Tim Wortmann

NanoLab: A nanorobotic system for automated pick-and-place handling and characterization of CNTs

Carbon nanotubes (CNTs) are one of the most promising materials for nanoelectronic applications. Before bringing CNTs into large-scale production, a reliable nanorobotic system for automated handling and characterization as well as prototyping of CNT-based components is essential. This paper presents the NanoLab setup, a nanorobotic system that combines specially developed key components such as electrothermal microgrippers and mobile microrobots inside a scanning electron microscope. The working principle and fabrication of mobile microrobots and electrothermal microgripper as well as their interaction and integration is described. Furthermore, the NanoLab is used to explore novel key strategies such as automated locating of CNTs for pick-and-place handling and methods for electrical characterization of CNTs. The results have been achieved within the framework of a European research project where the scientific knowledge will be transfered into an industrial system that will be commercially available for potential customers.

Combined nanorobotic AFM/SEM system as novel toolbox for automated hybrid analysis and manipulation of nanoscale objects

In this paper, the concept and first results of a novel toolbox for nanoscale characterization are presented. A nanorobotic AFM system is being developed and integrated into a high resolution SEM/FIB system allowing nanoanalysis, -manipulation and -structuring. The compact and modular AFM setup enables probe- as well as sample-scanning and uses self-sensing AFM cantilevers. Image fusion algorithms are developed to merge SEM and AFM information for hybrid analysis of nanoscale objects. A commercial AFM controller is embedded into a special control system architecture that allows for automation of nanomanipulation sequences.

MRI magnetic signature imaging, tracking and navigation for targeted micro/nano-capsule therapeutics

The propulsion of nano-ferromagnetic objects by means of MRI gradients is a promising approach to enable new forms of therapy. In this work, necessary techniques are presented to make this approach work. This includes path planning algorithms working on MRI data, ferromagnetic artifact imaging and a tracking algorithm which delivers position feedback for the microdevice and a propulsion sequence to enable interleaved magnetic propulsion and imaging. Using a dedicated software environment integrating path-planning methods and real-time tracking, a clinical MRI system is adapted to provide this new functionality for potential controlled interventional targeted therapeutic applications. Through MRI-based sensing analysis, this paper aims to propose a framework to plan a robust pathway to enhance the navigation ability to reach deep locations in human body. The proposed approaches are validated with different experiments.

VISUAL FEEDBACK METHODS FOR NANOHANDLING AUTOMATION

This paper presents different image processing methods and algorithms, which are needed to enable the reliable automation of nanohandling processes. These applications use the scanning electron microscope (SEM) as a visual sensor. SEMs are widespread and powerful tools for manipulations on the nanoscale. Due to the timing constraints in automated setups, the trade-off between SEM scanning speed and image quality is a concern for algorithm development. Tasks to be fulfilled on image data provided by the SEM include object recognition, object tracking and depth estimation. A selection of algorithms that have been applied in automated setups for nanomanipulation is discussed and validated.

Recognition and tracking of magnetic nanobots using MRI

By switching the gradient fields of a clinical magnetic resonance imaging (MRI) scanner, magnetic objects may be moved inside the cardiovascular system of the human body. The main field of application is seen in targeted drug therapy or embolization. A successful navigation of such devices requires continuous position determination. The occurrence of magnetic susceptibility artifacts can be exploited for this purpose. This article studies the effect of magnetic microscopic objects and nanoparticles on the process of MRI image formation in several imaging sequences. An MRI simulator based on evaluation of the Bloch equation is presented and applied for the simulation of artifact formation. Also, artifact properties are studied by experiments carried out on clinical MRI scanners, using magnetic objects placed into an agarose gel phantom. The transferability of the results from the gel phantom to a real tissue environment is proven. Based on the results, a two-stage procedure for visual servoing is proposed. It is initialized by object detection, carried out in a 3D scan. Object tracking is performed on fast 2D scans by template matching. The slice position is adjusted automatically in a feedback loop in order to follow object movements perpendicular to the image plane.

Fusion of AFM and SEM scans

Atomic Force Microscopy (AFM) and Scanning Electron Microscopy (SEM) are commonly used technologies for high resolution surface investigations. Combined AFM and SEM studies provide a thorough view of specimen topography and material properties, due to a large number of sophisticated imaging techniques. This work aims at providing a more meaningful representation of results from combined examinations, by applying methods of image fusion and visualization. Multiple application scenarios are discussed. According to the specification of requirements, three imaging procedures are presented in detail and applied to scans from a combined AFM and SEM study.

Vision feedback for automated nanohandling

The handling of nanoscale objects is a field with high prospects and good perspectives. This paper presents different necessary image processing methods and algorithms, which are needed to enable the reliable automation of nanohandling processes. The imaging sensor used to gain access to the nanoscale world is the scanning electron microscope (SEM). Tasks to be fulfilled on image data from the SEM include object recognition, object tracking and depth estimation. All these algorithms are discussed and validated.

Actuation and Tracking of Ferromagnetic Objects Using MRI

The MRI is a common medical imaging modality with powerful properties for diagnostic imaging. In order to enable robotic approaches for medical therapies like targeted drug delivery and others, the MRI systems suitability for actuation has been evaluated and exploited recently. The technologies used for imaging like coils, etc., can also be used to exert forces on ferromagnetic objects. In this article, a tracking algorithm for the three-dimensional tracking of ferromagnetic objects inside the MRI is presented. It only relies on the acquisition of single slices, which intersect the generated artifact volume. Additionally, some factors influencing the imaging and tracking are discussed, as well as the generated force measured and compared to theoretical values.

Automatic stitching of micrographs using local features

Combination of single images to panoramic views is a popular application of image stitching in digital photography. By applying the same principle to micrographs, a number of common limitations of microscopes such as aberrations or limited depth of field may be overcome. This paper adapts recent methods of image registration for different application areas in light- and electron microscopy. Especially the suitability of SIFT and SURF features for micrograph correspondence analysis is in the focus of investigations. Test scenarios covering a wide range of magnifications and image contents are discussed. Additionally, the acquisition of the single scans and finally the complete generation of high-resolution panoramic micrographs may be automated. The proposed system is not only suitable as a tool for surface inspections, but also as a navigational aid for micro-and nanorobotic applications.

Magnetic Resonance Imaging of Magnetic Particles for Targeted Drug Delivery

Recently there have been initial investigations towards magnetic resonance imaging (MRI) guided actuation and control of untethered devices inside the human cardiovascular system. This form of therapy has the potential to revolutionize today’s treatment of cancer and other diseases by providing an accuracy of targeted drug application far beyond conventional approaches. Additionally it is based on standard MRI hardware and does not require any special or tailored hardware. In this article, we present recent work that is focused on visual feedback for the position control of untethered magnetic devices in the MRI. For reliable recognition and tracking, a thorough understanding of the impact of magnetic material on the process of MRI image acquisition is required. A simulation of the image formation process has been implemented. Additionally, initial experimental results of MRI artifact imaging are presented.Copyright