Bio-conjugation of colloidal quantum dots of cadmium sulphides and supromolecular structures of protein-porin from bacteria of the genus <i>Yersinia</i>. Obtaining and characteristic
Cadmium sulfide fluorescence quantum dots (QDs) are promising materials for optics, optoelectronics, biology, and medicine. In recent years, significant progress has been achieved in the use of nanomaterials to create biosensors, including based on protein structures ones. Among others, native or artificially constructed biosensors based on ion-conducting channels are a very promising class of nanostructures. In this work, various approaches were tested for the formation of ordered supramolecular structures of Yersinia porins (Yersinia pseudotuberculosis and Y. ruckeri) labeled with QDs: (1) conjugation of the porin matrix with stabilized QDs previously obtained and (2) QDs synthesis in a porin matrix with supporting lipid bilayer preformed on mica. The sizes of QDs and their conjugates with proteins were measured using the method of dynamic light scattering (directly in an aqueous suspension). The surface morphology of the samples was studied by atomic force microscopy. To characterize the optical properties of the obtained conjugates scanning fluorescence spectroscopy was used. It was found that the luminescence intensity of bioconjugates substantially depends on the method of QDs preparation and on protein sample used in matrix (isolated porin or the porin-peptidoglycan complex). It was shown that, depending on the matrix type, a shift in the fundamental absorption edge of QDs is observed. This indicates the formation of QDs of different diameters and, therefore, the possibility of controlling their sizes by varying the structure of the protein matrix. The data obtained open the prospect of using QDs labeled nanostructures based on bacterial porins as biosensors.