Chunlei Wang, Ph.D. - US grants

Proposal Number: CBET-0709085
Principal Investigator: Madou, Marc
Affiliation: U. California Irvine
Proposal Title: NIRT: C-MEMS/C-NEMS for Miniature Biofuel Cells

In recent years, the quest for alternative sources that can autonomously power bioMEMS devices, especially those geared for in vivo applications, such as monitoring and drug delivery, has been the focus of research by scientists and engineers as new power sources will prove critical for the advancement of the field. Current batteries are still less than optimal and often present drawbacks related to safety, reliability and scalability. An ideal power source for implantable devices should take advantage of natural compounds present in the body of an individual and use them as fuel to produce power in a continuous and reproducible manner, as long as the patient's physiological functions remain steady. Biofuel cells, which are capable of converting biochemical energy into electrical energy, have been deemed as a potential solution to the drawbacks presented by conventional batteries, but the power density and operational lifetime requirements for implanted devices have not been met yet. To that end, we propose to integrate genetically engineered catalytic proteins and carbon-based 3 dimensional (3D) MEMS/NEMS structures to create new biofuel cells. The biofuel cell electrode surfaces, especially fractal electrode array, presents significantly increased surface area as compared to traditional architecture, increasing the biocatalyst loading capacity considerably for high power throughput. The genetically engineered enzymes inherently increase enzyme stability, consequently increasing biofeul cell lifetime. The scaled fractal electrode surface plays a role in wiring the enzymes to the biofuel cell anode, which increases the electron transfer efficiency from the enzyme to the electrode for an increase in the overall performance of the biofuel cells. Furthermore, C-MEMS/C-NEMS architectures will enable the reproducible fabrication of low cost carbon-based electrode structures.

We envision that this project will have an impact on the MEMS, NEMS and bioMEMS communities. Given that C-MEMS/NEMS technologies can be used in a number of fields as a substitute for siliconbased devices, the proposed technology should find applications not only in energy-related areas, such as biofuel cells, micro-batteries and super capacitors, but also in others, such as biosensing, drug delivery and actuators. The C-MEMS/NEMS approach gives the development engineers unprecedented freedom in the design and manufacture of high surface area conductive structures through the use of new materials and innovative fabrication techniques. The development of biofuel cells based on producing high aspect ratio 3D carbon structures in the mm to nm range by integrating ?top-down? and ?bottom-up? processing approaches and combining biological components with MEMS/NEMS structures should present advantages over traditionally used Si-based materials. Moreover, this could start a trend in the lithographic patterning of materials other than Si. Further, the proposed technologies could also have an impact on other industries and on the end-users. For example, the point-of-care diagnostic market, including implantable biosensors that track blood glucose levels and deliver insulin, is approximately a $7 billion to $8 billion market growing at around 10% per annum. Since our biofuel cells are ideal for use in miniaturized medical devices, we expect that they could have an impact both in in vivo as well as in vitro diagnostics and point-of-care situations.

The PIs have a well-established productive collaboration that has resulted in a good number of joint publications, grants, and advising of graduate and postdoctoral students. This project will further enhance the current interdisciplinary and collaborative effort of the groups of Dr. Madou at UCI, Dr. Wang at FIU and Drs. Bachas and Daunert at UK. The proposed collaborative research will allow us to combine ?bottom-up? biotechnology with ?top-down? micro/nanomanufacturing techniques for bio MEMS/NEMS applications. Such work will foster interdisciplinary interactions and will train students with different backgrounds, i.e., chemical/materials engineering, mechanical engineering, electrical engineering, and chemistry, in the broad areas of micro/nano fabrication of novel biomedical sensing devices and high capacity miniaturized power sources. Workshops and outreach programs will be conducted to broadly disseminate the results of this work and raise awareness to students (undergraduates and K-12) and the general public in bioMEMS and Nanobiotechnology. Moreover, this project broadens the participation of women in multidisciplinary science and engineering.

