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

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.

Author(s):  
H. Chinnasami ◽  
R. Devireddy

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.


RSC Advances ◽  
2020 ◽  
Vol 10 (44) ◽  
pp. 26319-26325
Author(s):  
Yu Cao ◽  
Wenjuan Han ◽  
Ziyang Pu ◽  
Xiaofeng Wang ◽  
Bo Wang ◽  
...  

The hierarchically porous PCL monolith was fabricated via nonsolvent-thermally induced phase separation method.


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