A thin polymer membrane, nano-suit, enhancing survival across the continuum between air and high vacuum

Yasuharu Takakua,g, Hiroshi Suzukib, Isao Ohtac, Daisuke Ishiid,e,g, Yoshinori Muranakac, Masatsugu Shimomurae,f,g, and Takahiko Hariyamaa,g,1
Departments of aBiology and bChemistry and cLaboratory for Ultrastructure Research, Research Equipment Center, Hamamatsu University School of Medicine, Handayama, Higashi-ku, Hamamatsu , Japan; dCenter for Fostering Young and Innovative Researchers, Nagoya Institute
of Technology, Gokiso-cho, Showa-ku, Nagoya , Japan; eWorld Premier International Research Centers Initiative–Advanced Institute for Materials Research and fInstitute of Multidisciplinary Research for Advanced Materials, Tohoku University, Katahira 2-1-1, Aoba-ku, Sendai 980-8577, Japan; and gCore Research for Evolutional Science and Technology, Japan Science and Technology Agency, Hon-cho 4-1-8, Kawaguchi 332-0012, Japan
Edited by David L. Denlinger, The Ohio State University, Columbus, OH, and approved March 8, 2013 (received for review December 10, 2012)

Most multicellular organisms can only survive under atmospheric pressure. The reduced pressure of a high vacuum usually leads to rapid dehydration and death. Here we show that a simple surface modification can render multicellular organisms strongly tolerant to high vacuum. Animals that collapsed under high vacuum continued to move following exposure of their natural extracellular surface layer (or that of an artificial coat-like polysorbitan monolaurate) to an elec- tron beam or plasma ionization (i.e., conditions known to enhance polymer formation). Transmission electron microscopic observations revealed the existence of a thin polymerized extra layer on the surface of the animal. The layer acts as a flexible “nano-suit” barrier to the passage of gases and liquids and thus protects the organism. Further- more, the biocompatible molecule, the component of the nano-suit, was fabricated into a “biomimetic” free-standing membrane. This concept will allow biology-related fields especially to use these membranes for several applications.

Visualizing nanoparticle mobility in liquid at atomic resolution

bDepartment of Biology, Indiana University at Bloomington, Bloomington, IN 47405, USA
cVirginia Tech Carilion Research Institute, Roanoke, VA 24016, USA. E-mail: debkelly@vt.edu; Fax: +1 540 985 3373; Tel: +1 540 526 2031

Received 11th February 2013, Accepted 28th February 2013
First published on the web 28th February 2013

Gold nanorods are widely known for their photothermal properties to treat solid tumors. Our work demonstrates the unrealized capacity to image these reagents in liquid at high resolution using Transmission Electron Microscopy (TEM). Here we perform the first atomic measurements of functionalized nanorods in solution while visualizing their dynamic behaviour with TEM.

The use of microfluidic-based devices has spurred new opportunities to visualize dynamic mobility at the molecular level.1,2 Using these tools scientists have recently watched, for the first time, the growth of nanocrystals into materials and the engulfment of nanoparticles into cells.3–6 These recent technological advancements in conjunction with high-resolution imaging provide a new opportunity to view nanoscale processes as they occur in solution.

A new mode of therapeutic intervention in cancer research employs the use of rod-shaped gold nanoparticles, appropriately termed “nanorods”. Nanorods injected into the circulation can be engineered to target, infiltrate and accumulate in solid tumors.7,8 Upon applying infrared radiation at the tumor site, the high photothermal conversion rate of the nanorods increase the temperature of the surrounding region to kill off cancerous cells.9,10 Although this application for the therapeutic use of nanorods is gaining popularity, the molecular behavior of these nanoparticles has never been observed. Here we present the first high-resolution view of how polyvinyl pyridine (PVP)-encapsulated gold nanorods migrate in liquid using in situ molecular microscopy. In doing so, we also introduce a novel system to view short-range diffusion properties of nanogold-based therapeutic reagents in a native environment.

NMR and AFM combined together for Imaging

Atomic force microscopy-coupled microcoils for cellular-scale nuclear magnetic resonance spectroscopy

Charilaos Mousoulis1, Teimour Maleki2, Babak Ziaie1,2,3, and Corey P. Neu1
1Weldon School of Biomedical Engineering, Purdue University, West Lafayette, Indiana 47907, USA
2Department of Electrical and Computer Engineering, Purdue University, West Lafayette, Indiana 47907, USA
3Birck Nanotechnology Center, Purdue University, West Lafayette, Indiana 47907



