Conclusion

Adsorption of antibody (Y)

Addition of reactive polymer

De sorption of non- grafted antibody

Adsorption of antibody (Y)

Addition of reactive polymer

"X

CH2 CH CH CH2

CH2 CH CH CH2

FIG. 14 Methodology for the covalent grafting or protein materials onto thermally sensitive latex particles.

ch3 oh nh antibody

FIG. 14 Methodology for the covalent grafting or protein materials onto thermally sensitive latex particles.

as the incubation temperature rose from below to above the Tvpt. The observed behavior has been discussed on the basis of two factors: (1) the possible adsorption via hydrophobic interaction attributed to the dehydration process of poly-(NIPAM) chains and (2) the electrostatic interaction between charges involved in the adsorption process as evidenced from the effect of pH and salinity. Concerning the effect of hydration and dehydration in protein adsorption, it has been shown in numerous studies that the adsorption of protein onto highly hydrophilic surfaces was low and in some cases negligible whatever the charge, whereas the adsorption onto charged hydrophobic surfaces has been reported to be high, with salinity, pH, and charge nature dependent. The reported results concerning protein adsorption onto poly(NIPAM)-based particles as a function of pH and salinity above the Tvpt (i.e., above the LCST of corresponding linear polymer) can only be discussed in terms of electrostatic interactions. Anyway, in the case of reported thermally sensitive colloidal particles, to point out the driven forces involved in the protein adsorption, the interaction between protein and non-charged poly( NIPAM) gel or chains should be investigated as a function of temperature.

The desorption study of preadsorbed proteins onto thermally sensitive polymer particles has been not extensively investigated as few investigators have focused on this aspect. The reported results revealed (1) the effect of adsorption time (above the Tvpt) on the desorption efficiency below the volume phase transition temperature, and (2) the effect of salinity and pH on the protein desorbed amount below the Tvpt. As a result of those investigations, the desorption was found to be total when the adsorption was performed in a short time without pH and salinity modification. In contrast, for long-term adsorption, the desorption was enhanced by reducing the attractive electrostatic interactions.

The chemical immobilization or controlled complexation of proteic material can be obtained by virtue of the effect of temperature, which governs the affinity between both species.

Was this article helpful?

0 0

Post a comment