Mouthuy P A, Ye H, Triffitt J, Oommen G, Cui Z
Institute of Biomedical Engineering, Department of Engineering Science, University of Oxford, UK.
Proc Inst Mech Eng H. 2010 Dec;224(12):1401-14. doi: 10.1243/09544119JEIM824.
Mimicking the zonal organization of the bone-cartilage interface will aid the production of functional osteochondral grafts for regeneration of skeletal joint defects. This study investigates the potential of the electrospinning technique to build a three-dimensional construct recapitulating the zonal matrix of this interface. Poly(lactic-co-glycolic acid) (PLGA) and PLGA-collagen solutions containing different concentrations of hydroxyapatite nanoparticles (nHAp) were electrospun on a thin layer of phosphate buffer saline solution spread on the collector in order to facilitate membrane detachment and recovery. Incorporation of increasing amounts of nHAp in PLGA solutions did not affect significantly the average diameter of the fibres, which was about 700 nm. However, in the presence of collagen, fibres with diameters below 100 nm were generally observed and the number of these fibres was inversely proportional to the ratio PLGA:collagen and proportional to the content of nHAp. PLGA membranes were rather hydrophobic, although the aqueous drop contact angles progressively fell from 125 degrees to 110 degrees when the content of nHAp was increased from 0 per cent to 50 per cent (w/v). PLGA-collagen membranes were more hydrophilic with contact angles between 60 degrees and 110 degrees; the values being proportional to the ratio PLGA:collagen and the content of nHAp. Also, the addition of nHAp from 0 per cent to 50 per cent (w/v) in the absence of collagen resulted in decreasing dramatically both the Young's modulus (Ym), from 34.3 +/- 1.8 MPa to 0.10 +/- 0.06 MPa, and the ultimate tensile strain (epsilon max), from a value higher than 40 per cent to 5 per cent. However, the presence of collagen together with nHAp allowed the creation of membranes much stiffer, although more brittle, as shown for membranes made with a ratio 8:2 and 10 per cent of nHAp, for which Ym = 70.0 +/- 6.6 MPa and epsilon max = 7 per cent.
模仿骨 - 软骨界面的分层结构将有助于制备功能性骨软骨移植物，用于修复骨骼关节缺损。本研究探讨了静电纺丝技术构建三维结构以重现该界面分层基质的潜力。将含有不同浓度羟基磷灰石纳米颗粒（nHAp）的聚（乳酸 - 乙醇酸共聚物）（PLGA）和PLGA - 胶原蛋白溶液静电纺丝到铺展在收集器上的一层磷酸盐缓冲盐溶液上，以促进膜的分离和回收。在PLGA溶液中增加nHAp的含量对纤维的平均直径没有显著影响，纤维平均直径约为700纳米。然而，在有胶原蛋白存在的情况下，通常会观察到直径低于100纳米的纤维，并且这些纤维的数量与PLGA:胶原蛋白的比例成反比，与nHAp的含量成正比。PLGA膜相当疏水，不过当nHAp的含量从0%增加到50%（w/v）时，水滴接触角从125度逐渐降至110度。PLGA - 胶原蛋白膜更亲水，接触角在60度到110度之间；其值与PLGA:胶原蛋白的比例以及nHAp的含量成正比。此外，在没有胶原蛋白的情况下，将nHAp的含量从0%增加到50%（w/v）会导致杨氏模量（Ym）从34.3±1.8兆帕急剧降至0.10±0.06兆帕，极限拉伸应变（εmax）从高于40%的值降至5%。然而，胶原蛋白与nHAp共同存在时能够制备出硬度更高但更脆的膜，例如对于以8:2比例和10%的nHAp制成的膜，其Ym = 70.0±6.6兆帕，εmax = 7%。
