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Dr. Smitha Rao
Department of Biomedical Engineering, Michigan Technological University, Houghton, MI 49931, USA

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Research Keywords & Expertise

0 MEMS
0 Nanotechnology
0 Cancer detection and therapy
0 Sensors and devices for biomedical sensing and implantable devices
0 Nanofiber scaffold for wound healing, tissue culture and sensing

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MEMS
Cancer detection and therapy

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Journal article
Published: 09 January 2020 in IEEE Open Journal of Engineering in Medicine and Biology
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Goal: Artificially engineering the tumor microenvironment in vitro as a vital tool for understanding the mechanism of tumor progression. In this study, we developed three-dimensional cell scaffold systems with different topographical features and mechanical properties but similar surface chemistry. The cell behavior was modulated by the topography and mechanical properties of the scaffold. Adenocarcinoma (MCF7), triple-negative (MDA-MB-231) and premalignant (MCF10AneoT) breast cancer cells were seeded on the scaffold systems. The cell viability, cell-cell interaction and cell-matrix interactions were analyzed. The preferential growth and alignment of specific population of cells were demonstrated. Among the different scaffolds, triple-negative breast cancer cells preferred honeycomb scaffolds while adenocarcinoma cells favored mesh scaffolds and premalignant cells preferred the aligned scaffolds. The 3D model system developed here can be used to support growth of only specific cell populations or for the growth of tumors. This model can be used for understanding the topographical and mechanical features affecting tumorigenesis, cancer cell growth and migration behavior of malignant and metastatic cancer cells.

ACS Style

Samerender Nagam Hanumantharao; Carolynn A. Que; Brennan J. Vogl; Smitha Rao. Engineered Three-Dimensional Scaffolds Modulating Fate of Breast Cancer Cells Using Stiffness and Morphology Related Cell Adhesion. IEEE Open Journal of Engineering in Medicine and Biology 2020, 1, 41 -48.

AMA Style

Samerender Nagam Hanumantharao, Carolynn A. Que, Brennan J. Vogl, Smitha Rao. Engineered Three-Dimensional Scaffolds Modulating Fate of Breast Cancer Cells Using Stiffness and Morphology Related Cell Adhesion. IEEE Open Journal of Engineering in Medicine and Biology. 2020; 1 (99):41-48.

Chicago/Turabian Style

Samerender Nagam Hanumantharao; Carolynn A. Que; Brennan J. Vogl; Smitha Rao. 2020. "Engineered Three-Dimensional Scaffolds Modulating Fate of Breast Cancer Cells Using Stiffness and Morphology Related Cell Adhesion." IEEE Open Journal of Engineering in Medicine and Biology 1, no. 99: 41-48.

Journals
Published: 16 December 2019 in RSC Advances
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Co-axial electrospinning of three immiscible polymers by sequentially blending in solvents of different boiling points to obtain biomimetic scaffolds.

ACS Style

Samerender Nagam Hanumantharao; Nastaran Alinezhadbalalami; Srinivas Kannan; Meghan Friske; Smitha Rao. Electrospun acellular scaffolds for mimicking the natural anisotropy of the extracellular matrix. RSC Advances 2019, 9, 40190 -40195.

AMA Style

Samerender Nagam Hanumantharao, Nastaran Alinezhadbalalami, Srinivas Kannan, Meghan Friske, Smitha Rao. Electrospun acellular scaffolds for mimicking the natural anisotropy of the extracellular matrix. RSC Advances. 2019; 9 (69):40190-40195.

Chicago/Turabian Style

Samerender Nagam Hanumantharao; Nastaran Alinezhadbalalami; Srinivas Kannan; Meghan Friske; Smitha Rao. 2019. "Electrospun acellular scaffolds for mimicking the natural anisotropy of the extracellular matrix." RSC Advances 9, no. 69: 40190-40195.

Review
Published: 19 July 2019 in Fibers
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Electrospinning and polymer blending have been the focus of research and the industry for their versatility, scalability, and potential applications across many different fields. In tissue engineering, nanofiber scaffolds composed of natural fibers, synthetic fibers, or a mixture of both have been reported. This review reports recent advances in polymer blended scaffolds for tissue engineering and the fabrication of functional scaffolds by electrospinning. A brief theory of electrospinning and the general setup as well as modifications used are presented. Polymer blends, including blends with natural polymers, synthetic polymers, mixture of natural and synthetic polymers, and nanofiller systems, are discussed in detail and reviewed.

ACS Style

Samerender Nagam Hanumantharao; Smitha Rao. Multi-Functional Electrospun Nanofibers from Polymer Blends for Scaffold Tissue Engineering. Fibers 2019, 7, 66 .

