The effect of polyelectrolyte chain length on layer-by-layer protein/polyelectrolyte assembly--an experimental study.
The effect of polyelectrolyte chain length on the formation of multilayered assemblies of alternating globular proteins and linear polyanions prepared by the layer-by-layer electrostatic adsorption technique was investigated. The systems studied were albumin/sodium poly(styrenesulfonate), immunoglobulin G/sodium poly(styrenesulfonate), albumin/sodium dextran sulfate, and albumin/heparin. The formation of assemblies was followed using FTIR multiple internal reflection spectroscopy. While the amount of polyelectrolyte adsorbed on the first (primary) protein layer did not depend on its molecular weight, the effect of polyelectrolyte chain length was clearly observed in the following steps of alternating adsorption. Some short-chain polyanion molecules were removed from the surface when a next protein layer was adsorbed from solution. The short polyanion chains were not able to make a sufficient number of ion pairs for stable interaction with additional protein molecules and left the surface as soluble protein/polyanion complexes. The most pronounced effect could be seen with sodium poly(styrenesulfonate) of Mw up to ca. 2 x 10(4), but a detectable effect could be traced even up to Mw ca. 8 x 10(4). Such a pronounced effect, however, was not observed with dextran sulfate. The effect of molecular weight of heparin was clearly observed but all heparins tested, regardless of their molecular weight, effectively assembled with albumin to form multilayer.
Houska
Milan
M
Institute of Macromolecular Chemistry, Academy of Sciences of the Czech Republic, 16206 Prague 6, Czech Republic. houska@imc.cas.cz
Brynda
Eduard
E
Bohatá
Karolina
K
D000327:Adsorption; D000418:Albumins / Q000737:chemistry; D000818:Animals; D002417:Cattle; D016264:Dextran Sulfate / Q000737:chemistry; D004573:Electrolytes / Q000737:chemistry; D006493:Heparin / Q000737:chemistry; D006801:Humans; D006863:Hydrogen-Ion Concentration; D007074:Immunoglobulin G / Q000737:chemistry; D007136:Immunoglobulins / Q000737:chemistry; D007477:Ions; D000071228:Polyelectrolytes; D011108:Polymers; D011137:Polystyrenes / Q000737:chemistry; D012492:Salts / Q000737:chemistry; D017550:Spectroscopy, Fourier Transform Infrared / Q000379:methods*; D013552:Swine; D013997:Time Factors
D000418:Albumins; D016264:Dextran Sulfate; D004573:Electrolytes; D006493:Heparin; D007074:Immunoglobulin G; D007136:Immunoglobulins; D007477:Ions; D000071228:Polyelectrolytes; D011108:Polymers; D011137:Polystyrenes; D012492:Salts; C003321:polystyrene sulfonic acid