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Patients with unresectable or nonablatable tumors are difficult to cure, but nanotherapy combining targeted nanoparticles has many severe side effects due to the toxicities of anticancer drugs. We found that acoustic energy can produce a local region with high concentration from a low concentration suspended liquid of nano-SiO2 particles at 2.5 MHz. Our calculated results show that the main reason for aggregation is the synthesized effect of the potential well of acoustic energy and streaming to trap them. In addition, the aggregated region can be manipulated to a targeted position in the vessel phantom by moving the ultrasound transducer external to the body. This noninvasive manipulation of suspended nanoparticles can rapidly increase the local drug concentration, but reduce the total dosage of anticancer drugs, which has the potential to be used for patients with advanced tumors by improving the physiological effects and reducing the side effects. [ABSTRACT FROM AUTHOR]

Scanning probe microscopy (SPM) based nanomanipulators always experience probe accuracy issues caused by uncertainties such as scanner hysteresis, drifts, and interaction forces. Although some SPMs contain internal position sensors, they can hardly sense real probe position due to the above uncertainties, especially when implementation scales down below 100 nm. Recently, we proposed a local-image-based nonvector space (NVS) control strategy for regulating nanomanipulator to enhance its accuracy (positioning error is generally maintained below $0.2\%$ of the operation range). Since the previous NVS control strategy employs only local image and pixel-wise information (neglecting global location and local coherence information), it can hardly track trajectories with relatively large “jump” and heavy noise, which might be inefficient for practical implementation. To tackle these problems, this study proposes a novel enhanced NVS (ENVS) control strategy, which performs rough global positioning control through dynamic hysteresis compensation for SPM scanners to solve the “jump” problem; to realize fine positioning control with possible heavily noisy feedback, the ENVS controller utilizes patch-wise-based rather than pixel-wise-based set feedback strategy, and the ENVS is built based on a newly established shape Lyapunov function. Testing results show that the ENVS control scheme can precisely track references with jump changes, such as the step signal. Furthermore, the ENVS controller is able to maintain its accuracy even with extremely noisy feedback. [ABSTRACT FROM AUTHOR]

Atomic force microscope (AFM) has been defined as the one of the most powerful instruments to explore micro/nanoworld in various fields. To lower imaging noise, AFMs are commonly equipped with open-loop nanopositioners (scanners). However, the hysteretic effect of the AFM positioners is a dominate factor that increases the position error during AFM-based manipulations. To reduce hysteresis, inverse compensation approach is an effective solution. Normally, one compensator is designed for the manipulation task with maximum working range, which may not be efficient enough for maintaining uniform accuracy for tasks with different working ranges. The objective of this study is to develop a working-range adapted compensator to tackle this challenge. First, a generalized method that can precisely model various types of hysteresis is required. To fulfill this, a flexible Prandtl–Ishlinskii (PI) type model, named extended unparallel PI model, is employed. Based on this model, an implicit hysteresis compensation approach is developed, and its stability condition and control gain optimization approach are proposed. Combining the modeling and compensation approaches, a working-range adapted hysteresis compensator is finally established. Experimental results demonstrate that the mean control errors of the compensator are uniformly below $5\%$ in different working ranges. [ABSTRACT FROM PUBLISHER]

Microscopy has been an indispensable tool for micro/nanosample imaging, manipulation, and characterization. However, viewing the micro/nanosample from multidirection is still a big challenge for current microscopy. To address the above issue, this paper proposes a novel nanorobotic manipulation system for the automatic alignment and multidirectional imaging under microscopes. First, a miniature rotation robot with three degrees of freedom is designed and integrated with a microscope. Then, a forward-backward alignment strategy containing three loops, i.e., position shift loop, angle loop, and magnification loop, is proposed to align the sample to the rotation axis of the robot automatically. After that, the sample is imaged from multidirection by rotating the robot with one revolution (360°). Finally, the alignment accuracy is evaluated and multi-directional images of various samples are implemented. This study provides a new way for the microscopic imaging, which is expected to exert a significant impact in multiple fields on a small scale, including microscopy imaging, microdefect detection, micromanipulation, in situ characterization, and so on. [ABSTRACT FROM AUTHOR]

Probing nanostructures (e.g., nanoelectronics) requires accurate and precise nanopositioning. Furthermore, since measuring I–V data from dc to GHz typically takes more than a minute, tolerance for position drift is stringent during the data collection process. This paper reports a closed-loop controlled nanomanipulation system for operation inside a scanning electron microscope. A new position sensing method with low power consumption is used to achieve nanometer sensing resolution and effective heat dissipation management. For automated probing of nanostructures, the position sensor-based closed-loop probing approach was found to be four times faster than visually servoed probing, and ten times faster compared to manual operation. Probing accuracy was determined to be better than 3 nm and a drift rate lower than 1 nm/min. [ABSTRACT FROM PUBLISHER]

