Barros Alexandre A, Rita Ana, Duarte C, Pires Ricardo A, Sampaio-Marques Belém, Ludovico Paula, Lima Estevão, Mano João F, Reis Rui L
3B's Research Group-Biomaterials, Biodegradables and Biomimetics, University of Minho, Headquarters of the European Institute of Excellence on Tissue Engineering and Regenerative Medicine, AvePark, 4806-909, Taipas, Guimarães, Portugal; ICVS/3B's - PT Government Associate Laboratory, Braga/Guimarães, Portugal.
J Biomed Mater Res B Appl Biomater. 2015 Apr;103(3):608-17. doi: 10.1002/jbm.b.33237. Epub 2014 Jun 26.
In this work, stents were produced from natural origin polysaccharides. Alginate, gellan gum, and a blend of these with gelatin were used to produce hollow tube (stents) following a combination of templated gelation and critical point carbon dioxide drying. Morphological analysis of the surface of the stents was carried out by scanning electron microscopy. Indwelling time, encrustation, and stability of the stents in artificial urine solution was carried out up to 60 days of immersion. In vitro studies carried out with simulated urine demonstrated that the tubes present a high fluid uptake ability, about 1000%. Despite this, the materials are able to maintain their shape and do not present an extensive swelling behavior. The bioresorption profile was observed to be highly dependent on the composition of the stent and it can be tuned. Complete dissolution of the materials may occur between 14 and 60 days. Additionally, no encrustation was observed within the tested timeframe. The ability to resist bacterial adherence was evaluated with Gram-positive Staphylococcus aureus and two Gram-negatives Escherichia coli DH5 alpha and Klebsiella oxytoca. For K. oxytoca, no differences were observed in comparison with a commercial stent (Biosoft(®) duo, Porges), although, for S. aureus all tested compositions had a higher inhibition of bacterial adhesion compared to the commercial stents. In case of E. coli, the addition of gelatin to the formulations reduced the bacterial adhesion in a highly significant manner compared to the commercial stents. The stents produced by the developed technology fulfill the requirements for ureteral stents and will contribute in the development of biocompatible and bioresorbable urinary stents.
在这项工作中，支架由天然来源的多糖制成。海藻酸盐、结冷胶以及它们与明胶的混合物被用于通过模板凝胶化和临界点二氧化碳干燥相结合的方法来制备中空管（支架）。通过扫描电子显微镜对支架表面进行形态分析。在人工尿液溶液中对支架的留置时间、结壳情况和稳定性进行了长达60天的浸泡研究。用模拟尿液进行的体外研究表明，这些管子具有很高的液体吸收能力，约为1000%。尽管如此，这些材料仍能保持其形状，并且没有出现广泛的肿胀行为。观察到生物吸收情况高度依赖于支架的组成，并且可以进行调整。材料可能在14至60天内完全溶解。此外，在测试的时间范围内未观察到结壳现象。用革兰氏阳性金黄色葡萄球菌以及两种革兰氏阴性大肠杆菌DH5α和产酸克雷伯菌评估了抵抗细菌粘附的能力。对于产酸克雷伯菌，与商用支架（Biosoft(®) duo，Porges）相比未观察到差异，不过，对于金黄色葡萄球菌，所有测试的组合物对细菌粘附的抑制作用均高于商用支架。对于大肠杆菌，与商用支架相比，在配方中添加明胶可显著降低细菌粘附。通过所开发技术生产的支架满足输尿管支架的要求，并将有助于生物相容性和可生物吸收性泌尿支架的开发。
