Mohan Neethu, Wilson Jijo, Joseph Dexy, Vaikkath Dhanesh, Nair Prabha D
Division of Tissue Engineering and Regeneration Technologies, Biomedical Technology Wing, Sree Chitra Tirunal Institute for Medical Sciences and Technology, Trivandrum, Kerala, India.
J Biomed Mater Res A. 2015 Dec;103(12):3896-906. doi: 10.1002/jbm.a.35506. Epub 2015 Aug 8.
The study investigated the potential of electrospun fiber assembled hydrogel, with physical gradients of chondroitin sulfate (CS) and sol-gel-derived bioactive glass (BG), to engineer hyaline and mineralized cartilage in a single 3D system. Electrospun poly(caprolactone) (PCL) fibers incorporated with 0.1% w/w of CS (CSL) and 0.5% w/w of CS (CSH), 2.4% w/w of BG (BGL) and 12.5% w/w of BG (BGH) were fabricated. The CS showed a sustained release up to 3 days from CSL and 14 days from CSH fibers. Chondrocytes secreted hyaline like matrix with higher sulfated glycosaminoglycans (sGAG), collagen type II and aggrecan on CSL and CSH fibers. Mineralization was observed on BGL and BGH fibers when incubated in simulated body fluid for 14 days. Chondrocytes cultured on these fibers secreted a mineralized matrix that consisted of sGAG, hypertrophic proteins, collagen type X, and osteocalcin. The CS and BG incorporated PCL fiber mats were assembled in an agarose-gelatin hydrogel to generate a 3D hybrid scaffold. The signals in the fibers diffused and generated continuous opposing gradients of CS (chondrogenic signal) and BG (mineralization) in the hydrogel. The chondrocytes were encapsulated in hybrid scaffolds; live dead assay at 48 h showed viable cells. Cells maintained their phenotype and secreted specific extracellular matrix (ECM) in response to signals within the hydrogel. Continuous opposing gradients of sGAG enriched and mineralized ECM were observed surrounding each cell clusters on gradient hydrogel after 14 days of culture in response to the physical gradients of raw materials CS and BG. A construct with gradient mineralization might accelerate integration to subchondral bone during in vivo regeneration.
该研究调查了具有硫酸软骨素（CS）和溶胶 - 凝胶衍生生物活性玻璃（BG）物理梯度的电纺纤维组装水凝胶在单一3D系统中构建透明软骨和矿化软骨的潜力。制备了掺入0.1% w/w CS（CSL）、0.5% w/w CS（CSH）、2.4% w/w BG（BGL）和12.5% w/w BG（BGH）的电纺聚己内酯（PCL）纤维。CS从CSL纤维中可持续释放3天，从CSH纤维中可持续释放14天。软骨细胞在CSL和CSH纤维上分泌出具有更高硫酸化糖胺聚糖（sGAG）、II型胶原蛋白和聚集蛋白聚糖的类透明软骨基质。当在模拟体液中孵育14天时，在BGL和BGH纤维上观察到矿化现象。在这些纤维上培养的软骨细胞分泌出由sGAG、肥大蛋白、X型胶原蛋白和骨钙素组成的矿化基质。将掺入CS和BG的PCL纤维垫组装在琼脂糖 - 明胶水凝胶中，以生成三维混合支架。纤维中的信号扩散并在水凝胶中产生连续相反的CS（软骨形成信号）和BG（矿化）梯度。软骨细胞被封装在混合支架中；48小时的活死检测显示细胞存活。细胞维持其表型，并根据水凝胶中的信号分泌特定的细胞外基质（ECM）。培养14天后，在梯度水凝胶上每个细胞簇周围观察到富含sGAG和矿化ECM的连续相反梯度，这是对原料CS和BG的物理梯度的响应。具有梯度矿化的构建体可能会在体内再生过程中加速与软骨下骨的整合。
