Mechanism of Lysozyme Uptake in Poly(acrylic acid) Microgels

Abstract

The uptake of lysozyme by oppositely charged poly(acrylic acid) microgels was investigated by micromanipulator-assisted light microscopy and confocal microscopy. Lysozyme was observed to distribute nonuniformly within the microgels, forming a core-shell structure with considerably higher lysozyme concentration in the shell than in the core. The core-shell formation can be divided into two periods. During the first of these, the shell is formed during rapid microgel deswelling, and with no lysozyme diffusing into the microgel core. This is followed by a second period, during which microgel deswelling is negligible and lysozyme diffuses into the microgel core. Thus, the shell which is initially formed as a result of fast lysozyme transport to the gel network and fast protein-microgel interactions is able to carry a mechanical load and prevents deswelling during the latter core diffusion period. These two distinct regimes of lysozyme loading were also successfully described theoretically, demonstrating the importance of lysozyme cluster formation for the observed phenomena.

Immobilization of lipase B within micron-sized poly-N-isopropylacrylamide hydrogel particles by solvent exchange

“…The location of the enzyme inside the polymer network was elucidated by using confocal laser scanning microscopy (CLSM). 20,21 To benefit from the low polydispersity and the high surface-to-volume ratio, it is more efficient to use smaller p-NIPAM particles. Welsch et al reached an enhanced activity of b-D-glucosidase after its immobilization within core-shell particles, where the core consisted of polystyrene and the shell consisted of p-NIPAM.…”

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].…”

High temporal resolution nanocalorimetry and its combination with micro- and nanofocus x-ray diffraction for study of functional nanostructured materials

“…Микрогели могут находить широкое практическое применение после моди фикации реакционными группами [16,17], поли мерными цепями [18,19], белками [20][21][22], благо родными металлами и оксидами [23][24][25][26][27], а также биоминералами. При помощи модификации водных микрогелей амфифильными лигандами, обладающими клиноподобной формой (рис.4), раз рабатываются новые адаптивные композиционные наноматериа лы (АКНМ).…”

“…The microgels can find wide practical applica tion after modification by the reaction groups [16,17], polymer chains [18,19], proteins [20][21][22], noble metals and oxides [23][24][25][26][27], a nd a l so by biom inera l s. By modification of aqueous micro gels using amphiphilic ligands, having a Vlike shape (Fig.4), the new adaptive composite nano materials (ACNM) are developed. They can be used, for example, for drug delivery.…”