In this brief, a B-spline-decomposition (BSD)-based approach to output tracking with preview is explored to achieve high-speed, large-range nanomanipulation in experiments. The BSD approach is developed to address challenges in preview-based output tracking of nonminimum-phase systems to achieve precision tracking with good robustness to dynamics variations and no demanding online computation. In the BSD approach, a library of output elements and their corresponding input elements is constructed a priori; then the previewed future desired trajectory is decomposed into a finite number of output elements, and the control input is synthesized using the corresponding input elements with chosen pre- and post-actuation times. The BSD technique uses the uniform B-splines to construct the output elements, the iterative learning control techniques to obtain the input elements, and the stable-inversion theory to quantify the pre- and post-actuation times. In this brief, we demonstrate and evaluate the BSD technique for preview-based precision tracking in experiments, by implementing it to a nanomanipulation application using a scanning probe microscope. The experiments showed that the tracking speed can be substantially improved using the BSD technique over using feedback control alone. [ABSTRACT FROM AUTHOR]

Although dielectrophoretic (DEP) assembly has been demonstrated to be an efficient way to align nanowires or nanotubes for making nanodevices based on one-dimensional nanostructures, misalignment is often observed in experimental implementation. This unfavorable observation discourages researchers’ enthusiasm in making devices by DEP. To make DEP assembly in a controllable fashion, theoretical and simulation studies are indispensable. However, traditional analysis on DEP is based on a zero-dimensional model derived from the interaction between a nonuniform electric field and dielectric particles, which might not be directly applicable to nanowires or nanotubes. In this paper, we propose an approach similar to finite element method to calculate the total DEP force and torque on the one-dimensional nanostructure by considering the dimensional effect. It is shown from the simulation that the magnitude of DEP force is related to the conductivity of the nanostructure and the frequency of the electric field, which provides feasibility on controllable and selective assembly of the nanowires or nanotubes. To study the trajectory of single nanowire or nanotube assembled by DEP, a comprehensive model involving DEP force, DEP torque, drag force, drag torque, and Brownian motion is proposed. The one-dimensional nanostructure is predicted from the simulation to either attach one electrode and align at certain direction or bridge the electrodes. The theoretical and simulation study indicate that the alignment of one-dimensional nanostructure is mainly related to its length, the gap size of the electrodes as well as the initial contact position of the nanowire or nanotube onto the electrode. The predication from the simulation has been confirmed by assembled zinc oxide nanowires and carbon nanotubes using DEP. [ABSTRACT FROM PUBLISHER]

Conventional scanning probe microscopy (SPM)-based nanomanipulations always have to face scanner accuracy problems such as hysteresis, nonlinearity, and thermal drift. Although some scanners consist of internal position sensors, the sensitivity is not high enough to monitor high-resolution nanomanipulations. Additionally, once the scan size decreases to a nanolevel such as less than 100 nm, the noise brought by sensors is large enough to affect the performance of the closed-loop motion control system. In this paper, a non-vector space control strategy based on compressive feedback is proposed in order to improve the accuracy of SPM-based nanomanipulations. In this approach, local images (or compressive data) are used as both the reference input and feedback for a non-vector space closed-loop controller which considers the local image (or compressive data) as a set. The controller is designed in non-vector space, and it requires no prior information on features or landmarks which are widely used in traditional visual servoing. In this paper, the atomic force microscopy is used as an example of SPM to implement the non-vector space control strategy for nanomanipulations. The motivation of designing such a non-vector space controller is to solve the accuracy problem in nanomanipulation. Without this technique, the SPM-based nanomanipulations, such as nanomeasurement and nanosurgery, are difficult to conduct, with accuracy controlled under several nanometers. In order to illustrate the contributions and potential applications of this non-vector controller, at the end of this paper, an application of carbon nanotube local electrical property characterization based on a non-vector space motion control is shown to clearly verify the concept. Compared with other research in the local electrical property characterization, the non-vector space controller can ensure that the measurement accuracy (position error) is controlled within a few nanometers, which also ensures the reliability of measurement results. Additionally, this non-vector space control method can be implemented into any kind of SPM to realize a real-time control for nanomanipulation such as nanofabrication and nanoassembly. [ABSTRACT FROM PUBLISHER]

One of the major limitations for Atomic Force Microscopy (AFM)-based nanomanipulation is that AFM only has one sharp tip as the end-effector, and can only apply a point force to the nanoobject, which makes it extremely difficult to achieve a stable manipulation. For example, the AFM tip tends to slip-away during nanoparticle manipulation due to its small touch area, and there is no available strategy to manipulate a nanorod in a constant posture with a single tip since the applied point force can make the nanorod rotate more easily. In this paper, a robotic nano-hand method is proposed to solve these problems. The basic idea is using a single tip to mimic the manipulation effect that multi-AFM tip can achieve through the planned high speed sequential tip pushing. The theoretical behavior models of nanoparticle and nanorod are developed, based on which the moving speed and trajectory of the AFM tip are planned artfully to form a nano-hand. In this way, the slip-away problem during nanoparticle manipulation can be get rid of efficiently, and a posture constant manipulation for nanorod can be achieved. The simulation and experimental results demonstrate the effectiveness and advantages of the proposed method. [ABSTRACT FROM PUBLISHER]

