The field of nucleic acid therapeutics has witnessed a significant surge in recent times, as evidenced by the increasing number of approved genetic drugs. However, current platform technologies containing plasmids, lipid nanoparticle-mRNAs, and adeno-associated virus vectors encounter various limitations and challenges. Thus, we are devoted to finding a novel nucleic acid vector and have directed our efforts toward investigating circular single-stranded DNA (CssDNA), an ancient form of nucleic acid. CssDNAs are ubiquitous, but generally ignored. Accumulating evidence suggests that CssDNAs possess exceptional properties as nucleic acid vectors, exhibiting great potential for clinical applications in genetic disorders, gene editing, and immune cell therapy. Here, we comprehensively review the discovery and biological effects of CssDNAs as well as their applications in the field of biomedical research for the first time. Undoubtedly, as an ancient form of DNA, CssDNA holds immense potential and promises novel insights for biomedical research.

中文翻译：

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环状单链 DNA：发现、生物效应和应用

近年来，核酸治疗领域出现了显着增长，批准的基因药物数量不断增加就证明了这一点。然而，当前包含质粒、脂质纳米颗粒-mRNA和腺相关病毒载体的平台技术遇到了各种限制和挑战。因此，我们致力于寻找一种新型核酸载体，并致力于研究环状单链DNA（CssDNA），这是一种古老的核酸形式。 CssDNA 无处不在，但通常被忽视。越来越多的证据表明，CssDNA 作为核酸载体具有特殊的特性，在遗传性疾病、基因编辑和免疫细胞治疗等临床应用中表现出巨大的潜力。在此，我们首次全面综述了CssDNA的发现、生物学效应及其在生物医学研究领域的应用。毫无疑问，作为 DNA 的一种古老形式，CssDNA 拥有巨大的潜力，并为生物医学研究带来新的见解。