Istituto per lo Studio dei Materiali Nanostrutturati (ISMN-CNR), Via P. Gobetti 101, Bologna 40129, Italy.
Acta Biomater. 2010 Mar;6(3):786-96. doi: 10.1016/j.actbio.2009.09.017. Epub 2009 Sep 27.
In recent years, interest in tissue engineering and its solutions has increased considerably. In particular, scaffolds have become fundamental tools in bone graft substitution and are used in combination with a variety of bio-agents. However, a long-standing problem in the use of these conventional scaffolds lies in the impossibility of re-loading the scaffold with the bio-agents after implantation. This work introduces the magnetic scaffold as a conceptually new solution. The magnetic scaffold is able, via magnetic driving, to attract and take up in vivo growth factors, stem cells or other bio-agents bound to magnetic particles. The authors succeeded in developing a simple and inexpensive technique able to transform standard commercial scaffolds made of hydroxyapatite and collagen in magnetic scaffolds. This innovative process involves dip-coating of the scaffolds in aqueous ferrofluids containing iron oxide nanoparticles coated with various biopolymers. After dip-coating, the nanoparticles are integrated into the structure of the scaffolds, providing the latter with magnetization values as high as 15 emu g(-)(1) at 10 kOe. These values are suitable for generating magnetic gradients, enabling magnetic guiding in the vicinity and inside the scaffold. The magnetic scaffolds do not suffer from any structural damage during the process, maintaining their specific porosity and shape. Moreover, they do not release magnetic particles under a constant flow of simulated body fluids over a period of 8 days. Finally, preliminary studies indicate the ability of the magnetic scaffolds to support adhesion and proliferation of human bone marrow stem cells in vitro. Hence, this new type of scaffold is a valuable candidate for tissue engineering applications, featuring a novel magnetic guiding option.
近年来，人们对组织工程及其解决方案的兴趣大大增加。特别是，支架已成为骨移植替代的基本工具，并与各种生物制剂结合使用。然而，这些传统支架在使用中存在一个长期存在的问题，即支架在植入后无法重新加载生物制剂。这项工作介绍了磁性支架作为一种全新的概念性解决方案。磁性支架能够通过磁场驱动吸引和摄取体内的生长因子、干细胞或其他与磁性颗粒结合的生物制剂。作者成功地开发了一种简单且廉价的技术，能够将标准的商用羟磷灰石和胶原支架转化为磁性支架。这个创新过程涉及到将支架浸入含有氧化铁纳米颗粒的水基铁磁流体中，这些纳米颗粒被各种生物聚合物所包裹。在浸入之后，纳米颗粒会被整合到支架的结构中，从而使支架在 10 kOe 下的磁化值高达 15 emu g(-)(1)。这些值适用于产生磁场梯度，从而在支架的周围和内部实现磁场导向。在这个过程中，磁性支架不会受到任何结构损坏，保持其特定的孔隙率和形状。此外，在模拟体液持续流动的 8 天内，它们也不会释放出磁性颗粒。最后，初步研究表明，磁性支架能够支持人骨髓干细胞在体外的黏附和增殖。因此，这种新型支架是组织工程应用的有价值候选者，具有新型的磁场导向功能。
