Provided herein, inter alia, are double stranded oligonucleotide molecules and methods of making the molecules. The double stranded oligonucleotide molecules include a first oligonucleotide strand comprising a first nucleic acid sequence bound to a second nucleic acid sequence through a first spacer, wherein said second nucleic acid sequence is bound to a third nucleic acid sequence through a second spacer and a second oligonucleotide strand comprising a fourth nucleic acid sequence bound to a fifth nucleic acid sequence through a third spacer, wherein said fifth nucleic acid sequence is bound to a sixth nucleic acid sequence through a fourth spacer, wherein the second nucleic acid sequence and the fifth nucleic acid sequence are hybridized to form a double stranded nucleic acid core of said double stranded oligonucleotide.