AMA Style

Samerender Nagam Hanumantharao, Smitha Rao. Multi-Functional Electrospun Nanofibers from Polymer Blends for Scaffold Tissue Engineering. Fibers. 2019; 7 (7):66.

Chicago/Turabian Style

Samerender Nagam Hanumantharao; Smitha Rao. 2019. "Multi-Functional Electrospun Nanofibers from Polymer Blends for Scaffold Tissue Engineering." Fibers 7, no. 7: 66.

Journal article
Published: 19 March 2019 in Materialia
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The fabrication of synthetic scaffolds that mimic the microenvironment of cells is a crucial challenge in materials science. The honeycomb morphology is one such bio-mimicking structure that possesses unique physical properties and high packing efficiency in a 3-dimensional space. Here, we present a novel method for electrospinning polycaprolactone-polyaniline with continuous, self-assembled, uniform, interwoven nanofibers forming patterns without the use of templates or porogens. By using the approach presented here, unique architectures mimicking the natural mechanical anisotropy of extracellular matrix were created by varying the electric field. Adult human dermal fibroblasts (HDFa) cells were successfully cultured on the nanofiber scaffolds without any external growth factors or post-processing of the nanofibers and compared to a commercially available dermal template. Our data indicates that despite identical chemical composition, the physical properties impact cell attachment, alignment and penetration into the scaffold. The mechanical strength of the fibers also plays a role with a distinct preference to fibers with high stiffness and ultimate tensile strength. Thus, by tuning the electric field, fibers with different physical properties and patterns can be fabricated for different applications.

ACS Style

Samerender Nagam Hanumantharao; Carolynn Que; Smitha Rao. Self-assembly of 3D nanostructures in electrospun polycaprolactone-polyaniline fibers and their application as scaffolds for tissue engineering. Materialia 2019, 6, 100296 .

AMA Style

Samerender Nagam Hanumantharao, Carolynn Que, Smitha Rao. Self-assembly of 3D nanostructures in electrospun polycaprolactone-polyaniline fibers and their application as scaffolds for tissue engineering. Materialia. 2019; 6 ():100296.

Chicago/Turabian Style

Samerender Nagam Hanumantharao; Carolynn Que; Smitha Rao. 2019. "Self-assembly of 3D nanostructures in electrospun polycaprolactone-polyaniline fibers and their application as scaffolds for tissue engineering." Materialia 6, no. : 100296.

Journal article
Published: 09 November 2018 in Medical Sciences
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Diabetic foot ulcers (DFU) are a major health problem associated with diabetes mellitus. Impaired nitric oxide (NO) production has been shown to be a major contributor to the dysregulation of healing in DFU. The level of impairment is not known primarily due to challenges with measuring NO. Herein, we report the actual level of NO produced by human dermal fibroblasts cultured under normal and high glucose conditions. Fibroblasts produce the extracellular matrix, which facilitate the migration of keratinocytes to close wounds. The results show that NO production was significantly higher in normal glucose compared to high glucose conditions. The real-time NO detected was compared to the nitrite present in the culture media and there was a direct correlation between real-time NO and nitrite in normal glucose conditions. However, real-time NO detection and nitrite measurement did not correlate under high glucose conditions. The inducible nitric oxide synthase (iNOS) enzyme responsible for NO production was upregulated in normal and high glucose conditions and the proliferation rate of fibroblasts was not statistically different in all the treatment groups. Relying only on nitrite to assess NO production is not an accurate determinant of the NO present in the wound bed in pathological states such as diabetes mellitus.

ACS Style

Maria P. Kwesiga; Emily Cook; Jennifer Hannon; Sarah Wayward; Caroline Gwaltney; Smitha Rao; Megan C. Frost. Investigative Study on Nitric Oxide Production in Human Dermal Fibroblast Cells under Normal and High Glucose Conditions. Medical Sciences 2018, 6, 99 .

AMA Style

Maria P. Kwesiga, Emily Cook, Jennifer Hannon, Sarah Wayward, Caroline Gwaltney, Smitha Rao, Megan C. Frost. Investigative Study on Nitric Oxide Production in Human Dermal Fibroblast Cells under Normal and High Glucose Conditions. Medical Sciences. 2018; 6 (4):99.

Chicago/Turabian Style

Maria P. Kwesiga; Emily Cook; Jennifer Hannon; Sarah Wayward; Caroline Gwaltney; Smitha Rao; Megan C. Frost. 2018. "Investigative Study on Nitric Oxide Production in Human Dermal Fibroblast Cells under Normal and High Glucose Conditions." Medical Sciences 6, no. 4: 99.

