Protamine adsorption

Polyelectrolyte multilayer microspheres, prepared by alternating adsorption of dextran sulfate and protamine on melamine formaldehyde cores followed by the partial decomposition of the core, were used to immobilise the peroxidase and glucose oxidase. Retention of enzymic activity of the peroxidase/glucose oxidase system incorporated into the microspheres was demonstrated. These bienzyme system immobilised in the microspheres can be applied for kinetic glucose assays [ 156]. 

We routinely use protamine sulfate as a linking agent to facilitate the adsorption of DNA to the microtiter plate. In our experiments, the... 

Stable polyelectrolyte microcapsules were produced by means of the layer-by-layer adsorption of protamine and alginic acid on the surface of calcium carbonate microcores followed by the cores dissolution at low pH. The capsules obtained were investigated by atomic force microscopy and confocal laser scanning microscopy. 

Adsorption of sulfophthalein and xanthene dyes by protamine sulfate/carboxymethylcellulose (PtS/CMC) layer-by-layer (LbL) films has been studied. The adsorbed amount of a dye depends on its nature, solvent, conditions of polyelectrolyte multilayers (PEMs) preparation. Addition of ethanol into solution and preliminary drying of PEMs increase adsorption of the dyes. Kinetics of a dye release from (PtS/CMC)2o films in acidic solution (pH 3.0) has been investigated. 

The quartz plates were preliminary cleaned and hydrophilized using a standard technique ("piranha", RCA). Protamine sulfate/carboxymethylcellulose (PtS/CMC) films were fabricated by the layer-by-layer (LbL) method from 1.5 mg/mL solutions of PtS (Mw 5000) and CMC (Mw 250000) in distilled water at pH 7.0. The method is described in details elsewhere [8]. The films containing up to 20 (PtS/CMC) bilayers were used for testing of dye adsorption. 

SPR was used to determine absolute heparin concentration in human blood plasma (Gaus and Hall, 1998). Protamine and polyethylenimine (PEI) were used to modify the sensor surface and were evaluated for their affinity to heparin. Heparin adsorption onto protamine in blood plasma was specific with a lowest detection Hmit of... 

U mL and a linear detection range of 0.2—2 U mL. Although heparin adsorption onto PEI in buffer solution had indicated superior sensitivity to that on protamine, in blood plasma it was not specific for heparin and adsorbed plasma species to a steady-state equilibrium. By reducing the incubation time and diluting the plasma samples with buffer to 50%, the nonspecific adsorption of plasma could be controlled and a PEI pretreated with blood plasma could be used successfully for heparin determination. Heparin adsorption in 50% plasma was Hnear between 0.05 and 1 U mL so that heparin plasma levels of 0.1—2 U mL could be determined with a relative error of 11% and an accuracy of 0.05 U mL. ... 

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