Recent advances in the study of Micro/Nano Robotics in France.

International audienceIn France, during the last decade, significant research activities have been performed in the field of micro and nano robotics. Generally speaking the microrobotic field deals with the design, the fabrication and the control of microrobots and microrobotic cells. These microrobots are intended to perform various tasks in the so-called Microworld. The scale effects from macroworld to microworld deeply affect robots in the sense that new hard constraints appear as well as new manufacturing facilities. Concerning the nanorobotics, in order to achieve high-efficiency and three-dimensional nanomanipulation and nanoassembly, parallel imaging/manipulation force microscopy and three-dimensional manipulation force microscope, as well as nanmanipulation in the scanning electron microscope, have been developed. Manipulation of nanocomponents, such as nanoparticles, nanowires and nanotubes, have been addressed to build two-dimensional nano patterns and three-dimensional nano structure

Optical trapping: optical interferometric metrology and nanophotonics

The two main themes in this thesis are the implementation of interference methods with optically trapped particles for measurements of position and optical phase (optical interferometric metrology) and the optical manipulation of nanoparticles for studies in the assembly of nanostructures, nanoscale heating and nonlinear optics (nanophotonics). The first part of the thesis (chapter 1, 2) provides an introductory overview to optical trapping and describes the basic experimental instrument used in the thesis respectively. The second part of the thesis (chapters 3 to 5) investigates the use of optical interferometric patterns of the diffracting light fields from optically trapped microparticles for three types of measurements: calibrating particle positions in an optical trap, determining the stiffness of an optical trap and measuring the change in phase or coherence of a given light field. The third part of the thesis (chapters 6 to 8) studies the interactions between optical traps and nanoparticles in three separate experiments: the optical manipulation of dielectric enhanced semiconductor nanoparticles, heating of optically trapped gold nanoparticles and collective optical response from an ensemble of optically trapped dielectric nanoparticles

Additive nanomanufacturing: a review

Additive manufacturing has provided a pathway for inexpensive and flexible manufacturing of specialized components and one-off parts. At the nanoscale, such techniques are less ubiquitous. Manufacturing at the nanoscale is dominated by lithography tools that are too expensive for small- and medium-sized enterprises (SMEs) to invest in. Additive nanomanufacturing (ANM) empowers smaller facilities to design, create, and manufacture on their own while providing a wider material selection and flexible design. This is especially important as nanomanufacturing thus far is largely constrained to 2-dimensional patterning techniques and being able to manufacture in 3-dimensions could open up new concepts. In this review, we outline the state-of-the-art within ANM technologies such as electrohydrodynamic jet printing, dip-pen lithography, direct laser writing, and several single particle placement methods such as optical tweezers and electrokinetic nanomanipulation. The ANM technologies are compared in terms of deposition speed, resolution, and material selection and finally the future prospects of ANM are discussed. This review is up-to-date until April 2014

Modulation of Photonic Mode Density in Silver Nanodisks and Far Field Focusing of Light by Coupled Plasmonic Nanorings

During the past twenty years, plasmonic nanostructures have evolved as one of the most promising candidates for applications in miniaturized optical and electronic devices, bio-sensors and photonic circuits, etc. Silver nanoparticles can interact with light more strongly than any known materials with similar dimensions, and support tunable optical properties based on their size, shape and sounding medium, which are more stable than optical properties of traditional pigments and dyes. Thanks to the recent progress in the synthesis of various silver nanoparticles with different shape and sizes, which has opened doors to the exciting research field of plasmonics. However, silver nanoparticles tend to aggregate when cast on substrates from its aqueous suspension, which compromises their plasmonic properties. In Chapter 2, we describe a simple and reliable method to immobilize silver nanoparticles on polymer coated substrates to mitigate aggregation and allow further chemical modification of silver nanoparticles, if needed. In this project, interesting nanostructured craters were discovered, which were extensively studied using atomic force microscopy (AFM). Fluorescence is widely used in many biosensing applications such as the quantification of disease markers, protein activity, cytokine and small molecule signals. Metallic nanoparticles alter fluorescence emission by influencing either the incident excitation field, or the radiative and non-radiative decay rates of dye molecules. In Chapter 3, we describe a simple method for tuning the shape of silver nanoparticles to synergistically achieve high fluorescence enhancements in an ensemble of dye molecules. Specifically, we show that the fluorescence emission from Rhodamine B (RhB) is enhanced by \u3e30 folds (with respect to RhB on bare glass) in the presence of Ag nanodisks due to a simultaneous increase in the excitation intensity and photon mode density. Moreover, our detailed finite-element simulations, which account for incident, scattered, and dipole radiated electric fields, evidenced that the enhancement is strongly dependent on the orientation of RhB dipole relative to Ag NPs and nanodisks. While aggregation of silver nanoparticles is not desirable, it facilitates creation of fascinating nanostructures that exhibit new properties due to the mystical coupling between plasmonic resonances of particles within the aggregate. Prior research has shown that such coupling leads to Fano resonances, greatly enhanced local electromagnetic fields, unidirectional scattering of light, etc. In Chapter 4, we describe a method for assembling silver nanoparticles into specific configurations, such as a linear chain or a nanoring by manipulating individual silver nanoparticles into such configurations with the help of the AFM tip. We discovered novel far field focusing properties of light by nonorings, which is a result of coupled plasmonic resonances of nanoparticles present within the nanoring

Nanopipettes as Monitoring Probes for the Single Living Cell: State of the Art and Future Directions in Molecular Biology.

