Table 1.
Chitosan: Survanta + Albumin: Charge Ratio | ||||
---|---|---|---|---|
Chitosan Concentration, mg/mL | 0.0005 | 0.005 | 0.05 | 0.5 |
n+/n− (Bulk)f | 3.46 × 10−2 | 0.346 | 3.46 | 34.6 |
n+/n− (Interface)g | 2.69 | 26.9 | 2.69 × 102 | 2.69 × 103 |
Average molecular weight of chitosan, 50–190 kDa
Calculated molecular weight for DPPC:POPG:PA (70:20:10 wt.), a lipid mixture similar in composition to Survanta
Albumin charge/molecule at pH 5.5 in 150 mM NaCl [75]
Calculated based on chitosan with average molecular weight of 120,000 with 80% of the monomers containing an amine group with pKa of 6.5 at a pH of 5.5
Based on published Survanta composition showing ~10% anionic lipids [46]
The charge ratio, n+/n−, of the cationic molecules (chitosan): anionic molecules (albumin and Survanta). For n+/n− bulk, the bulk concentrations of chitosan, albumin (2 mg/mL) and Survanta (800 μg/150 mL) are used.
For n+/n− interface, the interfacial concentration of albumin (5 mg/m2 [64]) and Survanta (800 μg/130 m2) are compared with the bulk chitosan concentration.
For chitosan concentrations of 0.0005 and 0.005 mg/mL, the bulk and interfacial charge ratios bracket an estimate for n+/n− = 1 indicating charge neutralization occurs over this concentration range.