Related Experiment Video
Updated: Jul 7, 2026

Cargo Loading onto Kinesin Powered Molecular Shuttles
Published on: November 3, 2010
Host-[2]rotaxanes as cellular transport agents
Vadims Dvornikovs1, Brian E House, Marcia Kaetzel
1Department of Chemistry, University of Cincinnati, Cincinnati, Ohio 45221, USA.
Abstract:
Host-[2]rotaxanes, containing a diarginine-derivatized dibenzo-24-crown-8 (DB24C8) ether as the ring and a cyclophane pocket or an aromatic cleft as one blocking group, are cell transport agents. These hosts strongly associate with a variety of amino acids, dipeptides, and fluorophores in water (1 mM phosphate buffer, pH 7.0), DMSO, and a 75/25 (v/v) buffer to DMSO solution. All peptidic guests in all solvent systems have association constants (K(A)'s) in the range of 1 x 10(4) to 5 x 10(4) M(-)(1), whereas the K(A) range for the fluorophores is 1 x 10(4) to 9 x 10(5) M(-)(1). Association constants for the cyclophane itself, cyclophane 3, are smaller. These values are in the 1 x 10(3) to 5 x 10(3) M(-)(1) range, which shows that the rotaxane architecture is advantageous for guest binding. Cyclophane-[2]rotaxane 1 efficiently transports fluorescein and a fluorescein-protein kinase C (PKC) inhibitor into eukaryotic COS-7 cells, including the nucleus. Interestingly, cleft-[2]rotaxane 2 does not transport fluorescein as efficiently, even though the results from the fluorescence assays show that both [2]rotaxanes bind fluorescein with the same ability.
Related Concept Videos
Electron Carriers
Over the many stages of cellular respiration, glucose breaks down into carbon dioxide and water. Electron carriers pick up electrons lost by glucose in these reactions, temporarily storing and releasing them into the electron...
Transcellular Transport of Solutes
Role of Reduced Coenzymes NADH and FADH₂
Oxidation and Reduction of Organic Molecules
The removal of an electron from a molecule, results in a...
Electron Transport Chain Components
Sulfur Assimilation

