Tetiana Serdiuk

Charge-driven selective localization of fluorescent nanoparticles in live cells

Covalent grafting of amino groups onto the carboxylic acid functionalities, naturally covering the surface of fluorescent nanoparticles produced from silicon carbide (SiC NPs), allowed tuning of their surface charge from negative to highly positive. Incubating 3T3-L1 fibroblast cells with differently charged SiC NPs demonstrates the crucial role of the charge in cell fluorescent targeting. Negatively charged SiC NPs concentrate inside the cell nuclei. Close to neutrally charged SiC NPs are present in both cytoplasm and nuclei while positively charged SiC NPs are present only in the cytoplasm and are not able to move inside the nuclei. This effect opens the door for the use of SiC NPs for easy and fast visualization of long-lasting biological processes taking place in the cell cytosol or nucleus as well as providing a new long-term cell imaging tool. Moreover, here we have shown that the interaction between charged NPs and nuclear pore complex plays an essential role in their penetration into the nuclei.

Impact of cell division on intracellular uptake and nuclear targeting with fluorescent SiC-based nanoparticles

Semiconductor nanoparticles (NPs) became important and wide-used tool for cell imaging because of their unique remarkable properties. Nevertheless, all previous investigations in this area were done on proliferating cells. For the first time, this work demonstrates strong influence of cell active proliferation/contact inhibition of proliferation on uptake of NPs. In addition, we show that cell division plays key-role in penetration of silicon carbide based NPs (SiC NPs) inside the cell nucleus. This may very likely concern other types of NPs able to reach the cell nuclei. In particular, observed effect of cell division gives perspectives for future selective cancer treatment with NPs.

Plasmon-Enhanced Photoluminescence of SiC Quantum Dots for Cell Imaging Applications

Strong photoluminescence enhancement of chemically inert and biocompatible SiC quantum dots (QDs) ensured by their near-field coupling with multipolar localized plasmons is experimentally demonstrated. The main physical mechanisms responsible for this phenomenon are described with the use of three-dimensional FDTD simulations. Nano-Ag/SiNX/glass plasmonic substrates were shown to be efficiently used for significant luminescence enhancement of fibroblast cells labeled with the SiC QDs. The proposed approach allows a plasmon-induced enhancement of fluorescent cell imaging.

Size tuning of luminescent silicon nanoparticles with meso-porous silicon membranes

Size tuning of silicon (Si) nanoparticles (NPs) with the use of meso-porous silicon (meso-PS) free-standing layers is reported for the first time. Accumulation of Si NPs inside the membrane pores during the filtering process (NP transport through the meso-PS) leads to an auto-filtration effect (called Si-by-Si (SBS) filtration) allowing more efficient size selection of the NPs. General complex fractal shape and surface chemistry of the whole porous network, layer thickness as well as a given initial NP size dispersion determine final size of the NPs in the filtered solution. Moreover, quantum of step-like NP size increasing equal to 0.12 nm was found.

Vapor phase mediated cellular uptake of sub 5 nm nanoparticles

Nanoparticles became an important and wide-used tool for cell imaging because of their unique optical properties. Although the potential of nanoparticles (NPs) in biology is promising, a number of questions concerning the safety of nanomaterials and the risk/benefit ratio of their usage are open. Here, we have shown that nanoparticles produced from silicon carbide (NPs) dispersed in colloidal suspensions are able to penetrate into surrounding air environment during the natural evaporation of the colloids and label biological cells via vapor phase. Natural gradual size-tuning of NPs in dependence to the distance from the NP liquid source allows progressive shift of the fluorescence color of labeled cells in the blue region according to the increase of the distance from the NP suspension. This effect may be used for the soft vapor labeling of biological cells with the possibility of controlling the color of fluorescence. However, scientists dealing with the colloidal NPs have to seriously consider such a NPs natural transfer in order to protect their own health as well as to avoid any contamination of the control samples.

Delivery of SiC-based nanoparticles into live cells driven by cell-penetrating peptides SAP and SAP-E

The delivery of SiC-based nanoparticles (SiC-NPs) into living eukaryotic cells is facilitated in the presence of cell-penetrating peptides, both cationic (SAP) and anionic (SAP-E). The SiC-NP surface functional group modification combined with rational CPP selection introduces an additional mode of delivery control.

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

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.