| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide molecules, compositions and methods for controlled delivery of substances into cells by transport molecules. <P>SOLUTION: There is provided a structure including A-X-B-C, wherein C is a cargo moiety, the B portion includes basic amino acids, X is a cleavable linker sequence, and the A portion includes acidic amino acids. Upon extracellular cleavage of X, the B-C portion is taken up, delivering the cargo to targeted cells. Cargo may be, for example, a contrast agent for diagnostic imaging, a chemotherapeutic drug, or a radiation-sensitizer for therapy. Cleavage of X allows separation of A from B, unmasking the normal ability of the basic amino acids in B to drag cargo C into cells near the cleavage event. X is cleaved extracellularly, preferably under physiological conditions. D-amino acids are preferred for the A and B portions, to minimize immunogenicity and nonspecific cleavage by background peptidases or proteases. <P>COPYRIGHT: (C)2013,JPO&INPIT |
