Described herein are modified guide RNAs such as a single guide RNA including, from 5′ to 3′, a single-stranded protospacer sequence, a first complementary strand of a binding region for the Cas9 polypeptide, an aptamer that binds a biotin-binding molecule, and a second complementary strand of the binding region for the Cas9 polypeptide. Also described is an RNP complex including the modified guide RNA and a Cas9 polypeptide or active fragment thereof. Also included are methods of modifying target genes in cells using the modified guide RNAs.