1
|
Rabih AAS, Kazemi M, Ménard M, Nabki F. Aluminum Nitride Out-of-Plane Piezoelectric MEMS Actuators. MICROMACHINES 2023; 14:700. [PMID: 36985106 PMCID: PMC10059770 DOI: 10.3390/mi14030700] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/17/2023] [Revised: 03/10/2023] [Accepted: 03/14/2023] [Indexed: 06/18/2023]
Abstract
Integrating microelectromechanical systems (MEMS) actuators with low-loss suspended silicon nitride waveguides enables the precise alignment of these waveguides to other photonic integrated circuits (PICs). This requires both in-plane and out-of-plane actuators to ensure high-precision optical alignment. However, most current out-of-plane electrostatic actuators are bulky, while electrothermal actuators consume high power. Thus, piezoelectric actuators, thanks to their moderate actuation voltages and low power consumption, could be used as alternatives. Furthermore, piezoelectric actuators can provide displacements in two opposite directions. This study presents a novel aluminum nitride-based out-of-plane piezoelectric MEMS actuator equipped with a capacitive sensing mechanism to track its displacement. This actuator could be integrated within PICs to align different chips. Prototypes of the device were tested over the range of ±60 V, where they provided upward and downward displacements, and achieved a total average out-of-plane displacement of 1.30 ± 0.04 μm. Capacitance measurement showed a linear relation with the displacement, where at -60 V, the average change in capacitance was found to be -13.10 ± 0.89 fF, whereas at 60 V the change was 11.09 ± 0.73 fF. This study also investigates the effect of the residual stress caused by the top metal electrode, on the linearity of the displacement-voltage relation. The simulation predicts that the prototype could be modified to accommodate waveguide routing above it without affecting its performance, and it could also incorporate in-plane lateral actuators.
Collapse
|
2
|
Zhou G, Lim ZH, Qi Y, Zhou G. Single-Pixel MEMS Imaging Systems. MICROMACHINES 2020; 11:E219. [PMID: 32093324 PMCID: PMC7074650 DOI: 10.3390/mi11020219] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/31/2020] [Revised: 02/18/2020] [Accepted: 02/19/2020] [Indexed: 11/16/2022]
Abstract
Single-pixel imaging technology is an attractive technology considering the increasing demand of imagers that can operate in wavelengths where traditional cameras have limited efficiency. Meanwhile, the miniaturization of imaging systems is also desired to build affordable and portable devices for field applications. Therefore, single-pixel imaging systems based on microelectromechanical systems (MEMS) is an effective solution to develop truly miniaturized imagers, owing to their ability to integrate multiple functionalities within a small device. MEMS-based single-pixel imaging systems have mainly been explored in two research directions, namely the encoding-based approach and the scanning-based approach. The scanning method utilizes a variety of MEMS scanners to scan the target scenery and has potential applications in the biological imaging field. The encoding-based system typically employs MEMS modulators and a single-pixel detector to encode the light intensities of the scenery, and the images are constructed by harvesting the power of computational technology. This has the capability to capture non-visible images and 3D images. Thus, this review discusses the two approaches in detail, and their applications are also reviewed to evaluate the efficiency and advantages in various fields.
Collapse
Affiliation(s)
- Guangcan Zhou
- Micro and Nano Systems Initiative, Department of Mechanical Engineering, National University of Singapore, Singapore 117575, Singapore; (G.Z.); (Z.H.L.); (Y.Q.)
| | - Zi Heng Lim
- Micro and Nano Systems Initiative, Department of Mechanical Engineering, National University of Singapore, Singapore 117575, Singapore; (G.Z.); (Z.H.L.); (Y.Q.)
| | - Yi Qi
- Micro and Nano Systems Initiative, Department of Mechanical Engineering, National University of Singapore, Singapore 117575, Singapore; (G.Z.); (Z.H.L.); (Y.Q.)