Journal article
Published: 10 April 2018 in Biosensors
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Point-of-care applications rely on biomedical sensors to enable rapid detection with high sensitivity and selectivity. Despite advances in sensor development, there are challenges in cancer diagnostics. Detection of biomarkers, cell receptors, circulating tumor cells, gene identification, and fluorescent tagging are time-consuming due to the sample preparation and response time involved. Here, we present a novel approach to target the enhanced metabolism in breast cancers for rapid detection using fluorescent imaging. Fluorescent analogs of fructose target the fructose-specific transporter GLUT5 in breast cancers and have limited to no response from normal cells. These analogs demonstrate a marked difference in adenocarcinoma and premalignant cells leading to a novel detection approach. The vastly different uptake kinetics of the analogs yields two unique signatures for each cell type. We used normal breast cells MCF10A, adenocarcinoma cells MCF7, and premalignant cells MCF10AneoT, with hepatocellular carcinoma cells HepG2 as the negative control. Our data indicated that MCF10AneoT and MCF7 cells had an observable difference in response to only one of the analogs. The response, observed as fluorescence intensity, leads to a two-point assessment of the cells in any sample. Since the treatment time is 10 min, there is potential for use in rapid on-site high-throughput diagnostics.

ACS Style

Srinivas Kannan; Vagarshak V. Begoyan; Joseph R. Fedie; Shuai Xia; Łukasz J. Weseliński; Marina Tanasova; Smitha Rao. Metabolism-Driven High-Throughput Cancer Identification with GLUT5-Specific Molecular Probes. Biosensors 2018, 8, 39 .

AMA Style

Srinivas Kannan, Vagarshak V. Begoyan, Joseph R. Fedie, Shuai Xia, Łukasz J. Weseliński, Marina Tanasova, Smitha Rao. Metabolism-Driven High-Throughput Cancer Identification with GLUT5-Specific Molecular Probes. Biosensors. 2018; 8 (2):39.

Chicago/Turabian Style

Srinivas Kannan; Vagarshak V. Begoyan; Joseph R. Fedie; Shuai Xia; Łukasz J. Weseliński; Marina Tanasova; Smitha Rao. 2018. "Metabolism-Driven High-Throughput Cancer Identification with GLUT5-Specific Molecular Probes." Biosensors 8, no. 2: 39.

Journal article
Published: 19 March 2018 in Chemical Communications
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A set of coumarin-based fluorescent sugar conjugates – ManCous is reported. ManCous are specific for fructose transporter GLUT5 and cover a broad range of the fluorescence spectrum providing essential tools for the evaluation of fructose transport capacity in live cells.

ACS Style

Vagarshak V. Begoyan; Shuai Xia; Joseph R. Fedie; Srinivas Kannan; Alexis Ferrier; Smitha Rao; Marina Tanasova; Lukasz Jan Jan Weselinski. Multicolor GLUT5-permeable fluorescent probes for fructose transport analysis. Chemical Communications 2018, 54, 3855 -3858.

AMA Style

Vagarshak V. Begoyan, Shuai Xia, Joseph R. Fedie, Srinivas Kannan, Alexis Ferrier, Smitha Rao, Marina Tanasova, Lukasz Jan Jan Weselinski. Multicolor GLUT5-permeable fluorescent probes for fructose transport analysis. Chemical Communications. 2018; 54 (31):3855-3858.

Chicago/Turabian Style

Vagarshak V. Begoyan; Shuai Xia; Joseph R. Fedie; Srinivas Kannan; Alexis Ferrier; Smitha Rao; Marina Tanasova; Lukasz Jan Jan Weselinski. 2018. "Multicolor GLUT5-permeable fluorescent probes for fructose transport analysis." Chemical Communications 54, no. 31: 3855-3858.

Conference paper
Published: 01 December 2017 in 2017 IEEE Life Sciences Conference (LSC)
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Rapid detection of carcinogenesis is the holy grail in timely cancer detection and point-of-care applications. Realization of these applications has been hampered by lack of specificity and/or selectivity of biomarkers and the low concentrations at which the biomarkers are available. A majority of the detection technologies rely on cell-receptor interactions, activation of specific receptors, gene identification and fluorescent tagging. All these techniques are time consuming and often require specialized equipment. Here we present a method to use the enhanced metabolism in breast cancer that relies on fructose for nutrition. Using fluorescent-labeled fructose analogs as reporter probes, we have demonstrated that cancer cells can be optically identified in a very short time due to the efficient internalization of the probe by cancer cells through the fructose-specific transporter. In our trials using breast cancer and normal cells, we were able to show an eight-times higher fluorescence in cancer cells compared to basal uptake in normal within 10 minutes. The cancer cells were distinguishable from normal cells by monitoring the accumulation of the coumarin-induced fluorescence using a conventional microscope and simple image processing.

