We study the adsorption/desorption, dispersion, phase transition, and collapse behavior of both insoluble lipid monolayers and soluble protein monolayers. This research can be applied to the development of lung surfactants for replacement therapy, surface modification of biosensor, and manufacturing of liposome for drug delivery system. We received a patent for developing a new method that measures the dynamic surface tension and contact angle simultaneously.

Due to the good biocompatibility and porous structure, collagen is often used as a biomaterial for cell culture, tissue template, and drug carrier application. Under proper conditions, purified collagen molecules can be reconstructed into a three-dimensional fibrous network. The microstructure of the reconstructed fiber matrix will affect the attachment of the cultured cells and the transport of the related metabolic molecules. In this study, we examine the microstructure of the reconstructed collagen matrix and attempt to obtain the diffusion coefficients of different molecules in different reconstructed conditions of collagen. Furthermore, we will build the theoretical model to predict the permeation properties from porous microstructures of collagen. The theoretical model established can be used to predict the transport behaviors of various molecules through a collagen matrix. Hopefully, this research will lead to a better understanding of the diffusion of molecules through tissue.

Ultra high molecular weight polyethylene (UHMWPE) has been commonly used in orthopedic implants. The main focus of this research is looking for the causes and the methods of improvement for the failure of total artificial knee arthroplasties. We will concentrate on the energy effect on the failure of UHMWPE. There are two main sources of energy in total artificial knee arthroplasties. One source of energy is caused by friction between the metal and polymer components. The other source of energy is from the Gamma irradiation for the sterilization of polyethylene. In this research, theoretical models based on theories of transport phenomena will be established to describe the transport behavior of friction heat and radiation energy in a polyethylene component. Hopefully, these theoretical models can be used to describe the dynamic behavior of wear, fatigue, and failure of the UHMWPE components from energy due to friction and sterilization. Together with outcomes from other labs under a same unified research project, we expect to find ways to improve the wear of the materials.