Magnetic switchable alginate beads
Magnetic switchable alginate beads
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DOI：
10.1007/s00396-011-2524-7
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发表时间：
2012-01-01
影响因子：
2.4
通讯作者：
Rehage, Heinz
中科院分区：
文献类型：
--
作者：
Degen, Patrick;Leick, Sabine;Rehage, Heinz
海藻酸钙珠粒被封装在广泛的产品中，包括食品、药品和化妆品配方。生物聚合物基质通常用于稳定活性成分并在明确定义的条件下提供受控释放。在这种情况下，它是高度感兴趣的研究磁诱导的吸引力，伸长，和胶囊或珠的破裂。在这项工作中，我们合成了新型的磁性可切换的海藻酸盐珠。磁敏感性是通过将磁性纳米颗粒（MNP）掺入海藻酸盐凝胶中来实现的。我们在挤压实验中测量了单个海藻酸盐珠的机械性能，通过在外场中刺激这些珠来测量水的蒸发和磁敏感性。在所有这些测量中，藻酸盐和纳米颗粒浓度系统地变化。我们可以证明，MNP的掺入产生了珠的磁响应，并减少了水的蒸发，但在压缩过程中对珠的机械稳定性没有影响。通过挤压数据的剪切模量的计算结果与流变频率扫描试验测得的剪切模量相比吻合良好。用扫描电子显微镜，我们可以分析这样的复合系统的分子结构，我们观察到均匀分布的凝胶基质内的MNP。
Calcium alginate beads are enclosed in a wide range of products including food, pharmaceuticals, and cosmetic formulations. The biopolymer matrix is often used to stabilize active ingredients and to provide a controlled release under well-defined conditions. In this context, it is of high interest to study the magnetic-induced attraction, elongation, and rupture of capsules or beads. In this work, we synthesized new types of magnetic switchable alginate beads. The magnetic sensitivity was achieved by incorporation of magnetic nanoparticles (MNPs) within the alginate gel. We measured the mechanical properties of single alginate beads in squeezing experiments, the evaporation of water and the magnetic sensitivity by stimulation of these beads in external fields. In all these measurements, the alginate and the nanoparticle concentration were systematically varied. We could show that the incorporation of MNPs generates a magnetic response of the beads and reduces the evaporation of water but has no influence on the mechanical stability of the beads during compression. Calculations of the shear modulus by means of the squeezing data result in good agreement in comparison to the shear moduli measured by rheological frequency sweep tests. With scanning electron microscopy, we could analyze the molecular structure of such composite systems, and we observed a homogeneous distribution of the MNPs within the gel matrix.