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  • 1. Copolovici, Dana Maria
    et al.
    Langel, Kent
    Eriste, Elo
    Langel, Ülo
    Stockholm University, Faculty of Science, Department of Neurochemistry. University of Tartu, Estonia.
    Cell-Penetrating Peptides: Design, Synthesis, and Applications2014In: ACS Nano, ISSN 1936-0851, E-ISSN 1936-086X, Vol. 8, no 3, p. 1972-1994Article, review/survey (Refereed)
    Abstract [en]

    The intrinsic property of cell-penetrating peptides (CPPs) to deliver therapeutic molecules (nucleic acids, drugs, imaging agents) to cells and tissues in a nontoxic manner has indicated that they may be potential components of future drugs and disease diagnostic agents. These versatile peptides are simple to synthesize, functionalize, and characterize yet are able to deliver covalently or noncovalently conjugated bioactive cargos (from small chemical drugs to large plasmid DNA) inside cells, primarily via endocytosis, in order to obtain high levels of gene expression, gene silencing, or tumor targeting. Typically, CPPs are often passive and nonselective yet must be functionalized or chemically modified to create effective delivery vectors that succeed in targeting specific cells or tissues. Furthermore, the design of clinically effective systemic delivery systems requires the same amount of attention to detail in both design of the delivered cargo and the cell-penetrating peptide used to deliver it.

  • 2. Krycka, Kathryn L.
    et al.
    Borchers, Julie A.
    Salazar-Alvarez, German
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK).
    Lopez-Ortega, Alberto
    Estrader, Marta
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK).
    Estrade, Sonia
    Winkler, Elin
    Daniel Zysler, Roberto
    Sort, Jordi
    Peiro, Francesca
    Dolors Baro, Maria
    Kao, Chi-Chang
    Nogues, Josep
    Resolving Material-Specific Structures within Fe3O4 vertical bar gamma-Mn2O3 Core vertical bar Shell Nanoparticles Using Anomalous Small-Angle X-ray Scattering2013In: ACS Nano, ISSN 1936-0851, E-ISSN 1936-086X, Vol. 7, no 2, p. 921-931Article in journal (Refereed)
    Abstract [en]

    Here it is demonstrated that multiple-energy, anomalous small-angle X-ray scattering (ASAXS) provides significant enhancement in sensitivity to internal material boundaries of layered nanoparticles compared with the traditional modeling of a single scattering energy, even for cases in which high scattering contrast naturally exists. Specifically, the material-specific structure of monodispersed Fe3O4 vertical bar gamma-Mn2O3 core vertical bar shell nanoparticles is determined, and the contribution of each component to the total scattering profile is identified with unprecedented clarity. We show that Fe3O4 vertical bar gamma-Mn2O3 core vertical bar shell nanoparticles with a diameter of 8.2 +/- 0.2 nm consist of a core with a composition near Fe3O4 surrounded by a (MnxFe1-x)(3)O-4 shell with a graded composition, ranging from x approximate to 0.40 at the Inner shell toward x approximate to 0.46 at the surface. Evaluation of the scattering contribution arising from the interference between material-specific layers additionally reveals the presence of Fe3O4 cores without a coating shell. Finally, it is found that the material-specific scattering profile shapes and chemical compositions extracted by this method are independent of the original input chemical compositions used in the analysis, revealing multiple-energy ASAXS as a powerful tool for determining internal nanostructured morphology even if the exact composition of the individual layers is not known a priori.

  • 3.
    Mezger, Anja
    et al.
    Stockholm University, Faculty of Science, Department of Biochemistry and Biophysics. Stockholm University, Science for Life Laboratory (SciLifeLab).
    Fock, Jeppe
    Antunes, Paula
    Østerberg, Frederik W.
    Boisen, Anja
    Nilsson, Mats
    Stockholm University, Faculty of Science, Department of Biochemistry and Biophysics. Stockholm University, Science for Life Laboratory (SciLifeLab).
    Hansen, Mikkel F.
    Ahlford, Annika
    Stockholm University, Faculty of Science, Department of Biochemistry and Biophysics. Stockholm University, Science for Life Laboratory (SciLifeLab).
    Donolato, Marco
    Scalable DNA-Based Magnetic Nanoparticle Agglutination Assay for Bacterial Detection in Patient Samples2015In: ACS Nano, ISSN 1936-0851, E-ISSN 1936-086X, Vol. 9, no 7, p. 7374-7382Article in journal (Refereed)
    Abstract [en]

