Our multidisciplinary research group focuses on nano-micro-macro scale devices for biomedical applications. We develop and deploy innovative materials, devices and systems to enable next-generation medical diagnosis and life science research. We aim to address various challenges in sensitivity, specificity, high-throughput, multiplexing, and cost etc. We are committed to realizing these goals by applying micro and nano-technological towards medical applications.
The projects performed to achieving our over-arching goals are listed below.
I. Point-of-care nucleic acid testing (NAT)
Nucleic acid testing (NAT) is currently the most sensitive method available for identifying the infectious pathogens. Nevertheless, NAT-based diagnosis developed to date mostly require sophisticated infrastructures, reagents, and skilled technicians. While readily available in reference laboratories, NATs such as PCR remains inaccessible in resource-limited settings. Although extensive efforts have been undertaken towards point-of-care (POC) molecular diagnosis, a fully validated “sample-in-answer-out” NAT system has not developed due to significant challenges of portability, sample preparation, and throughput. In response to this urgent need, we aim to develop low-cost field-deployable field-deployable NAT devices and systems, especially for infectious disease in resource-limiting areas. These NAT devices could be loaded with easily-obtainable raw biospecimen such as finger prick blood, making diagnostic testing faster and easier for identifying pathogens like Malaria, Zika, and HIV.
- G. Choi, D. Song, S. Shrestha, J. Miao, L. Cui and W. Guan. A field-deployable mobile molecular diagnostic system for malaria at the point of need. Lab on a Chip, 16, 4341 (2016).
II. Nanofluidics: device physics, fabrication and application
Molecule/ion transport at nanometer scale plays an important role in many biological, chemical, physical and engineering systems. Nanoscale channels offer a unique platform to explore new phenomena appearing for molecule confined in nanometers scales. New transport behavior and functionalities can be developed by taking advantage of the specific couplings occurring at these scales. The major challenges in nanofluidic research are the lack of fundamental understanding of the dynamic electric field coupling to the charged molecules at the nanoscale and the lack of reliable and low-cost top-down fabrication methods. We aim to understand the device physics of nanofluidic devices, to explore viable device fabrication and integration technologies and applications.
- X. Li, W. Guan, B. Weiner, and M. A. Reed. Direct Observation of Charge Inversion in Divalent Nanofluidic Devices. Nano Letters, 15, 5046 (2015).
- W. Guan, X. Li and M. A. Reed. Voltage Gated Ion and Molecule Transport in Engineered Nanochannels: Theory, Fabrication and Applications, Nanotechnology, 25, 122001 (2014). [Invited Review]
- W. Guan, and M. A. Reed. Electric Field Modulation of the Membrane Potential in Solid-State Ion Channels. Nano Letters, 12, 6441 (2012).
- W. Guan, R. Fan, and M. A. Reed. Field-effect reconfigurable ionic diode. Nature Communications, 2, 506 (2011).
III. Label-free microfluidic cell deformability sensing
The mechanical behavior of individual cells plays an important role in regulating various biological activities at the molecular and cellular level. It can serve as a promising label-free marker of cells’ physiological states. In the past decades, several technologies have been developed for understanding the association between the cell mechanical changes and human diseases. However, numerous technical challenges still remain for realizing high-throughput, robust and easy-to-perform measurements on single-cell mechanical properties.
- X. Yang, Z.Chen, J. Miao, L. Cui and W. Guan. High-throughput and label-free parasitemia quantification and stage differentiation for malaria-infected red blood cells. Biosensors and Bioelectronics, 98, 408 (2017).