| | - Guangya Zhou
- Micro and Nano Systems Initiative, Department of Mechanical Engineering, National University of Singapore, Singapore 117575, Singapore; (G.Z.); (Z.H.L.); (Y.Q.)
| |
Collapse
|
3
|
2D Au-Coated Resonant MEMS Scanner for NIR Fluorescence Intraoperative Confocal Microscope. MICROMACHINES 2019; 10:mi10050295. [PMID: 31052229 PMCID: PMC6562488 DOI: 10.3390/mi10050295] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/30/2019] [Revised: 04/22/2019] [Accepted: 04/26/2019] [Indexed: 02/06/2023]
Abstract
The electrostatic MEMS scanner plays an important role in the miniaturization of the microscopic imaging system. We have developed a new two-dimensional (2D) parametrically-resonant MEMS scanner with patterned Au coating (>90% reflectivity at an NIR 785-nm wavelength), for a near-infrared (NIR) fluorescence intraoperative confocal microscopic imaging system with a compact form factor. A silicon-on-insulator (SOI)-wafer based dicing-free microfabrication process has been developed for mass-production with high yield. Based on an in-plane comb-drive configuration, the resonant MEMS scanner performs 2D Lissajous pattern scanning with a large mechanical scanning angle (MSA, ±4°) on each axis at low driving voltage (36 V). A large field-of-view (FOV) has been achieved by using a post-objective scanning architecture of the confocal microscope. We have integrated the new MEMS scanner into a custom-made NIR fluorescence intraoperative confocal microscope with an outer diameter of 5.5 mm at its distal-end. Axial scanning has been achieved by using a piezoelectric actuator-based driving mechanism. We have successfully demonstrated ex vivo 2D imaging on human tissue specimens with up to five frames/s. The 2D resonant MEMS scanner can potentially be utilized for many applications, including multiphoton microendoscopy and wide-field endoscopy.
Collapse
|
4
|
MEMS Actuators for Optical Microendoscopy. MICROMACHINES 2019; 10:mi10020085. [PMID: 30682852 PMCID: PMC6412441 DOI: 10.3390/mi10020085] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/28/2018] [Revised: 12/26/2018] [Accepted: 12/28/2018] [Indexed: 01/21/2023]
Abstract
Growing demands for affordable, portable, and reliable optical microendoscopic imaging devices are attracting research institutes and industries to find new manufacturing methods. However, the integration of microscopic components into these subsystems is one of today's challenges in manufacturing and packaging. Together with this kind of miniaturization more and more functional parts have to be accommodated in ever smaller spaces. Therefore, solving this challenge with the use of microelectromechanical systems (MEMS) fabrication technology has opened the promising opportunities in enabling a wide variety of novel optical microendoscopy to be miniaturized. MEMS fabrication technology enables abilities to apply batch fabrication methods with high-precision and to include a wide variety of optical functionalities to the optical components. As a result, MEMS technology has enabled greater accessibility to advance optical microendoscopy technology to provide high-resolution and high-performance imaging matching with traditional table-top microscopy. In this review the latest advancements of MEMS actuators for optical microendoscopy will be discussed in detail.
Collapse
|
5
|
Liu T, Rajadhyaksha M, Dickensheets DL. MEMS-in-the-lens architecture for a miniature high-NA laser scanning microscope. LIGHT, SCIENCE & APPLICATIONS 2019; 8:59. [PMID: 31263558 PMCID: PMC6592906 DOI: 10.1038/s41377-019-0167-5] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/05/2018] [Revised: 05/24/2019] [Accepted: 05/30/2019] [Indexed: 05/16/2023]
Abstract
Laser scanning microscopes can be miniaturized for in vivo imaging by substituting optical microelectromechanical system (MEMS) devices in place of larger components. The emergence of multifunctional active optical devices can support further miniaturization beyond direct component replacement because those active devices enable diffraction-limited performance using simpler optical system designs. In this paper, we propose a catadioptric microscope objective lens that features an integrated MEMS device for performing biaxial scanning, axial focus adjustment, and control of spherical aberration. The MEMS-in-the-lens architecture incorporates a reflective MEMS scanner between a low-numerical-aperture back lens group and an aplanatic hyperhemisphere front refractive element to support high-numerical-aperture imaging. We implemented this new optical system using a recently developed hybrid polymer/silicon MEMS three-dimensional scan mirror that features an annular aperture that allows it to be coaxially aligned within the objective lens without the need for a beam splitter. The optical performance of the active catadioptric system is simulated and imaging of hard targets and human cheek cells is demonstrated with a confocal microscope that is based on the new objective lens design.
