My research is focused on developing next-generation field-deployable molecular imaging, sensing, and diagnostic tools for plants and human. These tools are essential to translate conventional laboratory diagnostic tests from the bench to the point of care for rapid field detection, personal health monitoring, as well as battling infectious diseases in the resource-limited settings. My group is currently studying two main research schemes, including the development of new portable microscopy devices for single-molecule detection as well as novel lab-on- a-chip systems for rapid sample preparation such as DNA extraction, amplification, and sequence-specific labeling. We also develop nanophotonics enhanced molecular diagnostic assays towards ultra-sensitive analysis. Our work spans broadly at the interface of engineering, chemistry, nanoscience, and biology.
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Honors and Awards
- Honorable Mention, the Chancellor’s Award for Postdoctoral Research, UCLA
- Bilsland Dissertation Fellowship, Purdue University
Postdoc Bioengineering University of California - Los Angeles 2016
Ph.D. Chemistry Purdue University 2012
M.S. Polymer Materials and Engineering Zhejiang University 2007
B.S. Polymer Materials and Engineering Zhejiang University 2005
- Liquid Metal-Based Biosensors: Fundamentals and Applications , ADVANCED FUNCTIONAL MATERIALS (2024)
- A Ratiometric Nonfluorescent CRISPR Assay Utilizing Cas12a-Induced Plasmid Supercoil Relaxation , (2023)
- Abaxial leaf surface-mounted multimodal wearable sensor for continuous plant physiology monitoring , SCIENCE ADVANCES (2023)
- CRISPR-Cas Biochemistry and CRISPR-Based Molecular Diagnostics , ANGEWANDTE CHEMIE-INTERNATIONAL EDITION (2023)
- Low-rate smartphone videoscopy for microsecond luminescence lifetime imaging with machine learning , PNAS NEXUS (2023)
- Precise in-field molecular diagnostics of crop diseases by smartphone-based mutation-resolved pathogenic RNA analysis , NATURE COMMUNICATIONS (2023)
- Single-use biosensors for biomanufacturing: Perspective on the state-of-the-art , CURRENT OPINION IN BIOMEDICAL ENGINEERING (2023)
- Unidirectional trans-cleaving behavior of CRISPR-Cas12a unlocks for an ultrasensitive assay using hybrid DNA reporters containing a 3' toehold , NUCLEIC ACIDS RESEARCH (2023)
Sub-picomolar lateral flow antigen detection with two-wavelength imaging of composite nanoparticles, BIOSENSORS & BIOELECTRONICS (2022)
- A Sensitive and Nonoptical CRISPR Detection Mechanism by Sizing Double-Stranded lambda DNA Reporter , ANGEWANDTE CHEMIE-INTERNATIONAL EDITION (2022)
In this proposal, we aim to study and develop a transformative plant wearable sensor that can be deployed on-plant for continuous monitoring of biotic and abiotic stresses of plants and their microenvironment to inform plant health status and early detection of plant diseases. This multifunctional plant wearable sensor will include an array of ligand-functionalzied chemiresistive sensors to profile plant leaf VOCs and nanowire-based flexible sensors to monitor microclimate in parallel. The sensors will be prepared on a light-transparent, gas-permeable, and stretach substrate for long-term wearibility on live plants. In addition, a signal transmitter will be developed for wireless data acquistion and transmission. The system will be thourughly tested on tomato plants in the greenhouse for stress monitoring and disease detection.
This CAREER proposal seeks to study the fundamental properties of CRISPR Cas proteins for nucleic acid detection through collateral nonspecific cleavage (or trans-cleavage). Systematic characterization, optimization, and control of the enzyme activity and kinetics of Cas proteins will convert genome-editing CRISPR-Cas platform into next-generation, rapid, and ultrasensitive biosensors. However, the detailed mechanism and properties of trans-cleavage are still not fully understood yet. Moreover, many existing CRISPR biosensors require pre-amplification steps to achieve high detection sensitivity, which significantly hinders their point-of-care (POC) applications. Our recent data (see Section RO1) suggest that trans-cleavage kinetics of Cas proteins in a one-pot reaction is different from the literature reports of pre-assembled and activated Cas-crRNA complex. Therefore, a revised enzymatic model is needed to accurately describe the enzymatic properties of CRISPR biosensor. As such, the overarching goal of this work is to understand and control the unique characteristics of CRISPR trans-nuclease and use the knowledge gained to design a chip-based, preamplification-free digital CRISPR (dCRISPR) sensor chip. The sensor chip will be coupled with a newly designed smartphone scope, EpiView, to form a cost-effective, smartphone-based testing platform for POC measurement of viral load of the human immunodeficiency virus (HIV) from finger prick blood.
Project is in support of PSI. We have developed faster and more reliable in-field detection methods for plant pathogens that will greatly reduce plant disease by reducing time from occurrence to detection and thus time to mitigation. Two new innovations in sensor technology have been developed including a smart-phone field-compatible molecular assay that uses a loop-mediated isothermal amplification (LAMP) sensor and a volatile-based sensor that will speed identification of plant pathogens in the field. In this project renewal, we will continue deploy and field test work a volatile organic compound (VOC) sensor and microneedle patch-supported LAMP sensors to differentiate two regulatory Phytophthora species of concern, P. ramorum and P. kernoviae. Phytophthora ramorum and P. kernoviae cause disease on nursery plants such as rhododendron, lilac and kalmia and important forestry tree species including oak and beech among others. Phytophthora kernoviae has not yet been found in the US. We will test the sensors in field tests and deploy them with inexpensive cartridges to run on a smartphone reader. We will also complete the modeling of historic late blight disease occurrence data using a near-real time mapping platform and the process based spatially explicit discrete time PoPS (Pest or Pathogen Spread) Forecasting Platform to develop predictive maps of pathogen risk of spread at regular intervals. The system will improve the response time of USDA APHIS PPQ and National Plant Diagnostic Network (NPDN) personnel to respond to emerging Phytophthora threats and improve economic return of growers as they use the digital diagnostic tools to prevent the spread of important Phytophthora diseases.
Emerging plant disease and pest outbreaks reduce food security, national security, human health, and the environment, with serious economic implications for North Carolina growers. These outbreaks may accelerate in coming decades due to shifts in the geographic distributions of pests, pathogens and vectors in response to climate change and commerce. Data-driven agbioscience tools can help growers solve pest and disease problems in the field more quickly but there is an urgent need to harness game-changing technologies. Computing devices are now embedded in our personal lives with sensors, wireless technology, and connectivity in the ÃƒÂ¢Ã¢â€šÂ¬Ã…â€œInternet of ThingsÃƒÂ¢Ã¢â€šÂ¬Ã‚Â (IoT) but these technologies have yet to be scaled to agriculture. Our interdisciplinary team will build transformative sensor technology to identify plant pathogens, link local pathogen data and weather data, bioinformatics tools (pathogen genotypes), and use data driven analytics to map outbreaks, estimate pest and pathogen risk and economic damage, in order to coordinate response to emerging diseases, and contain threats. Sensor-supported early and accurate detection of pathogens before an outbreak becomes wide-spread in growing crops will significantly reduce pesticide use and increase crop yields.
This project aims to develop a microfluidic filtering and imaging device for rapid sterility testing in biomanufacturing of biologics such as nucleic acid products and proteins. Current sterility testing is costly and time-consuming, requires a large sample volume, and is not amenable to in-line/continuous processes. In this project, a miniaturized testing chip that can perform pathogen separation, labeling and imaging will be developed to enable rapid sterility testing.