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■這些美味食物可能是由納米科技製造。資料圖片
納米科技是指設計和操控比人類頭髮還要小數以千倍計的物質，用途廣泛，可用作製造更輕更強的物料、更佳的化妝品及更美味的食物。
但科學家現在才開始探究這種微細物質所帶來的影響。研究指出，相比一些較大物質，納米大小的物質會對人類身體有不同影響。
傳統上，如果粒子是1至100納米(約人類頭髮直徑的萬分之一)，以及具有天然物料沒有的特質，就會被視為納米物質。
北卡羅來納州達勒姆的杜克大學一個小組相信，集中研究這些特質，或可找出納米科技所帶來的潛在危險。
在《自然納米科技》提交報告的杜克大學工程教授威斯納表示：「新品種的人造納米粒子多不勝數，所以我們要找方法收窄範圍。」
威斯納表示，那些少於30納米闊的最微細粒子，最有機會擁有一些特性，容易帶來風險。
他又稱，有些納米粒子會很容易與環境中其他化學物產生反應，又會擾亂某些細胞內的活動。
威斯納表示：「雖有報告指納米粒子越小，毒性越強，但現時仍未清楚反應增加會否加大對人類和環境的禍害。」
美國研究委員會去年12月的一份報告發現，政府偵測納米風險的計劃有嚴重不足，並呼籲美國要有全國計劃，確認並管理潛在風險。
現時市場有逾600種產品含有納米物質，大部分都是健美產品。很多研究員正研究如何擴大納米物質的應用至醫療、食物添加劑和電子產品。
■路透社
■羅國偉 資深翻譯員
Nanotech Safety: Smaller Particles May be Riskier
Nanotechnology, the design and manipulation of materials thousands of times smaller than the width of a human hair, has been hailed as a way to make strong, lightweight materials, better cosmetics and even tastier food.
But scientists are only starting to look at the impact such tiny objects may have. Some studies suggest nano-sized objects may have different effects in the body than larger ones.
Traditionally, a particle is deemed nano if its diameter is between 1 and 100 nanometers-about 1/10,000 the diameter of a human hair, and if it has properties not present in its naturally occurring counterpart.
But a team led by researchers at Duke University in Durham, North Carolina, believes focusing on these special properties may be a better way to look for any potential hazards posed by nanotechnology.
"There are an infinite number of potential new man-made nanoparticles, so we need to find a way to narrow our efforts," said Mark Wiesner, an engineering professor at Duke, whose study appears in the journal Nature Nanotechnology.
Wiesner said it appears the very smallest particles-those less than 30 nanometers in width-are most likely to have unique properties that could pose a risk.
He said some nanoparticles can be highly reactive with other chemicals in the environment and can also disrupt certain activities within cells.
"While there have been reports of nanoparticle toxicity increasing as the size decreases, it is still uncertain whether this increase in reactivity is harmful to the environment or human safety," Wiesner said.
Last December, a report by the National Research Council found serious gaps in the government's plan for determining if nanomaterials pose a risk and called for an effective national plan for identifying and managing potential risks.
Currently, more than 600 products involving nanomaterials are on the market. Most are health and beauty products, but many researchers are working on ways to use the materials for medical therapies, food additives and electronics. ■Reuters
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