The synthesis and complex study of protein – gold nano-complexes (PGC) came to the hot spot of nano-research because of their many favourable properties. The latest studies demonstrate that fluorescence and super paramagnetic PGCs can be produced by using appropriate proteins. These complexes provide new possibilities in the field of bioanalysis, for example fluorescence, and in the same time, light resistance PGCs seem to be suitable for detection of special target proteins. New medical diagnosis and therapeutic methods can be introduced by using super paramagnetic PGCs. In order to develop these types of novel applications, the precise knowledge of the mechanism of PGCs formation and that of their biocompatibility is of crucial importance but they are still not clearly understood. The effect of gold clusters on the structure and function of proteins is indispensable but it is also largely unexplored.

In the present project we intend to monitor the formation of different PGCs and study the effect of the central gold-clusters on the structural behaviours of the protein part. Moreover, we plan to apply vesicle-like cell-membrane model-systems whereby the observation of the interactions between PGCs and their biological lipid-milieu comes possible.

In the first period of the project, we will study the reaction between bovine serum albumin (BSA) and tetrachloroauric acid (HAuCl4·3H2O) in the function of temperature, pH, reaction time, and the concentration of further additives and then the fluorescence behaviour of the BSA@Au complex will be explored. The formation of the BSA@Au complex is accompanied by the change in BSA conformation. The formation of the central gold nanocluster, known as Au25 in the literature, and the whole BSA@Au complex will be studied by means of the time-resolved small angle X-ray scattering technique. Beside this nanostructural studies, we will use infrared and fluorescence spectroscopy to obtain fine structural information on the atomic scale for the explanation of the fluorescence features. In the second part of the project, we intend to utilize the results obtained on the BSA@Au nanocomplex in order to elaborate further PGCs embedding other target proteins and to produce novel type of materials in the field of medical-biological applications.

Róbert Mészáros, Imre Varga, Attila Bóta


Result_May 2020