This paper presents mechanism and controller design procedures of a new piezoactuated flexure XY stage for micro-/nanomanipulation applications. The uniqueness of the proposed stage lies in that it possesses an integrated parallel, decoupled, and stacked kinematical structure, which owns such properties as identical dynamic behaviors in X and Y axes, decoupled input and output motion, single-input-single-output (SISO) control, high accuracy, and compact size. Finite element analysis (FEA) was conducted to predict static performance of the stage. An XY stage prototype was fabricated by wire electrical discharge machining (EDM) process from the alloy material Al7075. Based on the identified plant transfer function of the micropositioning system, an H∞ robust control combined with a repetitive control (RC) was adopted to compensate for the unmodeled piezoelectric nonlinearity. The necessity of using such a combined control is also investigated. Experimental results demonstrate that the H∞ plus RC scheme improves the tracking response by 67% and 28% compared to the stand-alone H∞ for 1-D and 2-D periodic positioning tasks, respectively. Thus, the results illustrate the effectiveness of the proposed mechanism design and control approach. [ABSTRACT FROM PUBLISHER]

Atomic force microscopes (AFMs) have become a useful tool not only for imaging at the nanoscale resolution, but also a useful tool for manipulating nanoscale objects in nanoscale device prototyping and for studying molecular and cellular mechanisms in biology. This paper presents a method, called sequential parallel pushing (SPP), for efficient and automated nanoparticle manipulation. Instead of using tip scanning to fully locate the particle center, this method uses one scan line perpendicular to the pushing direction to determine the lateral coordinate of the particle center. The longitudinal position of the particle is inferred from the position where the tip loses contact with the particle through real-time analysis of vibration amplitude of the cantilever. The particle is then pushed from the determined lateral position along the current push direction toward the baseline of the target. This process is iterated until the particle reaches the target position. Experimental results show that the SPP algorithm, when compared with simple target-oriented pushing algorithms, not only reduces the number of scan lines but also decreases the number of pushing iterations. Consequently, the manipulation time has been decreased up to four times in some cases. The SPP method has been successfully applied to fabricate designed nanoscale patterns that are made of gold (10 \sim 15 nm diameter) particles and of 170 latex 50-nm diameter) particles. [ABSTRACT FROM PUBLISHER]

In this paper, single cells adhesion force was measured using a nanofork. The nanofork was used to pick up a single cell on a line array substrate inside an environmental scanning electron microscope (ESEM). The line array substrate was used to provide small gaps between the single cells and the substrate. Therefore, the nanofork could be inserted through these gaps in order to successfully pick up a single cell. Adhesion force was measured during the cell pick-up process from the deflection of the cantilever beam. The nanofork was fabricated using focused ion beam (FIB) etching process while the line array substrate was fabricated using nanoimprinting technology. As to investigate the effect of contact area on the strength of the adhesion force, two sizes of gap distance of line array substrate were used, i.e., 1~\mum and 2~\mum. Results showed that cells attached on the 1~\mum gap line array substrate required more force to be released as compared to the cells attached on the 1~\mum gap line array substrate. [ABSTRACT FROM PUBLISHER]

We performed single pulses current measurement on single cells using dual nanoprobe through environmental scanning electron microscope nanomanipulator system. The ability to characterize the electrical property of single cells can be used as a novel method for cell viability detection in quantitative and instantaneous manners. The nanoprobe was successfully fabricated using focused ion beam tungsten deposition and etching processes. The characteristics of the nanoprobe were examined from the energy dispersion spectrometry and noise analyses. In this paper, for the first time, the electrical property of single cells under their native condition was presented. In order to apply this method for cell viability detection, two types of cells were used, i.e., dead cells and live cells. The results showed that there is a significant difference on the electrical measurement data between dead and live cells. [ABSTRACT FROM PUBLISHER]

Cell-surface adhesion force is important for cell activities and the development of bio materials. In this paper, a method for in situ single cell (W303) adhesion force measurement was proposed based on nanorobotic manipulation system inside an environment scanning electron microscope (ESEM). An end effector was fabricated from a commercial atomic force microscope (AFM) cantilever by focused ion beam (FIB) etching. The spring constant of it was calibrated by nanomanipulation approach. Three kinds of hydrophilic and hydrophobic ITO plates were prepared by using VUV-irradiation and OTS coating techniques. The shear adhesion strength of the single yeast cell to each substrate was measured based on the deflection of the end effector. The results demonstrated that the cell adhesion force was larger under the wet condition in the ESEM environment than in the aqueous condition. It also showed that the cell adhesion force to hydrophilic surface was larger than that to the hydrophobic surface. Studies of single cell's adhesion on various plate surfaces and environments could give new insights into the tissue engineering and biological field. [ABSTRACT FROM PUBLISHER]

