Our previous studies showed that DNA hydrogels containing unmethylated CpG motifs effectively induced antigen-specific immune responses when combined with the appropriate antigens. A potential drawback of existing DNA hydrogels for further applications is the need for many oligodeoxynucleotide (ODN) types. Therefore, in this study, we attempted to optimize and minimize the nanostructured DNA units for DNA hydrogels to reduce the preparation cost, design difficulty, and possible risk of sequence-dependent off-target effects, and prepare DNA hydrogels with sustained retention ability. A Takumi-shaped unit with a stem and four flanking cohesive parts was constructed using one type of ODN with a palindromic sequence. A DNA hydrogel was prepared by mixing two Takumi-shaped units with complementary cohesive parts. The required length of the cohesive part was first examined using ODNs with 14 or 18 bases of stem length. Electrophoresis, melting temperature measurements, and viscoelastic analysis showed that the properties of the cohesive part determined the hydrogel properties. ODNs with a cohesive part consisting of GC-rich 5′-ccgcaagacg-3′ efficiently formed a hydrogel with sustained retention in mice after administration. Several ODNs with optimized cohesive sequences and different stem lengths and sequences were designed. Analyses showed that a stem of 10 bases or longer was required for efficient hydrogel formation, and ODNs with a 12-base stem part exhibited the most prolonged retention after subcutaneous injection into mice. Thus, the present study demonstrated the requirements of minimal DNA units for preparing DNA hydrogels with sustained retention ability.

中文翻译：

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由最小化的 Takumi 形 DNA 纳米结构组成的生物相容性 DNA 水凝胶在体内给药后表现出持续的保留


我们以前的研究表明，当与适当的抗原结合时，含有未甲基化 CpG 基序的 DNA 水凝胶可有效诱导抗原特异性免疫反应。现有 DNA 水凝胶用于进一步应用的一个潜在缺点是需要许多寡脱氧核苷酸 （ODN） 类型。因此，在本研究中，我们试图优化和最小化 DNA 水凝胶的纳米结构 DNA 单元，以降低制备成本、设计难度和序列依赖性脱靶效应的可能风险，并制备具有持续保留能力的 DNA 水凝胶。使用一种具有回文序列的 ODN 构建了一个具有茎和四个侧翼粘性部分的 Takumi 形单元。通过将两个 Takumi 形单元与互补的内聚部分混合来制备 DNA 水凝胶。首先使用具有 14 或 18 个碱基茎长度的 ODN 检查内聚部分的所需长度。电泳、熔融温度测量和粘弹性分析表明，内聚部分的特性决定了水凝胶的性能。具有由富含 GC 的 5'-ccgcaagacg-3' 组成的粘连部分的 ODN 在给药后有效地形成水凝胶，并在小鼠中持续保留。设计了几个具有优化的内聚序列和不同茎长和序列的 ODN。分析表明，有效形成水凝胶需要 10 个碱基或更长的茎，并且皮下注射到小鼠体内后，具有 12 个碱基茎部分的 ODN 表现出最长的保留时间。因此，本研究证明了制备具有持续保留能力的 DNA 水凝胶所需的最小 DNA 单位。