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Research projects

The following projects are part of the Biosensing Research Experience for Undergraduates (REU).

Project description and student learning:

The long-term goal of this REU research project is to understand how plants decode environmental stress-triggered local and systemic long-distance calcium signals during and after stress perception. To achieve the long-term research goal, our research team has been focusing on characterizing local and systemic cytosolic calcium signaling under various naturally occurring environmental stresses. One of these stresses is mechanical wounding stress, which can occur during growth through herbivory activities, wind blows and insect attacks. The research question, therefore, to be tested is how small cellular second messenger molecular calcium is involved in sensing and delivering stress-specific information as a cellular signaling molecule. The key approach to address the initial question is detecting the cellular calcium changes during plants’ stress responses, especially mechanical wounding stress. The research approach will be using genetically encoded protein-based cellular calcium biosensor. Our research team has developed a fluorescence protein-based cellular calcium biosensor to address many research questions, including the question mentioned above. The developed protein-based calcium biosensor is composed of two fluorescence proteins, “red fluorescence protein(RFP) called mCherry” and “green fluorescence protein (GFP)-based GCaMP6f,” and named CGf. Due to the fact that this calcium biosensor CGf was engineered by fusing RFP-based mCherry, an internal fluorescence reference, to GFP-based GCaMP6f, a calcium change indicator that directly associates and dissociates with cellular calcium upon changes in cellular calcium concentration, CGf provides the capability of measuring real-time calcium changes in plants by imaging RFP and GFP signals and measuring ration of GFP signals over RFP signals.

To take advantage of the newly developed cellular calcium biosensor CGf, REU researchers will express CGf into model plants Arabidopsis and model crop tomatoes to detect the wounding-triggered maximum calcium concentration and duration between calcium increase and decrease at the local site of wounding and distal systemic tissue. Therefore, REU students will utilize a high-end fluorescence microscope, which is fully automated with a package of analysis software modules, to capture real-time calcium changes in plants during wound stress response and the software package to calculate the ratio of CGf, indicating cellular calcium changes. Through the REU project from this research period, students will learn mechanisms of genetically engineered protein-based small molecule biosensors, how to develop genetically engineered small molecule biosensors, the biological functions of wound stress-triggered calcium signaling, and the strategies for improving plants’ stress resilience.

Faculty advisor:

Head shot of Won-Gyu Choi

Biochemistry & Molecular Biology Associate Professor Won-Gyu Choi
Dr. Won-Gyu Choi is from South Korea. He received his B.S./M.S. in biotechnology from Woosuk University in Korea and his Ph.D. in biochemistry and cellular and molecular biology from the University of Tennessee, Knoxville, in 2009. While earning his Ph.D., he studied characterizing biochemical and biological functions of members of aquaporins in Arabidopsis in plant development and stress responses. Then, as a postdoc at the University of Wisconsin-Madison, Dr. Choi began studying long-distance signals such as systemic calcium and ROS signaling in plants. He joined the 91�� in fall 2016 and is an associate professor at the Department of Biochemistry and Molecular Biology in the College of Agriculture, Biotechnology and Natural Resources (CABNR). He continues his study of the biological functions of long-distance calcium and ROS signaling in plants such as Arabidopsis, rice and tomatoes in response to environmental stresses such as temperature stresses, water stress and mechanical stress.

Phone: (775) 682-7336
Email: wgchoi@unr.edu
Building: HMS
Room: 217
Mailstop: 330

Project description and student learning:

Exfoliation is a low-cost manufacturing technique for producing 2D metal-oxide/metal thin films. Conventional methods of producing 2D thin films are costly and require expensive tools/operations. In this REU project, students will get the opportunity to have hands-on research training on low-cost methods of producing 2D thin films on PCB substrates. Surface characterizations (SEM and EDS analyses) will ensure the successful preparation of the thin films, which will be leveraged for interfacial adsorption studies. Once the film is produced, students will test the surface for interfacial studies of liquids and gases.

