Electrostatic interaction between chitosan-modified latex particles and bovine serum albumin

Electrostatic interaction between poly(methyl methacrylate) latex particles with different levels of chitosan modification and bovine serum albumin (B SA) was investigated. The critical flocculation concentration is in the ran ge 5-15 nmol dm(-3) for these latex products toward added BSA. A series of isothermal equilibrium adsorption experiments shows that the adsorption pro cess is divided into two distinct intervals. Adsorption of BSA on latex par ticles in intervals I and II is primarily controlled by charge neutralizati on and hydrophobic interaction, respectively. Intervals I and II can be rea sonably described by an empirical parabola equation and the Langmuir isothe rm model, respectively. The maximum amount of BSA adsorbed per unit weight of polymer particles was observed at pH congruent to 5. A maximum elution y ield of about 80% can be achieved using NaSCN as the elution electrolyte, a nd NaSCN is more effective in inducing desorption of BSA from the particle surface than NaCl. The chitosan content has very little effect on the inter action between latex particles and BSA. By contrast? the influence of the c ontent of 2,2'-azobis(2-amidinopropane) dihydrochloride, a cationic initiat or used in preparing the chitosan-modified latex products, on the BSA adsor ption process is significant.