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On a cellular level, biological processes begin with binding. Before a substance, whether a manmade pharmaceutical or the body's own antibodies, can enter a cell, it must find a firm footing adhering to the cell surface. This is accomplished by ligands, protein molecules tethered to the outside of a cell that are specifically designed to fit into surface receptors on the target cells.
Ligand-receptor pairs are as specific to one another as a lock
and key. Joyce
Wong, Clare Boothe Luce Assistant Professor of
Biomedical Engineering, has been investigating the factors
that govern ligand-receptor binding with the aim of creating
new systems for more effective, targeted drug delivery.
Wong and colleagues at the University of California, Santa Barbara, the University of California, Davis, Alza Corporation, and Strasbourg's Centre National de la Recherche Scientifique have been working on a series of experiments employing liposomes, artificially created microscopic sacs designed to carry potent drugs to targeted cells, polymer tethers, and a well-documented ligand-receptor pair, biotin-streptavidin.
They revealed that not only the interplay between the ligand and receptor is significant in the overall range, rate, and ultimate strength of the bond formation, but also the length and dynamics of the tether chain. Wong now plans to test these results in real cells, specifically the Anti-HER2 cells that are implicated in breast cancer. She is also investigating how other factors, such as the flow rate of blood carrying the therapeutic agents, impact binding. This work is also crucial to the development of other therapeutic modalities, such as the creation of bioengineered tissue.
This work was reported in the July 20, 2001 issue of the journal Science. |