This paper presents a microelectromechanical systems (MEMS) device for simultaneous electrical and mechanical characterization of individual nanowires. The device consists of an electrostatic actuator and two capacitive sensors, capable of acquiring all measurement data (force and displacement) electronically without relying on electron microscopy imaging. This capability avoids the effect of electron beam (e-beam) irradiation during nanomaterial testing. The bulk-microfabricated devices perform electrical characterization at different mechanical strain levels. To integrate individual nanowires to the MEMS device for testing, a nanomanipulation procedure is developed to transfer individual nanowires from their growth substrate to the device inside a scanning electron microscope. Silicon nanowires are characterized using the MEMS device for their piezoresistive as well as mechanical properties. It is also experimentally verified that e-beam irradiation can significantly alter the characterization results and must be avoided during testing.\hfill[2011-0031] [ABSTRACT FROM PUBLISHER]

We propose a buckling nanoneedle as a force sensor for stiffness characterization of single cells. The buckling nanoneedle was easily fabricated by using focused ion beam etching from a commercialized atomic force microscope cantilever. There are notable advantages of using buckling nanoneedle for single cells stiffness characterizations. First, severe cell damage from an excessive indentation force could be prevented. Second, large variations in single cells stiffness property could be easily detected either from the dented mark on the cell surface after the indentation and/or by comparing the buckling length of the nanoneedle during the indentation. The calibrations of the buckling nanoneedle were done experimentally and numerically. The calibration results from both methods showed a good agreement. The calibration data show the relationship between the indentation force and the buckling length of the nanoneedle. This relationship was used for obtaining force data during a nanoindentation experiment between a buckling nanoneedle and single cells. We performed in situ measurements of mechanical properties of individual W303 wild-type yeast cells by using a buckling nanoneedle inside an integrated SEM (ESEM)–nanomanipulator system. Finer local stiffness property of single cells was compared at different pressure and different temperature ranges. This detection method of the stiffness variations of the single cells could be applied in the future fast disease diagnosis based on single-cell stiffness analysis. [ABSTRACT FROM PUBLISHER]

Multiscale resolution imaging and manipulation are essential for applications ranging from defect screening in circuits to nanoscale manipulation, patterning, and lithography. In this paper, we introduce a variant of scanning thermal microscopy to image surfaces at both the micro- and nanoscale. Electrothermal imaging at the microscale is performed in a completely out-of-contact, i.e., “noncontact” or “off-contact,” mode with a microscale heater, followed by higher resolution nanoscale imaging in contact mode with a nanoscale probe tip. Using this methodology, the imaging and manipulation functions of a single probe can be decoupled completely. This off-contact imaging mode is useful for avoiding tip wear and can be performed safely at high velocities. We demonstrate imaging of microscale features at speeds of up to 2 mm/s. The lateral resolution is determined by the dimensions of the heater used for imaging. For the flying heights and heater dimensions used here, the 1–\sigma lateral spatial resolution limit in the off-contact mode is less than 10 \mum for 10-nm-tall features. A silicon nanowire attached to microscale electrodes is imaged to demonstrate the efficacy of this scheme. [ABSTRACT FROM PUBLISHER]

We report on the development and application of a silicon microdevice for the in situ quantitative mechanical characterization of single 1-D nanomaterials within a scanning electron microscope equipped with a quantitative nanoindenter. The design makes it possible to convert a compressive nanoindentation force applied to a shuttle to uniaxial tension on a specimen attached to a sample stage. Finite-element analysis and experimental calibration have been employed to extract the specimen stress versus strain curve from the indentation load versus displacement curve. The stress versus strain curves for three 200-300-nm-diameter Ni nanowire specimens are presented and analyzed. [ABSTRACT FROM AUTHOR]

Ionic polymer-metal composite (IPMC) actuators have promising applications in biomimetic robotics, biomedical devices, and micro/nanomanipulation. In this paper, a physics- based model is developed for IPMC actuators, which is amenable to model reduction and control design. The model is represented as an infinite-dimensional transfer function relating the bending displacement to the applied voltage. It is obtained by exactly solving the governing partial differential equation in the Laplace domain for the actuation dynamics, where the effect of the distributed surface resistance is incorporated. The model is expressed in terms of fundamental material parameters and actuator dimensions, and is thus, geometrically scalable. To illustrate the utility of the model in controller design, an Hinfin controller is designed based on the reduced model and applied to tracking control. Experimental results are presented to validate the proposed model and its effectiveness in real-time control design. [ABSTRACT FROM PUBLISHER]

