Center for Translational Nuclear Medicine and Molecular Imaging, Massachusetts General Hospital, 149 13th Street, Charlestown, Massachusetts 02129, USA.
J Am Chem Soc. 2012 Nov 28;134(47):19338-41. doi: 10.1021/ja309085b. Epub 2012 Nov 14.
We provide a new approach for fluorescent probe design termed "PEG-fluorochrome shielding", where PEGylation enhances quantum yields while blocking troublesome interactions between fluorochromes and biomolecules. To demonstrate PEG-fluorochrome shielding, fluorochrome-bearing peptide probes were synthesized, three without PEG and three with a 5 kDa PEG functional group. In vitro, PEG blocked the interactions of fluorochrome-labeled peptide probes with each other (absorption spectra, self-quenching) and reduced nonspecific interactions with cells (by FACS). In vivo, PEG blocked interactions with biomolecules that lead to probe retention (by surface fluorescence). Integrin targeting in vivo was obtained as the differential uptake of an (111)In-labeled, fluorochrome-shielded, integrin-binding RGD probe and a control RAD. Using PEG to block fluorochrome-mediated interactions, rather than synthesizing de novo fluorochromes, can yield new approaches for the design of actively or passively targeted near-infrared fluorescent probes.
我们提供了一种新的荧光探针设计方法，称为“PEG-荧光染料屏蔽”，其中聚乙二醇化可以提高量子产率，同时阻止荧光染料与生物分子之间的麻烦相互作用。为了证明 PEG-荧光染料屏蔽的效果，我们合成了带有荧光染料的肽探针，其中三个没有聚乙二醇，三个带有 5 kDa 的聚乙二醇官能团。在体外，PEG 阻止了荧光染料标记的肽探针之间的相互作用（吸收光谱，自猝灭），并减少了与细胞的非特异性相互作用（通过 FACS）。在体内，PEG 阻止了与导致探针保留的生物分子的相互作用（通过表面荧光）。体内整合素靶向作用是通过摄取（111）In 标记的、荧光染料屏蔽的、整合素结合的 RGD 探针和对照 RAD 的差异来实现的。使用 PEG 来阻止荧光染料介导的相互作用，而不是合成新的荧光染料，可以为设计主动或被动靶向近红外荧光探针提供新的方法。
