Author/Authors :
Eva J. Gordon، نويسنده , , Jason E. Gestwicki، نويسنده , , Laura E Strong، نويسنده , , Laura L Kiessling، نويسنده ,
Abstract :
Abstract
Background: Ring-opening metathesis polymerization (ROMP) is a powerful synthetic method for generating unique materials. The functional group tolerance of ruthenium ROMP initiators allows the synthesis of a wide range of biologically active polymers. We generated multivalent ligands that inhibit cell surface L-selectin, a protein that mediates lymphocyte homing and leukocyte recruitment in inflammation. We hypothesized that these ligands function through specific, multivalent binding to L-selectin. To examine this and to develop a general method for synthesizing multivalent materials with end-labels, we investigated functionalized enol ethers as capping agents in ruthenium-initiated ROMP.
Results: We synthesized a bifunctional molecule that introduces a unique end group by terminating ruthenium-initiated ROMP reactions. This agent contains an enol ether at one end and a masked carboxylic acid at the other. We conjugated a fluorescein derivative to an end-capped neoglycopolymer that had previously been shown to inhibit L-selectin function. We used fluorescence microscopy to visualize neoglycopolymer binding to cells displaying L-selectin. Our results suggest that the neoglycopolymers bind specifically to cell surface L-selectin through multivalent interactions.
Conclusions: Ruthenium-initiated ROMP can be used to generate biologically active, multivalent ligands terminated with a latent functional group. The functionalized polymers can be labeled with a variety of molecular tags, including fluorescent molecules, biotin, lipids or antibodies. The ability to conjugate reporter groups to ROMP polymers using this strategy has broad applications in the material and biological sciences.
Article Outline
* Introduction
* Results and discussion
*
o Synthesis of the bifunctional capping agent
o Conjugation of functionalized neoglycopolymer to fluorescein
* Significance
* Materials and methods
*
o Synthesis of capping agent 4
o
+ 2-(2-(2-benzyloxy)ethoxy)ethoxy)ethanol
+ 10-phenyl-3,6,9-trioxadecanoic acid (2)
+ 10-Phenyl-3,6,9-trioxadecanoic acid 2-(trimethylsilyl)ethyl ester
+ 3,6-Dioxa-8-hydroxy-octanoic acid 2-(trimethylsilyl)ethyl ester (3)
+ 3,6-Dioxa-8-al-octanoic acid 2-(trimethylsilyl)ethyl ester
+ Cis, trans 3,6,10-Trioxa-8,9-ene-undecanoic acid 2-(trimethylsilyl)ethyl ester (4).
o Synthesis of polymer 10
o Synthesis of polymer 11a
o Synthesis of polymer 14
o Conversion of polymer 14 to polymer 11b
o Deprotection of polymer 11a
o Synthesis of conjugate 16
o Fluorescence microscopy
* Acknowledgements
* References
Keywords :
* L-selectin , * Neoglycopolymer , * Multivalent , * Ring-opening metathesis polymerization , * Fluorescence microscopy