Morphology and Microstructure Evolution of Gold Nanostructures in the Limited Volume Porous Matrices

The modern development of nanotechnology requires the discovery of simple approaches that ensure the controlled formation of functional nanostructures with a predetermined morphology. One of the simplest approaches is the self-assembly of nanostructures. The widespread implementation of self-assembly is limited by the complexity of controlled processes in a large volume where, due to the temperature, ion concentration, and other thermodynamics factors, local changes in diffusion-limited processes may occur, leading to unexpected nanostructure growth. The easiest ways to control the diffusion-limited processes are spatial limitation and localized growth of nanostructures in a porous matrix. In this paper, we propose to apply the method of controlled self-assembly of gold nanostructures in a limited pore volume of a silicon oxide matrix with submicron pore sizes. A detailed study of achieved gold nanostructures' morphology, microstructure, and surface composition at different formation stages is carried out to understand the peculiarities of realized nanostructures. Based on the obtained results, a mechanism for the growth of gold nanostructures in a limited volume, which can be used for the controlled formation of nanostructures with a predetermined geometry and composition, has been proposed. The results observed in the present study can be useful for the design of plasmonic-active surfaces for surface-enhanced Raman spectroscopy-based detection of ultra-low concentration of different chemical or biological analytes, where the size of the localized gold nanostructures is comparable with the spot area of the focused laser beam

Highly Sensitive Coherent Anti-Stokes Raman Scattering Imaging of Protein Crystals

Serial crystallography at last generation X-ray synchrotron sources and free electron lasers enabled data collection with micrometer and even submicrometer size crystals, which have resulted in amazing progress in structural biology. However, imaging of small crystals, which although is highly demanded, remains a challenge, especially in the case of membrane protein crystals. Here we describe a new extremely sensitive method of the imaging of protein crystals that is based on coherent anti-Stokes Raman scattering

3D Silver Dendrites for Single-molecule Imaging by Surface-enhanced Raman Spectroscopy

Discovery of surface-enhanced Raman scattering (SERS) followed by evolution of optical systems and nanoengineering approaches has paved a path to detection of essential organic molecules on solid SERS-active substrates from solutions at concentrations attributed to single-molecule ones, i. e. below 10(-15) M. However, in practical terms confident SERS-imaging of single molecules is still quite a challenge. In present work, we fabricated and comprehensively characterized tightly-packed 3D silver dendrites with prevalent chevron morphology that demonstrated ultrahigh sensitivity as SERS-active substrates resulted in 10(-18) M detection limit. Using these substrates we achieved SERS-imaging of single 5-thio-2-nitrobenzoic acid (TNB) molecule released from the attomolar-concentrated solution of of 5,5 '-dithio-bis-[2-nitrobenzoic acid] (DTNB), which is vital compound for chemical and biomedical analysis. In contrast to generally accepted belief about adsorption of only uniform monomolecular TNB layer on surface of silver nanostructures, we showed formation of a coating constituted by TNB layer and DTNB nanoclusters on the dendrites' surface at 10(-6)-10(-12) M DTNB concentrations confirmed by presence/absence of disulfide bonds signature in the SERS-spectra and by scanning electron microscopy. DTNB concentrations below 10(-14) M resulted in adsorption of TNB molecules in separated spots on the surface of silver nanostructures

Therapy-induced secretion of spliceosomal components mediates pro-survival crosstalk between ovarian cancer cells

Abstract Ovarian cancer often develops resistance to conventional therapies, hampering their effectiveness. Here, using ex vivo paired ovarian cancer ascites obtained before and after chemotherapy and in vitro therapy-induced secretomes, we show that molecules secreted by ovarian cancer cells upon therapy promote cisplatin resistance and enhance DNA damage repair in recipient cancer cells. Even a short-term incubation of chemonaive ovarian cancer cells with therapy-induced secretomes induces changes resembling those that are observed in chemoresistant patient-derived tumor cells after long-term therapy. Using integrative omics techniques, we find that both ex vivo and in vitro therapy-induced secretomes are enriched with spliceosomal components, which relocalize from the nucleus to the cytoplasm and subsequently into the extracellular vesicles upon treatment. We demonstrate that these molecules substantially contribute to the phenotypic effects of therapy-induced secretomes. Thus, SNU13 and SYNCRIP spliceosomal proteins promote therapy resistance, while the exogenous U12 and U6atac snRNAs stimulate tumor growth. These findings demonstrate the significance of spliceosomal network perturbation during therapy and further highlight that extracellular signaling might be a key factor contributing to the emergence of ovarian cancer therapy resistance