To manufacture the diminutive synthetic particles the researchers
are using, UC Davis chemist Susan Kauzlarich uses inorganic quantum dots, which are semiconductors such as silicon.
"These are very small-sized particles of elemental silicon on which we can modify and put the Galcer that binds with HIV's GP120," said Kauzlarich, who has been at UC Davis for 15 years. "The process involves synthetic chemistry which takes advantage of new approaches to make nanoparticles that are stable. Because they emit light, or luminesce, we can tell exactly
how certain ligands inhibit the attachment of virus to cell walls. And what we're hoping to do is actually image this process."
Silicon is an attractive possibility
because unlike many other chemicals that carry harmful byproducts, silicon is a nontoxic biocompatible element.
"That means if I want to introduce silicon into a human being, it won't cause harm," said Kauzlarich, an inorganic materials chemist whose lab is using solution chemistry in an inert atmosphere to develop the nanoparticles.
Chemist Gang-Yu Liu uses a process called nanografting to engineer the GP120 binding sites, which measure no larger than 2 x 4 nanometers onto the surfaces. To accomplish this, her group has employed sharp probes, known as atomic force microscope cantilevers, to shave away molecules from planar surfaces
and the silicon nanoparticles
and thus create room for the synthetic ligands to attach.
"We can also image the particles so we can see the individual
proteins one by one," said Liu, who Kauzlarich calls the ringleader of the research team because she saw how all the scientists' work fit together. Imaging includes the use of total internal reflectance fluorimetry and atomic force microscopy.
Principal investigator and chemist Jacquelyn GervayHague has successfully manufactured the pertinent nanoparticles and has shown them to bind to the HIV and inhibit infection, but only at a rate of 60 to 70 percent.
"We believe by using nanotechniques
we can make artificial particles that are better capable of binding the virus than even the natural cells," said Gervay-Hague, "and we believe we can achieve 100 percent inhibition of viral replication using them. That's our goal."