This award provides funds to the Florida International University to acquire a Nanoimprinter for research and education. Nanoimprinting is not governed by the optical diffraction limit and has the capability of large area exposures with high throughput. It will enable researchers at FIU?s open-access lab to conduct several main cutting edge research projects, such as: the development of micro-batteries based on carbon nanoelectrodes; integrated nano-photonic devices based on polymers; the mechanics of nanostructured polymer materials; DNA array biomedical devices; Micro/Nano fluidic devices; and carbon-nanotube sensors. The proposed activities will advance knowledge in and across different fields. By acquiring this next level of capability, FIU researchers and collaborators will be able to perform research on nanotechnology devices and processes that have great potential for actual applications.
The successful development of the proposed projects, enabled by the Nanoimprinter acquisition, has broad implications in health care and homeland security. This instrumentation research will integrate undergraduate and graduate student?s training. Existing hands-on laboratory courses will be expanded to include experiments with this new nanoscale mass-production technology. Together with the exciting research topics, the enhanced infrastructure for research at FIU - one of the top Hispanic Serving Institutions in Florida - will attract more students from our underrepresented population into graduate school. A big impact on increasing the number of students in materials science, biomedical and electrical engineering from traditionally underrepresented groups is expected. Exposing graduate and undergraduate students to this new technology in an open-access laboratory will also help to boost interdisciplinary and multidisciplinary research collaboration across various research groups, blurring the boundary of departments and even institutions. The Nanoimprinter will be placed in the existing open-access Motorola Nanofabrication Research Facility, and will be easily accessible to campus users as well as other academic and industry users in south Florida.

In order to develop highly reproducible, highly selective, and miniaturized sensitive electrical DNA sensing platform, it is important to develop and study sensor-biological interface that is compatible with microfabrication processing and also provide the requisite sensitivity and stability when exposed to biological environments. Recent developments in Carbon-MicroElectroMechanical Systems and Carbon-NanoElectroMechanical Systems have led to simple fabrication techniques that result in novel micro/nano-scale carbon structures with high-aspect-ratio and high surface area. The research objective of this award is to advance fundamental research in the use of pyrolyzed carbon as a bio-sensing electrode material by testing and engineering various types of carbon electrodes with high surface areas and different arrangements, developing methods of increasing the surface immobilization efficiency of bio molecules, engineering techniques for bio molecules immobilization on polymer/carbon interfaces, and further understanding fundamental chemical and electrochemical phenomena occurring at or near bio/carbon or bio/polymer/carbon interfaces.

If successful, the results of this research will provide an opportunity to create next generation highly sensitive and highly selective inexpensive portable biosensors. This research will broaden the participation of women and minority students in science and engineering, and also foster interdisciplinary interactions with students (especially Hispanic minority students). The research results will be broadly disseminated to enhance scientific and technological understanding through presentation at conferences and publication in journals. In this project, we will effect graduate and undergraduate education and try to raise the awareness in state-of-arts MEMS device and biotechnology for elementary and high school students in local area. Newly developed technique will be highlighted in graduate courses.

This award is funded under the American Recovery and Reinvestment Act of 2009 (Public Law 111-5).

The goal of this project is to provide American student participants with a global perspective and opportunities for professional growth through international cooperative research training, networking and mentoring in the BioMEMS research field. This project will provide high quality educational and research experiences for 12 graduate and undergraduate students at Florida International University through active research participation in collaboration with the Kawarada research team at Waseda University in Japan. Each student will spend three months in summer to work with the Kawarada research group. Typical research topics include functionalization of carbon-based surfaces, diamond-based DNA sensors, and carbon-based bio-fuel cells. The knowledge that will result from this project is critically needed for breakthroughs required for the development of carbon based BioMEMS for energy and biological applications. This project will foster interdisciplinary interactions with investigators and students at all levels. Research results obtained from this project will be presented at various conferences and published in various journals. This project will broaden the participation and impact the recruitment of underrepresented groups, especially women and Hispanic students.

