Faculty Spotlight – Dr. Yi Zhao

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Dr. Yi ZhaoProfessor Yi Zhao joined the Department of Biomedical Engineering at The Ohio State University and founded the Laboratory for Biomedical Microsystems in October 2006. Prior to arriving at OSU he received his graduate training in manufacturing engineering at Boston University and in mechanical engineering at Tsinghua University, China.

Dr. Zhao’s research interests span a broad range of multidisciplinary fields in biomedical micro/nanotechnologies, with a specific emphasis on exploring materials science, engineering mechanics, and manufacturing technologies for Bio-Micro-Electro-Mechanical-Systems (Bio-MEMS), including:

  • Micro/nanofabrication strategies for micro total analytical systems
  • Sensors and actuators for investigating the mechanical/electrical interfaces between biological organisms and engineering environment at various length scales
  • Tissue engineering at the micro scale

More information and recent results can be found on the website of Laboratory for Biomedical Microsystems.

Examples of Recent Research

Microfabrication of non-photodefinable polymer materials into microstructures is one of the major challenges in the development of functional biomedical microchips. Figure 1 shows a gallery of microstructures made of non-photodefinable polydimethylsiloxane (PDMS) fabricated in our laboratory. By using a vacuum-assisted microfluidic approach, microstructures with the characteristic dimensions of less than 10 microm were successfully fabricated. This approach would provide a practical solution for creating polymer microstructures with complex geometries, as a powerful tool for the integration of various polymer based microfluidic and micromechanical components into biomedical microchips for complex functions of lab-on-chip applications.

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Figure 1: PDMS microstructures were demonstrated: (a) shows the schematics of a suspending microbridge (b) & (c) show two polymer helical microstructures with different turn densities.

Figure 2 shows on-chip skeletal muscle constructs fabricated using microstructures. By tuning the geometries of the underlying microstructures, the multi-layered constructs can have aligned morphology similar to that in the in vivo skeletal muscles. The ability of the chip to allow detachment of fabricated tissues further validates the utility of this approach for on-chip muscle tissues fabrication. The findings demonstrate that the on-chip device holds promise for providing an efficient means for guided muscle tissue construction. (This work was published in Biotechnology and Bioengineering, 2009, 102(2):624-631 and selected as the cover art of the issue 102(2)).

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Figure 2: The immunofluorescence images showing the myotube alignment with exposure to different surface topographies. (a) The actin filament staining showed that the myotube in different areas aligned at different angles. (b) The stained cell nuclei overlapped with the underlying microstructures showing the spatial correlation between the myotubes alignment and the microtopography (myosin heavy chain is stained red, actin is stained in green, cell nuclear is stained in blue).

Current Research Activities

Laboratory for Biomedical Microsystems currently consists of one doctoral student (Hansong Zeng) and two Master degree students (Ned Heffner and Edward Meier). Dr. Zhao is also mentoring several other graduate students through collaboration with peer faculty. The group is actively recruiting graduate and undergraduate students with diverse background in engineering and life science to strengthen the interdisciplinary research in Bio-MEMS. Current and pending projects include:

  • Combined micro/nanofibrous structures for functional tissue engineering (Figure 3), in collaboration with the NSF-sponsored MRSEC Center for Emergent Materials at OSU
  • Micro Droplet-based Motion Sensing System
  • On-Chip Blood Viscometer
  • Smart Massager for Quantitative Manual Therapy
  • Polymer Based MEMS Device for Biomechanical Sensing
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Figure 3: Microstructured nanofibrous materials were formed using a micropatterned collecting substrate.