Examining the behavior of a single cell within its natural environment is valuable for understanding both the biological processes that control the function of cells and how injury or disease lead to pathological change of their function. Single-cell analysis can reveal information regarding the causes of genetic changes, and it can contribute to studies on the molecular basis of cell transformation and proliferation. By contrast, whole tissue biopsies can only yield information on a statistical average of several processes occurring in a population of different cells. Electrowetting within a nanopipette provides a nanobiopsy platform for the extraction of cellular material from single living cells. Additionally, functionalized nanopipette sensing probes can differentiate analytes based on their size, shape or charge density, making the technology uniquely suited to sensing changes in single-cell dynamics. In this review, we highlight the potential of nanopipette technology as a non-destructive analytical tool to monitor single living cells, with particular attention to integration into applications in molecular biology

Characterization of NanoGUMBOS for future electronic devices

In our work on hybrid (organic-inorganic) electronic materials (HEMs), we have developed a reasonably facile method for characterizing GUMBOS or a Group of Uniform Materials Based on Organic Salts. In addition to the versatility of traditional ionic liquids (i.e.-solubility, melting point, viscosity), NanoGUMBOS are functionalizable to exhibit properties such as fluorescence, magnetic susceptibility, and even antimicrobial activity. However, given our interest in the electrical properties of HEMs, we have made first-time measurements of NanoGUMBOS, using conductive probe Atomic Force Microscopy (CP-AFM), in order to deduce their room temperature current-voltage characteristics. In conjunction with the nanoscale imaging of AFM alone, we have observed both the morphology and conductivity of these unique materials. Our results bode well for combining GUMBOS with substrates of more traditional materials, such as metals or semiconductors, to serve as the basis for future HEMs-based devices. We have also determined the optical characteristics of NanoGUMBOS using Raman Spectroscopy (RS). The Raman signatures can be used for detection of a nanoparticle and modeling the electron-phonon interaction inside the nanoparticle

Adaptive Critic Neural Network Force Controller for Atomic Force Microscope-Based Nanomanipulation

Automating the task of nanomanipulation is extremely important since it is tedious for humans. This paper proposes an atomic force microscope (AFM) based force controller to push nano particles on the substrates. A block phase correlation-based algorithm is embedded into the controller for the compensation of the thermal drift which is considered as the main external uncertainty during nanomanipulation. Then, the interactive forces and dynamics between the tip and the particle, particle and the substrate are modeled and analyzed. Further, an adaptive critic NN controller based on adaptive dynamic programming algorithm is designed and the task of pushing nano particles is demonstrated. This adaptive critic NN position/force controller utilizes a single NN in order to approximate the cost functional and subsequently the optimal control input is calculated. Finally, the convergence of the states, NN weight estimates and force errors are shown

Atomic force microscopy analysis of nanoparticles in non-ideal conditions

Nanoparticles are often measured using atomic force microscopy or other scanning probe microscopy methods. For isolated nanoparticles on flat substrates, this is a relatively easy task. However, in real situations, we often need to analyze nanoparticles on rough substrates or nanoparticles that are not isolated. In this article, we present a simple model for realistic simulations of nanoparticle deposition and we employ this model for modeling nanoparticles on rough substrates. Different modeling conditions (coverage, relaxation after deposition) and convolution with different tip shapes are used to obtain a wide spectrum of virtual AFM nanoparticle images similar to those known from practice. Statistical parameters of nanoparticles are then analyzed using different data processing algorithms in order to show their systematic errors and to estimate uncertainties for atomic force microscopy analysis of nanoparticles under non-ideal conditions. It is shown that the elimination of user influence on the data processing algorithm is a key step for obtaining accurate results while analyzing nanoparticles measured in non-ideal conditions

Electrons, Photons, and Force: Quantitative Single-Molecule Measurements from Physics to Biology

Single-molecule measurement techniques have illuminated unprecedented details of chemical behavior, including observations of the motion of a single molecule on a surface, and even the vibration of a single bond within a molecule. Such measurements are critical to our understanding of entities ranging from single atoms to the most complex protein assemblies. We provide an overview of the strikingly diverse classes of measurements that can be used to quantify single-molecule properties, including those of single macromolecules and single molecular assemblies, and discuss the quantitative insights they provide. Examples are drawn from across the single-molecule literature, ranging from ultrahigh vacuum scanning tunneling microscopy studies of adsorbate diffusion on surfaces to fluorescence studies of protein conformational changes in solution