Nature Biotechnology pp 192 - 197

An approach for rapidly screening and identifying combinations of chemicals that can penetrate the skin could make medicine by patch, rather than pill, more common. Skin patches are in widespread use for combating nicotine addiction or delivering contraceptive hormones, but most drugs have to be popped in the mouth or injected by needle. What's more, few approved chemicals are available to drug makers that can help therapeutics permeate skin. In the February issue of Nature Biotechnology, Samir Mitragotri and colleagues describe a large-scale screen that can find combinations of chemicals capable of transporting medicines across the skin.

The skin is a protective barrier that usually prevents protein drugs from crossing it. Scientists have discovered chemicals that enhance protein transport across the skin, but the chemicals that do this best are also likely to cause skin irritation. Mitragotri and colleagues have found that combinatorial screening can identify rare combinations of chemicals that improve drug delivery across the skin while minimizing irritation. Two chemicals are better than one because each can act on a different layer of the skin, allowing smaller doses to be used.

Protein drugs cannot generally be delivered in the form of pills because the proteins are broken down in the intestinal tract. Skin patches, once optimized, would avoid the need for delivery by injection, with the associated pain and risk of infection.

Nature Biotechnology pp 185 - 191

Scientists have recruited tiny viruses to search for new ways of targeting bacteria with antibiotics. The viruses, termed bacteriophages, give bacteria the equivalent of a nasty cold or worse! With this in mind, researchers decided to identify the parts of the bacteriophage that do damage to the bacteria. They then exploited this information both to identify the bacterial molecules targeted by the virus and to screen for new antibiotics that inhibit these molecules. In the February issue of Nature Biotechnology, Jing Liu and colleagues describe their screening system for identifying bacterial targets of phage proteins and show these can then be used as the targets of new antibacterial agents.

Using as a proof-of-principle the bacterium Staphylococcus aureus, which is the most common cause of food borne illness, the authors expressed every single protein from several bacteriophages in the bacterium, identifying 31 phage proteins that inhibit bacterial growth. They then determined the bacterial targets of these phage proteins and used this information to detect drugs that affect the target in similar ways to the phage protein. This new screening approach should provide a useful adjunct to traditional antibiotics because it exploits bacteriophages' bacterial killing mechanisms, refined over thousands of years of evolution, for the design of new antibacterial drugs.