Effect of ultrasonication on the stability of oligonucleotides adsorbed on nanoparticles and liposomes

Author： Zobel H.-P. Werner D. Gilbert M. Noe C. R. Stieneker F. Kreuter J. Zimmer A.

ISSN： 1464-5246

Source： Journal of Microencapsulation, Vol.16, Iss.4, 1999-07, pp. : 501-509

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Abstract

In the present study, oligonucleotides were adsorbed onto the surface of cationic liposomes and nanoparticles at different ratios. As a result, the surface charges of the colloidal carriers were decreased with increasing oligonucleotide concentration. At a certain oligonucleotide concentration, complete charge neutralization led to the aggregation of the carrier systems. Further increasing oligonucleotide concentrations reversed the surface charge of liposomes and nanoparticles to a negative one. Ultrasonication was investigated as a possible means for the homogenization of the formed aggregates. However, the use of ultrasonication led to a time-dependent damage of oligonucleotides adsorbed onto AH-Chol liposomes and MMAEMC-nanoparticles, as well as of unbound oligonucleotides. Nearly 60% of the oligonucleotides adsorbed to MMAEMCnanoparticles and 65% of ODNs adsorbed to the liposomes were degraded by the effect of cavitation produced by ultrasonication within 10min. In contrast, the oligonucleotides were protected from degradation when DEAE-stabilized PHCA-nanoparticles were employed as ODN carriers. More than 80% of the oligonucleotides entangled in thesurface matrix of these nanoparticles remained intact.