The development of miniaturized electronic systems such as smart cards, wireless sensors and sensor networks, and implantable devices, has stimulated the demand for miniaturized power sources. For these electronic devices, the power need ranges from several microwatts to hundreds of milliwatts, and the energy requirement is from several hundreds of microwatt-hours to several milliwatt-hours. In this project, an advanced and reliable micropower source with high energy density and high power density will be developed and investigated. The nano-enabled miniaturized electrode design is geared to take advantage of the scaling relationship between interface area and overall volume. This project will leverage and transform the PI's past and current research effort on microsupercapacitors and microbatteries into developing and investigating a novel hybrid micropower system. The fabrication method involved in this system is compatible with the semiconductor manufacturing process. The novel system could be integrated with microchips, energy harvesters, power management systems and sensing components. Through fundamental research, key insights into the physical and chemical processes that occur in the electrochemical power system can be obtained. The resulting knowledge is critically needed to achieve breakthroughs that are required for the development of on-chip level micropower. This project will engage graduate and undergraduate students in cutting-edge research, and broaden the participation of minority students and women in science and engineering. The newly developed techniques and research results will be broadly disseminated to the general public.

The objective of this project is to develop a hybrid micropower source with high energy density and high power density. An asymmetric on-chip level battery type hybrid microsupercapacitor will be designed, fabricated and investigated. This device will be a combination of a high power handling double-layer electrochemical capacitor microelectrode and a Li-ion based rechargeable battery microelectrode. In this research, an interdigital high-aspect-ratio microelectrode platform will be constructed by photolithography. Electrochemical active materials will be fabricated by electrostatic spray deposition. The design rules of the micropower system will be investigated based on balancing multiple factors, such as: charge, power, cycle life, and voltage window. The performance of the hybrid on-chip micropower system will be evaluated and optimized. The project will deliver a reliable stand-alone power source, that could be used as backup power for other energy harvesting systems. The unique electrode array architecture offers exciting possibilities for the optimization of ion and electron transport and capacity. This project will effectively integrate research and education in emerging micro- and nano-fabrication for on-chip micropower applications, and broaden the participation of minority students and women in science and engineering.

NON-TECHNICAL DESCRIPTION: In this project, tin oxide-coated carbon nanotubes are being used as a model material to investigate the mechanism for lithium storage. Tin oxide is considered one of the most promising metal-oxide anode materials for lithium ion batteries due to its high lithium ion storage capacity. However, the practical application of tin oxide as anode material is restricted by its large volume change (up to 300%) during charge-discharge cycles, which can cause its disintegration and electrical disconnection from the current collector. To circumvent this problem, a three-dimensional carbon nanotube-tin oxide core-shell nanowire array is being developed by growing tin oxide shells on vertically-aligned carbon nanotubes. The carbon nanotubes serve as the backbone of the tin oxide shell to buffer the large volume change, while the cylindrical tin oxide shell alleviates its degradation during the lithiation process. This project's outcomes will be beneficial to conventional lithium ion battery research and development, as well as on-chip micropower development. A better understanding of the electrochemical properties is making a significant contribution to the development and rational design of three-dimensional hierarchical electrode nanomaterials for lithium ion batteries. Each year, these researchers provide two public lectures to convey new knowledge of material science and technology. A diverse set of students are engaged in the research at Florida International University, a Hispanic-Serving Institution. Each year, graduate and undergraduate students participate in the research, and they have the opportunity to work at Sandia National Laboratories. Annually, 60 high school students and 10 high school teachers are invited for on-campus lab tours and research demonstrations.

TECHNICAL DETAILS: Carbon nanotube-metal oxide core-shell composite materials are promising candidates for application as anode materials in lithium ion batteries. However, the electrochemical lithiation-delithiation behavior and mechanism of this type of materials remain unclear. A comprehensive understanding of the lithiation mechanism at the nanoscale benefits the design and development of high-performance lithium ion battery materials. This project develops a synergistic approach for the synthesis and characterization of vertically aligned carbon nanotube-tin oxide core-shell nanowire arrays to manipulate their electrochemical property at the time of synthesis. The vertically-aligned carbon nanotube arrays are synthesized directly on a current collector using plasma enhanced chemical vapor deposition, and the tin oxide shell on the carbon nanotubes is synthesized via chemical-solution and vapor deposition routes. The microstructure and the electrochemical properties of the carbon nanotube-tin oxide core-shell nanowires are being investigated by a combination of electron microscopy, electron energy loss spectroscopy, energy dissipation spectroscopy, X-ray diffraction (both in situ and ex situ), charge-discharge measurement, cyclic voltammetry, electrochemical impedance spectroscopy, and in situ transmission electron microscopy observation of the lithiation process. The study provides a better understanding of the lithiation mechanism of the core-shell nanowire array and the influence of their microstructure on their electrochemical properties. The research results provide new insight into the electrochemical process of carbon nanotube-metal oxide composite materials in lithium ion batteries. Graduate and undergraduate students receive research training in advanced electrochemical material synthesis, characterization and design.

