Porous morphology and mechanical properties of poly(lactide-co-glycolide) hollow fiber membranes governed by ternary-phase inversion

et al. 2021

Bioactive Materials

Self Cite

Nerve conduits have been identified as one of the most promising treatments for peripheral nerve injuries, yet it remains unsolved how to develop ideal nerve conduits with both appropriate biological and mechanical properties. Existing nerve conduits must make trade-offs between mechanical strength and biocompatibility. Here, we propose a multi-nozzle additive-lathe 3D bioprinting technology to fabricate a bilayered nerve conduit. The materials for printing consisted of gelatin methacrylate (GelMA)-based inner layer, which was cellularized with bone marrow mesenchymal stem cells (BMSCs) and GelMA/poly(ethylene glycol) diacrylate (PEGDA)-based outer layer. The high viability and extensive morphological spreading of BMSCs encapsulated in the inner layer was achieved by adjusting the degree of methacryloyl substitution and the concentration of GelMA. Strong mechanical performance of the outer layer was obtained by the addition of PEGDA. The performance of the bilayered nerve conduits was assessed using in vitro culture of PC12 cells. The cell density of PC12 cells attached to cellularized bilayered nerve conduits was more than 4 times of that on acellular bilayered nerve conduits. The proliferation rate of PC12 cells attached to cellularized bilayered nerve conduits was over 9 times higher than that on acellular bilayered nerve conduits. These results demonstrate the additive-lathe 3D bioprinting of BMSCs embedded bilayered nerve conduits holds great potential in facilitating peripheral nerve repair.

Section: Discussionmentioning

confidence: 99%

where F was the compressive force per unit length and ε = ( OD − OD ′)/ OD is the compressive strain.…”

Section: Methodsmentioning

confidence: 99%

Additive-lathe 3D bioprinting of bilayered nerve conduits incorporated with supportive cells

Liu

et al. 2021

Bioactive Materials

Self Cite

“…These results were attributed to the decreasing porosity and pore size of the blend membranes. Obviously, compared with the dense membranes, the emergence of a large number of micropores with large pore size in membrane matrix will lead to the decrease of mechanical strength and the increase of elongation-at-break [52]. With the increase of NMP concentrations in core liquid and external coagulation bath, both the porosity and average pore size of blend membranes decreased as shown in Figure 4 and Table 3.…”

Section: Resultsmentioning

confidence: 99%

Effects of spinning conditions on structure and properties of aramid-based hollow fiber blend separation membranes

Shi

Journal of Industrial Textiles

et al. 2019

The rigid-rod-like poly(p-phenylene terephthalamide) (PPTA), as the raw material of aramid 1414, has the characteristics of high modulus and hydrophilicity. The flat sheet poly(vinylidene fluoride) (PVDF)/PPTA blend separation membranes with improved hydrophilicity and enhanced modulus have been successfully prepared using in situ polycondensation method in our previous study. In this study, PPTA/PVDF hollow fiber blend separation membranes with enhanced hydrophilicity and mechanical strength were fabricated through the dry–wet spinning technique. Monomers of PPTA were polymerized in the PVDF solution, and the polymerization system was directly used as the spinning solution to fabricate the hollow fiber blend membrane. The effects of spinning conditions including the air-gap distance; the composition of core fluid; and composition of coagulation bath on the structure and properties including the separation properties, surface hydrophilicity, and mechanical properties of PPTA/PVDF hollow fiber blend membranes were well investigated. Membrane surface and cross-sectional morphologies were observed through scanning electron microscope. The enhancements of these spinning conditions weakened the phase separation process as a result of the formation of a small pore structure. The pore size distribution, water flux, and solute rejection varied accordingly. Different spinning conditions have different effects on the mechanical and hydrophilic properties of the hollow fiber blend membranes. Compared with pure PVDF hollow fiber membrane, blend membranes fabricated under different spinning conditions exhibited enhanced surface hydrophilicity and tensile properties. Finally, the change rates of the pure water flux and the solute rejection with different spinning conditions were calculated to further analyze and compare the statistically significant effects.

“…The blend film of PVC and CA can be prepared by solution casting and phase transformation method 17–20 . However, asymmetric membranes prepared by phase inversion usually have dense epidermis and porous sublayers, resulting in low permeability and low‐solute selectivity, which hinders their wide application in industry 21 . In phase transformation technology, the pore size of membrane plays an important role in the performance of membrane, and pore‐forming agent plays a key role in the formation of pore size in asymmetric membrane 22,23 .…”

Section: Introductionmentioning

confidence: 99%

“…[17][18][19][20] However, asymmetric membranes prepared by phase inversion usually have dense epidermis and porous sublayers, resulting in low permeability and low-solute selectivity, which hinders their wide application in industry. 21 In phase transformation technology, the pore size of membrane plays an important role in the performance of membrane, and pore-forming agent plays a key role in the formation of pore size in asymmetric membrane. 22,23 Polyvinylpyrrolidone (PVP) is a good pore forming agent, which is easily soluble in water and various organic solvents, and has good solubility.…”

Section: Introductionmentioning

confidence: 99%

Improvement of filtration performance of polyvinyl chloride/cellulose acetate blend membrane via acid hydrolysis

J of Applied Polymer Sci

Tan

Yao

et al. 2020

Based on the hydrophilicity and biodegradability of cellulose acetate (CA), polyvinyl chloride (PVC)/CA blend membrane was prepared by solution comixing and phase transformation method. Then the CA in the blend membrane was partially hydrolyzed under acidic conditions to improve the hydrophilicity of the blend membrane, so as to improve the filtration performance of the PVC/CA blend membrane. The properties of the membranes were systematically characterized by Fourier transform infrared spectroscopy, differential scanning calorimeter, and scanning electron microscopy (SEM). The porosity, water contact angle, pure water flux (PWF), protein retention rate, and mechanical properties of the membrane were measured, and the effect of hydrolysis on the filtration performance of the blend membrane was analyzed.