Synthesis SS-PBAA-PEI

Synthesis of disulfide-containing poly(b-amino amine) crosslinked PEIs (SS-PBAA-PEIs)

Cystamine bisacrylamide
1. Dissolve 22.5 g cystamine dihydrochloride (0.1 mol) and 8.0 g NaOH (0.2 mol)  in water (100 ml) in a three-necked flask.

2. Cool the solution to 0 °C.

3. Add acryloyl chloride dichloromethane solution (0.2 mol, 20 ml) and aqueous NaOH solution (0.2 mol, 10 ml) simultaneously.

4. Stir the reaction mixture  at room temperature for 16 h.

5. Filter the raw product through a filter paper. Wash three times with water.

6. Crystallization using ethyl acetate.

7. Dry CBA by removing the solvent under vacuum.

SS-PBAA-PEIs

1.  Add 2-amine-1-ethanol (EA) or 5-amino-1-pentanol (PA) to CBA.

Sigma:

2-amino-1-ethanol (EA): 494577-1G, $133.50

5-amino-1-pentanol (PA): 123048-10G, $33.80; 123048-50G, $121.50

2. 4 different  SS-PBAA1-PEIs can be synthesized by varying the stoichiometric ratio (r) of the monomers (i.e. rEA/CBA or rPA/CBA)

3. For example:

Stir a mixture of EA (0.109 g, 1.8 mmol) and CBA (0.520 g, 2 mmol, stoichiometric ratio rEA/CBA = 0.9) in 5 ml of 25% aqueous methanol in the dark at 60 °C under a nitrogen atmosphere for 48 hours. This will yield  a homogeneous solution.

Add 0.276 g PEI in 2 ml of 25% aqueous methanol  to the SS-PBAA1 solution, react 24 hours at 45 oC under a nitrogen atmosphere. This will yield SS-PBAA1-PEI (4:1).

4. Dilute the transparent solution with water to 30 ml and acidify with 6 M HCl to pH 4, then dialyze against distilled water (molecular weight cut-off 8000) for 2 days to remove the unreacted reactants.

5. Lyophilize for 2 days to obtain SS-PBAA1-PEI.