Improvement of Mechanical Strength of Tissue Engineering Scaffold Due to the Temperature Control of Polymer Blend Solution

Polymeric scaffolds made of PCL/PLCL (ratio 1:3, respectively) blends have been developed by using the Thermally Induced Phase Separation (TIPS) process. A new additional technique has been introduced in this study by applying pre-heat treatment to the blend solution before the TIPS process. The main objective of this study is to evaluate the influence of the pre-heat treatment on mechanical properties. The mechanical evaluation showed that the mechanical strength of the scaffolds (including tensile strength, elastic modulus, and strain) improved as the temperature of the polymer blend solution increased. The effects on the microstructure features were also observed, such as increasing strut size and differences in phase separation morphology. Those microstructure changes due to temperature control contributed to the increasing of mechanical strength. The in vitro cell study showed that the PCL/PLCL blend scaffold exhibited better cytocompatibility than the neat PCL scaffold, indicated by a higher proliferation at 4 and 7 days in culture. This study highlighted that the improvement of the mechanical strength of polymer blends scaffolds can be achieved using a very versatile way by controlling the temperature of the polymer blend solution before the TIPS process.

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In vitro characterization of hierarchical 3D scaffolds produced by combining additive manufacturing and thermally induced phase separation

Journal of Biomaterials Science Polymer Edition ◽

10.1080/09205063.2020.1841535 ◽

2020 ◽

pp. 1-23

Author(s):

Azizeh-Mitra Yousefi ◽

Joseph Powers ◽

Kaylie Sampson ◽

Katherine Wood ◽

Carter Gadola ◽

...

Keyword(s):

Phase Separation ◽

Additive Manufacturing ◽

Thermally Induced Phase Separation ◽

3D Scaffolds ◽

Thermally Induced ◽

In Vitro Characterization

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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

Journal of Bioactive and Compatible Polymers ◽

10.1177/0883911518758354 ◽

2018 ◽

Vol 33 (4) ◽

pp. 397-415 ◽

Cited By ~ 2

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.

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