We performed in situ measurements of mechanical properties of individual W303 wild-type yeast cells by using an integrated environmental scanning electron microscope (ESEM)-nanomanipulator system. Compression experiments to penetrate the cell walls of single cells of different cell sizes (about 3-6 mu m diameter), environmental conditions (600 Pa and 3 mPa), and growth phases (early log, mid log, late log and saturation) were conducted. The compression experiments were performed inside ESEM, embedded with a 7 DOF nanomanipulator with a sharp pyramidal end effector and a cooling stage, i.e., a temperature controller. ESEM itself can control the chamber pressure. Data clearly show an increment in penetration force, i.e., 96plusmn2, 124 plusmn10, 163plusmn1, and 234plusmn14 nN at 3, 4, 5, and 6 mu m cell diameters, respectively. Whereas, 20-fold increase in penetration forces was recorded at different environmental conditions for 5 mu m cell diameter, i.e., 163plusmn1 nN and 2.95plusmn0.23 mu N at 600 Pa (ESEM mode) and 3 mPa (HV mode), respectively. This was further confirmed from quantitative estimation of average cell rigidity through the Hertz model, i.e., ESEM mode (3.31plusmn0.11 MPa) and HV mode (26.02plusmn3.66 MPa) for 5 mu m cell diameter. Finally, the penetration forces at different cell growth phases also show the increment pattern from log (early, mid, and late) to saturation phases, i.e., 161plusmn 25, 216plusmn15, 255 plusmn21, and 408plusmn41 nN, respectively. [ABSTRACT FROM PUBLISHER]

In this study, characterization of cellular mechanics of W303 yeast cells was conducted using nanoneedles inside an environmental SEM (ESEM). This enhanced ESEM system comprises a standard ESEM instrument as a nanoimaging tool, a cooling stage as a humidity controller for cellular biology and 7 degrees of freedom and linear actuators as nanomanipulator/effector. Four types of nanoneedles were used in our experiments, i.e., silicon (Si), titanium (Ti) coated Si, and two types of tungsten (W) nanoneedles. The Si and Ti nanoneedles were fabricated using 2 N/m spring constant cantilevers. While the W nanoneedles were fabricated using 0.09 and 2 N/m spring constant cantilevers (W0.09 and W2 nanoneedles). The Si, silicon-titanium (Si-Ti), W0.09, and W2 nanoneedles are suitable to be used for local stiffness characterization of single cells. This capability can be used in future for fast disease detection since disease cells may show different cell mechanics properties as compared to the normal cells. The Si-Ti and W2 nanoneedles can penetrate the cell without cell bursting, and this could be important in single cell surgery in future to avoid cell damage. [ABSTRACT FROM PUBLISHER]

The atomic force microscope (AFM) has been widely used as a nano-effector with a function of force sensing to detect interaction forces between an AFM tip and a sample, thereby controlling the process of the nanomanipulation. However, both the extent and accuracy of force application are significantly limited by the nonlinearity of the commonly used optical lever with a nonlinear position-sensitive detector (PSD). In order to compensate the nonlinearity of the optical lever, a nonlinear calibration method is presented. This method applies the nonlinear curve fit to a full-range position-voltage response of the photodiode, obtaining a continuous function of its voltage-related sensitivity. Thus, interaction forces can be defined as integrals of this sensitivity function between any two responses of photodiode voltage outputs, instead of rough transformation with a single conversion factor. The lateral position-voltage response of the photodiode, a universally acknowledged puzzle, was directly characterized by an accurately calibrated force sensor composed of a tippless piezoresistive microcantilever and corresponding electronics, regardless of any knowledge of the cantilevers and laser measuring system. Experiments using a rectangular cantilever (normal spring constant 0.24 N/m) demonstrated that the proposed nonlinear calibration method restrained the sensitivity error of normal position-voltage responses to 3.6% and extended the force application range. [ABSTRACT FROM PUBLISHER]

A nanolaboratory is one of the systems to realize various nanoscale fabrications and assemblies to develop novel nanodevices to integrate borderless technologies based on a nanorobotic manipulation system. We have presented the nanolaboratory inside electron microscopes including a transmission electron microscope (TEM), scanning electron microscope (SEM), and environmental-SEM (E-SEM) for three-dimensional (3D) and real-time nanomanipulation, nanoinstrumentation, and nanoassembly. The following is a presentation of our current work of nanomanipulation and nanoassembly based on the hybrid nanorobotic manipulation inside a TEM and an SEM toward carbon nanotube (CNT) applications. Single cell stiffness measurement has been also presented based on the nanorobotic manipulation system inside an E-SEM. [ABSTRACT FROM PUBLISHER]