We present the coupling of atomic force microscopy (AFM) and nuclear magnetic resonance (NMR) technologies to enable topographical, mechanical, and chemical profiling of biological samples. Here, we fabricate and perform proof-of-concept testing of radiofrequency planar microcoils on commercial AFM cantilevers. The sensitive region of the coil was estimated to cover an approximate volume of 19.4 × 103 μm3 (19.4 pl). Functionality of the spectroscopic module of the prototype device is illustrated through the detection of 1Η resonance in deionized water. The acquired spectra depict combined NMR capability with AFM that may ultimately enable biophysical and biochemical studies at the single cell level.
© 2013 AIP Publishing LLC

A biomimetic nanosponge that absorbs pore-forming toxins

• Che-Ming J. Hu,
• Ronnie H. Fang,
• Jonathan Copp,
• Brian T. Luk
• & Liangfang Zhang

• Nature Nanotechnology
   
  (2013)
   
  doi:10.1038/nnano.2013.54

Detoxification treatments such as toxin-targeted anti-virulence therapy^1, 2 offer ways to cleanse the body of virulence factors that are caused by bacterial infections, venomous injuries and biological weaponry. Because existing detoxification platforms such as antisera³, monoclonal antibodies⁴, small-molecule inhibitors^5, 6 and molecularly imprinted polymers⁷ act by targeting the molecular structures of toxins, customized treatments are required for different diseases. Here, we show a biomimetic toxin nanosponge that functions as a toxin decoy in vivo. The nanosponge, which consists of a polymeric nanoparticle core surrounded by red blood cell membranes, absorbs membrane-damaging toxins and diverts them away from their cellular targets. In a mouse model, the nanosponges markedly reduce the toxicity of staphylococcal alpha-haemolysin (α-toxin) and thus improve the survival rate of toxin-challenged mice. This biologically inspired toxin nanosponge presents a detoxification treatment that can potentially treat a variety of injuries and diseases caused by pore-forming toxins

Multicompartment Mesoporous Silica Nanoparticles with Branched Shapes: An Epitaxial Growth Mechanism

1. Teeraporn Suteewong¹,²,*, 
2. Hiroaki Sai¹,*, 
3. Robert Hovden³, 
4. David Muller³,⁴, 
5. Michelle S. Bradbury², 
6. Sol M. Gruner⁴,⁵,⁶,
7. Ulrich Wiesner¹,†

Mesoporous nanomaterials have attracted widespread interest because of their structural versatility for applications including catalysis, separation, and nanomedicine. We report a one-pot synthesis method for a class of mesoporous silica nanoparticles (MSNs) containing both cubic and hexagonally structured compartments within one particle. These multicompartment MSNs (mc-MSNs) consist of a core with cage-like cubic mesoporous morphology and up to four branches with hexagonally packed cylindrical mesopores epitaxially growing out of the cubic core vertices. The extent of cylindrical mesostructure growth can be controlled via a single additive in the synthesis. Results suggest a path toward high levels of architectural complexity in locally amorphous, mesostructured nanoparticles, which could enable tuning of different pore environments of the same particle for specific chemistries in catalysis or drug delivery.

Sperm Trajectories Form Chiral Ribbons

• Ting-Wei Su,
• Inkyum Choi,
• Jiawen Feng,
• Kalvin Huang,
• Euan McLeod
• & Aydogan Ozcan

• Scientific Reports
   
  3,
   
  Article number:
   
  1664
   
  doi:10.1038/srep01664

• We report the discovery of an entirely new three-dimensional (3D) swimming pattern observed in human and horse sperms. This motion is in the form of ‘chiral ribbons’, where the planar swing of the sperm head occurs on an osculating plane creating in some cases a helical ribbon and in some others a twisted ribbon. The latter, i.e., the twisted ribbon trajectory, also defines a minimal surface, exhibiting zero mean curvature for all the points on its surface. These chiral ribbon swimming patterns cannot be represented or understood by already known patterns of sperms or other micro-swimmers. The discovery of these unique patterns is enabled by holographic on-chip imaging of >33,700 sperm trajectories at >90–140 frames/sec, which revealed that only ~1.7% of human sperms exhibit chiral ribbons, whereas it increases to ~27.3% for horse sperms. These results might shed more light onto the statistics and biophysics of various micro-swimmers' 3D motion.

• 
  

Droplet Detachment by Air Flow for Microstructured SuperhydrophobicSurfaces

Pengfei Hao *, Cunjing Lv , and Zhaohui Yao
Department of Engineering Mechanics, Tsinghua University, Beijing 100084, China
Langmuir, Article ASAP
DOI: 10.1021/la400187c
Publication Date (Web): April 4, 2013
Copyright © 2013 American Chemical Society

http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/langd5/0/langd5.ahead-of-print/la400187c/aop/images/medium/la-2013-00187c_0008.gif

Quantitative correlation between critical air velocity and roughness of microstructured surface has still not been established systematically until the present; the dynamics of water droplet detachment by air flow from micropillar-like superhydrophobic surfaces is investigated by combining experiments and simulation comparisons. Experimental evidence demonstrates that the onset of water droplet detachment from horizontal micropillar-like superhydrophobic surfaces under air flow always starts with detachment of the rear contact lines of the droplets from the pillar tops, which exhibits a similar dynamic mechanism for water droplet motion under a gravity field. On the basis of theoretical analysis and numerical simulation, an explicit analytical model is proposed for investigating the detaching mechanism, in which the critical air velocity can be fully determined by several intrinsic parameters: water–solid interface area fraction, droplet volume, and Young’s contact angle. This model gives predictions of the critical detachment velocity of air flow that agree well with the experimental measurements.