Collapse
Affiliation(s)
- Tianbo Liu
- Electrical and Computer Engineering Department, Montana State University, Bozeman, MT 59715 USA
| | - Milind Rajadhyaksha
- Dermatology Department, Memorial Sloan Kettering Cancer Center, New York, NY 10022 USA
| | - David L. Dickensheets
- Electrical and Computer Engineering Department, Montana State University, Bozeman, MT 59715 USA
| |
Collapse
|
6
|
Wei L, Yin C, Liu JTC. Dual-axis confocal microscopy for point-of-care pathology. IEEE JOURNAL OF SELECTED TOPICS IN QUANTUM ELECTRONICS : A PUBLICATION OF THE IEEE LASERS AND ELECTRO-OPTICS SOCIETY 2019; 25:7100910. [PMID: 30872909 PMCID: PMC6411089 DOI: 10.1109/jstqe.2018.2854572] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
Dual-axis confocal (DAC) microscopy is an optical imaging modality that utilizes simple low-numerical aperture (NA) lenses to achieve effective optical sectioning and superior image contrast in biological tissues. The unique architecture of DAC microscopy also provides some advantages for miniaturization, facilitating the development of endoscopic and handheld DAC systems for in vivo imaging. This article reviews the principles of DAC microscopy, including its differences from conventional confocal microscopy, and surveys several variations of DAC microscopy that have been developed and investigated as non-invasive real-time alternatives to conventional biopsy and histopathology.
Collapse
Affiliation(s)
- Linpeng Wei
- Department of Mechanical Engineering, University of Washington, Seattle, WA 98195 USA, JTCL is also with the Department of Pathology at the University of Washington
| | - Chengbo Yin
- Department of Mechanical Engineering, University of Washington, Seattle, WA 98195 USA, JTCL is also with the Department of Pathology at the University of Washington
| | - Jonathan T C Liu
- Department of Mechanical Engineering, University of Washington, Seattle, WA 98195 USA, JTCL is also with the Department of Pathology at the University of Washington
| |
Collapse
|
7
|
Qiu Z, Piyawattanamatha W. New Endoscopic Imaging Technology Based on MEMS Sensors and Actuators. MICROMACHINES 2017; 8:mi8070210. [PMID: 30400401 PMCID: PMC6190023 DOI: 10.3390/mi8070210] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/31/2016] [Revised: 03/09/2017] [Accepted: 03/10/2017] [Indexed: 12/14/2022]
Abstract
Over the last decade, optical fiber-based forms of microscopy and endoscopy have extended the realm of applicability for many imaging modalities. Optical fiber-based imaging modalities permit the use of remote illumination sources and enable flexible forms supporting the creation of portable and hand-held imaging instrumentations to interrogate within hollow tissue cavities. A common challenge in the development of such devices is the design and integration of miniaturized optical and mechanical components. Until recently, microelectromechanical systems (MEMS) sensors and actuators have been playing a key role in shaping the miniaturization of these components. This is due to the precision mechanics of MEMS, microfabrication techniques, and optical functionality enabling a wide variety of movable and tunable mirrors, lenses, filters, and other optical structures. Many promising results from MEMS based optical fiber endoscopy have demonstrated great potentials for clinical translation. In this article, reviews of MEMS sensors and actuators for various fiber-optical endoscopy such as fluorescence, optical coherence tomography, confocal, photo-acoustic, and two-photon imaging modalities will be discussed. This advanced MEMS based optical fiber endoscopy can provide cellular and molecular features with deep tissue penetration enabling guided resections and early cancer assessment to better treatment outcomes.