ACS Style

Joseph Fedie; Srinivas Kannan; Vagarshak Begoyan; Shuai Xia; Suhel Shaikh; Marina Tanasova; Smitha Rao. Fructose uptake-based rapid detection of breast cancer. 2017 IEEE Life Sciences Conference (LSC) 2017, 162 -165.

AMA Style

Joseph Fedie, Srinivas Kannan, Vagarshak Begoyan, Shuai Xia, Suhel Shaikh, Marina Tanasova, Smitha Rao. Fructose uptake-based rapid detection of breast cancer. 2017 IEEE Life Sciences Conference (LSC). 2017; ():162-165.

Chicago/Turabian Style

Joseph Fedie; Srinivas Kannan; Vagarshak Begoyan; Shuai Xia; Suhel Shaikh; Marina Tanasova; Smitha Rao. 2017. "Fructose uptake-based rapid detection of breast cancer." 2017 IEEE Life Sciences Conference (LSC) , no. : 162-165.

Journal article
Published: 23 September 2015 in Sensors
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In this paper, we report a power management system for autonomous and real-time monitoring of the neurotransmitter L-glutamate (L-Glu). A low-power, low-noise, and high-gain recording module was designed to acquire signal from an implantable flexible L-Glu sensor fabricated by micro-electro-mechanical system (MEMS)-based processes. The wearable recording module was wirelessly powered through inductive coupling transmitter antennas. Lateral and angular misalignments of the receiver antennas were resolved by using a multi-transmitter antenna configuration. The effective coverage, over which the recording module functioned properly, was improved with the use of in-phase transmitter antennas. Experimental results showed that the recording system was capable of operating continuously at distances of 4 cm, 7 cm and 10 cm. The wireless power management system reduced the weight of the recording module, eliminated human intervention and enabled animal experimentation for extended durations.

ACS Style

Cuong M. Nguyen; Pavan Kumar Kota; Minh Q. Nguyen; Souvik Dubey; Smitha Rao; Jeffrey Mays; J.-C. Chiao. Wireless Power Transfer for Autonomous Wearable Neurotransmitter Sensors. Sensors 2015, 15, 24553 -24572.

AMA Style

Cuong M. Nguyen, Pavan Kumar Kota, Minh Q. Nguyen, Souvik Dubey, Smitha Rao, Jeffrey Mays, J.-C. Chiao. Wireless Power Transfer for Autonomous Wearable Neurotransmitter Sensors. Sensors. 2015; 15 (9):24553-24572.

Chicago/Turabian Style

Cuong M. Nguyen; Pavan Kumar Kota; Minh Q. Nguyen; Souvik Dubey; Smitha Rao; Jeffrey Mays; J.-C. Chiao. 2015. "Wireless Power Transfer for Autonomous Wearable Neurotransmitter Sensors." Sensors 15, no. 9: 24553-24572.

Journal article
Published: 01 June 2015 in IEEE Transactions on Power Electronics
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In this paper, we investigated the effect of power combining and delivering in multiinput and multioutput wireless energy transmission systems, which consist of more than one transmitter antennas as sources and more than one receiver antennas as loads and repeaters. Theoretical expressions were developed to model the system operation that can be in a large-scale wireless energy network architecture. System characteristics, such as power transfer between antennas, power losses induced in each antenna, wireless efficiency, coil misalignment, and power fluctuation due to the loss of frequency synchronization were examined by theory and verified with experiments. Measurement results matched well with the theory demonstrating the feasibility of combining and delivering power with high efficiencies in large-scale wireless energy transmission systems.

ACS Style

Minh Quoc Nguyen; Young Chou; Dakota Plesa; Smitha Rao; Jung-Chih Chiao. Multiple-Inputs and Multiple-Outputs Wireless Power Combining and Delivering Systems. IEEE Transactions on Power Electronics 2015, 30, 6254 -6263.

AMA Style

Minh Quoc Nguyen, Young Chou, Dakota Plesa, Smitha Rao, Jung-Chih Chiao. Multiple-Inputs and Multiple-Outputs Wireless Power Combining and Delivering Systems. IEEE Transactions on Power Electronics. 2015; 30 (11):6254-6263.

Chicago/Turabian Style

Minh Quoc Nguyen; Young Chou; Dakota Plesa; Smitha Rao; Jung-Chih Chiao. 2015. "Multiple-Inputs and Multiple-Outputs Wireless Power Combining and Delivering Systems." IEEE Transactions on Power Electronics 30, no. 11: 6254-6263.

