Chem. Listy 102, s1394−s1398 (2008) II Central European Symposium on Plasma Chemistry 2008 s1394 THE CHEMISTRY OF GOLD CLUSTERS IN PLASMA GENERATED WITH MALDI, LASER DESORPTION IONISATION AND LASER ABLATION FROM VARIOUS PRECURSORS E. M. PEÑA-MÉNDEZ a* , J. R. HERNÁNDEZ-FERNAUD b , R. NAGENDER c , J. HOUŠKA c , and J. HAVEL c,d a Department of Analytical Chemistry, Nutrition and Food Chemistry. Faculty of Chemistry,University of La Laguna, Campus de Anchieta, 38071 – La Laguna,Tenerife, Spain, b Servicio de Proteómica, Unidad de Investigación Mixta ULL-HUC, Edificio de Enfermería, Campus de Ofra, s/n La Cuesta 38320, Tenerife, Spain, c Department of Chemistry, Faculty of Science, Masaryk University, Kotlarska 2, 61137 Brno, Czech Republic, d Department of Physical Electronics, Faculty of Science, Masaryk University, Kotlarska 2, 61137 Brno, Czech Republic 1. Introduction Nanotechnology is a rapidly growing science of produc- ing and utilizing among others nano-sized particles. Their unique size-dependent properties make them superior and indispensable as they show unusual physical, chemical and biological properties. Nanomaterials are already having a huge impact on nanotechnology and nanomedicine 1 . Nano- materials are present in toothpaste, sunscreens, sanitary ware coatings, medicaments, and even in food products but they can also represent health risks, like for example silver 2 . Generally, the behavior of metal particles with well- defined nanostructures has become one of the most active research areas. The inorganic nanoparticles exhibit signifi- cantly distinct physical, chemical and biological properties from their bulk counterparts. Discoveries in the past decade have demonstrated that the electromagnetic, optical and cata- lytic properties of noble-metal nanoparticles are strongly in- fluenced by shape and size. Nanogold represents a tiny parti- cle from a few gold atoms up to hundreds/thousands of atoms. This has motivated an upsurge in research on the synthesis routes that allow better control of shape and size for various nano-biotechnological applications 3,4 . Gold nanoparticles (GNP) are quite important in elec- tronics, bio-analytics and in nano-medicine. They are pro- duced by various technologies, mostly by chemical methods but also by laser ablation. 1.1. Short historical overview GNP have been known for a long time but they were called colloidal gold. The history of GNP goes back to ancient times, for example, the so-called „Elixir of Life“, searched by alchemists, was a potion made of gold. Colloidal gold was used since Roman times to colour glass in yellow or red and famous bohemian ruby glass is also based on nano-gold. Paracelsus in the 16 th century created a potion called Aurum Potabile, Herschel in 1842 used colloidal gold to record im- ages on paper, etc. but Faraday in 1857 was perhaps the first one to understand that the colour of gold solutions was due to the small size of gold particles. 1.2. Applications of GNP in medicine As nano gold is quite reactive, the gold particles are usually covered with a suitable layer of inorganic 5 and organic material (Fig. 1), e.g. with thiols, sugars, etc. 6,7 . Such func- tionalized GNP are stable and are used in bioanalytics and biomedicine. Most recently gold colloids have gained significant at- tention in the field of biomedicine. Due to their several exclu- sive properties, metallic gold acquired an excellent profile for use in these biomedical applications. Gold nanoparticles have a great impact in the medical society and they were used in cancer diagnosis, treatment and as a drug delivery vector for biological or pharmacological agents 8−14 . GNP have been applied as a drug carrier in diagnostic and medical fields as they comprise some explicit properties such as i) they are easily fabricated ii) they have a very good capacity to bind to target cancer cells, carbohydrates, antibod- ies, proteins, pharmacological agents rather than other nanoparticles 15−19 . It was recently reported that GNP can be used to detect some toxic metals like mercury in human body and in envi- ronmental bodies such as rivers, streams, lakes and oceans. When mercury contaminated fish and shell fish are ingested by children and women, it is dangerous to their health. Even if there are several conventional mathods 20 , a sensitive and ac- curate colorimetric method was developed which can detect mercury at nano-molar level by using DNA-functionalized gold nanoparticles. During the last decade, fluorescence based assays have gained a prior position in immunochemistry-based in vitro diagnosis and in vivo imaging assays. In this field, radio chemical labels and chromophores have several advantages such as high sensitivity and potential for easy multiplexing. But these traditional radio chemical labels and organometallic chromophores were replaced by Au-QDs, where QDs are quantum dots, because of their exclusive characteristics in- cluding size dependent controllable emission spectra, narrow band width, broad excitation, high extinction coefficient and potential stability against photobleaching 21 . Fig. 1. Schema of nano gold formation from Au(III) salt