This paper aims to investigate the preparation and characterisation of the alginate nanoparticles (NPs) as antigen delivery system loaded by diphtheria toxoid (DT). For this purpose, both the loading capacity (LC) and Loading efficiency (LE) of the alginate NPs burdened by DT are evaluated. Moreover, the effects of different concentrations of sodium alginate and calcium chloride on the NPs physicochemical characteristics are surveyed in addition to other physical conditions such as homogenization time and rate. To do so, the NPs are characterised using particle size and distribution, zeta potential, scanning electron microscopy, encapsulation efficiency, in vitro release study and FT-IR spectroscopy. Subsequently, the effects of homogenization time and rate on the NPs are assessed. At the meantime, the NPs LC and efficiency in several DT concentrations are estimated. The average size of the NPs was 400.7 and 276.6 nm for unloaded and DT loaded, respectively. According to the obtained results, the zeta potential of the blank and DT loaded NPs are estimated as -23.7 mV and -21.2 mV, respectively. Whereas, the LC and LE were >80% and >90%, in that order. Furthermore, 95% of the releasing DT loaded NPs occurs at 140 h in the sustained mode without any bursting release. It can be concluded that the features of NPs such as morphology and particle size are strongly depended on the calcium chloride, sodium alginate concentrations and physicochemical conditions in the NPs formation process. In addition, appropriate concentrations of the sodium alginate and calcium ions would lead to obtaining the desirable NPs formation associated with the advantageous LE, LC (over 80%) and sustained in vitro release profile. Ultimately, the proposed NPs can be employed in vaccine formulation for the targeted delivery, controlled and slow antigen release associated with the improved antigen stability.

中文翻译：

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研究负载在海藻酸钠纳米颗粒上的白喉类毒素的制备和表征。

本文旨在研究海藻酸盐纳米颗粒 (NPs) 作为白喉类毒素 (DT) 负载抗原传递系统的制备和表征。为此，评估了 DT 负载的藻酸盐 NPs 的负载能力 (LC) 和负载效率 (LE)。此外，研究了不同浓度的海藻酸钠和氯化钙对纳米粒子物理化学特性的影响，以及其他物理条件，如均质时间和速率。为此，使用粒径和分布、zeta 电位、扫描电子显微镜、封装效率、体外释放研究和 FT-IR 光谱对 NP 进行表征。随后，评估了均质化时间和速率对 NPs 的影响。与此同时，估计了几个 DT 浓度下的 NPs LC 和效率。未加载和加载 DT 的 NP 平均尺寸分​​别为 400.7 和 276.6 nm。根据获得的结果，空白和 DT 负载 NP 的 zeta 电位分别估计为 -23.7 mV 和 -21.2 mV。而 LC 和 LE 依次为 >80% 和 >90%。此外，95% 的释放 DT 负载的 NP 在持续模式下发生在 140 小时，没有任何突发释放。可以得出结论，纳米颗粒的形态和粒径等特征在很大程度上取决于纳米颗粒形成过程中的氯化钙、海藻酸钠浓度和物理化学条件。此外，适当浓度的海藻酸钠和钙离子将导致获得与有利的 LE、LC (超过 80%) 和持续体外释放曲线相关的理想 NPs 形成。最终，所提出的 NPs 可用于疫苗制剂中，用于靶向递送、受控和缓慢的抗原释放，从而提高抗原稳定性。