Quaternary Ammonium Polyethyleneimine: Antibacterial Activity

Table 3

Characterization of PEI-based nanoparticles at different degrees of N-methylation.

Code	Inhibition concentrationa	Elemental analysisb			C/Nc	Particle size (nm)d	Zeta potential (mV)e
		%N
F1	NA∗	6.52	29.90	51.12	3.86	36 ± 28	79 ± 25
F2	NA∗	6.06	28.13	52.60	3.86	20 ± 20	79 ± 38
F3	80 𝜇g/mL	7.22	36.39	46.62	3.86	34 ± 29	97 ± 20

Cross-linked PEI nanoparticles were reacted with octyl halide at 1 : 1 mole ratio (primary amine of PEI/alkylating agent) followed by N-methylation with various equivalents of methyl iodide, under the same conditions as described in experimental section.
∗ Not active at 80 𝜇g/mL or below.
a Concentration of the tested compound used for a complete inhibition of >10⁶   S. aureus growth. b Found Nitrogen, Carbon, and Iodine content of QA-PEI (elemental analysis). c C/N was determined by elemental analysis of the alkylated samples before methylation step whereas C/N of the nonalkylated PEI was found to be 2.26.
d Apparent particle size of QA-PEI nanoparticles (diameter). e Zeta potential of QA-PEI nanoparticles.