Nanomanipulation and nanofabrication with an atomic force microscope (AFM) or other scanning probe microscope (SPM) are a precursor for nanomanufacturing. It is still a challenging task to accomplish nanomanipulation automatically. In ambient conditions without stringent environmental controls, the task of nanomanipulation requires extensive human intervention to compensate for the spatial uncertainties of the SPM. Among these uncertainties, the thermal drift, which affects spatial resolution, is especially hard to solve because it tends to increase with time, and cannot be compensated simultaneously by feedback from the instrument. In this paper, a novel automatic compensation scheme is introduced to measure and estimate the drift one-step ahead. The scheme can be subsequently utilized to compensate for the thermal drift so that a real-time controller for nanomanipulation can be designed, as if the drift did not exist. Experimental results show that the proposed compensation scheme can predict drift with a small error, and therefore, can be embedded in the controller for manipulation tasks. [ABSTRACT FROM PUBLISHER]

The main problem of atomic force microscopy (AFM)-based nanomanipulation is the lack of real-time visual feedback. Although this problem has been partially solved by virtual reality technology, the faulty display caused by random drift and modeling errors in the virtual reality interface are still limiting the efficiency of the AFM-based nanomanipulation. Random drift aroused from an uncontrolled manipulation environment generates a position error between the manipulation coordinate and the true environment. Modeling errors due to the uncertainties of the nanoenvironment often result in displaying a wrong position of the object. Since there is no feedback to check the validity of the display, the faulty display cannot be detected in real time and leads to a failed manipulation. In this paper, a real-time fault detection and correction (RFDC) method is proposed to solve these problems by using the AFM tip as an end effector as well as a force sensor during manipulation. Based on the interaction force measured from the AFM tip, the validity of the visual feedback is monitored in real time by the developed Kalman filter. Once the faulty display is detected, it can be corrected online through a quick local scan without interrupting manipulation. In this way, the visual feedback keeps consistent with the true environment changes during manipulation, which makes it possible for several operations to finish without an image scan in between. The theoretical study and the implementation of the RFDC method are elaborated. Experiments of manipulating nanomaterials including nanoparticles and nanorods have been carried out to demonstrate its effectiveness and efficiency. [ABSTRACT FROM PUBLISHER]

Nanomanipulation using the atomic force microscope (AFM) has been extensively investigated for many years. But the efficiency and accuracy of AFM-based nanomanipulation are still major issues due to the nonlinearities and uncertainties in nanomanipulation operations. The deformation of the cantilever caused by manipulation force is one of the most major nonlinearities and uncertainties. It causes difficulties in accurately controlling the tip position, and results in missing the position of the object. The softness of the conventional cantilevers also causes the failure of manipulation of sticky nano-objects because the tip can easily slip over the nano-objects. In this paper, an active atomic force microscopy probe is used as an adaptable end effector to solve these problems by actively controlling the cantilever's flexibility or rigidity during nanomanipulation. A control voltage is applied to the piezo layer of the adaptable end effector to exert a reverse bending moment on the cantilever to balance the bending moment caused by the interaction force during manipulation. Thus, the adaptable end effector is controlled to maintain straight shape during manipulation. A detailed model of the adaptable end effector is presented in the paper. Control of the adaptable end effector employing an optimal LQR control law is derived and implemented. The experimental results verify the validity of the model and effectiveness of the controller. The nanomanipulation results also prove the increased efficiency of AFM-based nanomanipulation using the adaptable end effector [ABSTRACT FROM PUBLISHER]

This paper addresses nanoscale path planning and motion control, which is essential in nanomanufacturing applications such as microstereolithography (muSTL), dip-pen-nanolithography (DPN), and scanning applications for imaging and manipulation of nanoscale surface phenomena, with the magnetic levitation (maglev) technology. We identified the motion trajectories commonly used in industrial applications along with the challenges in optimal path planning to meet the nanoscale motion-control objectives and achieve precise positioning and maximum throughput simultaneously. The key control parameters in path planning are determined, and control design methodologies, including a well-damped lead-lag controller and an optimal linear quadratic regulator are proposed to satisfy the positioning requirements. The proposed methodologies were implemented individually and collectively. The experimental results are presented in this paper to illustrate their effectiveness in planning optimal trajectories. The damped lead-lag controller exhibited the command overshoot values of as small as 0.37%, and the multivariable LQ controller reduced the dynamic coupling among the axes by 97.1% as compared with the decoupled single-input-single-output (SISO) lead-lag controllers. The position resolution of 5 nm was achieved in x and y with the errors in command tracking as small as 4.5 nm. The maglev stage demonstrated excellent performances for the chosen nanomanufacturing applications in terms of position resolution and accuracy, and speed [ABSTRACT FROM PUBLISHER]

The article focuses on the advantages of virtual reality, which is a powerful technology for solving today's real-world problems. It allows the scientist to gain a deeper understanding of the micro-nanoworld by allowing immersive visualization in three dimensions. It enables a scientist to use personal intuition to steer a simulation towards more favorable or realistic results. However, some problems still occur including time delay or the lag between a user action in the real world.