Collapse
Affiliation(s)
- Zhen Qiu
- Department of Radiology, Stanford University, Stanford, CA 94305, USA.
| | - Wibool Piyawattanamatha
- Departments of Biomedical and Electronics Engineering, King Mongkut's Institute of Technology Ladkrabang, Bangkok 10520, Thailand.
| |
Collapse
|
8
|
Li G, Li H, Duan X, Zhou Q, Zhou J, Oldham KR, Wang TD. Visualizing Epithelial Expression in Vertical and Horizontal Planes With Dual Axes Confocal Endomicroscope Using Compact Distal Scanner. IEEE TRANSACTIONS ON MEDICAL IMAGING 2017; 36:1482-1490. [PMID: 28252391 DOI: 10.1109/tmi.2017.2673022] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
The epithelium is a thin layer of tissue that lines hollow organs, such as colon. Visualizing in vertical cross sections with sub-cellular resolution is essential to understanding early disease mechanisms that progress naturally in the plane perpendicular to the tissue surface. The dual axes confocal architecture collects optical sections in tissue by directing light at an angle incident to the surface using separate illumination and collection beams to reduce effects of scattering, enhance dynamic range, and increase imaging depth. This configuration allows for images to be collected in the vertical as well as horizontal planes. We designed a fast, compact monolithic scanner based on the principle of parametric resonance. The mirrors were fabricated using microelectromechanical systems (MEMS) technology and were coated with aluminum to maximize near-infrared reflectivity. We achieved large axial displacements [Formula: see text] and wide lateral deflections >20°. The MEMS chip has a 3.2×2.9 mm2 form factor that allows for efficient packaging in the distal end of an endomicroscope. Imaging can be performed in either the vertical or horizontal planes with [Formula: see text] depth or 1 ×1 mm2 area, respectively, at 5 frames/s. We systemically administered a Cy5.5-labeled peptide that is specific for EGFR, and collected near-infrared fluorescence images ex vivo from pre-malignant mouse colonic epithelium to reveal the spatial distribution of this molecular target. Here, we demonstrate a novel scanning mechanism in a dual axes confocal endomicroscope that collects optical sections of near-infrared fluorescence in either vertical or horizontal planes to visualize molecular expression in the epithelium.
Collapse
|
9
|
Li H, Duan X, Qiu Z, Zhou Q, Kurabayashi K, Oldham KR, Wang TD. Integrated monolithic 3D MEMS scanner for switchable real time vertical/horizontal cross-sectional imaging. OPTICS EXPRESS 2016; 24:2145-55. [PMID: 26906790 PMCID: PMC5802237 DOI: 10.1364/oe.24.002145] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/16/2015] [Revised: 01/12/2016] [Accepted: 01/23/2016] [Indexed: 05/26/2023]
Abstract
We present an integrated monolithic, electrostatic 3D MEMS scanner with a compact chip size of 3.2 × 2.9 mm(2). Use of parametric excitation near resonance frequencies produced large optical deflection angles up to ± 27° and ± 28.5° in the X- and Y-axes and displacements up to 510 μm in the Z-axis with low drive voltages at atmospheric pressure. When packaged in a dual axes confocal endomicroscope, horizontal and vertical cross-sectional images can be collected seamlessly in tissue with a large field-of-view of >1 × 1 mm(2) and 1 × 0.41 mm(2), respectively, at 5 frames/sec.
