The present invention pertains to complexes comprising sterols and saponins. The complexes are capable of binding a genetic determinant including a polynucleotide. The complexes may further comprise a lipophilic moiety, optionally a lipophilic moiety comprising a contacting group and/or a targeting ligand, and/or a saccharide moiety. The complexes may further comprise an immunogenic determinant and/or an antigenic determinant and/or a medicament and/or a diagnostic compound. The complexes may in even further embodiments be encapsulated by an encapsulation agent including a biodegradable microsphere. The present invention also pertains to pharmaceutical compositions and methods of treatment of an individual by therapy and/or surgery, methods of cosmetic treatment, and diagnostic methods practised on the human or animal body.