Title: 3D C-NEMS Based Aptasensors

Brief description of project Goals: Design, fabricate, evaluate and optimize three dimensional on-chip electrochemical aptasensors based on Carbon-NanoElectroMechanical Systems (C-NEMS).


Nontechnical Abstract:
The increased amount of proteins such as platelet-derived growth factor (PDGF) can be observed in the early tumorigenesis as well as cancer progression. The PI will focus on developing on-chip capacitive aptasensors employing aptamers as recognition element using unique three dimensional graphene based micropillar arrays, which could deliver high sensitivity, good stability and low detection limits. The miniaturized reconfigurable electrode design is geared to take advantage from the scalable relationship between the interfacial area and overall volume. This project will contribute to the research, education, and diversity goals and strongly support FIUBeyondPossible2020 strategic plan. It will broaden the participation of minority students and women in science and engineering, and foster interdisciplinary interactions. Beyond the impact on the microfabrication research community, this project will have broader impact on cancer diagnosis. The knowledge generated and the key issues identified in this project will impact a broad area of sensor fabrication and development.

Technical Abstract:
The increased amount of proteins such as platelet-derived growth factor (PDGF) can be observed in the early tumorigenesis as well as cancer progression. In this project, the PI will focus on developing on-chip aptasensors employing aptamers as recognition element based on unique 3D C-MEMS (Carbon-MicroElectroMechanical Systems) and C-NEMS (Carbon-NanoElectroMechanical Systems) platforms. The goal of this project is to design, fabricate, evaluate and optimize the 3D C-NEMS based on-chip electrochemical aptasensors that deliver superior performance (i.e., high sensitivity, good stability, low detection limits).The PI plans to (1) fabricate 3D high-aspect-ratio microelectrode arrays with interdigital fingers by C-MEMS technique; (2) deposit carbon based nanomaterials onto the C-MEMS using electrostatic spray deposition and electrophoretic deposition; (3) functionalize the whole-carbon platform with active chemical groups for efficient and stable immobilization of aptamers; (4) develop and evaluate an electrochemical label-free aptasensor for PDGF protein detection based on characterizing electrochemical impedance and capacitive behaviors. 3D C-NEMS platform will have great advantages and is one of the best solutions to achieve high-sensitivity biosensors. Employing unique C-NEMS technique aptasensors can be fabricated repeatedly with desired dimensions, structures, and material properties. The miniaturized electrode design is geared to take advantage from the scalable relationship between the interfacial area and overall volume. This project will contribute to the research, education, and diversity goals and strongly support FIUBeyondPossible2020 strategic plan. It will broaden the participation of minority students and women in science and engineering. The newly developed technique will be highlighted in the PI's graduate/undergraduate courses. Beyond the impact on the MEMS and NEMS community in academia, the proposed research will have broader impact on cancer diagnosis. The knowledge generated and the key issues identified in this project will impact a broad area of sensor fabrication and development. It is anticipated that the successful implementation of this device in the clinical arena will have significant impact on the early detection, morbidity, and mortality for the large number of patients with cancers, as well as establishing an innovative realm of biomedical technology.