    We demonstrate a nanoparticle-based assay for the detection of bacteria causing urinary tract infections in patient samples with a total assay time of 4 h. This time is significantly shorter than the current gold standard, plate culture, which can take several days depending on the pathogen. The assay is based on padlock probe recognition followed by two cycles of rolling circle amplification (RCA) to form DNA coils corresponding to the target bacterial DNA. The readout of the RCA products is based on optomagnetic measurements of the specific agglutination of DNA-bound magnetic nanoparticles (MNPs) using low-cost optoelectronic components from Blu-ray drives. We implement a detection approach, which relies on the monomerization of the RCA products, the use of the monomers to link and agglutinate two populations of MNPs functionalized with universal nontarget specific detection probes and on the introduction of a magnetic incubation scheme. This enables multiplex detection of Escherichia coli, Proteus mirabilis and Pseudomonas aeruginosa at clinically relevant concentrations, demonstrating a factor of 30 improvement in sensitivity compared to previous MNP-based detection schemes. Thanks to the universal probes, the same set of functionalized MNPs can be used to read out products from a multitude of RCA targets, making the approach truly scalable for parallel detection of multiple bacteria in a future integrated point of care molecular diagnostics system.

  • 4. Moreno-Pescador, Guillermo
    et al.
    Florentsen, Christoffer D.
    Østbye, Henrik
    Stockholm University, Faculty of Science, Department of Biochemistry and Biophysics.
    Sønder, Stine L.
    Boye, Theresa L.
    Veje, Emilie L.
    Sonne, Alexander K.
    Semsey, Szabolcs
    Nylandsted, Jesper
    Daniels, Robert
    Stockholm University, Faculty of Science, Department of Biochemistry and Biophysics.
    Bendix, Poul Martin
    Curvature- and Phase-Induced Protein Sorting Quantified in Transfected Cell-Derived Giant Vesicles2019In: ACS Nano, ISSN 1936-0851, E-ISSN 1936-086X, Vol. 13, no 6, p. 6689-6701Article in journal (Refereed)
    Abstract [en]

    Eukaryotic cells possess a dynamic network of membranes that vary in lipid composition. To perform numerous biological functions, cells modulate their shape and the lateral organization of proteins associated with membranes. The modulation is generally facilitated by physical cues that recruit proteins to specific regions of the membrane. Analyzing these cues is difficult due to the complexity of the membrane conformations that exist in cells. Here, we examine how different types of membrane proteins respond to changes in curvature and to lipid phases found in the plasma membrane. By using giant plasma membrane vesicles derived from transfected cells, the proteins were positioned in the correct orientation and the analysis was performed in plasma membranes with a biological composition. Nanoscale membrane curvatures were generated by extracting nanotubes from these vesicles with an optical trap. The viral membrane protein neuraminidase was not sensitive to curvature, but it did exhibit strong partitioning (coefficient of K = 0.16) disordered membrane regions. In contrast, the membrane repair protein annexin 5 showed a preference for nanotubes with a density up to 10-15 times higher than that on the more flat vesicle membrane. The investigation of nanoscale effects in isolated plasma membranes provides a quantitative platform for studying peripheral and integral membrane proteins in their natural environment.

  • 5.
    Nordlund, Gustav
    et al.
    Stockholm University, Faculty of Science, Department of Biochemistry and Biophysics.
    Ng, Jovice Boon Sing
    Stockholm University, Faculty of Science, Department of Physical, Inorganic and Structural Chemistry.
    Bergström, Lennart
    Stockholm University, Faculty of Science, Department of Physical, Inorganic and Structural Chemistry.
    Brzezinski, Peter
    Stockholm University, Faculty of Science, Department of Biochemistry and Biophysics.
    A Membrane-reconstituted Multisubunit Functional Proton Pump on Mesoporous Silica Particles2009In: ACS Nano, ISSN 1936-0851, E-ISSN 1936-086X, Vol. 3, no 9, p. 2639-2646Article in journal (Refereed)
    Abstract [en]