This paper proposes a nanorobotic fiber fabrication method which uses proximal probes to draw polymer fibers down to few hundred nanometers in diameter and several hundred micrometers in length. Using proximal probes such as Atomic Force Microscope (AFM) and Scanning Tunneling Microscope (STM) or glass micropipettes, liquid polymers dissolved in a solvent are drawn. During drawing, the solvent evaporates in real-time which solidifies the fiber. Controlling the drawn fibers trajectory and solidification in three-dimensions (3-D), suspended fibers, fiber cantilevers, custom 3-D fibers, and fiber networks, are proposed to be fabricated. Poly(methyl methacrylate) (PMMA) polymer dissolved in chlorobenzene is used to form a variety of suspended polymer fibers with diameters from few microns to 200nm. Fabrication of crossed and linear networks of fibers is also demonstrated. Viscoelastic modeling of polymer fiber drawing is realized using a finite element method to test the significance of the drawing speed and velocity profile on the extensional behavior of the drawn fiber. Since the mechanical properties of the drawn micro/nanofibers could vary from the bulk polymer material significantly, mechanical characterization of suspended fibers using an AFM and a Nanoindenter setup is proposed. Extending this technique to a variety of nonconductive and electroactive polymer fibers, many novel applications in micro/nanoscale sensors, actuators, fibrillar structures, and optical and electronic devices would become possible [ABSTRACT FROM PUBLISHER]

A new 2-degrees of freedom compliant parallel micromanipulator (CPM) utilizing flexure joints is proposed for two-dimensional nanomanipulation in this paper. By a proper selection of actuators, flexure hinges, and materials, this system is constructed and analyzed by a pseudorigid-body model, architectural optimization, and finite-element analysis. Both the position and velocity kinematic modelings are established, and afterwards, statics analysis is performed. In view of the physical constraints imposed by pizeo-actuators and flexure hinges, the CPM's workspace area is determined. And in order to achieve a maximum workspace subjected to the given dexterity indices, kinematic optimization of the design parameters is carried out, which results in a manipulator satisfying the operational requirements. Furthermore, the finite-element analysis has been undertaken to validate the analytical modeling, and the influence of architectural parameters on CPM performance has been evaluated as well. [ABSTRACT FROM AUTHOR]

Nanoassembly using atomic force microscopy (AFM) is a promising technique for nanomanufacturing. Most AFM-based nanoassembly schemes are implemented either manually using haptic devices or in an interactive way between the users and the atomic force microscope images. These schemes are time consuming and inefficient. Therefore, the computer-aided design (CAD)-guided automated nanoassembly using AFM is desirable for nanomanufacturing. In this paper, a general framework for CAD-guided automated nanoassembly using AFM is developed. Based on the CAD model of a nanostructure, the manipulation paths for both nanoparticles and nanorods are generated automatically. A local scanning method is developed to compensate for the random drift that may cause the failure of the nanoassembly. The experimental results demonstrate that the developed general framework can be employed to manufacture nanostructures efficiently. The research work opens a door to the CAD-guided automated nanomanufacturing using AFM. [ABSTRACT FROM AUTHOR]

Manipulation of nanoparticles with atomic force microscopes (AFMs) has been under development for a decade and is now well established as a technique for prototyping nanodevices and for other applications. Until now, the manipulation process for particles with sizes of a few nanometers has been very labor intensive. This severely limits the complexity of the structures that can be built. Particle sizes on the order of 10 nm are comparable to the spatial uncertainties associated with AFM operation, and a user in the loop has been needed to compensate for these uncertainties. This paper addresses thermal drift, which is the major cause of errors for AFMs operating in ambient conditions. It is shown that drift can be estimated efficiently by using Kalman filtering techniques. This approach has firm theoretical foundations and is validated by the experimental results presented in this paper. Manipulation of groups of 15-nm particles is demonstrated under program control, without human intervention over a long period of time, in ambient air and at room temperature. Coupled with existing methods for high-level motion planning, the manipulation capabilities introduced here will permit assembling, from the bottom up, nanostructures that are more complex than those being built today with AFMs. [ABSTRACT FROM AUTHOR]

A real-time augmented reality (AR) user interface for nanoscale interaction and manipulation applications using an atomic force microscope (AFM) is presented. Nanoscale three-dimensional (3-D) topography and force information sensed by an AFM probe are fed back to a user through a simulated AR system. The sample surface is modeled with a B-spline-based geometry model, upon which a collision detection algorithm determines whether and how the spherical AFM tip penetrates the surface. Based on these results, the induced surface deformations are simulated using continuum micro/nanoforce and Maugis-Dugdale elastic contact mechanics models, and 3-D decoupled force feedback information is obtained in real time. The simulated information is then blended in real time with the force measurements of the AFM in an AR human machine interface, comprising a computer graphics environment and a haptic interface. Accuracy, usability, and reliability of the proposed AR user interface is tested by experiments for three tasks: positioning the AFM probe tip close to a surface, just in contact with a surface, or below a surface by elastically indenting. Results of these tests showed the performance of the proposed user interface. This user interface would be critical for many nanorobotic applications in biotechnology, nanodevice prototyping, and nanotechnology education [ABSTRACT FROM PUBLISHER]

