Provided herein are methods for inducing CRISPR/Cas-based gene regulation (e.g., genome editing or gene expression) of a target nucleic acid (e.g., target DNA or target RNA) in a cell. The methods include using modified single guide RNAs (sgRNAs) that enhance gene regulation of the target nucleic acid in a primary cell for use in ex vivo therapy or in a cell in a subject for use in in vivo therapy. Additionally, provided herein are methods for preventing or treating a genetic disease in a subject by administering a sufficient amount of a modified sgRNA to correct a mutation in a target gene associated with the genetic disease.