A biological polymer assembly with a biological polymer that contains at least 90 percent of tubulin and a positively charged segment. The positively charged segment has a molecular weight of at least about 5,000 Daltons, a bulk electrical conductivity of at least about 10−7 ohms−1 meter−1 Siemens,...http://www.google.com.tw/patents/US20050215764?utm_source=gb-gplus-share專利 US20050215764 - Biological polymer with differently charged portions