Fundamental principles of interfacial studies will enable students to understand basic science practices. Lastly, students will be able to test and differentiate different molecules so that the platform can be utilized as an interfacial sensor. Toward that goal, interdigitated electrodes will be leveraged for automated data acquisition, sensor calibration, specificity and sensitivity analyses.

Faculty advisor:

Head shot of M. Rashed Khan

Chemical & Materials Engineering Assistant Professor M. Rashed Khan
Dr. Khan’s Advanced Interfaces and Soft Materials (AIM) laboratory leverages multidisciplinary expertise in basic science (chemistry, biology and physics) and engineering principles to study interfaces of soft materials, i.e., polymers, gels and liquid metals. Dr. Khan’s group explores the human brain — the most complex soft materials — and leverages the acquired knowledge to solve basic research and societal problems. Towards that, we frequently need to utilize the fundamental understanding of microfluidics, surface chemistry, electrochemistry, molecular rheology and data-driven ML/AI models. Dr. Khan’s group has ongoing federally-funded research collaborations with the Nevada Center for Water Resiliency (NCWR) and the Nevada Water Innovation Institute (NWII) to solve problems associated with water resiliency and self-sufficiency. Also, Dr. Khan’s group studies neurodegenerative diseases in collaboration with neurosurgeons (Mayo Clinic, MN), neuroscientists (University of UNR), ML/AI experts (CSE, UNR), sensor and data experts (EBME, UNR and EE, UTT), and FSI-specialists (ME, UNR).

Phone: (775) 784-1798
Email: mrkhan@unr.edu
Building: LME
Room: 307
Mailstop: 0388
Website:
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Project description and student learning:

Researchers persistently strive to enhance the attributes of biosensors, encompassing heightened sensitivity, exceptional selectivity, swift response times, versatile multi-detection capabilities and cost-effective, uncomplicated fabrication processes. This study will focus on developing an advanced optical fiber-based plasmonic biosensor with high sensitivity and a low detection limit to rapidly and accurately detect target analytes. The proposal focuses on utilizing Surface Plasmon Resonance (SPR) technology, which involves detecting changes in the optical properties of metal-dielectric interfaces caused by the binding of target analytes. The research findings could significantly impact healthcare, diagnostics and environmental monitoring, contributing to improved public health and safety. The main project goal is to design and fabricate an optical fiber-based plasmonic biosensor with enhanced sensitivity and specificity. This biosensor will incorporate a biological recognition element in contact with a transduction element to convert biological events into measurable signals efficiently.

Students will learn interdisciplinary exploration approaches across optical sensing, nanotechnology, material science and biochemistry. Tasks encompass:

Simulation and modeling: Employ tools like COMSOL Multiphysics for biosensor simulation. Optimize design parameters to enhance sensitivity and efficacy.
Material preparation: Experiment with sol-gel methods to create varied-porosity AZO, po-AZO thin films and nanofiber coatings. Master material formation with diverse dopant concentrations.
Device fabrication: Employ lab techniques to deposit nanoparticles, nanofibers and thin films onto optical fibers, actualizing proposed biosensor structures.

Faculty advisor:

Electrical & Biomedical Engineering Associate Professor Jeongwon Park
Dr. Park joined the Department of Electrical and Biomedical Engineering at the 91��, as an associate professor in July 2019. Prior to that, he was an associate professor at the School of Electrical Engineering and Computer Science at the University of Ottawa, Canada (2016-2021, currently adjunct professor) and a scientist at SLAC National Accelerator Laboratory, Stanford University (2014 -2016). For six years (2008-2014), he served as a senior technologist to support the corporate chief technology officer (CTO) and business units at Applied Materials. In addition, he has been a guest researcher at Lawrence Berkeley National Laboratory (2005-2008), an adjunct professor in the Department of Electrical Engineering at Santa Clara University (2009-2016) and a visiting scholar in the Department of Electrical Engineering at Stanford University (2013-2014).