The main problem in nanomanipulation and nanoassembly using atomic force microscopy (AFM) is its lack of real-time visual feedback during manipulation. Fortunately, this problem has been solved by our recently developed augmented reality system, which includes real-time force feedback and real-time "videolized" visual feedback. Through the augmented reality interface, the operator can monitor real-time changes of the nanoenvironment during nanomanipulation through a movie-like AFM image. In this paper, the behavior of some nanowires under pushing is theoretically analyzed and the interaction among the tip, substrate, and nanowires has been modeled. Based on these models, the real-time interactive forces can be used to locally update the AFM image in order to obtain movie-like visual feedback in video frame rate. This augmented reality enhanced system capable of manipulation of nanoparticles and nanowires helps the operator to perform several operations without the need of a new image scan. AFM-based nanoassembly becomes feasible through this newly developed system. [ABSTRACT FROM PUBLISHER]

Nanorobotics encompasses the design, fabrication, and programming of robots with overall dimensions below a few micrometers, and the programmable assembly of nanoscale objects. Nanorobots are quintessential nanoelectromechanical systems (NEMS) and raise all the important issues that must be addressed in NEMS design: sensing, actuation, control, communications, power, and interfacing across spatial scales and between the organic/inorganic and biotic/abiotic realms. Nanorobots are expected to have revolutionary applications in such areas as environmental monitoring and health care. This paper begins by discussing nanorobot construction, which is still at an embryonic stage. The emphasis is on nanomachines, an area which has seen a spate of rapid progress over the last few years. Nanoactuators will be essential components of future NEMS. The paper's focus then changes to nanoassembly by manipulation with scanning probe microscopes (SPMs), which is a relatively well established process for prototyping nanosystems. Prototyping of nanodevices and systems is important for design validation, parameter optimization and sensitivity studies. Nanomanipulation also has applications in repair and modification of nanostructures built by other means. High-throughput SPM manipulation may be achieved by using multitip arrays. Experimental results are presented which show that interactive SPM manipulation can be used to accurately and reliably position molecular-sized components. These can then be linked by chemical or physical means to form subassemblies, which in turn can be further manipulated. Applications in building wires, single-electron transistors, and nanowaveguides are presented. [ABSTRACT FROM AUTHOR]

In this paper, a teleoperated nanoscale touching system is proposed, and continuum nanoscale contact mechanics models are introduced. The tele-nanorobotic system consists of a piezoresistive nanoprobe with a sharp tip as the nanorobot and force-topology sensor, a custom-made 1-degree-of-freedom haptic device for force-feedback, three-dimensional (3D) virtual reality (VR) graphics display of the nano world for visual feedback, and a force-reflecting servo type scaled teleoperation controller. Using this system, one-dimensional and 3D touching experiments and VR simulations are realized. Scaling of nano-forces is one of the major issues of the scaled teleoperation system since nanometer scale forces are dominated by surface forces instead of inertial forces as in the macro world. As the force scaling approach, a heuristic rule is introduced where nano-forces are linearly scaled with an experimentally determined scaling parameter. Simulation results and preliminary experiments of touching silicon and InAs quantum dot nanostructures show that adhesion forces at the nanoscale can be felt repeatedly at the operator's hand, and the proposed system enables the nanoscale surface topography and contact/noncontact nano-force feedback. [ABSTRACT FROM PUBLISHER]

When a gold colloidal suspension is subjected to ac electric field, “gold pearl chains” will form due to the dielectrophoretic (DEP) force. Our latest experiments show that the formation rate of gold pearl chains, which tends to zero at high and low frequency limits and has a maximum at a narrow mid range of frequency, is dependent on the applied field frequency. This letter analyzes the frequency-dependent DEP manipulation of gold colloid suspensions using the protoplast model. Simulated results show that the relationship curve between the frequency of applied field and the velocity of gold colloids motion due to DEP agrees with our experimental observations. In addition, the orders of magnitude of the velocity due to various effects in our experimental system, such as DEP force, Brownian motion, gravity, and fluid flows induced by electric field, were also estimated. The result implies that the DEP-based manipulation of less than 2 nm gold colloids is extremely difficult to be controlled. [ABSTRACT FROM PUBLISHER]

Nanoscale manipulation is a basic ability needed to realize many of the nanotechnology applications. We demonstrate an ion bean molding technique to shape the configuration of nanostructures. As an example, the native curvature of a carbon nanotube in an atomic force microscope tip and its undesirable angle with respect to the surface are removed by this technique to render the nanotube straight. The straightened nanotube is effectively used in a semiconductor profilometry application. The ion beam molding technique is also shown to be effective in creating a desirable net shape of nanotubes. As mechanical deformation determines electrical and other properties of nanotubes, such manipulation may be of use in nanodevice fabrication. [ABSTRACT FROM PUBLISHER]