Surface Engineering of Polymeric Colloidal Crystals by Temperature - Pressure Annealing.

Polymer colloidal crystals (PCCs) have been widely explored as acoustic and optical metamaterials and as templates for nanolithography. However, fabrication impurities and fragility of the self-assembled structures are critical bottlenecks for the device's efficiency and applications. We have demonstrated that temperature-assisted pressure [ annealing results in the mechanical strengthening of PCCs, which improves with the annealing temperature.

Fast Photoactuation and Environmental Response of Humidity-Sensitive pDAP-Silicon Nanocantilevers.

Multi-responsive nanomembranes are a new class of advanced materials that can be harnessed in complex architectures for micro and nano-manipulators, artificial muscles, energy harvesting, soft robotics, and sensors. The design and fabrication of responsive membranes must meet such challenges as trade-offs between responsiveness and mechanical durability, volumetric low-cost production ensuring low environmental impact, and compatibility with standard technologies or biological systems This work demonstrates the fabrication of multi-responsive, mechanically robust poly(1,3-diaminopropane) (pDAP) nanomembranes and their application in fast photoactuators. The pDAP films are developed using a plasma-assisted polymerization technique that offers large-scale production and versatility of potential industrial relevance.

Comparing Mfd- and UvrD-dependent models of transcription coupled DNA repair in live Escherichia coli using single-molecule tracking.

During transcription-coupled DNA repair (TCR) the detection of DNA damage and initiation of nucleotide excision repair (NER) is performed by translocating RNA polymerases (RNAP), which are arrested upon encountering bulky DNA lesions. Two opposing models of the subsequent steps of TCR in bacteria exist. In the first model, stalled RNAPs are removed from the damage site by recruitment of Mfd which dislodges RNAP by pushing it forwards before recruitment of UvrA and UvrB.

Control of Intermolecular Interactions toward the Production of Free-Standing Interfacial Polydopamine Films.

Aggregation of the polydopamine (PDA) molecular building blocks at the air/water interface leads to obtaining large surface nanometric-thin films. This mechanism follows two possible pathways, namely, covalent or non-covalent self-assembly, which result in a different degree of structure order and, consequently, different structural properties. Control of this mechanism could be vital for applications that require true self-support PDA free-standing films, for example, electrochemical sensing or membrane technology.

Size-dependent nanoscale soldering of polystyrene colloidal crystals by supercritical fluids.

Hypothesis: Polymer particles self-assembled into colloidal crystals have exciting applications in photonics, phononics, templates for nanolithography, and coatings. Cold soldering utilizing polymer plasticization by supercritical fluids enables a novel, low-cost, low-effort, chemical-free means for uniform mechanical strengthening of fragile polymer colloidal crystals at moderate temperatures. Here, we aim to elucidate the role of particle size and gas-specific response for the most efficient soldering, exploring the full potential of this method.

Nanomolar Nitric Oxide Concentrations in Living Cells Measured by Means of Fluorescence Correlation Spectroscopy.

Measurement of the nitric oxide (NO) concentration in living cells in the physiological nanomolar range is crucial in understanding NO biochemical functions, as well as in characterizing the efficiency and kinetics of NO delivery by NO-releasing drugs. Here, we show that fluorescence correlation spectroscopy (FCS) is perfectly suited for these purposes, due to its sensitivity, selectivity, and spatial resolution. Using the fluorescent indicators, diaminofluoresceins (DAFs), and FCS, we measured the NO concentrations in NO-producing living human primary endothelial cells, as well as NO delivery kinetics, by an external NO donor to the immortal human epithelial living cells.

Fast Light-Driven Motion of Polydopamine Nanomembranes.

The actuation of micro- and nanostructures controlled by external stimuli remains one of the exciting challenges in nanotechnology due to the wealth of fundamental questions and potential applications in energy harvesting, robotics, sensing, biomedicine, and tunable metamaterials. Photoactuation utilizes the conversion of light into motion through reversible chemical and physical processes and enables remote and spatiotemporal control of the actuation. Here, we report a fast light-to-motion conversion in few-nanometer thick bare polydopamine (PDA) membranes stimulated by visible light.

