絹のおかげで冷蔵せずに保存
(c) Fiorenzo Omenetto, Tufts University
カイコの繭に由来する物質，フィブロインを使った技術で，熱に弱いワクチンや抗生物質を冷蔵せずに長期間保存できることが明らかとなった。世界中でワクチンのほぼ半分が，低温流通に関する問題で使えなくなるという。この新たな技術は従来の安定化技術と比べ，広い温度範囲で新三種混合ワクチン，ペニシリン，テトラサイクリンの効力を維持する機能に優れていた。例えば，テトラサイクリンは溶液を37℃で保存すると，4週間で活性が80%失われたが，新技術で安定化すると活性の低下はなかった。薬剤の無駄をなくすだけでなく，薬剤コーティングした埋め込み型デバイスなど，最新の薬剤送達技術にも役立つと期待される。（吉田素子）
New Silk Technology Preserves Heat-Sensitive Drugs for Months without Refrigeration
Single Silk Device Can Store & Deliver Vaccine or Antibiotic without Costly "Cold Chain"
Researchers at Tufts University School of Engineering have discovered a way to maintain the potency of vaccines and other drugs -- that otherwise require refrigeration -- for months and possibly years at temperatures above 110 degrees F, by stabilizing them in a silk protein made from silkworm cocoons. Importantly, the pharmaceutical-infused silk can be made in a variety of forms such as microneedles, microvesicles and films that allow the non-refrigerated drugs to be stored and administered in a single device.
The Tufts findings address a serious obstacle to the effective use of life-saving pharmaceuticals: keeping them cold. Most vaccines, enzymes, and antibodies and many antibiotics and other drugs require constant refrigeration from manufacture to delivery to maintain their effectiveness.
International health experts estimate that nearly half of all global vaccines are lost due to breakdowns in the "cold chain." Even in industrialized nations, loss of drug efficacy at body temperature is a serious problem for advanced pharmaceutical delivery systems such as implantable drug-coated devices.
The research will be published before print in the Proceedings of the National Academy of Sciences (PNAS) Online Early Edition the week of July 9, 2012.
Tufts biomedical engineers led by David L. Kaplan, Ph.D., found that silk stabilization preserved the efficacy of the measles, mumps and rubella (MMR) vaccine, as well as penicillin and tetracycline, at a wide range of temperatures (at least up to 60 degrees C or 140 F) significantly better than other options such as collagen encapsulants, dried powders and solutions.
［単語和訳］
Heat-Sensitive：熱に弱い Refrigeration：冷蔵 Vaccine：ワクチン Antibiotic：抗生物質 Costly：高価な Cold Chain：低温流通体系
Researchers：研究者 potency：力価 stabilizing：～を安定化させること protein：タンパク質 silkworm：カイコ cocoons：繭 Importantly：重要なことには pharmaceutical-infused：薬剤を染み込ませた microneedles：マイクロニードル（微小な針） microvesicles：微小包 non-refrigerated：冷却されていない be administered：投与される
obstacle：障害物 life-saving：命を救う enzymes：酵素 antibodies：抗体 effectiveness：有効性
industrialized：工業化した implantable：埋め込み型 drug-coated：薬剤をコーティングした
the Proceedings of the National Academy of Sciences：米国科学アカデミー紀要（雑誌名） Online：オンラインの
biomedical engineers：生物医学工学者 Ph.D.：博士 stabilization：安定化 efficacy：有効性 measles, mumps and rubella：はしか・おたふく風邪・風疹 penicillin：ペニシリン tetracycline：テトラサイクリン significantly：顕著に collagen：コラーゲン encapsulants：カプセル材料 solutions：溶液
