Clustered regularly interspaced short palindromic repeats (CRISPR) technology has transformed molecular biology and the future of gene-targeted therapeutics. CRISPR systems comprise a CRISPR-associated (Cas) endonuclease and a guide RNA (gRNA) that can be programmed to guide sequence-specific binding, cleavage, or modification of complementary DNA or RNA. However, the application of CRISPR-based therapeutics is challenged by factors such as molecular size, prokaryotic or phage origins, and an essential gRNA cofactor requirement, which impact efficacy, delivery and safety. This Review focuses on chemical modification and engineering approaches for gRNAs to enhance or enable CRISPR-based therapeutics, emphasizing Cas9 and Cas12a as therapeutic paradigms. Issues that chemically modified gRNAs seek to address, including drug delivery, physiological stability, editing efficiency and off-target effects, as well as challenges that remain, are discussed.

成簇的规则间隔短回文重复序列 （CRISPR） 技术改变了分子生物学和基因靶向治疗的未来。CRISPR 系统包括 CRISPR 相关 （Cas） 核酸内切酶和向导 RNA （gRNA），可以对其进行编程以指导互补 DNA 或 RNA 的序列特异性结合、切割或修饰。然而，基于 CRISPR 的疗法的应用受到分子大小、原核或噬菌体来源以及必需的 gRNA 辅因子要求等因素的挑战，这些因素会影响疗效、递送和安全性。本综述重点介绍 gRNA 的化学修饰和工程方法，以增强或实现基于 CRISPR 的疗法，强调 Cas9 和 Cas12a 作为治疗范式。讨论了化学修饰的 gRNA 寻求解决的问题，包括药物递送、生理稳定性、编辑效率和脱靶效应，以及仍然存在的挑战。