A5089285304- Force Microscopy Techniques and Applications
- Molecular Junctions and Nanostructures
- Mechanical and Optical Resonators
- Surface and Thin Film Phenomena
- Advanced Memory and Neural Computing
- Cellular Mechanics and Interactions
- Graphene research and applications
- Neural dynamics and brain function
- Neural Networks and Reservoir Computing
- Fullerene Chemistry and Applications
- Near-Field Optical Microscopy
- Advanced Electron Microscopy Techniques and Applications
- Photoreceptor and optogenetics research
- Electron and X-Ray Spectroscopy Techniques
- Neuroscience and Neural Engineering
- Surface Chemistry and Catalysis
- Advanced Materials Characterization Techniques
- Advanced MEMS and NEMS Technologies
- Extracellular vesicles in disease
- Carbon Nanotubes in Composites
- Advanced Chemical Physics Studies
- thermodynamics and calorimetric analyses
- Microfluidic and Bio-sensing Technologies
- Integrated Circuits and Semiconductor Failure Analysis
- Nanopore and Nanochannel Transport Studies
University of California, Los Angeles
2015-2024
California NanoSystems Institute
2015-2024
National Institute for Materials Science
2014-2024
Kyushu Institute of Technology
2021-2024
UCLA Health
2012-2023
Geological Society of America
2021
Camber Collective (United States)
2021
Universidade de Fortaleza
2021
Medical College of Wisconsin
2018
Yale University
2018
We report the specific transduction, via surface stress changes, of DNA hybridization and receptor-ligand binding into a direct nanomechanical response microfabricated cantilevers. Cantilevers in an array were functionalized with selection biomolecules. The differential deflection cantilevers was found to provide true molecular recognition signal despite large nonspecific responses individual Hybridization complementary oligonucleotides shows that single base mismatch between two 12-mer is...
Experiments on individual molecules using scanning probe microscopies have demonstrated an exciting diversity of physical, chemical, mechanical, and electronic phenomena. They permitted deeper insight into the quantum electronics molecular systems provided unique information their conformational mechanical properties. Concomitant developments in experimentation theory allowed a diverse range to be studied, varying complexity from simple diatomics biomolecular systems. At level molecule,...
Surface stress changes and kinetics were measured in situ during the self-assembly of alkanethiols on gold by means a micromechanical sensor. Self-assembly caused compressive surface that closely followed Langmuir-type adsorption up to monolayer coverage. The at coverage increased linearly with length alkyl chain molecule. These observations interpreted terms differences potential. This highly sensitive sensor technique has broad range applicability specific chemical biological interactions.
Using scanning tunneling microscopy, we have studied local surface modifications induced by point contact of a tunnel tip with metallic surfaces. Two distinct types topographical modification are found which correlate directly the chemical condition as determined spectroscopy. Observation dynamics transition from regime to permits an evaluation gap distance prior contact. At spacings s\ensuremath{\lesssim}3 A\r{} significant decrease in apparent barrier height is observed just before...
We report the first study of electrical contact with an individual molecule (${\mathrm{C}}_{60}$). Using a scanning tunneling microscope tip, current $I$ flowing as function tip displacement $s$ towards is investigated [ $I\left(s\right)$ characteristics]. The increases approximately exponentially in tunnel regime, but this behavior changes significantly established. From data and calculations for ${\mathrm{C}}_{60}$ we determine apparent resistance 54.80 M $\ensuremath{\Omega}$ junction at...
Two-dimensional positioning of intact individual molecules was achieved at room temperature by a controlled lateral “pushing” action the tip scanning tunneling microscope. To facilitate this process, four bulky hydrocarbon groups were attached to rigid molecule. These maintained sufficiently strong interactions with surface prevent thermally activated diffusional motion, but nevertheless allowed controllable translation. Simulations demonstrated crucial role flexure during process. results...
Light emission characteristics from the tunnel gap of a scanning tunneling microscope are used to elucidate interaction electrons with tip-induced plasmon modes on Ag, Au, and Cu surfaces. Enhanced redshifted spectra observed in regime. Model calculations optical this range agree well experimental data. Isochromat demonstrate that principal excitation process occurs via inelastic tunneling.
Recently biomechanics of cancer cells, in particular stiffness or elasticity, has been identified as an important factor relating to cell function, adherence, motility, transformation and invasion. We report on the nanomechanical responses metastatic cells benign mesothelial taken from human body cavity fluids using atomic force microscopy. Following our initial study (Cross et al 2007 Nat. Nanotechnol. 2 780-3), we biophysical properties patient-derived effusion address influence morphology...
Experimental visualization and verification of a single-molecule rotor operating within supramolecular bearing is reported. Using scanning tunneling microscope, single molecules were observed to exist in one two spatially defined states laterally separated by 0.26 nanometers. One was identified as rotating state the other an immobilized state. Calculations energy barrier for rotation these show that it below thermal at room temperature above
We demonstrate that the cell wall of living Saccharomyces cerevisiae (baker's yeast) exhibits local temperature-dependent nanomechanical motion at characteristic frequencies. The periodic motions in range 0.8 to 1.6 kHz with amplitudes ∼3 nm were measured using cantilever an atomic force microscope (AFM). Exposure cells a metabolic inhibitor causes cease. From strong frequency dependence on temperature, we derive activation energy 58 kJ/mol, which is consistent cell's metabolism involving...
All living systems contain naturally occurring nanoparticles with unique structural, biochemical, and mechanical characteristics. Specifically, human saliva exosomes secreted by normal cells into via exocytosis are novel biomarkers showing tumor-antigen enrichment during oral cancer. Here we show the substructure of single exosomes, using a new ultrasensitive low force atomic microscopy (AFM) exhibiting substructural organization unresolvable in electron microscopy. We correlate data field...
Background Exosomes, derived from endocytic membrane vesicles are thought to participate in cell-cell communication and protein RNA delivery. They ubiquitous most body fluids (breast milk, saliva, blood, urine, malignant ascites, amniotic, bronchoalveolar lavage, synovial fluids). In particular, exosomes secreted human saliva contain proteins nucleic acids that could be exploited for diagnostic purposes. To investigate this potential use, we isolated characterized their structural...
Learning abilities are demonstrated using a single solid-state atomic switch, wherein the formation and dissolution of metal filament controlled depending on history prior switching events. The strength memorization level gradually increases when number input signals is increased. Once forms bridge, electrons flow in ballistic mode long-term achieved (see figure). Detailed facts importance to specialist readers published as "Supporting Information". Such documents peer-reviewed, but not...
Atomic switch networks (ASNs) have been shown to generate network level dynamics that resemble those observed in biological neural networks. To facilitate understanding and control of these behaviors, we developed a numerical model based on the synapse-like properties individual atomic switches random nature wiring. We validated against various experimental results highlighting possibility functionalize plasticity differences between an isolation its behaviors network. The effects changing...
Forces acting between tunnel tip and sample during scanning tunneling microscopy were explored experimentally. Force gradients detected as resonance shifts of cantilever beams used stage. Beam deflections caused by force variations also recorded. We present data for tungsten tips polycrystalline silver surfaces prepared under UHV conditions. Large positive found the range distances investigated. maps show pronounced features correlating directly with topographic images.