(6m) Biocompatible Zwitterionic Polymers for Medical Applications

Polymer biomaterials have been extensively used in various biomedical applications, such as (i) increasing the biocompatibility of implantable tissue-/blood- contacting artificial medical devices, (ii) engineering functional tissues and promoting the healing process in tissue regeneration, and (iii) providing spatial and temporal control over the release of therapeutic agents in drug delivery and nanomedicine. Conventional polymer biomaterials such as poly(2-hydroxyethyl methacrylate) (poly(HEMA)) and poly(ethylene glycol) (PEG) have been investigated for decades and their potential issues have gradually emerged. As novel alternatives, bioinspired zwitterionic polymer materials such as poly(2-methacryloyloxyethyl phosphorylcholine) [poly(MPC)], poly(carboxybetaine methacrylate) [poly(CBMA)], and poly(sulfobetaine methacrylate) [poly(SBMA)] show unique and prominent performance. With 10 years of research experience in the zwitterionic polymer field and a Ph.D. in Materials Engineering from The University of Tokyo (Japan) under the guidance of Prof. Kazuhiko Ishihara and a postdoctoral training in the Department of Chemical Engineering in the University of Washington (USA) under the guidance of Prof. Shaoyi Jiang, I am always seeking to design novel zwitterionic materials, aiming to further develop promising healthcare technologies and deliver cutting-edge biomedical breakthroughs. My main research interests include, but not limited to the following areas:

• Biocompatible surface zwitterionization of tissue-/blood- contacting medical devices

I started my research with exploring the nonfouling mechanisms of zwitterionic polymers at the molecular level. The project involved developing, evaluating, and optimizing super-hydrophilic zwitterionic biocompatible polymers to serve as antifouling coatings for various biomedical devices, proving healthcare professionals with innovative tools for addressing medical needs without posing additional risks to patients. Medical implements come into contact with human blood and other fluids, as well as non-human cells, tissues, and proteins on a regular basis. Traditional tools and devices containing hydrophobic surfaces could cause negative biological reactions in the patient being treated, while also degrading the performance and lifespan of medical implements over time. I have developed super-hydrophilic zwitterionic polymers that are especially useful as coatings for medical implements, as they significantly reduce the number of undesirable reactions that traditionally occur between medical instruments, especially implantable devices, and the patient’s surrounding biological environment.

• 3D crosslinked zwitterionic polymer hydrogel bioelectronics for regenerative medicine

Polymer hydrogels infiltrated with high water contents have been extensively studied in tissue engineering due to i) resemblance to biological tissues and ii) tunable physical modules to minimize mechanical mismatch with various biological tissues. Biocompatible zwitterionic polymer hydrogels with remarkable flexibility in the design of their electrical, mechanical, and biological properties render hydrogels a unique bridging material to the biological world. In this project, I have developed two unique hydrogels: (a) a redox-active polymer hydrogel able to reversibly and spontaneously encapsulate living cells while preserving high biocompatibility, providing a mild environment to explore the fate of encapsulated stem cells/cancer cells/bacteria for regenerative medicine/cancer therapy/biofuel cells/biosensor under electrical stimulations; (b) a biocompatible, stretchable, conformable and highly electronic conductive zwitterionic hydrogel with tunable mechanical strength serve as an implanted artificial tissue with no foreign body reaction to alternate injured tissue and/or promote/sensor the healing of injured tissue via electrical signals. The 3D printing technology will be used to rapidly manufacture personalized tissue engineering scaffolds and even directly print functional tissue and organs.

• Zwitterionic polymer nanoparticles as non-invasive vectors for nanomedicine

This project includes understanding of fundamental interaction mechanisms between zwitterionic nanomaterials and lipid-bilayer membrane of living cells, and it has involved molecular-level design of a zwitterionic nanoprobe to monitoring the dynamic distribution of biomolecules (e.g., mRNA) in living cells in real time which could aid in the early detection of cell pathogenesis. Standard in vitro assays such as DNA microarrays, reverse transcription polymerase chain reaction (RT-PCR), and Northern blotting can quantify changes in gene expression levels of a cell population. However, none of these methods can be applied to living cells. Cells must be lysed to extract specific macromolecules for these procedures and thus can only offer a static view of cellular events at a given moment. Therefore, to overcome the limitations and enable the live imaging of mRNA in cells, I have developed a non-invasive nanoprobe through the conjugation of zwitterionic polymer and molecular beacons with a special designed nucleotide base sequence. This new material can provide: (a) a quick non-invasive cell membrane penetration in minutes which is faster than any other polymer biomaterials found so far; (b) a high degree of sensitivity as well as high spatial and temporal resolution; (c) remarkable flexibility in the design of base sequences to specific binding other molecules in vivo.

Teaching Interests:

With my education background and research experience, I am capable of teaching core courses at both undergraduate and graduate levels, including Chemical Engineering Principles, Chemical Engineering Laboratory, Thermodynamics and Kinetics, Transport Processes, Surface and Colloid Science, and Surface Analysis. In addition, I would be delighted in teaching the following courses as well: Chemical Kinetics and Reactor Design, Advanced Surface Analysis, Biomaterials/Nanomaterials, Polymer Chemistry & Physics, Principles of Molecular Engineering, Polymer Processing & Characterization, Polymer Science and Engineering, and Electrochemical Engineering. Furthermore, I would like to develop courses at the intersection of chemical engineering, materials science and engineering, and bioengineering, such as Bioinspired Design of Materials, Advanced Topics in Biomaterials, and Engineering Materials for Biomedical Applications.

I will create an active classroom/lab for my students and encourage students across diverse backgrounds to discuss each other to inspire their learning. I will set aside regular office hours to help my students on their study, scientific research and campus life. In addition, undergraduate students who are interested in scientific research will be encouraged to enter the lab to practice what they have learned in class or start a co-project with seniors under my supervision. For graduate students, I will create a lab environment fulfilled with curiosity to stimulate their research interest. I will also provide them with plenty of opportunities to attend domestic and international conferences. I believe that my passion, endeavor, experience and international education background will inspire me to motivate and mentor the next generation of students in their careers.