Preparation, Luminescent Properties and Bioimaging Application of Quantum Dots Based on Si and SiC

International audience ; Well-known, the interest to the colloidal solution with quantum dots (QDs) lies in their fluorescence properties. Among the advantages of QDs are the high resistance to photooxidation, the size and composition variation allowing to obtain the narrow emission spectra with high quantum yield from the ultraviolet to the near infrared region. In this chapter we present the last achievements in forming and bio-medical applications of luminescent Si and SiC QDs. It is shown that a broad size distribution of Si QDs are obtained at electrochemical etching. The dimensions of the Si QDs undergone filtering in colloidal solution vary discretely with a radius quantum equal to 0.12 nm. Existing of this quantum may correspond to step-like increasing of Si QDs radius on one new shell at the surface of Si QDs. The formed QDs show intense luminescent in visual region. However, one of the major drawbacks of Si QDs for bio-medical application is instability over time in water or buffer solutions. To overcome this drawback the several methods of surface functionalization are discussed. The SiC QDs are stable in water solutions and do not require supplementary surface functionalisation for bioimaging. A strong fluorescence from the SiC QDs, which undoubtedly penetrate into the cell, has been observed. The studying of health and cancer cells using SiC QDs shows that simple modification of surface charge of QDs gives strong opportunity to target the same QDs in intracellular space with their preferential localisation inside or outside the cell nucleus.