The present invention relates to a novel structure of nucleic acid complex in which bioactive nucleic acid can be introduced into cells, to a composition comprising the nucleic acid complex for treatment and diagnosis of diseases, and to a method for regulating the expression of a target gene using the same and, more specifically, to a nucleic acid complex in which a bioactive nucleic acid is complementarily combined with a carrier peptide nucleic acid modified to have a positive charge overall, to a composition comprising the nucleic acid complex for treatment and diagnosis of diseases, and to a method for regulating the expression of a target gene using the same.
