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【medical-news】更安全有效的化疗新策略
A Loose Grip Provides Better Chemotherapy
ScienceDaily (Feb. 4, 2011) — Researchers at Case Western Reserve University have developed a little bomb that promises a big bang for cancer patients.
Preliminary tests show an anti-cancer drug loosely attached to gold nanoparticles starts accumulating deep inside tumors within minutes of injection and can be activated for an effective treatment within two hours. The same drug injected alone takes two days to gather and attacks the tumor from the surface -- a far less effective route.
The work, titled "Deep Penetration of a PDT Drug into Tumors by Noncovalent Drug-Gold Nanoparticle Conjugates," is published February 4 in the online edition of the Journal of the American Chemical Society.
Speeding anti-cancer drugs directly into tumors enables patients to receive lower doses of the toxic chemicals, thereby saving healthy tissue from damage and other harsh side effects suffered in traditional chemotherapy.
"We hope to lower the dosage by at least a factor of 10," said Clemens Burda, a professor of chemistry at Case Western Reserve and the senior author of the paper.
The key to success? The scientists tied an anti-cancer drug to golden missiles using a weak chemical interaction called a noncovalent bond. In molecule construction, a covalent bond is a heavy rope lashed and knotted; a noncovalent bond is a shoestring tied in a bow.
"Very often, additions to chemical systems change properties of the components of the system," Burda said. Attempts by his and other research groups to use covalent bonds for drug delivery have resulted in such complications and less than hoped-for results.
The researchers, who come from a breadth of disciplines, found that by using a noncovalent bond to attach the drug to coated gold, they eliminated interference among the desired properties of each component.
Burda's group sought to simplify the process by using materials that have well-known properties.
Gold nanoparticles have large surface areas that permit packing a lot in a tiny space. The element is inert inside the body and at less than 5 nanometers across, or less than 1/10,000 the width of a human hair, the particles quickly flow out of the blood stream and across cancer cell membranes to accumulate inside tumors.
A coat of polyethylene glycol links tightly to the gold while providing cargo space to attach other materials.
The coated gold provides an environment to physically prevent activation of the photodynamic therapy drug silicon phthalocyanine, preventing unintended toxic exposures to healthy tissues.
The loosely-held drug is released from the nanoparticle through the attraction of the drug to the lipid membrane of cancer cells. Laser light switches on the freed silicon phthalocyanine, which breaks down and kills cancer cells, shrinking the tumor.
After delivering the drug, the nanoparticles pass through the kidneys and clear the body within a week.
Burda teamed with Yu Cheng, Joseph D. Meyers, Ann-Marie Broome, Malcolm E. Kenney and James Basilion, all of Case Western Reserve.
Their work received a $1.2 million grant from the National Institutes of Health late this fall, to continue development. 欢迎大家积极提供生物及生命工程信息 - 业界热点资讯版 - 爱爱...http://news.dxy.cn/bbs/topic/18651896研究证实中草药可降低化疗毒性 http://news.dxy.cn/... http://www.fiercepharma.com/stor ... otc-meds/2010-11-04 “医药生命科学动态版”与...www.iiyi.com/...3-1917435.html-1天前-快照-生命工程信息 - 业界热点资讯版 - 爱爱..." (内部刊物 免费交流)文件类型:PDF/Adobe Acrobat- 文字版开展药物治疗 197 人次;专科 转诊 19 人次. 经过及时有效的心理干预,受灾群众心理... 到实处.联合多学科专家共同诊治病人 , 科学应用手术、化疗、放疗、生物治疗、中医药...wsj.sh.gov.cn/...le/医学信息10.pdf-2011-01-28-药学快讯(版权页)文件类型:PDF/Adobe Acrobat- 文字版安全且有效的.但他又说,另有一些规章制度方面的问题仍然存在.克劳福德在说了上述话 ... 新一代抗肿瘤化疗药--紫杉肽日前已经通过中国医学科学院肿瘤医院伦理委员会论 第31 ...www.lib.gdpu.edu.cn/...839.pdf-2011-01-19-药学快讯(版权页)"[标签:content2]
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作者:admin@医学,生命科学 2011-02-06 12:38
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