We prepared two types of multidimensional gradient hydrogels by simple electrophoresis using spherical graphite electrode. To explore their application in controlled drug release, rhodamine B (RB) and sodium salicylate (SS) were used as oppositely charged drug models respectively to in situ loading into the hydrogels by electrostatic interaction with the charged components accordingly. In both cases, the model drugs and the charged components of the hydrogels were gradiently distributed with the drug concentration increased from the gel surface to the gel core. For the crosslinking gradient hydrogel prepared at 2 V, the network size near the gel surface is about 3 times that of the gel core, and the release rate is 0.85 times of that of the non-gradient hydrogel. For the polymer chain gradient hydrogel prepared at 2.5 V, the relative content of polymer chain near the core of the gel is 2.5 times that of the gel surface, and the release rate is 0.71 times of the non-gradient hydrogel.

中文翻译：

---

多维梯度水凝胶及其在缓释中的应用

我们使用球形石墨电极通过简单的电泳制备了两种类型的多维梯度水凝胶。为了探索它们在药物控释中的应用，罗丹明 B (RB) 和水杨酸钠 (SS) 分别用作带相反电荷的药物模型，通过与带电组分的静电相互作用原位加载到水凝胶中。在这两种情况下，模型药物和水凝胶的带电组分呈梯度分布，药物浓度从凝胶表面到凝胶核心增加。对于2 V制备的交联梯度水凝胶，凝胶表面附近的网络尺寸约为凝胶核的3倍，释放速率为非梯度水凝胶的0.85倍。对于在 2.5 V 下制备的聚合物链梯度水凝胶，