Mini-Microsystems Seminar Series
The objective of this seminar series, organized by graduate students in the MicroSystems Initiative, is to encourage interactions and collaborations among microsystems researchers. Graduate students and postdocs will give short talks (15-20 min.) focusing on fabrication and characterization (rather than results). The combined range of micromachining expertise in the audience (including faculty members) will allow constructive suggestions on approaches and methods, and the audience will gain valuable know-how.
Seminars consist of two presentations followed by discussion. Talks are informal and cover all aspects of microsystems: sensors, actuators, microfluidics, integrated systems, etc.
The seminar series is sponsored by the Institute for Systems Research (ISR). Seminars for Fall 2015 are held every month, typically on Thursdays at 4:00 p.m. in the ISR conference room, 1146 A.V. Williams. Complimentary cookies and beverages are provided.
For more information or to volunteer to give a talk, please contact Hyun Jung (hjung130201@gmail.com).
Years... 2015
Speakers...
Charalambides |
Jung |
Penskiy |
Restaino |
Sritharan |
Vogtmann |
Wiederoder |
Zang
Events are listed in reverse chronological order.
2015
Fall 2015
Dec 10
Magnetically-Actuated Ultra Compliant MEMS Mechanisms
Dana Vogtmann
Ph.D. Candidate, Mechanical Engineering (Bergbreiter)
[Abstract]
Abstract
This work presents highly flexible elastomer and silicon micro mechanisms actuated using embedded permanent magnets manipulated by an external magnetic field. The mechanisms are fabricated using a process to incorporate elastomer hinges and other features into silicon MEMS, and a method for embedding small magnets via press-fit into an elastomer sleeve. Fabricated mechanisms have demonstrated in-plane bending, out of plane bending, and underactuated compliant gripping. In-plane bending mechanisms have achieved up to 150◦ of deflection, out of plane bending mechanisms have achieved up to 90◦ bending perpendicular to the surface of the chip, and the 4.4 mm x 3.8 mm x 0.3 mm gripper can passively grip objects up to 1.5 mm in size and as small as 0.5 mm. The mechanisms demonstrated can ultimately be used as actuated portions of larger mechanisms, for out-of-plane assembly, or for on-chip manipulation.
An in situ operando MEMS platform for characterization of Li-ion battery electrodes
Hyun Jung
Ph.D. Candidate, Electrical Engineering (Ghodssi)
[Abstract]
Abstract
This work presents an in situ operando approach that allows characterization of lithium-ion battery electrodes. A MEMS sensor is designed and integrated with a commercially available Raman spectroscope to enable monitoring the stress and structural changes in the electrodes. An interferometric method with an enhanced image processing algorithm is applied for analyzing the crystal phase-dependent stress changes while the structural changes are monitored using Raman spectroscopy. New capabilities of our platform are highlighted, allowing visual observation of crystal phase-dependent structural changes in the electrode. Simultaneous characterization of the stress and structural changes are achieved concurrently in situ operando. The results show excellent agreement with previous literature reports on both phenomena.
Nov 12
Towards High Force MEMS Actuators for Millirobotics Applications
Ivan Penskiy
Ph.D. Candidate, Mechanical Engineering (Bergbreiter)
[Abstract]
Abstract
MEMS technologies offer vast range of possibilities for manufacturing microscale devices. Yet, its capabilities are commonly used only in the sensor applications. Despite a lot of effort and research, MEMS actuators and actuated mechanisms are mostly limited to academia and have not found the same commercial success.
In this talk I will discuss our take on developing a high force (tens of mN) electrostatic motor for the millirobotics applications. The motor utilizes gap-closing actuation to produce the force, and the large displacements are achieved by implementing the inchworm driving principle. The first generation of the motors was manufactured in a single mask SOI process and demonstrated a maximum speed of 4.8 mm/s and a maximum force of 1.88 mN at 110 V. The second motor generation takes advantage of “zipping” actuation which promises to increase the driving force up to an order of magnitude according to analytical estimations.