Collapse
Affiliation(s)
- Haijun Li
- Department of Internal Medicine, Division of Gastroenterology, University of Michigan, Ann Arbor, MI, USA
| | - Xiyu Duan
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI, USA
| | - Zhen Qiu
- Department of Internal Medicine, Division of Gastroenterology, University of Michigan, Ann Arbor, MI, USA
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI, USA
| | - Quan Zhou
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI, USA
| | - Katsuo Kurabayashi
- Department of Mechanical Engineering, University of Michigan, Ann Arbor, MI, USA
| | - Kenn R. Oldham
- Department of Mechanical Engineering, University of Michigan, Ann Arbor, MI, USA
| | - Thomas D. Wang
- Department of Internal Medicine, Division of Gastroenterology, University of Michigan, Ann Arbor, MI, USA
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI, USA
- Department of Mechanical Engineering, University of Michigan, Ann Arbor, MI, USA
| |
Collapse
|
10
|
Duan X, Li H, Qiu Z, Joshi BP, Pant A, Smith A, Kurabayashi K, Oldham KR, Wang TD. MEMS-based multiphoton endomicroscope for repetitive imaging of mouse colon. BIOMEDICAL OPTICS EXPRESS 2015; 6:3074-83. [PMID: 26309768 PMCID: PMC4541532 DOI: 10.1364/boe.6.003074] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/20/2015] [Revised: 07/03/2015] [Accepted: 07/21/2015] [Indexed: 05/08/2023]
Abstract
We demonstrate a handheld multiphoton endomicroscope with 3.4 mm distal diameter that can repetitively image mouse colon in vivo. A 2D resonant MEMS mirror was developed to perform beam scanning in a Lissajous pattern. The instrument has an effective numerical aperture of 0.63, lateral and axial resolution of 2.03 and 9.02 μm, respectively, working distance of 60 μm, and image field-of-view of 300 × 300 μm(2). Hoechst was injected intravenously in mice to stain cell nuclei. We were able to collect histology-like images in vivo at 5 frames/sec, and distinguish between normal and pre-malignant colonic epithelium.
Collapse
Affiliation(s)
- Xiyu Duan
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI, USA
| | - Haijun Li
- Department of Internal Medicine, Division of Gastroenterology, University of Michigan, Ann Arbor, MI, USA
| | - Zhen Qiu
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI, USA
- Department of Internal Medicine, Division of Gastroenterology, University of Michigan, Ann Arbor, MI, USA
| | - Bishnu P. Joshi
- Department of Internal Medicine, Division of Gastroenterology, University of Michigan, Ann Arbor, MI, USA
| | - Asha Pant
- Department of Internal Medicine, Division of Gastroenterology, University of Michigan, Ann Arbor, MI, USA
| | - Arlene Smith
- Department of Internal Medicine, Division of Gastroenterology, University of Michigan, Ann Arbor, MI, USA
| | - Katsuo Kurabayashi
- Department of Mechanical Engineering, University of Michigan, Ann Arbor, MI, USA
- Department of Electrical Engineering, University of Michigan, Ann Arbor, MI, USA
| | - Kenn R. Oldham
- Department of Mechanical Engineering, University of Michigan, Ann Arbor, MI, USA
| | - Thomas D. Wang
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI, USA
- Department of Internal Medicine, Division of Gastroenterology, University of Michigan, Ann Arbor, MI, USA
- Department of Mechanical Engineering, University of Michigan, Ann Arbor, MI, USA
| |
Collapse
|
11
|
Shahid W, Qiu Z, Duan X, Li H, Wang TD, Oldham KR. Modeling and Simulation of a Parametrically Resonant Micromirror With Duty-Cycled Excitation. JOURNAL OF MICROELECTROMECHANICAL SYSTEMS : A JOINT IEEE AND ASME PUBLICATION ON MICROSTRUCTURES, MICROACTUATORS, MICROSENSORS, AND MICROSYSTEMS 2014; 23:1440-1453. [PMID: 25506188 PMCID: PMC4262121 DOI: 10.1109/jmems.2014.2315518] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/10/2023]
Abstract
High frequency large scanning angle electrostatically actuated microelectromechanical systems (MEMS) mirrors are used in a variety of applications involving fast optical scanning. A 1-D parametrically resonant torsional micromirror for use in biomedical imaging is analyzed here with respect to operation by duty-cycled square waves. Duty-cycled square wave excitation can have significant advantages for practical mirror regulation and/or control. The mirror's nonlinear dynamics under such excitation is analyzed in a Hill's equation form. This form is used to predict stability regions (the voltage-frequency relationship) of parametric resonance behavior over large scanning angles using iterative approximations for nonlinear capacitance behavior of the mirror. Numerical simulations are also performed to obtain the mirror's frequency response over several voltages for various duty cycles. Frequency sweeps, stability results, and duty cycle trends from both analytical and simulation methods are compared with experimental results. Both analytical models and simulations show good agreement with experimental results over the range of duty cycled excitations tested. This paper discusses the implications of changing amplitude and phase with duty cycle for robust open-loop operation and future closed-loop operating strategies.
