Synthesis AP-CBA

cationic poly(amido amine)s with an equal feeding mole ratio of N,N′-methylene bisacrylamide (MBA) and 1-(2-aminoethyl)piperazine (AP).

N,N′-methylenebisacrylamide (MBA, 96%), 146072-100G, $30.80
N’N’-Cystamine bisacrylamide (CBA)

All polymerizations were carried out under a nitrogen atmosphere. A typical procedure is as follows:

1. Add 2.61 g (20 mmol) of AP to a solution of 3.15 g (20 mmol) of MBA in 30 mL of distilled water or mixture solvent of water and DMF. (The volume ratios of water and DMF are 4/1, 3/2, 3/7, and 1/9, respectively.)

2. Polymerization at 60 °C under vigorous stirring for 60 h.

3. Concentrate by rotary evaporation.

4. Precipitate with 300 mL of acetone under stirring.

5. Dissolve in water

6. Precipitate again with acetone.

7. Dry under vacuum at 60 °C for 24 h.

Reaction Conditions and Characterization Data
no.	water/		DB	Mw (×10 )	Mw/Mn   ratio of primary/
	DMF (V/V)					secondary/tertiary
							amines    
PAA1	100/0 		0.44	8.48		1.25	13/18/69
PAA2	80/20		0.31	9.32		1.26	8/23/69
PAA3	60/40		0.21	9.18		1.30	7/26/67
PAA4	30/70		0.11	9.34		1.85	6/29/65
PAA5	10/90		0.06	8.03		1.82	4/31/65

PAA1 (highly branched, made in pure water) has the best transfection efficiency and the lowest toxicity. But the efficiency is still lower than PEI25 (or equal).