CAREER: Enabling Methods for Micro-Cantilever Based Nanotechnology

University Of Illinois At Urbana-Champaign, Urbana IL

Investigators

Abstract

Nanotechnology is set to revolutionize the human condition through fundamental contribution to science and technology. The ability to control and manipulate matter at atomic scales wields an immense potential - especially in areas of biology, material science and physics. Its impact is already evident from the remarkable feats achieved in the last two decades towards the goals of probing and manipulating matter at atomic scales. The potential of this technology is evident from its proposed use in quantum computing, quantum information, drug discovery and tailoring material with atomic scale specificity. Micro-cantilever based principles, (Atomic Force Microscopy for example) form the main methods by which matter is investigated and manipulated at the nanoscale. Devices based on these principles were the first to demonstrate the feasibility of routine interrogation, control and manipulation of matter at atomic scales. Even though impressive science has resulted with their use significant challenges need to be met to tap their full potential. This proposal is geared towards harnessing this potential thereby enabling the nanotechnology promise to be realized. Under the proposal's goals the PI will exploit a fundamental idea that complex dynamics often manifest themselves as an abrupt change in the qualitative behavior of the dynamics that can be employed to provide unparalleled resolution in detection of changes in the environment. Theoretical and experimental tools to understand the complex dynamics and the parameters that control and trigger the abrupt change will be developed. These parameters will be associated with the property being detected. It is evident that robust broadband nanopositioning is a necessity to realize the goal of interrogating and manipulating matter at the nanoscale. Present methods predominantly employ ad-hoc methods that result in large deficits in achievable bandwidth as they fail to address the multi-objective concerns of nonlinear behavior of piezoelectric actuators, coupling effects, the effects of positioner dynamics on imaging and the uncertain and diverse environment. The PI will develop a paradigm for robust broadband nanopositioning with emphasis on nano imaging. This paradigm will be utilized in realizing a new state of the art atomic force microscope. The microcantilever force sensor provides for a unique specificity with which bio-affinity between various molecules can be unravelled. Based on this feature there are various combinatorial strategies that utilize microcantilevers for drug discovery. Several of the associated objectives fall under the rubric of resource allocation problems. These optimization problems are non-convex and computationally complex. The PI will develop a unique and attractive theoretical direction for combinatorial resource allocation problems that several groups in the control community are addressing. The algorithms will be based on the central concepts of the deterministic annealing method used by the data compression community. There will be an emphasis on obtaining global optima in the presence of algebraic and dynamic constraints on the resources. Related metrics will be researched for the drug discovery problem in collaboration with a molecular biologist. Data in many microcantilever based strategies are stored in predetermined patterns. For example, the nanoarrays store bio-assays in arrays of cells that are well characterized and in IBM's data storage devices data is stored in the form of bits arranged in a prespecified pattern. During the retrieval of the data the micro-cantilever tip geometry convolves with the data and has the potential to significantly lower the spatial resolution. The PI will develop methods for image restoration using unique methods that he has pioneered that exploit the pattern in the way the data is stored. Such a problem transcends AFM applications and the PI will focus on developing a general framework and specialize it to the AFM applications. Broader Impacts: This proposal brings together researchers from the traditional areas of engineering, mathematics, physics and biology. It is at the confluence of dynamic systems and control theory, control applications, numerical analysis and optimization theory. All of the proposed goals are geared towards nanotechnology - the successful completion of the proposed project will give a good theoretical understanding of the devices and translate into huge technological and economic gains. The experimental aspects of the proposed research will be accomplished in collaboration with Asylum Research, Bioforce Nanosciences Inc. and IBM Research Lab, Zurich. This provides an opportunity for the labs involved to learn the tools and methods of different areas and for outreach to the industry. The graduate students involved will be trained in a unique interdisciplinary manner that exposes them to the diverse set of expertise mentioned. They will be trained both in the theoretical and experimental aspects as is warranted by the proposal needs. 1