Collapse
Affiliation(s)
- Wajiha Shahid
- Mechanical Engineering Department, University of Michigan, Ann Arbor, MI 48105 USA
| | - Zhen Qiu
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI 48109 USA
| | - Xiyu Duan
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI 48109 USA
| | - Haijun Li
- Department of Internal Medicine-Gastroenterology Division, University of Michigan, Ann Arbor, MI 48109 USA
| | - Thomas D. Wang
- Department of Biomedical Engineering, Department of Internal Medicine-Gastroenterology Division, University of Michigan, Ann Arbor, MI 48109 USA
| | - Kenn R. Oldham
- Mechanical Engineering Department, University of Michigan, Ann Arbor, MI 48105 USA
| |
Collapse
|
12
|
Singh VK, Anis A, Banerjee I, Pramanik K, Bhattacharya MK, Pal K. Preparation and characterization of novel carbopol based bigels for topical delivery of metronidazole for the treatment of bacterial vaginosis. MATERIALS SCIENCE & ENGINEERING. C, MATERIALS FOR BIOLOGICAL APPLICATIONS 2014; 44:151-8. [PMID: 25280691 DOI: 10.1016/j.msec.2014.08.026] [Citation(s) in RCA: 84] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/29/2014] [Revised: 07/10/2014] [Accepted: 08/05/2014] [Indexed: 02/07/2023]
Abstract
The current study reports the development of bigels using sorbitan monostearate-sesame oil organogel and carbopol 934 hydrogel. The microstructures and physicochemical properties were investigated by microscopy, viscosity measurement, mechanical analysis and differential scanning calorimetry analysis. Fluorescence microscopy confirmed the formation of oil-in-water type of emulsion gel. There was an increase in the strength of the bigels as the proportion of the organogel was increased in the bigels. The developed bigels showed shear-thinning flow behavior. The stress relaxation study suggested viscoelastic nature of the bigels. The developed bigels were biocompatible. Metronidazole, drug of choice for the treatment of bacterial vaginosis, loaded bigels showed diffusion-mediated drug release. The drug loaded gels showed good antimicrobial efficiency against Escherichia coli. In gist, the developed bigels may be used as delivery vehicles for the vaginal delivery of the drugs.
Collapse
Affiliation(s)
- Vinay K Singh
- Department of Biotechnology & Medical Engineering, National Institute of Technology, Rourkela-769008, Odisha, India
| | - Arfat Anis
- SABIC Polymer Research Center, Department of Chemical Engineering, King Saud University, Riyadh-11421, Saudi Arabia
| | - Indranil Banerjee
- Department of Biotechnology & Medical Engineering, National Institute of Technology, Rourkela-769008, Odisha, India
| | - Krishna Pramanik
- Department of Biotechnology & Medical Engineering, National Institute of Technology, Rourkela-769008, Odisha, India
| | - Mrinal K Bhattacharya
- Department of Botany and Biotechnology, Karimganj College, Karimganj-788710, Assam, India
| | - Kunal Pal
- Department of Biotechnology & Medical Engineering, National Institute of Technology, Rourkela-769008, Odisha, India.
