Hai-Quan Mao
Assistant Professor of Materials Science and Engineering and Whitaker Biomedical Engineering Institute (Joint Appointment)

Postdoctoral Associate, Biomedical Engineering, Johns Hopkins University School of Medicine, 1995-1999

Ph.D. Polymeric Biomaterials, Wuhan University, 1993

B.S. Chemistry, Wuhan University, 1988

	Phone: 410-516-8792	Fax: 410-516-5293	Email: hmao@jhu.edu

Prof. Mao's research interest is in the design, synthesis and application of polymeric materials for drug and gene delivery and tissue engineering.

1. Functional polymeric materials for tissue engineering

Cell-substrate interaction is a key parameter in regulating cellular behavior in many tissue-engineering systems. It has become one of the central themes to identify and engineer the topological, biochemical and mechanical attributes of the 3-D scaffolds that influence the cell-scaffold interaction, which in turn controls cell adhesion, morphology, function, proliferation, differentiation, apoptosis, etc. The configuration of the scaffold needs to be optimized for each tissue engineering application as the regulating factors for each type of cells differ. For example, a substrate with collagen coating or RGD ligands would be suitable for many types of cells, would induce significant loss of hepatocyte-specific functions, reflecting hepatocyte dedifferentiation. In contrast, a polymeric substrate with surface immobilized hepatocyte specific ligand (galactose moiety) could mediate hepatocyte spheroid formation and maintain the synthetic functions of the hepatocytes.

2. Polymeric materials for non-viral gene delivery

The development of safe and efficient vectors or carriers for in vivo gene transfer has been one of the key challenges in fulfilling the promises of gene therapy. Viral vectors, while efficient in gene transfer in vivo, pose safety concerns that are unlikely to abate in the near future, rendering synthetic carriers attractive alternatives. The synthetic vectors including cationic liposomes and polycations, while offering better safety profile, continue to suffer from low gene transfer efficiency. Mechanistic studies are being undertaken by many laboratories to identify the rate-limiting steps in the non-viral gene transfer process. Much more controlled and systematic studies are needed in order to reveal the structure-function relationship. On the other hand, the optimal characteristics of a gene carrier are most likely cell-type and plasmid-specific. The route of administration in vivo would also greatly influence the effectiveness of the gene carrier. An array of gene carriers will eventually be needed for various applications.

Selected Publications

C. Yin, L. Ying, P. C. Zhang, R. X. Zhuo, E. T. Kang, K. W. Leong, and H. Q. Mao, “High density of immobilized enhances hepatocyte attachment and function,” J.Biomed. Mater. Res. In press.

J. L. Chew, C. B. Wolfowicz, H. Q. Mao, K. W.Leong, and K. W. Chua, “Chitosan nanoparticles containing plasmid DNA encoding house dust mite allergen, Der p 1 for oral vaccination in mice,” Vaccine. In press.

H. F. Lu, W. S. Lim, P. C. Zhang, J. Wang, Z. Q. Tang, S. M. Chia, H. Yu, K. W.Leong, and H. Q. Mao, “Galactosylated PVDF membrane promotes hepatocyte attachment and functional maintenance,” Biomaterials. In press.

C. Yin, S. M. Chia, C. H. Quek, H. Yu, R. X. Zhuo, K. W. Leong, and H. Q. Mao, “Microcapsules with improved mechanical stability for hepatocyte culture,” Biomaterials 24, 1771-1780 (2003}.

C. Yin, K. Liao, H. Q. Mao, K. W. Leong, R. X. Zhuo, and V. Chan, “Adhesion contact dynamics of HepG2 cells on galactose immobilized substrates, " Biomaterials 24, 837-850 (2003).

Z. Zhao, J. Wang, H. Q. Mao, and K. W. Leong, “Polyphosphoester,” Adv. Drug Delivery Rev. 55, 483-499 (2003).

J. Wang, P. C. Zhang, H. Q. Mao, and K. W. Leo, “Enhanced gene expression in mouse muscle by sustained release of plasmid DNA using PPE-EA as a carrier,” Gene Therapy 9, 1254-1261 (2002).

J. Wang, P. C. Zhang, H. F. Lu, N. Ma, S. Wang, H. Q. Mao, and K. W. Leong, "New polyphosphoramidate with spermidine side chain mediates efficient gene transfer,” J. Controlled Rel. 83(1), 157-168 (2002)

J. Wang, H. Q. Mao, and K. W. Leong, “A novel biodegradable gene carrier based on polyphosphoester,” J. Am. Chem. Soc.123, 9480-9481 (2001).

H. Q. Mao, K. Roy, V. L. Truong-Le, K. Janes, K. Y. Lin, Y. Wang, J. T. August, K. W. Leong, “Chitosan-DNA nanoparticles as gene delivery vehicles," J. Controlled Rel. 70, 399-421 (2001).

A. C. A. Wan, H. Q. Mao, S. Wang, K. W. Leong, L. Ong, H. Yu, “Fabrication of poly{phosphoester) nerve guides by immersion precipitation and the control of porosity,” Biomaterials 22,1147-1156 (2001).

V. Chan, H. Q. Mao, and K. W. Leong, “Chitosan-induced perturbation of dipalmitoyl-sn-glycero-3-phosphocholine membrane bilayer,” Langmuir 17, 3749-3756 (2001).

K. Roy, H. Q. Mao, S. K. Huang, and K. W. Leong, “Oral gene delivery with chitosan-DNA nanoparticles generates immunological protection in a murine model of peanut allergy,” Nature Medicine, 5, 387-391 (1999).

"Poly(phosphoester)s”, in Encyclopedia of Controlled Drug Delivery. pp. 45-60. First Edition, Ed. E. Mathiowitz, Johns Wiley & Sons, Inc. New York, NY, (July, 1999).