    We have investigated formation of a proteolipid membrane surrounding mesoporous silica particles with a diameter of 550 nm and pore sizes of 3.0 nm. A multisubunit redox-driven proton pump, cytochrome c oxidase, was incorporated into the membrane and we show that the enzyme is fully functional, both with respect to catalysis of O2 reduction to water, and charge separation across the membrane. The orientation of cytochrome c oxidase in the membrane was found to be the same (~70/30 %) in the lipid vesicles and in the silica-particle supported lipid membrane, which provides information on the mechanism by which the vesicles adsorb to the surface. Furthermore, cytochrome c oxidase could maintain a proton electrochemical gradient across the supported proteomembrane, i.e. the membrane system was proton tight, defining an interior particle compartment that is separated from the surrounding aqueous media. Such a biofunctional cellular interface, supported onto a colloid that has a connected interior cytoskeleton-like pore structure, provides a basis for functional studies of membrane-bound transport proteins, and also for applications within pharmaceutical drug delivery.

  • 6. Russell, Camilla
    et al.
    Welch, Ken
    Jarvius, Jonas
    Cai, Yixiao
    Brucas, Rimantas
    Nikolajeff, Fredrik
    Svedlindh, Peter
    Nilsson, Mats
    Stockholm University, Faculty of Science, Department of Biochemistry and Biophysics. Stockholm University, Science for Life Laboratory (SciLifeLab). Uppsala University, Sweden.
    Gold Nanowire Based Electrical DNA Detection Using Rolling Circle Amplification2014In: ACS Nano, ISSN 1936-0851, E-ISSN 1936-086X, Vol. 8, no 2, p. 1147-1153Article in journal (Refereed)
    Abstract [en]

    We present an electrical sensor that uses rolling circle amplification (RCA) of DNA to stretch across the gap between two electrodes, interact with metal nanoparticle seeds to generate an electrically conductive nanowire, and produce electrical signals upon detection of specific target DNA sequences. RCA is a highly specific molecular detection mechanism based on DNA probe circularization. With this technique, long single-stranded DNA with simple repetitive sequences are produced. Here we show that stretched RCA products can be metalized using silver or gold solutions to form metal wires. Upon metallization, the resistance drops from T Omega to k Omega for silver and to Omega for gold. Metallization is seeded by gold nanoparticles aligned along the single-stranded DNA product through hybridization of functionalized oligonucleotides. We show that combining RCA with electrical DNA detection produces results in readout with very high signal-to-noise ratio, an essential feature for sensitive and specific detection assays. Finally, we demonstrate detection of 10 ng of Escherichia coli genomic DNA using the sensor concept.

  • 7. Shao, Yue
    et al.
    Jiang, Zhiping
    Zhang, Yunjing
    Wang, Tongzhou
    Zhao, Peng
    Zhang, Zhe
    Yuan, Jiayin
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK).
    Wang, Hong
    All-Poly(ionic liquid) Membrane-Derived Porous Carbon Membranes: Scalable Synthesis and Application for Photothermal Conversion in Seawater Desalination2018In: ACS Nano, ISSN 1936-0851, E-ISSN 1936-086X, Vol. 12, no 11, p. 11704-11710Article in journal (Refereed)
    Abstract [en]

    Herein, we introduce a straightforward, scalable, and technologically relevant strategy to manufacture charged porous polymer membranes (CPMs) in a controllable manner. The pore sizes and porous architectures of CPMs are well-controlled by rational choice of anions in poly(ionic liquid)s (PILs). Continuously, heteroatom-doped hierarchically porous carbon membrane (HCMs) can be readily fabricated via morphology-maintaining carbonization of as-prepared CPMs. These HCMs, as photothermal membranes, exhibited excellent performance for solar seawater desalination, representing a promising strategy to construct advanced functional nanomaterials for portable water production technologies.