Phone: (775) 784-6975
Email: jepark@unr.edu
Building: SEM
Room: 329
Mailstop: 0260
Website:
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Project description and student learning:

REU students first will learn how to characterize our nanocrystals with respect to their optical properties (brightness, optical spectra and lifetime) as well as the concept/instrument of time-resolved luminescence measurement. They then will work on the development of the bioassays using NCs with long luminescence lifetime as signal transducers. The detailed assay development will include the preparation of all reagents such as capture antibody, antigen, detection antibody conjugated with nanocrystals, the optimization of bioassay parameters (e.g., the amount of capture antibody, the assay time, etc.) towards achieving a lower limit of detection, and the assay signal reading using both time-resolved and non-time-resolved luminescence instruments to compare the assay performance.

Faculty advisor:

Xiaoshan Zhu in a lab holding up a beaker

Electrical & Biomedical Engineering Associate Professor Xiaoshan (Sean) Zhu
Dr. Zhu’s group has been developing safe and scalable synthetic routes of I(II)-III-VI NCs (e.g., Cu-In-S/ZnS and Ag-In-S/ZnS) where nonstoichiometry or doping strategies are further applied to achieve excellent optical properties. Specifically, his group is interested in adopting transition metals to dope these quaternary NCs to achieve NC optical properties benefitting their specific applications in biosensing/imaging. These desired optical features include long fluorescence lifetimes, low excitation energy levels, no emission reabsorptions and high brightness. To achieve these features, his group studies the effects of the interaction of dopant energy levels with host NC lattice fields on NC optical properties. The experimental approaches include tuning host NC compositions, which determine host NC lattice fields, as well as changing dopant spatial distribution and concentrations in host NCs. Dr. Zhu’s group also is applying these NCs for biomedical applications.

Phone: (775) 682-6298
Email: xzhu@unr.edu
Building: SEM
Room: 337A
Mailstop: 0260
Website:

Project description and student learning:

We will design recyclable sensing materials using reversible dithioacetal polymers developed in our lab. The polymer is capable of dynamic transformations of macromolecular structures, which will allow us to develop sensing functionalities during this project and be able to degrade back to the monomers after use. Dynamic covalent polymers based on numerous functional groups such as disulfides, thioesters, lactones, carbonates, acetals, etc. have received increasing interest in the past decade. The use of dithioacetal chemistry has not been widely investigated in polymer chemistry. We have demonstrated that linear polydithioacetals can be synthesized from dithiol and benzaldehyde monomers. They depolymerize in refluxing toluene to form a mixture of macrocyclic dithioacetal compounds. The degradation products can be readily repolymerized to the original material at room temperature. Given their straightforward synthesis, tunability and inherent recyclability, this project will expand the functionalities of dithioacetal polymers for biosensing applications. Students will learn how to synthesize polymeric materials from small molecules, characterize their structures and evaluate their thermal, mechanical and sensing properties.

Faculty advisor:

Head shot of Ying Yang

Chemistry Assistant Professor Ying Yang
Dr. Yang is an NSF CAREER Awardee of 2023. Research at the Yang Lab in the Department of Chemistry at the 91��, is at the interface of chemistry and materials. Dr. Yang and her group design and synthesize functional polymers with inherent recyclability for various applications. As biosensors are becoming more widely used for health monitoring, their end-of-life management must be considered. The sensing devices often contain parts that are made of plastics, adhesives or hydrogels, which are not recyclable. For example, the mass use of COVID test kits during the pandemic generated large amounts of plastic waste. Thus, there is a pressing need to design biosensing devices with sustainability in mind.

