Development of delivery strategies for CRISPR-Cas9 genome editing

The clustered regularly interspaced short palindromic repeats(CRISPR)and CRISPR-related protein 9(Cas9)genome editing system has attracted much attention due to its powerful genome editing capacity.However,CRISPR-Cas9 components are easily degraded by acids,enzymes,and other substances in the body fluids after entering the organism,thus efficiently delivering the CRISPRCas9 system into targeted organs or cells has been a central theme for promoting the application of CRISPR-Cas9 technology.Although several physical methods and viral vectors have been developed for CRISPR-Cas9 delivery,their clinical application still suffers from disadvantages,such as the risks of mutagenesis,cell damage,and poor specificity.As an alternative,non-viral nanocarriers hold great promise for circumventing these challenges.Furthermore,with aim to realize more efficient and precise genome editing and reduce the undesirable side effects,stimuli-responsive nanocarriers are designed for the spatiotemporal CRISPR-Cas9 delivery in responsive to various stimuli.In this review,we will summarize the recent progress in delivery strategies for CRISPR-Cas9 genome editing.The mechanisms and advantages of these strategies were reviewed,providing a comprehensive review of the rational design of materials and techniques for efficient and precise genome editing.At last,the potential challenges of current CRISPR-Cas9 delivery are discussed.