| Objective:Blended thermoplastic polyurethane TPU/P(LLA-CL) microyarn /nanofibrous scaffolds were respectively fabricated via dynamic liquid electrospinning and traditional electrospinning. Physical and chemical properties of these two scaffolds were evaluated, including surface morphology, mechanical properties and so on. To investigate the biocompatibility of these two kinds of scaffolds by compounding with rabbit adipose stem cells.Materials and Methods:1. TPU and P(LLA-CL) were dissolved in 1,1,1,3,3,3- hexafluoro-2-propanol(HFIP) according to the weight ratio 100/0, 75/25, 50/50, 25/75, 0/100. TPU/P(LLA-CL) microyarn/microfibrous scaffolds were respectively fabricated via dynamic liquid electrospinning and traditional electrospinning. Both of the scaffolds were characterized by scanning electron microscope(SEM), fiber/yarn diameter, fiber/yarn porosity, fiber/yarn pore size, tensile strength and elongation at break, and fourier transforms infrared spectroscopy(FTIR).2. Rabbit adipose derived stem cells(ADSCs) were isolated and cultured and labeled with enhanced green fluorescent protein(EGFP). Microfibrous and microyarn scaffolds were cut into 0.5cm×0.5cm ADSCs squares(n=3), there are three groups including microyarn, nanofiber and control group. Then, ADSCs were seeded on the nanofibrous samples and microyarn samples for female pelvic-floor tissue. They were observed using inverted microscope, scanning electron microscopy and inverted fluorescence microscopy. After ADSCs seeded on samples 1d, 4d and 7d, the morphology and adhesion of morphology on the samples were observed by SEM, the viabilities and proliferation of cells on these samples and 24-well polystyrene plates(TCP) control were assayed using the Cell Counting Kit-8 assay; cell infiltration on nanofibrous and microyarn scaffolds were evaluated by Hematoxylin and eosin staining(HE).Results:1. Microyarns possessed more surface roughness and less uniformity than nanofibers; The mean diameter of microyarn scaffolds to be significantly larger than that of nanofibers(14.05±2.21?m vs. 1.132±0.18?m, P(27)0.05); microyarn scaffolds possessed significant larger pore sizes than nanofiber scaffolds(550.78±142.60?m2 vs. 69.05±19.18?m2, P(27)0.05); and the porosity of microyarn scaffold were higher than nanofiber scaffold(79.09±3.22% vs. 61.8±1.64%, P(27)0.05). There was no significant difference between the mechanical properties of microyarn and microfibrous scaffolds at the same weight ratio of TPU/P(LLA-CL) scaffolds(P(29)0.05). Mean tensile strength and elongation at break of nanofibrous scaffolds increased gradually and significantly with an increasing weight ratio of TPU. However, microyarn scaffolds of TPU/P(LLA-CL) with a weight ratio of 50:50 possessed higher tensile strength compared with pure P(LLA-CL), pure TPU and TPU/P(LLA-CL) at other weight ratios. Fourier-transform infrared spectroscopy demonstrated that the intermolecular bonds were not present between the TPU and P(LLA-CL). The morphology of ADSCs on pelvic-tissue engineering scaffolds were observed by SEM and inverted fluorescence microscopy showed that ADSCs labeled with exhibited polygonal shape, could grow well along or within blended microyarns, and migrate into the novel 3D scaffolds.2. ADSCs adhesion was observed using CCK-8 assay by counting the cells 4 h after seeding. There was no significant difference in cell absorbance value between nanofibrous and microyarn scaffolds at 1 d and 4 d(p>0.05). At 7 d, microyarn scaffolds put up significantly higher cell absorbance value than that observed on nanofibrous scaffolds and TCP(p<0.05), there were significant difference in cell absorbance value between TCP, nanofibrous and microyarn scaffolds(p<0.05). HE staining exhibited that cell infiltration on microyarn scaffolds was significantly enhanced. On day 1, day 4 and even on day 7, ADSCs had respectively migrated to within nanofibrous scaffolds to the average depth of 36.50±3.08?m vs. 37.06±2.23?m vs. 40.17±4.96?m, there was no significant difference in average cell ingrowth depth at between 1d and 4d(p =0.06), 4d and 7d(P=0.06), 1d and 7d(P=0.22). However, on day 1, day 4 and on day 7, ADSCs had respectively migrated through the entire microyarn scaffolds to the average depth of 250.00±33.62?m vs. 350.90±38.92?m vs. 449.01±51.73 ?m. There were significant difference in average cell ingrowth depth to microyarn scaffolds between 1d and 4d(p(27)0.05), 4d and 7d(p(27)0.05), 1d and 7d(p(27) 0.05).Conclusions:A novel TPU/P(LLA-CL) microyarn scaffold was fabricated by dynamic liquid electrospinning, which is a three dimensional structure with high porosity and large pore size. Mean tensile strength and elongation at break of microyarn scaffolds highly close to natural vaginal wall tissue. It can better simulate the natural extracellular matrix and is a kind of potential pelvic tissue engineering scaffolds. |
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