Conference paper
Published: 01 May 2015 in 2015 IEEE MTT-S International Microwave Symposium
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Wireless networking sensor nodes for environment monitoring in Internet of Things (IOT) are reported in this work. The IOT network includes individual self-sustaining nodes wirelessly transmitting sensor signals to hubs that can be shared in the Internet Cloud. Each node consists of an optimized energy harvesting module, a System-on-Chip (SoC) integrated low-power Bluetooth Smart transceiver, and multi-functional sensor array to monitor environmental parameters. The energy harvesting module is able to adapt and collect energy from solar power, ambient radio waves, and direct wireless power transmission (WPT). The sensor arrays include pH sensor, temperature sensor, photo-detector, electromagnetic wave detector and acoustic noise detector. The SoC processes data and transmits compressed information about environmental conditions to the hub. This platform demonstrated the concepts of combining power harvesting techniques and low-power sensors for the IoT applications.

ACS Style

Cuong M. Nguyen; Jeffrey Mays; Dakota Plesa; Smitha Rao; Minh Nguyen; J.-C. Chiao; Nguyen Cuong M.. Wireless sensor nodes for environmental monitoring in Internet of Things. 2015 IEEE MTT-S International Microwave Symposium 2015, 1 -4.

AMA Style

Cuong M. Nguyen, Jeffrey Mays, Dakota Plesa, Smitha Rao, Minh Nguyen, J.-C. Chiao, Nguyen Cuong M.. Wireless sensor nodes for environmental monitoring in Internet of Things. 2015 IEEE MTT-S International Microwave Symposium. 2015; ():1-4.

Chicago/Turabian Style

Cuong M. Nguyen; Jeffrey Mays; Dakota Plesa; Smitha Rao; Minh Nguyen; J.-C. Chiao; Nguyen Cuong M.. 2015. "Wireless sensor nodes for environmental monitoring in Internet of Things." 2015 IEEE MTT-S International Microwave Symposium , no. : 1-4.

Journal article
Published: 12 February 2015 in Sensors
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Flexible iridium oxide (IrOx)-based micro-electrodes were fabricated on flexible polyimide substrates using a sol-gel deposition process for utilization as integrated pseudo-reference electrodes for bio-electrochemical sensing applications. The fabrication method yields reliable miniature on-probe IrOx electrodes with long lifetime, high stability and repeatability. Such sensors can be used for long-term measurements. Various dimensions of sol-gel iridium oxide electrodes including 1 mm × 1 mm, 500 µm × 500 µm, and 100 µm × 100 µm were fabricated. Sensor longevity and pH dependence were investigated by immersing the electrodes in hydrochloric acid, fetal bovine serum (FBS), and sodium hydroxide solutions for 30 days. Less pH dependent responses, compared to IrOx electrodes fabricated by electrochemical deposition processes, were measured at 58.8 ± 0.4 mV/pH, 53.8 ± 1.3 mV/pH and 48 ± 0.6 mV/pH, respectively. The on-probe IrOx pseudo-reference electrodes were utilized for dopamine sensing. The baseline responses of the sensors were higher than the one using an external Ag/AgCl reference electrode. Using IrOx reference electrodes integrated on the same probe with working electrodes eliminated the use of cytotoxic Ag/AgCl reference electrode without loss in sensitivity. This enables employing such sensors in long-term recording of concentrations of neurotransmitters in central nervous systems of animals and humans.

ACS Style

Cuong M. Nguyen; Smitha Rao; Xuesong Yang; Souvik Dubey; Jeffrey Mays; Hung Cao; Jung-Chih Chiao. Sol-Gel Deposition of Iridium Oxide for Biomedical Micro-Devices. Sensors 2015, 15, 4212 -4228.

AMA Style

Cuong M. Nguyen, Smitha Rao, Xuesong Yang, Souvik Dubey, Jeffrey Mays, Hung Cao, Jung-Chih Chiao. Sol-Gel Deposition of Iridium Oxide for Biomedical Micro-Devices. Sensors. 2015; 15 (2):4212-4228.

Chicago/Turabian Style

Cuong M. Nguyen; Smitha Rao; Xuesong Yang; Souvik Dubey; Jeffrey Mays; Hung Cao; Jung-Chih Chiao. 2015. "Sol-Gel Deposition of Iridium Oxide for Biomedical Micro-Devices." Sensors 15, no. 2: 4212-4228.

Conference paper
Published: 01 November 2014 in IEEE SENSORS 2014 Proceedings
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Monitoring of structural health plays a crucial role in condition-based maintenance and prediction of unsafe or damaged infrastructures. We have developed an interdigitated capacitive (IDC) strain sensor integrated in a wireless monitoring system that could be used for structural health monitoring (SHM). The 125-μm thin brass IDC sensors were fabricated by laser micromachining followed by an encapsulation in a deformable polymer. The wireless monitoring system was implemented using a commercial wireless module Texas Instruments eZ430-RF2500 for use with multiple sensors simultaneously. A graphical user interface (GUI) was developed to store data and perform real-time analysis remotely. The wireless communication distance was up to 35 m inside buildings. The sensors were characterized and the entire system was demonstrated with both single and dual sensors. Our system is also capable of multi-modality sensing for continuous and real-time monitoring.

