In
this work, the influence of the ionic strength and phosphate
ions on poly(l-lysine) hydrodynamic radius, conformation
and persistence lengths has been studied for molar masses comprised
between 3000 and 70 000 g/mol. Mark–Houwink coefficients
have been obtained via the determination of poly(l-lysine)
hydrodynamic radius using Taylor dispersion analysis. The influence
of phosphate ions and ionic strength on the solvent quality (poor,
Θ, or good solvent) for poly(l-lysine) have been studied
in details. Quantitative data on hydrodynamic radius, persistence
length, Mark–Houwink coefficients are provided at pH 7.4, in
the range of 10 mM to 1 M ionic strength, and for different phosphate
ion concentrations from 0.1 mM to 50 mM under physiological conditions
(154 mM ionic strength, pH 7.4). The strong influence of phosphate
ions on poly(l-lysine) properties was finally illustrated
by studying the interactions (stoichiometry, binding constant, and
cooperativity) between poly(l-lysine) of DP 50 and human
serum albumin, in the absence and in the presence of phosphate ions
at pH 7.4