Ing. Petráková získala další ocenění

Na konferenci 2010 MRS Fall Meeting pořádané společností materials Research Society v Bostonu získala naše doktorandka Ing. Vladimíra Petráková (Řezáčová) 1. cenu za nejlepší studentskou prezentaci Symposia A - Diamond Electronics and Bioelectronics -- Fundamentals to Applications IV za práci:

On the Mechanism of Charge Transfer between Neutral and Negatively Charged Nitrogen-vacancy Color Centers in Diamond. Vladimira Rezacova1,2, Milos Nesladek3, Petr Cigler4, Miroslav Ledvina4, Jan Kucka5, Jan Stursa5, Jan Ralis5, Jiri Vacik5, Peter Mojzes6, Andrew Taylor1, Irena Kratochvilova1 and Frantisek Fendrych1; 1Academy of Sciences of the Czech Republic, Institute of Physics, v.v.i, Prague, Czech Republic; 2Czech Technical University, Faculty of Biomedical Engineering, Kladno, Czech Republic; 3IMOMEC division, IMEC, Institute for Materials Research, University Hasselt, Diepenbeek, Belgium; 4Gilead Science and IOCB Research Center, Institute of Organic Chemistry and Biochemistry, v.v.i., Academy of Sciences of the Czech Republic, Prague, Czech Republic; 5Institute of Nuclear Physics, Academy of Sciences of the Czech Republic, v.v.i, Rez near Prague, Czech Republic; 6Charles University in Prague, Faculty of Mathematics and Physics, Prague, Czech Republic.

The presented work aims for the development of optically-traceable intracellular nanodiamond sensors, where photoluminescence can be changed by biomolecular attachment/delivery event. Nanodiamond (ND) [1] brings advantages over classical fluorescent markers used for in vivo and in vitro imaging in living cells by offering a cellular delivery combined with strong and stable photoluminescence (PL) originating at nitrogen-vacancy (NV) or other lattice point defects. In our recent works, we have demonstrated the influence of atomic functional termination on changes in the occupation of NV- and NV0 states, with NV- quenching upon H- termination. In the present work we have studied interaction of ND with variously charged macromolecules. Explicitly we compare covalent (H, OH, COOH, etc.) and noncovalent (positively and negatively charged polymers) charge interactions with the surface shallow-laying NV centres. NV photoluminescent (PL) centres in high-pressure high-temperature ND of 30 nm size were produced by irradiation by 10.6 MeV protons. The HPHT ND was compared with single crystal CVD diamond (SC CVD) plates in which the individual NV centres were produced by shallow N-implantation. ND and SC CVD were annealed, chemically oxidized and further on hydrogenated in H-plasma. Raman and PL (excited by 514 nm and 532 nm) spectra were recorded from untreated, treated (nitrogen implanted and annealed) and from oxidised / hydrogenated samples at room temperature. Spectra were also taken from colloidal dispersions (i.e. in liquid) of ND with various negatively and positively charged polymers, using microfluidic setup. Oxidized samples and colloid solution of ND with positively charged polymers exhibited strong NV PL, while NV PL of hydrogenated ND and for ND dispersed with negatively charged polymers was significantly comparatively lower. The results are supported by theoretical modelling of density of state distribution for various surface interactions. [1] Krueger A., Chem. Eur. J., 14, 1382-1390, (2008)