ACS Style

Hung Cao; Chokri Jebali; Ammar B. Kouki; Shreyas Thakar; Cuong M. Nguyen; Smitha Rao; J.-C. Chiao. Development of a laser micro-machined interdigitated capacitive strain sensor for structural health monitoring applications. IEEE SENSORS 2014 Proceedings 2014, 1741 -1744.

AMA Style

Hung Cao, Chokri Jebali, Ammar B. Kouki, Shreyas Thakar, Cuong M. Nguyen, Smitha Rao, J.-C. Chiao. Development of a laser micro-machined interdigitated capacitive strain sensor for structural health monitoring applications. IEEE SENSORS 2014 Proceedings. 2014; ():1741-1744.

Chicago/Turabian Style

Hung Cao; Chokri Jebali; Ammar B. Kouki; Shreyas Thakar; Cuong M. Nguyen; Smitha Rao; J.-C. Chiao. 2014. "Development of a laser micro-machined interdigitated capacitive strain sensor for structural health monitoring applications." IEEE SENSORS 2014 Proceedings , no. : 1741-1744.

Journal article
Published: 30 June 2014 in IEEE Transactions on Nanotechnology
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Iridium oxide (IrO x ) nanotubes have been grown on microelectrodes utilizing a patterned nanoporous aluminum oxide (AAO) template to form a micro pH sensor. A layer of 900-nm thick aluminum sputtered on a silicon wafer was locally anodized at various voltages to investigate the morphology of the patterned AAO templates. The electrode position of IrO x inside the supportive AAO template was carried out to yield IrO x nanotubes with a diameter ranging from 80 to 110 nm, corresponding to the AAO pore sizes. The fabrication processes produced free-standing IrO x nanotubes on top of the 50 × 100 μm 2 micro-scale electrodes. Material characterization along with fabrication parameters was investigated. Potentiometric responses of the miniature sensors to hydrogen ions in terms of sensitivity, repeatability, response time, and reliability were performed. Super-Nernstian response was achieved. pH measurements for higher resolution targeting biological applications and sensor temperature dependence were also conducted.

ACS Style

Cuong M. Nguyen; Smitha Rao; Young-Sik Seo; Kyle Schadt; Yaowu Hao; J.-C. Chiao. Micro pH Sensors Based on Iridium Oxide Nanotubes. IEEE Transactions on Nanotechnology 2014, 13, 945 -953.

AMA Style

Cuong M. Nguyen, Smitha Rao, Young-Sik Seo, Kyle Schadt, Yaowu Hao, J.-C. Chiao. Micro pH Sensors Based on Iridium Oxide Nanotubes. IEEE Transactions on Nanotechnology. 2014; 13 (5):945-953.

Chicago/Turabian Style

Cuong M. Nguyen; Smitha Rao; Young-Sik Seo; Kyle Schadt; Yaowu Hao; J.-C. Chiao. 2014. "Micro pH Sensors Based on Iridium Oxide Nanotubes." IEEE Transactions on Nanotechnology 13, no. 5: 945-953.

Conference paper
Published: 01 June 2014 in 2014 IEEE MTT-S International Microwave Symposium (IMS2014)
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In this work, we present for the first time a multi-input and multi-output (MIMO) wireless power transmission system in which there are more than one source (transmitter antenna) and more than one load (receiver antenna). Theoretical expressions are developed to analyze the power transfer between antennas, power loss induced in each antenna and system efficiency of wireless power transfer. The theoretical model is verified with measurements in a prototype system consisting of two transmitter, two receiver and one repeater coils. Experimental results match well with theory demonstrating wireless power combining and delivering in the MIMO system.

ACS Style

Minh Quoc Nguyen; Dakota Plesa; Smitha Rao; J.-C. Chiao; Davor Plesa. A multi-input and multi-output wireless energy transfer system. 2014 IEEE MTT-S International Microwave Symposium (IMS2014) 2014, 1 -3.

AMA Style

Minh Quoc Nguyen, Dakota Plesa, Smitha Rao, J.-C. Chiao, Davor Plesa. A multi-input and multi-output wireless energy transfer system. 2014 IEEE MTT-S International Microwave Symposium (IMS2014). 2014; ():1-3.

Chicago/Turabian Style

Minh Quoc Nguyen; Dakota Plesa; Smitha Rao; J.-C. Chiao; Davor Plesa. 2014. "A multi-input and multi-output wireless energy transfer system." 2014 IEEE MTT-S International Microwave Symposium (IMS2014) , no. : 1-3.