  • 8. Talyzin, Alexandr V.
    et al.
    Luzan, Serhiy
    Anoshkin, Ilya V.
    Nasibulin, Albert G.
    Jiang, Hue
    Kauppinen, Esko I.
    Mikoushkin, Valery M.
    Shnitov, Vladimir V.
    Marchenko, Dmitry E.
    Noréus, Dag
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK).
    Hydrogenation, Purification, and Unzipping of Carbon Nanotubes by Reaction with Molecular Hydrogen: Road to Graphane Nanoribbons2011In: ACS Nano, ISSN 1936-0851, E-ISSN 1936-086X, Vol. 5, no 6, p. 5132-5140Article in journal (Refereed)
    Abstract [en]

    Reaction of single-walled carbon nanotubes (SWNTs) with hydrogen gas was studied in a temperature interval of 400-550 degrees C and at hydrogen pressure of 50 bar. Hydrogenation of nanotubes was observed for samples treated at 400-450 degrees C with about 1/3 of carbon atoms forming covalent C-H bonds, whereas hydrogen treatment at higher temperatures (550 degrees C) occurs as an etching. Unzipping of some SWNTs Into graphene nanoribbons is observed as a result of hydrogenation at 400-550 degrees C Annealing in hydrogen gas at elevated conditions for prolonged periods of time (72 h) is demonstrated to result also in nanotube opening, purification of nanotubes from amorphous carbon, and removal of carbon coatings from Fe catalyst particles, which allows their complete elimination by acid treatment.

  • 9. van Asbeck, Alexander H.
    et al.
    Beyerle, Andrea
    McNeill, Hesta
    Bovee-Geurts, Petra H. M.
    Lindberg, Staffan
    Stockholm University, Faculty of Science, Department of Neurochemistry.
    Verdurmen, Wouter P. R.
    Hällbrink, Mattias
    Stockholm University, Faculty of Science, Department of Neurochemistry.
    Langel, Ülo
    Stockholm University, Faculty of Science, Department of Neurochemistry.
    Heidenreich, Olaf
    Brock, Roland
    Molecular Parameters of siRNA-Cell Penetrating Peptide Nanocomplexes for Efficient Cellular Delivery2013In: ACS Nano, ISSN 1936-0851, E-ISSN 1936-086X, Vol. 7, no 5, p. 3797-3807Article in journal (Refereed)
    Abstract [en]

    Cell-penetrating peptides (CPPs) are versatile tools for the intracellular delivery of various biomolecules, including siRNA. Recently, CPPs were introduced that showed greatly enhanced delivery efficiency. However, the molecular basis of this increased activity is poorly understood. Here, we performed a detailed analysis of the molecular and physicochemical properties of seven different siRNA-CPP nanoparticles. In addition, we determined which complexes are internalized most efficiently into the leukemia cell-line SKNO-1, and subsequently inhibited the expression of a luctferase reporter gene. We demonstrated effective complexation of siRNA for all tested CPPs, and optimal encapsulation of the siRNA was achieved at very similar molar ratios independent of peptide charge. However, CPPs with an extreme high or low overall charge proved to be exceptions, suggesting an optimal range of charge for CPP-siRNA nanoparticle formation based on opposite charge. The most active CPP (PepFect6) displayed high serum resistance but also high sensitivity to decomplexation by polyanionic macromolecules, indicating the necessity for partial decomplexation for efficient uptake. Surprisingly, CPP-siRNA complexes acquired a negative zeta-potential in the presence of serum. These novel insights shed light on the observation that cell association is necessary but not sufficient for activity and motivate new research into the nature of the nanoparticle-cell interaction. Overall, our results provide a comprehensive molecular basis for the further development of peptide-based olipnudeotide transfection agents.

