SIMS2015 Session NN-ThP: Nanomaterials and Nanotechnology Poster Session

ToF-SIMS and XPS study of single-step orthogonal chemical functionalizations on micro/nano-patterned gold

Francisco Palazon^(1)(*), Didier Léonard⁽²⁾, Thierry Le Mogne⁽³⁾, Mickaël Desbrosses⁽²⁾, Francesca Zuttion⁽¹⁾, Céline Chevalier⁽⁴⁾, Thomas Géhin⁽¹⁾, Geneviève Grenet⁽¹⁾, Magali Phaner-Goutorbe⁽¹⁾, Eliane Souteyrand⁽¹⁾, Yann Chevolot⁽¹⁾, Jean-Pierre Cloarec⁽¹⁾

(1) Université de Lyon, Institut des Nanotechnologies de Lyon, Site École Centrale de Lyon, CNRS UMR 5270, 36 Avenue Guy de Collongue, 69134 Écully, France.

(2) Université de Lyon, Institut des Sciences Analytiques, Université Claude Bernard Lyon 1/CNRS/ENS de Lyon, UMR 5280, 5 rue de la Doua, 69100 Villeurbanne, France.

(3) Ecole Centrale de Lyon, LTDS, 36 Avenue Guy de Collongue, 69134 Ecully, France

(4) Laboratoire Nanotechnologies & Nanosystèmes (UMI-LN2 3463), Université de Sherbrooke, 3000 Boulevard de l’Université, Sherbrooke, Québec J1K 0A5, Canada

(*) Current address: Department of Nanochemistry, Istituto Italiano di Tecnologia, Genoa, Italy

The current evolution of nanotechnology stresses the importance of patterned surfaces with different materials. Simultaneously, nanofabrication has evolved into the synthesis of colloidal nano-objects with different geometries (spheres, rods, tubes) and different chemical composition. These nano-objects are very promising for their unprecedented physico-chemical properties (e.g: supraconductivity). However, the integration of such nano-objects onto complex systems implies their precise placement onto a patterned surface (e.g: nanotube bridging two microelectrodes).

This issue is especially relevant in the field of nanoplasmonic biosensors where transduction only happens at nanometric « hot spots » on the surface. Therefore, target molecules have to be selectively immobilized onto those nanostructures to be detected and contribute to the biosensor output signal. However, in order to take full advantage of such nanopatterned transducers, it is crucial to selectively place the target biomolecules onto the different « hot spots ».

Herein, single-step orthogonal chemical functionalizations have been developed on micro and nano-patterned gold on silica surfaces to allow the selective binding of nano-objects or biomolecules onto specific regions. Different thiols and silanes were used to this end. The orthogonality of the functionalizations was proven by Time-of-Flight Secondary Ion Mass Spectrometry (ToF-SIMS) (molecular information, mapping) together with Polarization-Modulated InfraRed Reflection Absorption Spectroscopy (PM-IRRAS) and X-ray Photoelectron Spectroscopy (XPS).

Semiconductor materials are widely investigated because of their applications in many fields such as electronics, optics, catalysis and gas sensing [1]. In particular, much research has been devoted to the synthesis, characterization and application of metal oxide semiconductors, owing to their stability, low cost synthesis and non-toxic nature. In this category, NiO and ZnO have been extensively studied. NiO is a transparent p-type semiconductor with a wide band gap in the range of 3.6–3.8 Ev, which has good chemical stability and good electrical properties [2] and ZnO is a transparent n-type semiconductor with a band gap of 3.2 Ev, which exhibits unique catalytic, electrical, gas sensing, and optical properties [3].

Here, we report, for the first time, the synthesis of Ni_1-xZn_xO nanoparticles and Ni_1-xZn_xO/ZnO nanocomposites using metal malonates as single batch precursors, followed by thermal decomposition at relatively low temperature. The analysis of the precursors by ICP-AES and FTIR confirmed their structure as being Ni_1-xZn_x(OOCCH₂COO).2H₂O. The presence of mixed phase nanoparticles after thermal decomposition of the precursors was confirmed by ToF-SIMS and XRD. Precisely, the presence of Zn in the NiO nanoparticles with a saturation around 10-20% Zn, was directly established by ToF-SIMS. In this range of concentrations, XRD only shows reflections corresponding the NiO rocksalt structure, but with a lattice parameter increasing with the Zn percentage, indicating a solid solution of Zn in the NiO crystals. Electrical measurements were performed on Ni_1-xZn_xO films deposited by drop coating and the results show an increase of conductivity with increasing the amount of Zn in the NiO structure. Preliminary tests of gas sensing were conducted and will also be reported.

[1] B. G. Yacobi, Semiconductor materials: an introduction to basic principles, Springer, New York, 2003.

[2] E. R. Beach, K. Shqau, S. E. Brown, S. J. Rozeveld, P. A. Morrisa, Mater. Chem. Phys. 115 (2009) 371–377.

[3] B. D. Aleksandra, X.Y. Chen, Y.H. Leung, et al., J. Mater. Chem. 22 (2012) 6526–6535.

Herein, we systematically prepared various GNMs under controlled experimental conditions and rendered them to time-of-flight secondary ion mass spectrometry (TOF-SIMS) analysis. The hydrophobic GNMs were pressed onto indium foil to overcome the hydrophilicity of silica support. Characteristic fragment ions of GNMs were readily identified by TOF-SIMS operated with a Bi3+ primary ion gun. The information-rich TOF-SIMS spectra were useful for providing chemical structure information and identifying marker to assist followed bioassay study.

Model in vitro and in vivo bioassay studies were carried out using HeLa cells and zebrafish embryos/adult as testing organisms, respectively. After applying appropriate dose of GNMs to the testing organisms for a specific time period, the GNMs was readily detected by TOF-SIMS ion image, which is useful to delineate the spatial distribution of GNMs in different sub-cellular parts and organs. The chemical information from tissues around GNMs offers clue leading to abnormalities and distribution requires the use of additional analytical techniques such as confocal laser scanning microscopy.

In summary, our preliminary results demonstrate that TOF-SIMS is a potential analytical technique to assist GNMs-related research work. Research progress towards this direction will also be presented.

[1] Zhu, Y. W.; Murali, S.; Cai, W. W.; Li, X. S.; Suk, J. W.; Potts, J. R.; Ruoff, R. S. Advanced Materials2010, 22, 3906.

[2] Huang, X.; Qi, X.; Boey, F.; Zhang, H. Chemical Society Reviews2012, 41, 666.

Jastrzębska, A. M.; Kurtycz, P.; Olszyna, A. R. Journal of Nanoparticle Research2012, 14, 1.