Nanoparticles Mimic Viruses.(Brief Article)

Chemists at Washington University in St. Louis (Tel: 314/935-5272) have created tiny synthetic polymer particles that mimic viruses and show potential for a new direction in gene therapy and other biomedical applications. The nanoparticle has the unlikely name of knedel (k-ned-l) because of its similarity to a popular Polish dumpling filled either with meat or sweets.

The knedels are shell cross-linked structures surrounding a hydrophobic, or water insoluble, core domain. They are too small to be seen with the naked eye, with their diameters ranging from 10 nm to 100 nms. In fact, they are of similar size to many globular proteins and viruses. In the body, they are expected to escape detection by the immune system.

Karen L. Wooley, phD, a professor of chemistry in arts and sciences, recently announced that she and her Washington University colleagues, Jianquan Liu, phD and Qi Zhang, phD, both research assistants in chemistry, and Tomasz Kowaleski, phD, research assistant professor in chemistry, have successfully hollowed out the knedel core to produce "nanocages," and attached a fluorescent tag to the core. They also attached a polypeptide called protein transduction domain (PTD) to the exterior of the nanostructure. They got this idea from Steven F. Dowdy, phD, assistant professor of pathology at the Washington University School of Medicine in St. Louis. Dowdy demonstrated the efficiency with which PTD transduces proteins into cells.

With the aid of very powerful microscopes, Wooley and her colleagues were able to detect the peptide-bearing knedels binding to the cell surfaces. Another group of nanoparticles without the PTD but with fluorescent tags did not bind to target cells.

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