Conference paper
Published: 01 April 2014 in Texas Symposium on Wireless and Microwave Circuits and Systems
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In this paper, we investigate wireless power transfer using multiple repeater antennas through air and building materials. The system architecture includes one transmitter antenna, one receiver antenna and repeater antennas in a cascade arrangement. All antennas were loop coils made of Litz wires with 15 cm-radii and 10 turns. The transmitter antenna was driven by a high efficiency class-E power amplifier (PA) while receiver antenna was connected to a load. System efficiency including both amplifier efficiency and wireless link efficiency was determined as the ratio between the output power received at the load and the input power fed into the amplifier. Theoretical model based on circuit theory was introduced to calculate the system characteristics such as power transfer, wireless efficiency and power loss induced in each antenna. Experiment setups up to two repeaters were built and conducted to validate the theory model. Experimental and theoretical results agreed well and the results confirmed the parasitic effects of building materials to the wireless power transfer system performance.

ACS Style

Minh Quoc Nguyen; Souvik Dubey; Smitha Rao; C. Chiao; J.-C. Chiao. Wireless power transfer via air and building materials using multiple repeaters. Texas Symposium on Wireless and Microwave Circuits and Systems 2014, 1 -4.

AMA Style

Minh Quoc Nguyen, Souvik Dubey, Smitha Rao, C. Chiao, J.-C. Chiao. Wireless power transfer via air and building materials using multiple repeaters. Texas Symposium on Wireless and Microwave Circuits and Systems. 2014; ():1-4.

Chicago/Turabian Style

Minh Quoc Nguyen; Souvik Dubey; Smitha Rao; C. Chiao; J.-C. Chiao. 2014. "Wireless power transfer via air and building materials using multiple repeaters." Texas Symposium on Wireless and Microwave Circuits and Systems , no. : 1-4.

Conference paper
Published: 01 April 2014 in Texas Symposium on Wireless and Microwave Circuits and Systems
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This work introduces a new approach of optimizing the efficiency of a wireless power transmission system in terms of mutual inductance. A circuit model was developed in PSpice to simulate the effect of mutual inductance by inductive coupling on power transfer efficiency. Experiments were conducted at 1.3 MHz with variations of distance between coils and coil sizes to change the mutual inductance in the equivalent circuit. Experimental results agreed well with the simulation model. The optimal mutual inductance to reach maximum power transfer efficiency for the inductive coupling system driven by a class-E amplifier was identified with respect to different coil sizes and distances. This method can guide the design strategy of the transmitter and receiver coils for specific applications.

ACS Style

Minh Quoc Nguyen; Peter Woods; Zachariah Hughes; Young-Sik Seo; Smitha Rao; J.-C. Chiao. A mutual inductance approach for optimization of wireless energy transmission. Texas Symposium on Wireless and Microwave Circuits and Systems 2014, 1 -4.

AMA Style

Minh Quoc Nguyen, Peter Woods, Zachariah Hughes, Young-Sik Seo, Smitha Rao, J.-C. Chiao. A mutual inductance approach for optimization of wireless energy transmission. Texas Symposium on Wireless and Microwave Circuits and Systems. 2014; ():1-4.

Chicago/Turabian Style

Minh Quoc Nguyen; Peter Woods; Zachariah Hughes; Young-Sik Seo; Smitha Rao; J.-C. Chiao. 2014. "A mutual inductance approach for optimization of wireless energy transmission." Texas Symposium on Wireless and Microwave Circuits and Systems , no. : 1-4.

Journal article
Published: 30 January 2014 in IEEE Transactions on Microwave Theory and Techniques
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This paper presents design and optimization methods for spiral coils utilized for wireless power transfer in wireless medical implant applications. A theoretical model was examined for near-field distributions of spiral-type transmitter antennas in both orthogonal components. Finite-element simulations were performed to verify the theoretical radiation patterns. Receiver antenna voltages were measured at planes of interest as a means to map field distributions. Theoretical, simulation, and experimental results were conducted in free space and they agreed well. Understanding the orthogonal field components and their distributions in various distances between the worn transmitter coil outside the body and the receiver coil of implant that has a much smaller size provides a means to find the optimal location and angle to harvest maximum energy. The analysis method for near-field wireless power transmission can be utilized to determine design strategies of the transmitter spiral coil with considerations also in the amplifier circuit and physical constraints in practical scenarios to obtain maximum power and link efficiency for the implant devices. The method can be extended to investigate field distributions affected by human tissues, which construct a much more complex environment, and will be conducted in future works.

ACS Style

Minh Quoc Nguyen; Zachariah Hughes; Peter Woods; Young-Sik Seo; Smitha Rao; J.-C. Chiao. Field Distribution Models of Spiral Coil for Misalignment Analysis in Wireless Power Transfer Systems. IEEE Transactions on Microwave Theory and Techniques 2014, 62, 920 -930.