Microfluidic Optical Sensor Enhancement using Refractive Index Matching Fluids
Michael Wiederoder
Ph.D. Candidate, BioEngineering (DeVoe)
[Abstract]
Abstract
Microfluidic flow-through assays with porous volumetric capture elements are advantageous compared to conventional planar sensor surfaces because the decreased diffusion lengths and higher reaction site density can reduce detection limits and total assay time. Unfortunately for optically based assays, light scattering caused by refractive index mismatch between the solid substrate and fluid within its pores presents an inherent limitation that significantly reduces signal. In this study an index matching solution was infused through porous polymer based monoliths within a glass capillary and silica-based volumetric capture elements within thermoplastic microchannels to enhance optical signal of fluorescence and absorbance based immunoassays. For the fluorescence based direct assay FITC tagged IgG was captured on a polymer monolith within a glass capillary before index matching with the monolith precursor solution. For the absorbance based direct and sandwich immunoassays gold nanoparticle immunoconjugates specific to the target antigen were captured and silver enhanced to achieve a concentration dependent color change before introduction of an aqueous sucrose solution with a refractive index similar to silica. The simple technique enabled an improved detection limit and greater dynamic range than similar thermoplastic, planar based assays. The demonstrated techniques are applicable to low-cost, disposable, optically based point of care diagnostic devices to improve detection limits and reduce total assay times.
Oct 15
Inkjet-fabricated SERS sensors on paper for biosensing
Stephen M Restaino
Ph.D. Candidate, Bioengineering (White)
[Abstract]
Abstract
As a bio/chemical sensing technique, surface enhanced Raman spectroscopy (SERS) offers sensitivity comparable to that of fluorescence detection while providing highly specific information about the analyte. Although single molecule identification with SERS was demonstrated nearly 20 years ago, today a need exists to develop practical solutions for point-of-sample and point-of-care SERS systems. Recently, we demonstrated the fabrication of SERS substrates by inkjet printing silver and gold nanostructures onto paper and other microporous membranes. Using these devices, we have been able to achieve detection limits comparable to conventional nanofabricated plasmonic substrates. Furthermore, we leverage the fluidic properties of paper to enhance the performance of the SERS devices while also enabling unprecedented ease of use. In this talk, I will discuss use of inkjet-fabricated paper SERS substrates as a detection device for biological macromolecules in an easy‐to‐use format with a low number of steps. The targeted biomarker is specifically detected with SERS through a single step competitive displacement, which dramatically reduces the number of steps as compared to conventional assays. Moreover, we further improve the usability of the assay by incorporating a paper SERS device with a fluidic cartridge format. The wicking nature of the paper sensor eliminates manual sample application steps and is much simpler than the world-to-chip interface of microfluidic devices. The introduction of this paper‐based SERS assay is a significant step towards highly sensitive, low-cost, and, importantly, easy to use multiplexed biological assays.
Microfabricated Elastomer Tactile Sensors for Robotic Fingertip Systems
Alexi Charalambides
Ph.D. Candidate, Mechanical Engineering (Bergbreiter)
[Abstract]
Abstract
The design and implementation of tactile sensors on robots has been a topic of research over the past 30 years, and current challenges include mechanically flexible sensing skins, high dynamic range sensing (i.e.: high force range and force resolution), multi-axis sensing, high sensor area density, and integration between the sensors and robot. This talk focuses on addressing some of these challenges through a microfabrication process that incorporates conductive and dielectric elastomers in a re-usable mold, and novel sensor designs for multi-axis sensing that improve force range without sacrificing resolution. The proposed work involves the integration onto a robot system for detection of incipient slip and force localization.
Sept 24
Capillary microfluidics for controlled and accelerated biosensing probe assembly on-chip
Faheng Zang
Ph.D. Candidate, Electrical and Computer Engineering Department (Ghodssi)
[Abstract]
Abstract
An autonomous integrated microsystem comprising capillary microfluidics and impedimetricsensors was developed for rapid transducer functionalization and antibody sensing. Using open-channel microfluidics,Tobacco mosaicvirus-like particles (VLPs) are autonomously delivered on the impedance sensor, forming a dense functional bioreceptorlayer due to enhanced surface evaporation-assisted assembly. The label-free antibody detection after the 15-minute sensor functionalization highlights the potential of the integrated system for rapid biosensing.
Electroosmotic Soft Actuators
Deepa Sritharan
Ph.D. Candidate, Mechanical Engineering (Smela)
[Abstract]
Abstract
My research is on the development of microfluidic soft actuators. Electroosmotic fluid flow occurs upon applying an electric field, which is used to inflate a membrane. We envision applications of these actuators for biomedical flow control and for creating modular smart structures. We have developed a novel fabrication process that can be scaled up and adapted to fabricate many actuators in parallel.