Neurons and other parts of brain vidualized

See through brains

Bilayer Thickness Mismatch Controls Domain Size in Model Membranes

J. Am. Chem. Soc., Article ASAP
DOI: 10.1021/ja3113615
Publication Date (Web): February 7, 2013
Copyright © 2013 American Chemical Society

Frederick A. Heberle *†, Robin S. Petruzielo §, Jianjun Pan †, Paul Drazba , Norbert Kučerka □, Robert F. Standaert †‡#, Gerald W. Feigenson , and John Katsaras *†◊
†Biology & Soft Matter and ‡Biosciences Divisions, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States

The observation of lateral phase separation in lipid bilayers has received considerable attention, especially in connection to lipid raft phenomena in cells. It is widely accepted that rafts play a central role in cellular processes, notably signal transduction. While micrometer-sized domains are observed with some model membrane mixtures, rafts much smaller than 100 nm—beyond the reach of optical microscopy—are now thought to exist, both in vitro and in vivo. We have used small-angle neutron scattering, a probe free technique, to measure the size of nanoscopic membrane domains in unilamellar vesicles with unprecedented accuracy. These experiments were performed using a four-component model system containing fixed proportions of cholesterol and the saturated phospholipid 1,2-distearoyl-sn-glycero-3-phosphocholine (DSPC), mixed with varying amounts of the unsaturated phospholipids 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC) and 1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC). We find that liquid domain size increases with the extent of acyl chain unsaturation (DOPC:POPC ratio). Furthermore, we find a direct correlation between domain size and the mismatch in bilayer thickness of the coexisting liquid-ordered and liquid-disordered phases, suggesting a dominant role for line tension in controlling domain size. While this result is expected from line tension theories, we provide the first experimental verification in free-floating bilayers. Importantly, we also find that changes in bilayer thickness, which accompany changes in the degree of lipid chain unsaturation, are entirely confined to the disordered phase. Together, these results suggest how the size of functional domains in homeothermic cells may be regulated through changes in lipid composition.

Scientist find exoplanet that contains water and Carbon dioxide

Published Online March 14 2013
Science 22 March 2013:
Vol. 339 no. 6126 pp. 1398-1401
DOI: 10.1126/science.1232003

Detection of Carbon Monoxide and Water Absorption Lines in an Exoplanet Atmosphere


Determining the atmospheric structure and chemical composition of an exoplanet remains a formidable goal. Fortunately, advancements in the study of exoplanets and their atmospheres have come in the form of direct imaging—spatially resolving the planet from its parent star—which enables high-resolution spectroscopy of self-luminous planets in jovian-like orbits. Here, we present a spectrum with numerous, well-resolved molecular lines from both water and carbon monoxide from a massive planet orbiting less than 40 astronomical units from the star HR 8799. These data reveal the planet’s chemical composition, atmospheric structure, and surface gravity, confirming that it is indeed a young planet. The spectral lines suggest an atmospheric carbon-to-oxygen ratio that is greater than that of the host star, providing hints about the planet’s formation.

http://www.sciencemag.org/content/339/6126/1398.full

Ultrafast Tryptophan-to-Heme Electron Transfer in Myoglobins Revealed by UV 2D Spectroscopy

Published Online February 7 2013
Science 29 March 2013:
Vol. 339 no. 6127 pp. 1586-1589
DOI: 10.1126/science.1230758

1Laboratory of Ultrafast Spectroscopy, École Polytechnique Fédérale de Lausanne, CH-1015 Lausanne, Switzerland.

Tryptophan is commonly used to study protein structure and dynamics, such as protein folding, as a donor in fluorescence resonant energy transfer (FRET) studies. By using ultra-broadband ultrafast two-dimensional (2D) spectroscopy in the ultraviolet (UV) and transient absorption in the visible range, we have disentangled the excited state decay pathways of the tryptophan amino acid residues in ferric myoglobins (MbCN and metMb). Whereas the more distant tryptophan (Trp7) relaxes by energy transfer to the heme, Trp14 excitation predominantly decays by electron transfer to the heme. The excited Trp14→heme electron transfer occurs in <40 picoseconds with a quantum yield of more than 60%, over an edge-to-edge distance below ~10 angstroms, outcompeting the FRET process. Our results raise the question of whether such electron transfer pathways occur in a larger class of proteins.