Osteo-Induction of Human Adipose Derived Stem Cells Cultured on Poly (L-Lactic Acid) Scaffolds Prepared by Thermally Induced Phase Separation Method

2015 ◽  
Author(s):  
H. Chinnasami ◽  
R. Devireddy
Keyword(s):  
Stem Cells ◽  
Compressive Strength ◽  
Lactic Acid ◽  
Phase Separation ◽  
Pore Size ◽  
Adipose Derived Stem Cells ◽  
Thermally Induced Phase Separation ◽  
Thermally Induced ◽  
Bio Compatibility ◽  
Cells Cultured

Bio-degradable Poly (l-lactic acid) (PLLA) scaffolds synthesized using thermally induced phase separation (TIPS) method was used to load cryo-preserved human adipose derived stem cells (hASCs). To make the scaffolds, PLLA-Dioxane solutions were formed by dissolving PLLA in 1,4-Dioxane with three different compositions (wt/vol). These PLLA-Dioxane solutions, frozen in three different cooling rates were lyophilized at 0.037bar and −70°C for 48hrs resulting in porous PLLA scaffolds. Based on the porosity, pore size and compressive strength, a suitable scaffold was chosen to investigate its bio-compatibility and osteo-inductive potential.

Structure–property relation of porous poly (l-lactic acid) scaffolds fabricated using organic solvent mixtures and controlled cooling rates and its bio-compatibility with human adipose stem cells

2018 ◽  
Vol 33 (4) ◽  
pp. 397-415 ◽  
Author(s):  
Harish Chinnasami ◽  
Jeff Gimble ◽  
Ram V Devireddy
Keyword(s):  
Stem Cells ◽  
Cell Proliferation ◽  
Lactic Acid ◽  
Phase Separation ◽  
Mechanical Strength ◽  
Separation Method ◽  
Thermally Induced Phase Separation ◽  
Cooling Rates ◽  
Thermally Induced ◽  
Pore Sizes

Thermally induced phase separation method was used to make porous three-dimensional poly (l-lactic acid) scaffolds. The effect of imposed thermal profile during freezing of the poly (l-lactic acid) in dioxane solution on the scaffold was characterized by their micro-structure, porosity (%), pore sizes’ distribution, and mechanical strength. The porosity (%) decreased considerably with increasing concentrations of poly (l-lactic acid) in the solution, while a decreasing trend was observed with increasing cooling rates. The mechanical strength increases with increase in poly (l-lactic acid) concentration and also with increase in the cooling rate for both types of solvents. Therefore, mechanical strength was increased by higher cooling rates while the porosity (%) remained relatively consistent. Scaffolds made using higher concentrations of poly (l-lactic acid; 7% and 10% w/v) in solvent showed better mechanical strength which improved relatively with increasing cooling rates (1°C–40°C/min). This phenomenon of enhanced structural integrity with increasing cooling rates was more prominent in scaffolds made from higher initial poly (l-lactic acid) concentrations. Human adipose–derived stem cells were cultured on these scaffold (7% and 10% w/v) prepared by thermally induced phase separation at all cooling rates to measure the cell proliferation efficiency as a function of their micro-structural properties. Mean pore sizes played a crucial role in cell proliferation than percent porosity since all scaffolds were >88% porous. The viability percent of human adipose tissue–derived adult stem cells increased consistently with longer periods of culture. Thus, poly (l-lactic acid) scaffolds prepared by thermally controlled thermally induced phase separation method could be a prime candidate for making ex vivo tissue-engineered grafts for surgical implantation.

The Effect of Stretching on UHWMPE Microporous Film by Thermally Induced Phase Separation Method

2020 ◽  
Vol 993 ◽  
pp. 906-914
Author(s):  
Xiao Na Wang ◽  
Yue Mu ◽  
Guo Qun Zhao ◽  
Jia Cheng Gao ◽  
You Lei Zhou ◽  
...  
Keyword(s):  
Phase Separation ◽  
Pore Structure ◽  
Pore Size ◽  
Liquid Paraffin ◽  
Great Influence ◽  
Practical Significance ◽  
Microporous Membranes ◽  
Thermally Induced Phase Separation ◽  
Thermally Induced ◽  
Stretching Ratio

UHMWPE microporous membranes were prepared via thermally induced phase separation(TIPS) combining with stretching. TIPS method was adopted to resolve processing difficulties of UHMEPE, and the subsequent stretching was used to optimize pore structure. The preparation process utilized liquid paraffin (LP) as the diluent. The effect of different stretching ratios on pore structure was investigated through SEM, XRD and mercury intrusion test. The results indicated that stretching process not only greatly improved the pore size uniformity and pore distribution uniformity, but also had a great influence on pore size controlling. When the stretching ratio was lower than 80%, the pore size was concentrated in nano-region which pore size distribution was around 0.02-0.03 μm. While the stretching ratio was larger than 80%, due to bridging breakage and liquid paraffin movement, pore size was concentrated in the micron area where pore size mainly distributed around 1μm, which had a practical significance for controlling the pore size of membranes in industrial production. And it’s obtained that at the same concentration of UHMWPE, the microporous membranes prepared in this study have more uniform pore structures than those reported previously.

Preparation of PLLA/HAP/β-TCP Composite Scaffold for Bone Tissue Engineering

2014 ◽  
Vol 513-517 ◽  
pp. 143-146 ◽  
Author(s):  
Xue Jun Wang ◽  
Tao Lou ◽  
Jing Yang ◽  
Zhen Yang ◽  
Kun Peng He
Keyword(s):  
Mechanical Properties ◽  
Tissue Engineering ◽  
Lactic Acid ◽  
Phase Separation ◽  
Bone Tissue Engineering ◽  
Bone Tissue ◽  
Composite Scaffold ◽  
Thermally Induced Phase Separation ◽  
Composite Scaffolds ◽  
Thermally Induced

In this study, a nanofibrous poly (L-lactic acid) (PLLA) scaffold reinforced by Hydroxyapatite (HAP) and β-tricalcium phosphate (β-TCP) was fabricated using the thermally induced phase separation method. The composite scaffold morphology showed a nanofibrous PLLA matrix and evenly distributed β-TCP/HAP particles. The composite scaffold had interconnective micropores and the pore size ranged 2-10 μm. Introducing β-TCP/HAP particles into PLLA matrix significantly improved the mechanical properties of the composite scaffold. In summary, the new composite scaffolds show a great deal promise for use in bone tissue engineering.

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