AMA Style

Minh Quoc Nguyen, Zachariah Hughes, Peter Woods, Young-Sik Seo, Smitha Rao, J.-C. Chiao. Field Distribution Models of Spiral Coil for Misalignment Analysis in Wireless Power Transfer Systems. IEEE Transactions on Microwave Theory and Techniques. 2014; 62 (4):920-930.

Chicago/Turabian Style

Minh Quoc Nguyen; Zachariah Hughes; Peter Woods; Young-Sik Seo; Smitha Rao; J.-C. Chiao. 2014. "Field Distribution Models of Spiral Coil for Misalignment Analysis in Wireless Power Transfer Systems." IEEE Transactions on Microwave Theory and Techniques 62, no. 4: 920-930.

Journal article
Published: 22 January 2014 in Micromachines
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We report a novel approach to study cell migration under physical stresses by utilizing established growth factor chemotaxis. This was achieved by studying cell migration in response to epidermal growth factor (EGF) chemoattraction in a gradually tapered space, imposing mechanical stresses. The device consisted of two 5-mm-diameter chambers connected by ten 600 µm-long and 10 µm-high tapered microchannels. The taper region gradually changes the width of the channel. The channels tapered from 20 µm to 5 µm over a transition length of 50 µm at a distance of 250 µm from one of the chambers. The chemoattractant drove cell migration into the narrow confines of the tapered channels, while the mechanical gradient clearly altered the migration of cells. Cells traversing the channels from the wider to narrow-end and vice versa were observed using time-lapsed imaging. Our results indicated that the impact of physical stress on cell migration patterns may be cell type specific.

ACS Style

Smitha M. N. Rao; Uday Tata; Victor K. Lin; Jung-Chih Chiao. The Migration of Cancer Cells in Gradually Varying Chemical Gradients and Mechanical Constraints. Micromachines 2014, 5, 13 -26.

AMA Style

Smitha M. N. Rao, Uday Tata, Victor K. Lin, Jung-Chih Chiao. The Migration of Cancer Cells in Gradually Varying Chemical Gradients and Mechanical Constraints. Micromachines. 2014; 5 (1):13-26.

Chicago/Turabian Style

Smitha M. N. Rao; Uday Tata; Victor K. Lin; Jung-Chih Chiao. 2014. "The Migration of Cancer Cells in Gradually Varying Chemical Gradients and Mechanical Constraints." Micromachines 5, no. 1: 13-26.

Research article
Published: 19 January 2014 in Journal of Nanotechnology
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Nanoparticles (NPs) have been introduced as a suitable alternative in manyin vivobioapplications. The risks of utilizing nanoparticles continue to be an ongoing research. Furthermore, the various chemicals used in their synthesis influence the cytotoxic effects of nanoparticles. We have investigated the cytotoxicity of Porous Hollow Au Nanoparticles (PHAuNPs) on cancer cell lines PC-3, PC-3ML, and MDA-MB-231 and the normal cell line PNT1A. Cell proliferation for the different cells in the presence of different concentrations of the PHAuNPs was assessed after 24 hours and 72 hours of incubation using MTT assay. The study also included the cytotoxic evaluation of pegylated PHAuNPs. Identical cell seeding densities, particle concentrations, and incubation times were employed for these two types of Au nanoparticles. Our results indicated that (1) impact on cell proliferation was concentration dependent and was different for the different cell types without cellular necrosis and (b) cellular proliferation might be impacted more based on the cell line.

ACS Style

Smitha Rao; Chienwen Huang; Uday Tata; Peter Wu; Nikhil Arora; Jinsung Ahn; Victor K. Lin; Yaowu Hao; J.-C. Chiao. Evaluation of Cytotoxic Effects of Different Concentrations of Porous Hollow Au Nanoparticles (PHAuNPs) on Cells. Journal of Nanotechnology 2014, 2014, 1 -7.

AMA Style

Smitha Rao, Chienwen Huang, Uday Tata, Peter Wu, Nikhil Arora, Jinsung Ahn, Victor K. Lin, Yaowu Hao, J.-C. Chiao. Evaluation of Cytotoxic Effects of Different Concentrations of Porous Hollow Au Nanoparticles (PHAuNPs) on Cells. Journal of Nanotechnology. 2014; 2014 ():1-7.

Chicago/Turabian Style

Smitha Rao; Chienwen Huang; Uday Tata; Peter Wu; Nikhil Arora; Jinsung Ahn; Victor K. Lin; Yaowu Hao; J.-C. Chiao. 2014. "Evaluation of Cytotoxic Effects of Different Concentrations of Porous Hollow Au Nanoparticles (PHAuNPs) on Cells." Journal of Nanotechnology 2014, no. : 1-7.