Adsorption of bacteriophages on polypropylene labware affects the reproducibility of phage research.

Hydrophobicity is one of the most critical factors governing the adsorption of molecules and objects, such as virions, on surfaces. Even moderate change of wetting angle of plastic surfaces causes a drastic decrease ranging from 2 to 5 logs of the viruses (e.g.

Synthesis, characterization and in vitro cytotoxicity studies of poly-N-isopropyl acrylamide gel nanoparticles and films.

In this work, we show synthesis that leads to thermoreponsive poly-N-isopropyl acrylamide (pNIPAM) nanogels with sizes below 100 nm, irrespectively of the surfactant to crosslinker ratio. We also show that in many environments the temperature induced pNIPAM collapse at Lower Critical Solution Temperature (LCST) of 32.5 °C is accompanied by gel nanoparticles' aggregation.

Chromatin and transcriptome changes in human myoblasts show spatio-temporal correlations and demonstrate DPP4 inhibition in differentiated myotubes.

Although less attention was paid to understanding physical localization changes in cell nuclei recently, depicting chromatin interaction maps is a topic of high interest. Here, we focused on defining extensive physical changes in chromatin organization in the process of skeletal myoblast differentiation. Based on RNA profiling data and 3D imaging of myogenic (NCAM1, DES, MYOG, ACTN3, MYF5, MYF6, ACTN2, and MYH2) and other selected genes (HPRT1, CDH15, DPP4 and VCAM1), we observed correlations between the following: (1) expression change and localization, (2) a gene and its genomic neighbourhood expression and (3) intra-chromosome and microscopical locus-centromere distances.

Fluorescent Submicron-Sized Poly(heptafluoro--butyl methacrylate) Particles with Long-Term Stability.

Fluorescent submicron particles of fluorinated methacrylate (HFMBA) with long-term stability have been synthesized and characterized with regard to their potential applications. Rhodamine B (RBITC) isothiocyanate was used as the fluorescent component. The core-shell structure of the particles effectively protected the dye against bleaching.

Single-molecule imaging of DNA gyrase activity in living Escherichia coli.

Bacterial DNA gyrase introduces negative supercoils into chromosomal DNA and relaxes positive supercoils introduced by replication and transiently by transcription. Removal of these positive supercoils is essential for replication fork progression and for the overall unlinking of the two duplex DNA strands, as well as for ongoing transcription. To address how gyrase copes with these topological challenges, we used high-speed single-molecule fluorescence imaging in live Escherichia coli cells.

Silver and ultrasmall iron oxides nanoparticles in hydrocolloids: effect of magnetic field and temperature on self-organization.

Micro/nanostructures, which are assembled from various nanosized building blocks are of great scientific interests due to their combined features in the micro- and nanometer scale. This study for the first time demonstrates that ultrasmall superparamagnetic iron oxide nanoparticles can change the microstructure of their hydrocolloids under the action of external magnetic field. We aimed also at the establishment of the physiological temperature (39 °C) influence on the self-organization of silver and ultrasmall iron oxides nanoparticles (NPs) in hydrocolloids.

Theranostic liposomes as a bimodal carrier for magnetic resonance imaging contrast agent and photosensitizer.

The present study is focused on the development of liposomes bearing gadolinium chelate (GdLip) providing two functionalities for magnetic resonance imaging (MRI) and photodynamic therapy of cancer. A lipid derivative of gadolinium(III) diethylenetriamine pentaacetic acid salt (GdDTPA1) was inserted in the liposomal membrane and served as MRI contrast agent whereas a zinc phthalocyanine (ZnPc) was used as a model photosensitizer. In addition to conventional liposomes, pegylated lipids were used for the preparation of "stealth" liposomes.

Second Harmonic Generation Response in Thermally reconstructed Multiferroic β'- Gd(MoO) Thin Films.

