DAVIS, Calif., March 19 -- Using nanotechnology to stop human immunodeficiency viruses (HIV) from entering cells is the ultimate aim of a new project at the University of California, Davis (UC Davis). The researchers hope to create tiny particles that can interfere with the proteins that viruses such as HIV use to attach to cells. "The idea is to make decoys for the virus," said Jacquelyn Gervay Hague, professor of chemistry at UC Davis and principal investigator on the grant. HIV attaches itself to a host cell through a protein called gp120 on the virus surface. Gp120 sticks to the CD4 protein on human white blood cells and also to a fatty molecule called galactosyl ceramide, or GalCer. GalCer is found in the membranes of many different types of cell, including cells lining the gut and vagina. Researchers think that binding of gp120 to GalCer may be important in sexual transmission of HIV. GalCer can form patterns in the cell membrane that allow many gp120 proteins to bind in a specific manner, Gervay Hague said. Materials scientist Marjorie Longo and her lab are studying how GalCer forms these patterns in artificial membranes and how they affect binding to viruses. If the researchers find a pattern that maximizes binding, they will use tools developed by chemist Gang-yu Liu to recreate those patterns on lipid-coated "quantum dots," tiny particles a few tens of atoms in size. The quantum dots are made by Susan Kauzlarich, a professor of chemistry who studies these very small particles. The particles will be tested for antiviral activity by Satya Dandekar, professor and chair of microbiology and immunology at the UC Davis School of Medicine. The researchers' ultimate goal is to create a quantum dot that can stick to the virus and prevent it from entering human cells. The group has already made gold nanoparticles coated with a nonpatterned membrane. These particles are not toxic to cells and were able to bind gp120, Gervay Hague said. The work is funded by a $1.2 million Nanoscale Interdisciplinary Research Team grant from the National Science Foundation.