There are disclosed compositions and methods to render nucleic acids resistant to nuclease digestion while maintaining sequence selective hybridization competency. The approach relies on utilizing nucleic acids as the polar head group of a nucleic acid-polymer amphiphile in order to assemble well-defined, discrete micellar nanoparticles. Dense packing of nucleic acid in the micelle corona allows for hybridization of complementary oligonucleotides while prohibiting enzymatic degradation.