Effect of Nonionic Surfactant on the Desorption of Oligonucleotide

Since the adsorption of oligonucleotides onto coated cationic latex particles is reduced irrespective of pH and ionic strength, ODN desorption was first investigated by washing the latex particles bearing adsorbed ODN (at pH 5, 10 mM ionic strength) with a borate buffer (10 mM, pH 9.2) containing 1 wt % Triton X-405 surfactant. In this case, the washing step was performed by removing and replacing 25% v/v of the supernatant. The desorption yield was clearly affected compared to surfactant-free buffer as illustrated in Fig. 15, in which the residual adsorbed amount is reported as a function of washing steps. Desorption yield at acidic pH still remains low because the supernatant was not totally

Washing Steps

FIG. 15 Residual adsorbed dT35 onto bare and precoated latex particles as a function of washing steps. Adsorption was performed onto bare latex particles at pH 5 and 10-M ionic strength. (Precoated particles: colloidal particles bearing a small amount of adsorbed Triton-X405.) (From Ref. 11.)

Washing Steps

FIG. 15 Residual adsorbed dT35 onto bare and precoated latex particles as a function of washing steps. Adsorption was performed onto bare latex particles at pH 5 and 10-M ionic strength. (Precoated particles: colloidal particles bearing a small amount of adsorbed Triton-X405.) (From Ref. 11.)

replaced. Consequently, a plateau with a nonnegligible residual amount of adsorbed ODN is reached, even after five washes. Anyway, the utilization of buffer containing noncharged surfactant enhances the desorption efficiency, which may be attributed to surface modification property (due to the surfactant adsorption) and to slight exchange between ODNs and free surfactant molecules.

Was this article helpful?

0 0

Post a comment