Abstract: The invention relates to a method for manipulating, isolating, detecting or amplifying a target nucleic acid in a sample by hybridization with an oligonucleotide-oligocation conjugate, comprising allowing said nucleic acid to react with an oligonucleotide-oligocation conjugate comprising at least A1 and Bj linked together directly or via a linker, wherein. A, is an i-mer oligonucleotides, with i=3 to 50, where Ai is an oligomer with naturally or non naturally occurring nucleobases and/or pentafuranosyl groups and/or native phosphodiester bonds, optionally comprising a marker group. Bj is a j-mer organic oligocation moiety, with j=1 to 50, where B is —HPO3—R1—(NH—R2)n—NH—R3—O—, where R1, R2 and R3 are lower alkylene, identical or different, NH—R2 moieties being identical or different when n is >1; HPO3—R1—CH(X)—R3—O—, where Ri and R3, identical or different, are lower alkylene and X is putrescine, spermidine or spermine residue.