  • 10.
    Wetterskog, Erik
    et al.
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK).
    Tai, Cheuk-Wai
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK).
    Grins, Jekabs
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK).
    Bergström, Lennart
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK).
    Salazar-Alvarez, German
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK).
    Anomalous Magnetic Properties of Nanoparticles Arising from Defect Structures: Topotaxial Oxidation of Fe1-xO|Fe3-δO4 Core|Shell Nanocubes to Single-Phase Particles2013In: ACS Nano, ISSN 1936-0851, E-ISSN 1936-086X, Vol. 7, no 8, p. 7132-7144Article in journal (Refereed)
    Abstract [en]

    Here we demonstrate that the anomalous magnetic properties of iron oxide nanoparticles are correlated with defects in their interior. We studied the evolution of microstructure and magnetic properties of biphasic core|shell Fe1–xO|Fe3−δO4 nanoparticles synthesized by thermal decomposition during their topotaxial oxidation to single-phase nanoparticles. Geometric phase analysis of high-resolution electron microscopy images reveals a large interfacial strain at the core|shell interface and the development of antiphase boundaries. Dark-field transmission electron microscopy and powder X-ray diffraction concur that, as the oxidation proceeds, the interfacial strain is released as the Fe1–xO core is removed but that the antiphase boundaries remain. The antiphase boundaries result in anomalous magnetic behavior, that is, a reduced saturation magnetization and exchange bias effects in single-phase nanoparticles. Our results indicate that internal defects play an important role in dictating the magnetic properties of iron oxide nanoparticles.

  • 11. Yin, Ming-Jie
    et al.
    Zhao, Qiang
    Wu, Jushuai
    Seefeldt, Karoline
    Yuan, Jiayin
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK). Max Planck Institute of Colloids and Interfaces, Germany.
    Precise Micropatterning of a Porous Poly(ionic liquid) via Maskless Photolithography for High-Performance Nonenzymatic H2O2 Sensing 2018In: ACS Nano, ISSN 1936-0851, E-ISSN 1936-086X, Vol. 12, no 12, p. 12551-12557Article in journal (Refereed)
    Abstract [en]

    Porous poly(ionic liquid)s (PILs) recently have been serving as a multifunctional, interdisciplinary materials platform in quite a few research areas, including separation, catalysis, actuator, sensor, and energy storage, just to name a few. In this context, the capability of photopatterning PIL microstructures in a porous state on a substrate is still missing but is a crucial step for their real industrial usage. Here, we developed a method for in situ rapid patterning of porous PIL microstructures via a maskless photolithography approach coupled with a simple electrostatic complexation treatment. This breakthrough enables design of miniaturized sensors. As exemplified in this work, upon loading Pt nanoparticles into porous PIL microstructures, the hybrid sensor showed outstanding performance, bearing both a high sensitivity and a wide detection range.

  • 12.
    Zhu, Chuantao
    et al.
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK).
    Monti, Susanna
    Mathew, Aji P.
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK).
    Cellulose Nanofiber-Graphene Oxide Biohybrids: Disclosing the Self-Assembly and Copper-Ion Adsorption Using Advanced Microscopy and ReaxFF Simulations2018In: ACS Nano, ISSN 1936-0851, E-ISSN 1936-086X, Vol. 12, no 7, p. 7028-7038Article in journal (Refereed)
    Abstract [en]

    The self-assembly of nanocellulose and graphene oxide into highly porous biohybrid materials has inspired the design and synthesis of multifunctional membranes for removing water pollutants. The mechanisms of self-assembly, metal ion capture, and cluster formation on the biohybrids at the nano- and molecular scales are quite complex. Their elucidation requires evidence from the synergistic combination of experimental data and computational models. The AFM-based microscopy studies of (2,2,6,6-tetramethylpiperidine-l-oxylradical)-mediated oxidized cellulose nanofibers (TOCNFs), graphene oxide (GO), and their biohybrid membranes provide strong, direct evidence of self-assembly; small GO nanoparticles first attach and accumulate along a single TOCNF fiber, while the long, flexible TOCNF filaments wrap around the flat, wide GO planes, thus forming an amorphous and porous biohybrid network. The layered structure of the TOCNFs and GO membrane, derived from the self-assembly and its surface properties before and after the adsorption of Cu(II), is investigated by advanced microscopy techniques and is further clarified by the ReaxFF molecular dynamics (MD) simulations. The dynamics of the Cu(II)-ion capture by the TOCNF and GO membranes in solution and the ion cluster formation during drying are confirmed by the MD simulations. The results of this multidisciplinary investigation move the research one step forward by disclosing specific aspects of the self-assembly behavior of biospecies and suggesting effective design strategies to control the pore size and robust materials for industrial applications.

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