synthesis of nanoparticles. The cost decrease and less harmful synthesis methods have been the motivation in comparison to other synthesis techniques where harmful reductive organic species produce hazardous by-products. This environment-friendly aspect has now become a major social issue and is instrumental in combatting environmental pollution through reduction or elimination of hazardous materials. This review describes a brief overview of the research on green synthesis of silver metal nanoparticles and the influence of the method on their size and morphology.