Eniko T Enikov

Eniko T Enikov

Professor, Aerospace-Mechanical Engineering
Associate Professor, BIO5 Institute
Department Affiliations
Contact
(520) 621-4506

Work Summary

Dr. Enikov's area of expertise is the design of micro-actuators, MEMS devices, and sensors. Ongoing projects include the production of Inflatable Drug-Delivery Stents through the process of Dynamic Stabilization of Electro-Spinning. The research will examine theoretically the feasibility of trapping charged fibers and will establish the required trapping parameters.

Research Interest

Dr. Enikov's area of expertise is the design of micro-actuators, MEMS devices, and sensors. After completion of his training, he established the Advanced Micro- and Nanosystems Laboratory at the University of Arizona, where they have carried out numerous research projects involving precision assembly of micro-systems under optical feedback, development of wet actuators using ion-exchange polymers, pressure sensors, and accelerometers. In the last 8-years, his research has applied micro-technology to the development of medical devices. More specifically, they have developed a through-the-eye lid tactile tonometer capable of estimating intraocular pressure using an array of MEMS sensors. A second invention pertains to the development of an implantable ventricular peritoneal shunt with flow sensing capabilities. The present project represents a major focus of his laboratory. They have completed several early-stage studies on tactile tonometery supporting the present application. Given Dr. Enikov's technical background and prior effort in the area of tactile tonometery, he believes he is uniquely qualified to lead the proposed effort.

Publications

Palaria, A., & Enikov, E. T. (2006). Experimental analysis of the stability of electrostatic bits for assisted nano-assembly. Journal of Electrostatics, 64(1), 1-9.

Abstract:

Scanning probe microscopy(SPM)-based nanolithography with injected charges into layered electrets, such as silicon dioxide (SiO2) and silicon nitride, is a promising tool with far-reaching applications, such as controlled nano-assembly of macro-molecules and data storage. Despite its potential, some practical limitations exist. This paper describes an experimental investigation of the process of charging and charge dissipation in SiO2 using an AFM probe tip and surface potential (Kelvin probe) microscopy. The stability of charge bits on hexamethyl disilazane(HMDS)-treated SiO2 under low dielectric constant liquids, fluorocarbon, and benzene has been demonstrated. Results from a numerical simulation of a theoretical charging model, in which the charge traps are assumed to be localized on the silicon/SiO2 interface, are also presented. The charge transport mechanism considered is modified Fowler-Nordheim tunneling. © 2005 Elsevier B.V. All rights reserved.

Enikov, E. T., Gibson, M. T., & Ritty, S. J. (2009). Novel extrusion system for the encapsulation of drug releasing bio-medical micro-robots. 2009 ICME International Conference on Complex Medical Engineering, CME 2009.

Abstract:

This paper examines the design and testing of a novel extrusion system for the biocompatible coating of drug delivering micro-robots. The encapsulation system creates monodisperse droplets of sodium alginate containing the micro-robots within a coaxial laminar flow of a continuous oil phase. The extrusion process allows the experimenter to control the size of the drug carrying droplets which have been subsequently tested as vehicles to deliver a model drug (Horseradish peroxidase). Comparison with other coating techniques such as dip-coating shows significant increase in the drug storing capacity. A demonstration of the use of ultrasound as a possible trigger of the drug release has also been presented. The significant increase in the observed drug release rate shows enhancement over previously tested passive diffusion and magnetic modulation methods. Together, these two aspects of micro-robotic drug delivery concept introduce a new approach to drug-delivering microrobots with large drug-storage capacity, ability to propel the robots using magnetic forces, and trigger the drugrelease by remote application of ultrasonic stimulation. ©2009 IEEE.

Enikov, E. T., Kedar, S. S., & Lazarov, K. V. (2005). Analytical model for analysis and design of V-shaped thermal microactuators. Journal of Microelectromechanical Systems, 14(4), 788-798.

Abstract:

An analytical solution of the thermoelastic bending/budding problem of thermal microactuators is presented. V-shaped beam actuators are modeled using the theory of beam-column buckling. Axial (longitudinal) deformations including first-order nonlinear strain-displacement relations and thermal strains are included. The resulting nonlinear transcendental equations for the reaction forces are solved numerically and the solutions are compared with a nonlinear finite element (FE) model. A test actuator has also been fabricated and characterized. The obtained accuracy of the prediction is within 1.1% of the nonlinear FE solution and agrees well with the experimental data. A corresponding one-dimensional (1-D) heat transfer model has also been developed and validated against experimental i-V measurements at various temperatures. The developed analytical models are then used to analyze maximum stress and the heat transfer paths. It has been confirmed that the heat flux toward the substrate is a dominant heat dissipation route in sacrificially released devices. © 2005 IEEE.

Enikov, E. T., & Seo, G. S. (2006). Numerical analysis of muscle-like ionic polymer actuators. Biotechnology Progress, 22(1), 96-105.

PMID: 16454498;Abstract:

Ionic polymers are a promising material for the development of muscle-like actuators. These materials are capable of undergoing significant deformation when structured as metal-polymer-metal composite sheets. The mechanical characteristics of these sheets, such as flexibility, softness, and ability to undergo large deformation in direct contact with water, have led some to consider these as possible artificial muscles. This paper describes the numerical analysis of an electrochemical model of the deformation of muscle-like polymers. A general continuum model describing the transport and deformation processes of these actuators is briefly presented, along with a detailed description of the simulation scheme used to predict deformation, current, and mass transport. The predictions of the model are compared with experimental data, indicating a significant role of water transport in the large-scale deformation. The model is also used to draw a comparison between the performance of natural muscles and muscle-like polymer actuators. © 2006 American Chemical Society and American Institute of Chemical Engineers.

Enikov, E. T., Clark, S., & Minkov, L. (2003). Micro-assembly cell with dual optical/computer vision control for electrostatic gripping of MEMS. Proceedings of SPIE - The International Society for Optical Engineering, 5267, 269-280.

Abstract:

This paper describes the development of a miniature assembly cell for microsystems. The cell utilizes a transparent electrostatic gripper allowing the use of computer vision for part alignment with respect to the gripper. Part to assembly alignment is achieved via optical triangulation using a fiber-coupled laser and a position sensitive detector (PSD). The system layout, principle of operation and design are described along with the visual and optical control algorithms and their implementation. Experimental measurements of the performance of the stage indicate normal and tangential gripping forces in the range of 0.03-2.5 mN and 1.-9. mN respectively. The visual search algorithm limits the feature tracking speed to 111ms /search. The alignment accuracy of the visual and optical proportional position feedback controls were determined to be ±7 μm and ±10 μm respectively.