| |
Collapse
|
13
|
Choi J, Qiu Z, Rhee CH, Wang T, Oldham K. A three-degree-of-freedom thin-film PZT-actuated microactuator with large out-of-plane displacement. JOURNAL OF MICROMECHANICS AND MICROENGINEERING : STRUCTURES, DEVICES, AND SYSTEMS 2014; 24:075017. [PMID: 25506131 PMCID: PMC4262122 DOI: 10.1088/0960-1317/24/7/075017] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
A novel three degree-of-freedom microactuator based on thin-film lead-zirconate-titanate (PZT) is described with its detailed structural model. Its central rectangular-shaped mirror platform, also referred to as the stage, is actuated by four symmetric PZT bending legs such that each leg provides vertical translation for one corner of the stage. It has been developed to support real-time in vivo vertical cross-sectional imaging with a dual axes confocal endomicroscope for early cancer detection, having large displacements in three axes (z, θx, θy) and a relatively high bandwidth in the z-axis direction. Prototype microactuators closely meet the performance requirements for this application; in the out-of-plane (z-axis) direction, it has shown more than 177 μm of displacement and about 84 Hz of structural natural frequency, when two diagonal legs are actuated at 14V. With all four legs, another prototype of the same design with lighter stage mass has achieved more than 430 μm of out-of-plane displacement at 15V and about 200 Hz of bandwidth. The former design has shown approximately 6.4° and 2.9° of stage tilting about the x-axis and y-axis, respectively, at 14V. This paper also presents a modeling technique that uses experimental data to account for the effects of fabrication uncertainties in residual stress and structural dimensions. The presented model predicts the static motion of the stage within an average absolute error of 14.6 μm, which approaches the desired imaging resolution, 5 μm, and also reasonably anticipates the structural dynamic behavior of the stage. The refined model will support development of a future trajectory tracking controller for the system.
Collapse
Affiliation(s)
- Jongsoo Choi
- Department of Mechanical Engineering, University of Michigan, 2350 Hayward St., Ann Arbor, MI 48109, USA
| | - Zhen Qiu
- Department of Biomedical Engineering, University of Michigan, 2200 Bonisteel Blvd., Ann Arbor, MI 48109, USA
| | - Choong-Ho Rhee
- Department of Mechanical Engineering, University of Michigan, 2350 Hayward St., Ann Arbor, MI 48109, USA
| | - Thomas Wang
- Department of Mechanical Engineering, University of Michigan, 2350 Hayward St., Ann Arbor, MI 48109, USA
- Department of Biomedical Engineering, University of Michigan, 2200 Bonisteel Blvd., Ann Arbor, MI 48109, USA
- Department of Internal Medicine, University of Michigan, 109 Zina Pitcher Pl., Ann Arbor, MI 48109, USA
| | - Kenn Oldham
- Department of Mechanical Engineering, University of Michigan, 2350 Hayward St., Ann Arbor, MI 48109, USA
| |
Collapse
|
14
|
Qiu Z, Rhee CH, Choi J, Wang TD, Oldham KR. Large Stroke Vertical PZT Microactuator With High-Speed Rotational Scanning. JOURNAL OF MICROELECTROMECHANICAL SYSTEMS : A JOINT IEEE AND ASME PUBLICATION ON MICROSTRUCTURES, MICROACTUATORS, MICROSENSORS, AND MICROSYSTEMS 2014; 23:256-258. [PMID: 25506187 PMCID: PMC4262091 DOI: 10.1109/jmems.2014.2303643] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/13/2023]
Abstract
A thin-film piezoelectric microactuator using a novel combination of active vertical translational scanning and passive resonant rotational scanning is presented. Thin-film lead-zirconate-titanate unimorph bending beams surrounding a central platform provide nearly 200-μm displacement at 18 V with bandwidth greater than 200 Hz. Inside the platform, a mirror mount, or mirror surface, supported by silicon dioxide spring beams can be excited to resonance by low-voltage; high-frequency excitation of the outer PZT beams. Over ±5.5° mechanical resonance is obtained at 3.8 kHz and ±2 V. The combination of large translational vertical displacements and high-speed rotational scanning is intended to support real-time cross-sectional imaging in a dual axes confocal endomicroscope.
