Uswatta Suren P, Okeke Israel U, Jayasuriya Ambalangodage C
Department of Bioengineering, The University of Toledo, Toledo, OH 43614, USA.
Department of Bioengineering, The University of Toledo, Toledo, OH 43614, USA; Department of Orthopaedic Surgery, The University of Toledo, Toledo, OH 43614, USA.
Mater Sci Eng C Mater Biol Appl. 2016 Dec 1;69:505-12. doi: 10.1016/j.msec.2016.06.089. Epub 2016 Jun 28.
In this study we have fabricated porous injectable spherical scaffolds using chitosan biopolymer, sodium tripolyphosphate (TPP) and nano-hydroxyapatite (nHA). TPP was primarily used as an ionic crosslinker to crosslink nHA/chitosan droplets. We hypothesized that incorporating nHA into chitosan could support osteoconduction by emulating the mineralized cortical bone structure, and improve the Ultimate Compressive Strength (UCS) of the scaffolds. We prepared chitosan solutions with 0.5%, 1% and 2% (w/v) nHA concentration and used simple coacervation and lyophilization techniques to obtain spherical scaffolds. Lyophilized spherical scaffolds had a mean diameter of 1.33mm (n=25). Further, portion from each group lyophilized scaffolds were soaked and dried to obtain Lyophilized Soaked and Dried (LSD) scaffolds. LSD scaffolds had a mean diameter of 0.93mm (n=25) which is promising property for the injectability. Scanning Electron Microscopy images showed porous surface morphology and interconnected pore structures inside the scaffolds. Lyophilized and LSD scaffolds had surface pores <10 and 2μm, respectively. 2% nHA/chitosan LSD scaffolds exhibited UCS of 8.59MPa compared to UCS of 2% nHA/chitosan lyophilized scaffolds at 3.93MPa. Standardize UCS values were 79.98MPa and 357MPa for 2% nHA/chitosan lyophilized and LSD particles respectively. One-way ANOVA results showed a significant increase (p<0.001) in UCS of 1% and 2% nHA/chitosan lyophilized scaffolds compared to 0% and 0.5% nHA/chitosan lyophilized scaffolds. Moreover, 2% nHA LSD scaffolds had significantly increased (p<0.005) their mean UCS by 120% compared to 2% nHA lyophilized scaffolds. In a drawback, all scaffolds have lost their mechanical properties by 95% on the 2nd day when fully immersed in phosphate buffered saline. Additionally live and dead cell assay showed no cytotoxicity and excellent osteoblast attachment to both lyophilized and LSD scaffolds at the end of 14th day of in vitro studies. 2% nHA/chitosan scaffolds showed higher osteoblast attachment than 0% nHA/chitosan scaffolds.
在本研究中，我们使用壳聚糖生物聚合物、三聚磷酸钠（TPP）和纳米羟基磷灰石（nHA）制备了可注射的多孔球形支架。TPP主要用作离子交联剂，用于交联nHA/壳聚糖液滴。我们假设将nHA掺入壳聚糖中可以通过模拟矿化皮质骨结构来支持骨传导，并提高支架的极限抗压强度（UCS）。我们制备了nHA浓度为0.5%、1%和2%（w/v）的壳聚糖溶液，并使用简单的凝聚和冻干技术来获得球形支架。冻干的球形支架平均直径为1.33mm（n = 25）。此外，将每组冻干支架的一部分进行浸泡和干燥，以获得冻干浸泡干燥（LSD）支架。LSD支架的平均直径为0.93mm（n = 25），这对于可注射性来说是一个有前景的特性。扫描电子显微镜图像显示了支架内部的多孔表面形态和相互连接的孔隙结构。冻干支架和LSD支架的表面孔隙分别小于10μm和2μm。2% nHA/壳聚糖LSD支架的UCS为8.59MPa，而2% nHA/壳聚糖冻干支架的UCS为3.93MPa。2% nHA/壳聚糖冻干颗粒和LSD颗粒的标准化UCS值分别为79.98MPa和357MPa。单因素方差分析结果显示，与0%和0.5% nHA/壳聚糖冻干支架相比，1%和2% nHA/壳聚糖冻干支架的UCS显著增加（p<0.001）。此外，与2% nHA冻干支架相比，2% nHA LSD支架的平均UCS显著增加（p<0.005），增加了120%。一个缺点是，当完全浸入磷酸盐缓冲盐水中时，所有支架在第2天就失去了95%的机械性能。此外，活细胞和死细胞检测显示，在体外研究的第14天结束时，冻干支架和LSD支架均无细胞毒性，且成骨细胞附着良好。2% nHA/壳聚糖支架比0% nHA/壳聚糖支架显示出更高的成骨细胞附着率。