International research collaboration and globally engaged workforce development are essential to tackle the complex challenges of nanoscience and nanotechnology. The goal of this project is to provide US student participants with a global perspective and opportunities for professional growth through international collaborative research training, networking and mentoring in the field of functional nanomaterials. This project will provide high quality educational and research experiences for 6 graduate and undergraduate students at Florida International University (FIU) through active research participation in collaboration with Kochi University of Technology (KUT) in Japan. Each student will spend 10 weeks in summer to work in a KUT research group. The project will impact total of 18 U.S. student participants, especially underrepresented minority students, with a global perspective and research opportunities for professional growth through international cooperative research training in nanoscience and nanotechnology. It will contribute to development of a diverse and globally engaged workforce with high quality research skills. The project will also help broaden the participation and impact the recruitment and retention of students from underrepresented groups through a series of well-designed and structured recruitment, selection, pre-departure, post-travel, research training and professional development activities. The participating students’ feedback and evaluation will provide guidelines for effective involvement of the faculty and students in international research collaboration and workforce development.

Functional nanomaterials have been attracting much interest because of their unprecedented chemical and physical properties as well as potential applications. In the last twenty years, there is rapid development on synthesis of functional nanomaterials and control of their specific properties which enable unique applications of nanomaterials in nanoelectronics, energy, environmental, and biomedical applications. In parallel to the materials synthesis and devices development, various characterization tools such as high-resolution transmission electron microscopy, X-ray photoelectron spectroscopy (XPS), scanning probe microscopy, surface-enhanced Raman spectroscopy, confocal microscope have allowed us to explore the fundamental studies on the origin of the physiochemical properties of the functional nanomaterials. However, there are several key challenges need to be addressed before the nanomaterials can reach the full potential in the practical applications. This project will address some of the critical need in nanomaterials research field in an interdisciplinary and international collaboration effort. The structure-performance relationship between the nanomaterials and device applications will be studied and established. The project will enable better control of crystallinity and surface functionality of functional nanomaterials, better understanding the origin of the physiochemical properties, and could further enable advanced electronic, photonic, electrochemical, and sensing devices. The knowledge that will result from this project is critically needed for breakthroughs required for the synthesis, characterization, and application of nanomaterials.

This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

Electric double-layer capacitors (EDLC) are a subset of electrochemical capacitors that can store and deliver electrical energy at dc and relatively far-from-dc frequencies with effective capacitance between that of aluminum electrolytic capacitors and secondary batteries. They are mostly employed in conventional energy storage applications as secondary power source, such as microprocessors and solar batteries. They have also been demonstrated as efficient energy devices in oscillators and filters circuits, fractional-order controllers, and fractional-order resonators. However, because of the nature and porous structure of their electrodes and the interfacial electrochemistry of their electrodes/electrolyte phase, many fundamental aspects of their performance metrics are still not well understood, and rational design is practically nonexistent. In particular, EDLCs exhibit a dissipative, resistive-capacitive behavior when operating away from dc with an impedance angle anywhere between -90 and 0 deg. In this project, miniaturized EDLCs based on structured 2D and 3D electrode arrays will be designed and fabricated with the objective of understanding and controlling their non-ideal, fractional-order behavior. We will develop and study the effect of doped electrolytes in order to tune the electric-field-induced ionic transport in the presence of physical obstacles. The expected outcome is a general procedure and design rules to apply in order to fine-tune and control the impedance phase shift of EDLCs and their energy-power performance. Modeling and simulation using mean-field Poisson-Nernst-Plank model will be carried out in order to provide a fundamental understanding of the frequency response of the devices. System-level modeling using fractional-order mathematical tools and equivalent circuit models will also be developed in connection with RC-based circuitry. The controllable fractional-order behavior of the EDLCs will be verified and their frequency-domain application will be demonstrated. This project will contribute to the research, education, and diversity goals of Florida International University.

The objectives of this project are to tackle the lack of knowledge on the frequency-domain metrics and performance of factional-order capacitors using both experimental and modeling approaches. We aim to investigate the following: (1) electrode-electrolyte interface specifications and electrolyte parameters that enable the tuning of the electrical characteristics of an EDLC over an extended frequency bandwidth; (2) the electro-kinetic effects taking place in the supporting electrolyte of an EDLC, and how they affect the frequency-domain metrics of the device; (3) modeling using 3D-circuit interconnects and finite-element methods to understand the overall electric characteristics; and (4) the frequency response of the EDLCs and their application in (frequency-domain) filtering and (time-domain) memory applications.

This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.