Collapse
Affiliation(s)
- Zhen Qiu
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI 48109 USA
| | - Choong-Ho Rhee
- Department of Mechanical Engineering, University of Michigan, Ann Arbor, MI 48109 USA
| | - Jongsoo Choi
- Department of Mechanical Engineering, University of Michigan, Ann Arbor, MI 48109 USA
| | - Thomas D. Wang
- Department of Internal Medicine, Biomedical Enginering, and Mechanical Engineering, University of Michigan, Ann Arbor, MI 48109 USA
| | - Kenn R. Oldham
- Department of Mechanical Engineering, University of Michigan, Ann Arbor, MI 48109 USA
| |
Collapse
|
15
|
Qiu Z, Khondee S, Duan X, Li H, Mandella MJ, Joshi BP, Zhou Q, Owens SR, Kurabayashi K, Oldham KR, Wang TD. Vertical cross-sectional imaging of colonic dysplasia in vivo with multi-spectral dual axes confocal endomicroscopy. Gastroenterology 2014; 146:615-7. [PMID: 24440675 PMCID: PMC4029422 DOI: 10.1053/j.gastro.2014.01.016] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/07/2014] [Accepted: 01/10/2014] [Indexed: 12/02/2022]
Abstract
Pathologists evaluate histology sectioned perpendicular to the tissue surface, or vertical cross-section. This orientation (XZ-plane) enables evaluation of mucosal differentiation in the basilar-to-luminal direction. Current endomicroscopes use a conventional (single axis) optical design. Imaging is limited to horizontal cross-sections (XY-plane) where the micro-anatomy is frequently similar across the field-of-view (FOV). In the dual axes configuration, light is delivered and collected off-axis, and images can be detected over a much larger range of intensities. Molecular images collected using fluorescence can improve specificity for disease detection and reveal functional properties about tissue. Proper interpretation of these images requires correlation with the micro-anatomy. We aim to demonstrate the simultaneous collection of two fluorescence images in vivo in vertical cross-sections using a dual axes confocal endomicroscope. An overlay of molecular and anatomical images from normal and dysplastic mouse colonic mucosa will be displayed in real time.
Collapse
Affiliation(s)
- Zhen Qiu
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI, 48109, United States
| | - Supang Khondee
- Department of Internal Medicine, Division of Gastroenterology, University of Michigan, Ann Arbor, MI, 48109, United States,Pharmaceutical Science Department, School of Pharmaceutical Sciences, University of Phayao, Thailand
| | - Xiyu Duan
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI, 48109, United States
| | - Haijun Li
- Department of Internal Medicine, Division of Gastroenterology, University of Michigan, Ann Arbor, MI, 48109, United States
| | - Michael J. Mandella
- Department of Pediatrics, Stanford University School of Medicine, Stanford, CA 94305, United States
| | - Bishnu P. Joshi
- Department of Internal Medicine, Division of Gastroenterology, University of Michigan, Ann Arbor, MI, 48109, United States
| | - Quan Zhou
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI, 48109, United States
| | - Scott R. Owens
- Department of Pathology, University of Michigan, Ann Arbor, MI, 48109, United States
| | - Katsuo Kurabayashi
- Department of Mechanical Engineering, University of Michigan, Ann Arbor, MI, 48109, United States,Department of Electrical Engineering, University of Michigan, Ann Arbor, MI, 48109, United States
| | - Kenn R. Oldham
- Department of Mechanical Engineering, University of Michigan, Ann Arbor, MI, 48109, United States
| | - Thomas D. Wang
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI, 48109, United States,Department of Internal Medicine, Division of Gastroenterology, University of Michigan, Ann Arbor, MI, 48109, United States,Department of Mechanical Engineering, University of Michigan, Ann Arbor, MI, 48109, United States
| |
Collapse
|