Gd(MoO) (GMO) is a well-studied multiferroic material that exhibits full ferroelectric and ferroelastic behavior at room temperature. However, its difficult stabilization in thin films has prevented the study and exploitation of its multiferroic properties in different architectures. Here, we report on the study of GMO thin films deposited on Si(001) substrates by Pulsed Laser Deposition (PLD).

EPR Oximetry Sensor-Developing a TAM Derivative for In Vivo Studies.

Oxygenation is one of the most important physiological parameters of biological systems. Low oxygen concentration (hypoxia) is associated with various pathophysiological processes in different organs. Hypoxia is of special importance in tumor therapy, causing poor response to treatment.

Structural properties of the intrinsically disordered, multiple calcium ion-binding otolith matrix macromolecule-64 (OMM-64).

Fish otoliths are calcium carbonate biominerals that are involved in hearing and balance sensing. An organic matrix plays a crucial role in their formation. Otolith matrix macromolecule-64 (OMM-64) is a highly acidic, calcium-binding protein (CBP) found in rainbow trout otoliths.

Temperature dependent FCS studies using a long working distance objective: Viscosities of supercooled liquids and particle size.

In this work, we describe new experimental setups for Fluorescence Correlation Spectroscopy (FCS) where a long working distance objective is used. Using these setups, FCS measurements in a broad temperature range for a small sample volume of about 50 μl can be performed. The use of specially designed cells and a dry long working distance objective was essential for avoiding temperature gradients in the sample.

Release and cytotoxicity studies of magnetite/Ag/antibiotic nanoparticles: An interdependent relationship.

Though the cytotoxic properties of magnetite nanoparticles (NPs) are rather well investigated and known to be dose dependent and rather low, surface functionalization can drastically change their properties. To determine whether the cytotoxicity of magnetite/Ag/antibiotic NPs may be associated, among other things, with iron, silver and antibiotic release, this study investigates the release profiles and cytotoxicity of magnetite/Ag/rifampicin and magnetite/Ag/doxycycline NPs compares it similar profiles from magnetite, magnetite/Ag NPs and antibiotics. It was established that the studied NPs released not only water-soluble substances, such as antibiotics, but also poorly-soluble ones, such as iron and silver.

Structure and Dimensions of Core-Shell Nanoparticles Comparable to the Confocal Volume Studied by Means of Fluorescence Correlation Spectroscopy.

In some applications the dye distribution within fluorescently labeled nanoparticles and its stability over long periods of time are important issues. In this article we study numerically and experimentally the applicability of fluorescence correlation spectroscopy (FCS) to resolve such questions. When the size of fluorescently labeled particles is comparable to or larger than the confocal volume, the effective confocal volume seen in FCS experiments is increasing.

Peptide-functionalized ZCIS QDs as fluorescent nanoprobe for targeted HER2-positive breast cancer cells imaging.

In this paper, the synthesis of alloyed CuInZnxS2+x quantum dots (ZCIS QDs), their transfer into aqueous solution via a polymer coating technique, and the use of these nanocrystals to selectively target HER2-positive cells, are reported. By optimizing first the ZnS shell deposition process onto the CuInS2 core, and next the encapsulation of the dots with the amphiphilic poly(maleic anhydride-alt-1-octadecene) (PMAO) polymer, water-dispersible ZCIS QDs were successfully prepared. The nanocrystals with a photoluminescence quantum yield of 35% were purified via centrifugation and ultracentrifugation and high quality nanoparticles with narrow size distributions and surface charges were obtained.

Rapamycin Loaded Solid Lipid Nanoparticles as a New Tool to Deliver mTOR Inhibitors: Formulation and in Vitro Characterization.

Recently, the use of mammalian target of rapamycin (mTOR) inhibitors, in particular rapamycin (Rp), has been suggested to improve the treatment of neurodegenerative diseases. However, as Rp is a strong immunosuppressant, specific delivery to the brain has been postulated to avoid systemic exposure. In this work, we fabricated new Rp loaded solid lipid nanoparticles (Rp-SLN) stabilized with polysorbate 80 (PS80), comparing two different methods and lipids.