Antibiotic-resistant superbugs have become a big public-health concern, but the existing antibacterial cleaners and soaps on the market are often based on harsh chemicals that kill everything they come into contact with or leach out into the environment. In other cases, their effect is only temporary.

Now scientists are working on a new crop of antimicrobials -- microscopic weapons that prevent or defeat bugs -- to improve their effectiveness, kill specific types of bugs, or reduce their potential side effects on people and the environment. Researchers hope the new antimicrobials can be used to attack bacteria, viruses and fungus on everything from the human body to materials used to build homes, hospitals, boats and medical devices.

Researchers at Rensselaer Polytechnic Institute in Troy, N.Y., recently developed a new way to kill methicillin-resistant Staphylococcus aureus, or MRSA -- one of the most widespread and deadliest superbugs -- on contact using tiny tubes coated with proteins to destroy the bugs by deflating them like balloons.

Some 53 million individuals world-wide are believed to be infected with MRSA, according to a 2006 paper published in the Lancet. In the U.S., more than 275,000 were hospitalized with MRSA-related infections between 1999 and 2005, according to national data.

When Rensselaer professor Jonathan Dordick, a biochemical engineer, began his research in the 1990s, he wanted to figure out how to make enzymes -- proteins that speed up biological reactions -- work better in environments in which they don't typically occur. He hoped to create items like self-cleaning fabric, in which enzymes embedded in cotton could simply be activated by water to remove stains.

In his team's recent work, published last month in an American Chemical Society journal called ACS Nano, Dr. Dordick, Professor Ravi Kane and other colleagues investigated whether enzymes could be added to tubes a million times smaller in diameter than a human hair. These 'nanotubes,' could be inserted, along with the enzyme, into paint or other substances.

'Then we asked, how can we use this technology and apply it to major problems in society?' says Dr. Dordick. They identified superbugs as one such challenge.

In nature, bacteria use enzymes to kill other bacteria. The researchers chose the enzyme lysostaphin, which is known to kill the Staphylococcus bacteria. Lysostaphin breaks down one piece of the bacteria's cell wall, and like a pin popping a balloon, causes the cell to 'deflate.'

First they had to figure out how to successfullyattach the lysostaphin to the nanotube. Then, they made sure the enzymes didn't leach into the environment by soaking the combination in solution. After placing a glass plate covered with the enzyme-coated nanotubes in a laboratory dish, the researchers added MRSA.

They found that within two hours the enzyme combination killed more than 99% of MRSA. And, as expected, it didn't kill other kinds of bacteria, like E. coli. The goal is to add the enzyme-coated nanotubes to paint and other substances to coat hospital walls or medical instruments, says Dr. Dordick.

In something like paint, which doesn't involve direct contact with a person, a product could hit the market within two years at a cost of 10% more than the current retail price of paint, says Dr. Dordick.

Several questions remain about safety and the duration of effectiveness of the compound. If the enzyme remains in a dry environment, like on a hospital wall, early testing suggests it would work for up to six months, Dr. Dordick says.

Shirley S. Wang

• contact [´kɔntækt] n.接触；联系 v.联络 (初中英语单词)
• working [´wə:kiŋ] a.工人的；劳动的 (初中英语单词)
• medical [´medikəl] a.医学的；医疗的 (初中英语单词)
• institute [´institju:t] n.学院 vt.建立；设置 (初中英语单词)
• research [ri´sə:tʃ] n.&vi.调查；探究；研究 (初中英语单词)
• fabric [´fæbrik] n.织物；结构；组织 (初中英语单词)
• chemical [´kemikəl] a.化学的 n.化学制品 (初中英语单词)
• journal [´dʒə:nəl] n.日记；日报；杂志 (初中英语单词)
• attach [ə´tætʃ] v.附；使隶属；使依恋 (初中英语单词)
• combination [,kɔmbi´neiʃən] n.结合；联合；团体 (初中英语单词)
• solution [sə´lu:ʃən] n.解答；解决；溶解 (初中英语单词)
• involve [in´vɔlv] vt.卷缠；包括；使专注 (初中英语单词)
• compound [kəm´paund] n.&a.混合(的) v.合成 (初中英语单词)
• environment [in´vaiərənmənt] n.郊区；周围；条件 (高中英语单词)
• specific [spi´sifik] a.具体的；特有的 (高中英语单词)
• potential [pə´tenʃəl] n.&a.潜在的；可能的 (高中英语单词)
• diameter [dai´æmitə] n.直径 (高中英语单词)
• balloon [bə´lu:n] n.气球 (高中英语单词)
• successfully [sək´sesfəli] ad.成功地 (高中英语单词)
• laboratory [lə´bɔrətəri] n.实验室；研究室(所) (高中英语单词)
• bacteria [bæk´tiəriə] n.细菌 (英语四级单词)
• widespread [´waidspred] a.广布的；普遍的 (英语四级单词)
• retail [´ri:teil, ri´teil] n.&a.&v.零售(商品的) (英语四级单词)
• microscopic [,maikrə´skɔpik] a.(象)显微镜的 (英语六级单词)
• fungus [´fʌŋgəs] n.真菌；菌类 (英语六级单词)
• biological [,baiə´lɔdʒikəl] a.生物学(上)的 (英语六级单词)
• duration [djuə´reiʃən] n.持久；持续期间 (英语六级单词)