Editing Synthesis Dextran-Agmatine

== Reagents  ==

<span style="line-height: 1.5em;">Pharmacia:&nbsp;</span>Dextran T-40 (M w 1⁄4 40,000) 

Sigma: 4-Aminobutylg-uanidine sulfate (agmatine, 97%), '''p-toluenesulfonyl chloride '''(TsCl, 99%), lauric&nbsp;acid (98%),&nbsp;triethanolamine 

1,1′-Carbonyldiimidazole (CDI, 98%): &nbsp;Alfa Aesar,&nbsp;http://www.sigmaaldrich.com/catalog/product/aldrich/115533,&nbsp;115533-5G, $28.50, 115533-10G, $43.60 

== Synthesis of&nbsp;tosylated dextran  ==

The synthesis procedures of tosylated dextran were depicted in Scheme 1. The&nbsp;detailed preparation of tosylated dextran at anhydroglucose units (AGU)/tosyl&nbsp;chloride 1⁄4 1:3(mol/mol) (Dex-Ts3) was described as a typical example. Dextran (2 g,&nbsp;12.4 mmol) was dispersed in 20 mL of water, and the pH was adjusted to 13 with&nbsp;NaOH. The solution was stirred vigorously and placed on ice. Tosyl chloride (7.2 g,&nbsp;37.2 mmol) in 20 mL of acetonitrile was added dropwise with stirring over 30 min,&nbsp;causing immediate formation of a white precipitate. After 3 h of stirring at the room&nbsp;temperature, the precipitate was removed by suction filtration and the filtrate was&nbsp;dialyzed in ultrapure water for 5 days and the Dex-Ts3 was collected by&nbsp;lyophilization. 

<br> 

== Synthesis of lauryl tosylated dextran  ==

<br>The Dex-Ts3 was selected to prepare lauryl tosylated dextran. Briefly, to 3 mL<br>solution of lauric acid (1.8 mmol) in DMSO, was added 3 mL solution CDI<br>(1.8 mmol) in DMSO. After stirring for 3 h at 80 � C, the solution of dextran<br>(6 mmol) in 5 mL DMSO was added. The mixture was allowed to react for 6 h at<br>80 � C under stirring. The raw product was isolated by precipitation in 100 mL<br>ethanol and washed several times with ethanol. The product was dialyzed in<br>ultrapure water for 5 days and the resultant lauryl tosylated dextran was collected<br>by lyophilization. 

<br> 

== Synthesis of dextran-agmatine (Dex-Agm) and lauryl dextran-agmatine (Dex-L-Agm) conjugates  ==

<br>The synthesis of dextran-agmatine and lauryl dextran-agmatine conjugates was&nbsp;based on previous method [25,26] with a slight modification. Agmatine (25 mmol) 

and tosylated dextran or lauryl tosylated dextran (5 mmol) were dissolved in water&nbsp;(30 mL) containing triethanolamine (20 mL) at 85 � C with stirring for 24 h under N 2 .<br>The resulting solution was adjusted to pH 7 and dialyzed against ultrapure water for&nbsp;5 days, followed by lyophilization to obtain the Dex-Agm and the Dex- L -Agm&nbsp;conjugates. The preparation of Dex-Agm with different substitution degrees of&nbsp;agmatine was carried out by varying the molar ratio of dextran/tosyl chloride.<br> [[Image:Dextran-Agmatine.png]] 

[[Image:Alkahol to tosylate.png]]&nbsp; 

<br> 

[[Image:Dextran agmatine transfection efficiency.png]] 

[[Category:Paul]] [[Category:Transfection]]