Cyclodextrin Polyrotaxanes as a Highly Modular Platform for the Development of Imaging Agents

Abstract

Selectively functionalized cyclodextrins with a bodipy fluorescent tag or Gd(3+) complex were synthetized and threaded onto a polyammonium chain to form polyrotaxanes. This modular supramolecular assembly makes an ideal platform for bimodal (fluorescent and MRI) imaging applications.

A Theranostic Agent Combining a Two‐Photon‐Absorbing Photosensitizer for Photodynamic Therapy and a Gadolinium(III) Complex for MRI Detection

“…[3] We assume that the [DPP-ZnP-GdDOTA] À complex has one inner-sphere water molecule, analogously to GdDOTAa nd all similarD OTA derivatives. The relaxivity of [DPP-ZnP-GdDOTA] À is in the same order of magnitude as those reported for variousn anosized objects such as MOFs, [15] polyrotaxanes, [16] micelles, [17] ands lightly lower than that of optimizedg old nanoparticles. It is only slightly lower than the re-laxivity of P760 (r 1 % 25 s À1 mm À1 between 20 and 60 MHz) with an approximatelyd ouble molecularw eight( MW = 5.3 kDa), which was previously developed as al ow diffusion, fast clearance blood pool agent.…”

“…[14] In P760, aG dDOTAc ore is decorated with four large (though not rigid) hydrophilic arms,t hus the Gd III is in the barycenter of the molecule and takes full advantage of the slow rotationo ft he entire system. The relaxivity of [DPP-ZnP-GdDOTA] À is in the same order of magnitude as those reported for variousn anosized objects such as MOFs, [15] polyrotaxanes, [16] micelles, [17] ands lightly lower than that of optimizedg old nanoparticles. [18] The relaxivity profiles display ah igh field peak with am aximum at around2 0MHz, whichi s characteristic of slow rotation ( Figure 3).…”

Cyclodextrins as Protective Agents of Protein Aggregation: An Overview

“…[29] Upon adding bCyD to the peptide, the CD spectrum suggested random coil structure, which was maintained even if the sample was kept at room temperature for 1week. This fact indicatedt hat bCyD inhibited conformational changes in Ab (12)(13)(14)(15)(16)(17)(18)(19)(20)(21)(22)(23)(24)(25)(26)(27)(28) from random coil to b sheet in solution.T he role of bCyD was correlated to its ability to include the Phe19 and Phe20 side chains, which thusi nhibited aggregation.P he19 interactions have ak ey role in the formation of Ab oligomers and fibrils. [30] Twoy ears later,n ew studies on the interactions between Ab-peptide, full length as well as fragments of various sizes, and a-, b-, or gCyD were performed through NMR diffusion studies and 1 HNMR chemical shiftanalysis.…”

“…These have been obtained by shapingt he hydrophobic nature and size of the CyD cavity to match the specific requirements of the ad hoc attached molecule. [14][15][16] An umber of simple randomly functionalized derivatives such as alkylated and sulfonated CyDs have been synthesized. These derivatives have different abilities to include hydrophobic molecules, and they have been widely used.…”

Lanthanide‐Containing Rotaxanes, Catenanes, and Knots

“…Arguably, this is provided by work that involves incorporation of kinetically stable Gd(III) complexes into (poly)rotaxane structures for magnetic resonance imaging (MRI). [38][39][40] For example, Vives, Hasenknopf and co-workers prepared cyclodextrin (CD) polyrotaxanes where each CD threaded upon a polymeric alkylammonium axle component is functionalized with either a Gd-DOTA derivative or fluorescent bodipy fragment to generate a target bimodal imaging agent (Figure 18). [38] The measured molar relaxivities for all the polyrotaxane samples prepared were greater than for the widely used Gd-DOTA, consistent with less rapid "tumbling" of the larger polyrotaxanes in solution.…”