Interaction between lysozyme and poly(acrylic acid) microgels

Transport of poly-l-lysine into oppositely charged poly(acrylic acid) microgels and its effect on gel deswelling

“…When oppositely charged substances interact with swollen polyelectrolyte gels, osmotic deswelling occurs. This deswelling behavior has been reported for a number of cationic surfactants [7][8][9][10][11][12][13][14], drug molecules [15][16][17], polymers [18], and proteins [19][20][21][22][23][24] binding to anionic gel networks. The rate and extent of this deswelling depends on the strength of interaction, which can be tuned, e.g., by changing salt concentration and pH, but also on the concentration of added substance and on its distribution within the gel during the shrinking process.…”

“…We observed that pLys distributed differently in pAA gels depending on peptide size and pH, and that shells formed under some conditions. In a parallel study, we observed such shell formation also for lysozyme in pAA microgels [24]. Since these previous investigations concerned quasi-static properties, the aim of the present study was to investigate the influence of pH, electrolyte concentration, and peptide size on binding, transport, and distribution of pLys in pAA microgels, and to relate this to the kinetic deswelling behavior of the gel particles, as well as to shell formation.…”

Interaction between lysozyme and colloidal poly(NIPAM-co-acrylic acid) microgels

“…Charged microgel networks typically swell extensively in water due to a high osmotic swelling pressure from counterions inside the network [8,10], and the fixed charges give them a capacity to bind large amounts of oppositely charged proteins [12][13][14][15]. For gels of larger size ($1 cm 3 ), here denoted macrogels, the mechanism has been described as ion exchange, driven to a large extent by the gain in entropy from the release of network counterions, accompanied by osmotic collapse of the network [16][17][18][19][20].…”

“…Considering the potential for drug delivery there are surprisingly few reports on the interaction between microgels and oppositely charged proteins in the literature [7,[13][14][15][25][26][27][28]. Eichenbaum et al studied the uptake of some proteins by poly(methacrylic acid-co-acrylic acid) microgels (4-10 lm in diameter) [13].…”

“…We previously investigated the interactions between poly (acrylic acid) microgels (60-80 lm in diameter) and the positively charged protein lysozyme [14,15]. Lysozyme uptake and distribution within the microgel particles, and its effect on microgel deswelling, was studied as a function of pH, ionic strength and lysozyme concentration.…”