Phone: (775) 327-2227
Email: yingy@unr.edu
Building: CB
Room: 316C
Mailstop: 0216
Website:

Project description and student learning:

Targeted delivery and real-time molecular diffusion of drugs into synthetic hydrogels have the potential to bring new insights into treating diseases such as brain cancer. However, delivery methods and molecular diffusion studies are poorly understood in the literature. Real-time diffusion analyses are even more complicated, requiring alternative engineering tools currently nonexistent in the literature. Towards that broader goal, in this project, students will be able to discover how neuroimages are leveraged to produce tissue-mimicking soft materials. A range of delivery systems will be tested to analyze diffusion in soft materials. In-situ determination of drug dispersion will be studied, leveraging materials compatible with tissue-related studies. Students will focus on answering fundamental questions, which will help them broaden their biomedical, neuroscience and neuroengineering knowledge.

Faculty advisors:

Psychology Associate Professor Lars Strother
Dr. Lars Strother is an associate professor of cognitive and brain sciences in Psychology. He is also the director of the 91��’s NIH Center of Biomedical Research Excellence (COBRE) Neuroimaging Facility, part of the Center for Integrative Neuroscience. The facility provides access to state-of-the-art brain imaging technology, including Magnetic Resonance Imaging (MRI). The facility also provides technical support for acquiring MRI-based data including diffusion imaging and functional MRI and resources for analyzing various MRI data. Dr. Strother’s lab focuses on the use of MRI to study cognitive, perceptual and motor systems in the human brain.

Department: Psychology
Department: Institute for Neuroscience
Phone: (775) 682-8678
Email: lars@unr.edu
Building: EMM
Room: 404
Mailstop: 0296

Head shot of Rashed Kahn

Phone: (775) 784-1798
Email: mrkhan@unr.edu
Building: LME
Room: 307
Mailstop: 0388
Website:
Website:

Project description and student learning:

Oxide-based materials are known for their multifunctionality. They have been used successfully in catalysis, light-driven reactions and electrochemical processes. As a result, they have found applications in the fields of energy, environment and biotechnology. Further, the role of oxide type, shape, size, aspect ratio and geometry have shown interesting optical, catalytic, electronic and mechano-chemical properties. Depending on the type of oxide used, multiple of the aforementioned properties can be tailored for a specific application. Besides, oxides also can function as a robust and reliable platform to incorporate other materials such as organics and inorganics to achieve specialized tasks or improve the properties of the underlying oxide. In this study, we will focus on the application of one such oxide with the following specific goals.

The impact of the shape and features of a representative oxide on electrochemical properties
Evaluation of the features of oxide and its effects on chemical and/or biochemical sensing
Role of additives in promoting the effective sensing using an oxide-based platform

This project will involve teaching how to synthesize an oxide of various shape and features. Simple optical-based characterization and more complex surface-based characterization of the oxide will be taught. Basic electrochemical characterization tools will be introduced to the students. Based on the type of data obtained, the students will be provided with appropriate analytes as the target for sensing. The results of surface features and oxide shape will be co-related with the analyte detection. If the student is interested, cross-cutting applications involving sensing also will be offered on a case-to-case basis. While candidates with background in physical chemistry, materials synthesis, biology / environmental science / earth science are encouraged to apply, all interested students are welcome as well.

Faculty advisor:

Head shot of Ravi Subramanian

Chemical & Materials Engineering Associate Professor Ravi Subramanian
Dr. Subramanian’s research focus on metal-oxide-based sensors for environmental monitoring.

Phone: (775) 784-4686
Email: ravisv@unr.edu
Building: LME
Room: 309
Mailstop: 0388

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Research projects

Tissue Engineering for Biosensing

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Understanding of Mechanical Wound-triggered Calcium Signaling in Plants

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Exfoliated Metal-Oxide/Metal Thin Films to Differentiate Emerging Molecules

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Optical Fiber-Based Biosensors

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Time-Resolved Luminescence Bioassays Using Long-lived Luminescence Nanocrystals

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Development of Sustainable Sensing Materials

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In-situ Sensing of Molecular Diffusion Harnessing Soft Materials Derived from Neuroimages

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Development of Metal Oxide-Based Sensors for Biochemical Applications

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