Department of Biomedical Engineering, I-Shou University, College of Medicine, No. 8, Yida Rd., Jiaosu Village, Yanchao District, Kaohsiung City 82445, Taiwan.
Mater Sci Eng C Mater Biol Appl. 2013 Dec 1;33(8):4859-66. doi: 10.1016/j.msec.2013.08.005. Epub 2013 Aug 14.
Volvox sphere is a bio-mimicking concept of an innovative biomaterial structure of a sphere that contains smaller microspheres which then encapsulate chemicals, drugs and/or cells. The volvox spheres were produced via a high-voltage electrostatic field system, using alginate as the primary material. Encapsulated materials tested in this study include staining dyes, nuclear fast red and trypan blue, and model drugs, bovine serum albumin (BSA) and cytochrome c (CytC). The external morphology of the volvox spheres was observed via electron microscopy whereas the internal structure of the volvox spheres was observed via an optical microscope with the aid of the staining dyes, since alginate is colorless and transparent. The diameter of the microspheres was about 200 to 300 μm, whereas the diameter of the volvox spheres was about 1500 μm. Volvox spheres were durable, retaining about 95% of their mass after 4 weeks. Factors affecting entrapment efficiency, such as temperature and concentration of the bivalent cross-linker, were compared followed by a 7-day in vitro release study. The encapsulation efficiency of CytC within the microspheres was higher at cold (4°C) and warm (50°C) temperatures whereas temperature has no obvious effect on the BSA encapsulation. High crosslinking concentration (25% w/v) of calcium chloride has resulted higher entrapment efficiency for BSA but not for CytC. Furthermore, volvox spheres showed a different release pattern of BSA and CytC when compared to microspheres encapsulating BSA and CytC. Despite the fact that the mechanisms behind remain unclear and further investigation is required, this study demonstrates the potential of the volvox spheres for drug delivery.
水螅球是一种具有创新性的生物材料结构的仿生概念，它由包含更小微球的球体组成，这些微球随后包裹化学物质、药物和/或细胞。水螅球是通过高压静电场系统生产的，使用海藻酸钠作为主要材料。在这项研究中测试的封装材料包括染色染料、核固红和台盼蓝，以及模型药物牛血清白蛋白（BSA）和细胞色素 c（CytC）。通过电子显微镜观察水螅球的外部形态，通过光学显微镜观察水螅球的内部结构，借助染色染料，因为海藻酸钠是无色透明的。微球的直径约为 200 至 300 微米，而水螅球的直径约为 1500 微米。水螅球具有耐用性，在 4 周后保留约 95%的质量。比较了影响包封效率的因素，如二价交联剂的温度和浓度，随后进行了 7 天的体外释放研究。CytC 在微球中的包封效率在冷（约 4°C）和热（约 50°C）温度下较高，而温度对 BSA 的包封没有明显影响。氯化钙的高交联浓度（25%w/v）导致 BSA 的包封效率更高，但 CytC 则不然。此外，与包封 BSA 和 CytC 的微球相比，水螅球显示出 BSA 和 CytC 不同的释放模式。尽管其背后的机制尚不清楚，需要进一步研究，但这项研究表明了水螅球在药物传递方面的潜力。
