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Evaluation of the Biocompatibility and Mechanical Stability of PVA/alginate Composite Scaffolds

Agosthinghage Dona, Dinesha Thejani
http://rave.ohiolink.edu/etdc/view?acc_num=toledo1639925307628226

Abstract Details

2021, Doctor of Philosophy, University of Toledo, Biomedical Engineering.
Load-bearing soft tissue (LBSTs) injuries are multi-causal, resulting from physical activities, infection, and aging, affecting a wide array of patients. These injuries are expensive to treat and require long-term care, increasing the health care cost burden by billions of dollars annually in the United States. Commonly reported injuries of LBSTs, such as damage to knee menisci and nucleus pulposi, could be addressed by a tissue-engineered scaffold. This study investigated a novel PVA/alginate composite scaffold as a potential tissue-engineered construct that can be used to treat LBST injuries. PVA with embedded alginate beads was physically crosslinked by repeated freezing and thawing to produce composite scaffolds (PVA-ALG scaffolds). After crosslinking, bovine articular chondrocytes were seeded in these constructs. All the constructs maintained cell viability and had compressive properties similar to nucleus pulposi. Among the PVA concentrations used, 10% PVA produced constructs with a high compressive modulus (5.49 kPa) that could be handled easily during the fabrication process. Further characterization of 10% PVA-ALG showed that the scaffolds promoted cell growth. SEM micrographs and nitrogen adsorption analysis showed that the PVA-ALG scaffolds are mostly macroporous. These constructs also contained a significant amount of micropores and some mesopores. As the PVA concentration increased, the surface area of the scaffolds increased, and the porosity decreased in the scaffolds. In addition, the swelling decreased with the increase in the PVA concentration. However, the material properties in all the constructs were favorable for cell growth. After 11 weeks in PBS, 10% PVA-ALG scaffolds showed 68% degradation (reduction in weight in the swollen state) with neutral degradation products. Cell proliferation studies showed that the chondrocytes expanded well in both alginate beads and PVA regions, even though the cell growth was higher in alginate. While live/dead cell analysis helped determine the cell growth at 1 mm depth, histological analysis proved useful in evaluating cell growth in the inner regions of the sample. Gene expression studies and histological analysis indicated that the PVA-ALG scaffolds provided an environment favorable for the chondrocytes to maintain their cartilaginous phenotype. However, colorimetric analyses failed to evaluate the overall cell growth as the scaffolds interacted with MTT, resazurin, and WST-1 dyes. Optimizing the cell seeding method used in the scaffolds could yield a more homogenous cell proliferation. Also, higher cell seeding densities could help distribute more cells in the scaffold, thereby achieving faster cell growth. During the fabrication process, the compressive modulus of 10% PVA-ALG scaffolds dropped by 27% compared to non-sterile PVA hydrogels due to autoclave sterilization. Longer freeze times and higher freeze-thaw cycles yielded 10% PVA-ALG scaffolds with higher mechanical strength while encouraging good cell growth. The studies performed can be used as a framework to develop PVA-ALG scaffolds with more consistent cell seeding mechanisms and optimum crosslinking conditions to suit a variety of load-bearing soft tissues. In addition, this study presented several characterization methods that can be utilized in evaluating the viability of the PVA-ALG scaffold for LBST regeneration.
Arunan Nadarajah (Advisor)
Patricia Relue (Committee Member)
Halim Ayan (Committee Member)
Kelly Marbaugh (Committee Member)
R. Mark Wooten (Committee Member)
216 p.
Biomedical Engineering; Materials Science; Polymers
Tissue engineering; Cartilage; Scaffolds; Hydrogels; Polyvinyl alcohol; Alginate; Chondrocytes

Recommended Citations

Citations

  • Agosthinghage Dona, D. T. (2021). Evaluation of the Biocompatibility and Mechanical Stability of PVA/alginate Composite Scaffolds [Doctoral dissertation, University of Toledo]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=toledo1639925307628226

    APA Style (7th edition)

  • Agosthinghage Dona, Dinesha. Evaluation of the Biocompatibility and Mechanical Stability of PVA/alginate Composite Scaffolds. 2021. University of Toledo, Doctoral dissertation. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=toledo1639925307628226.

    MLA Style (8th edition)

  • Agosthinghage Dona, Dinesha. "Evaluation of the Biocompatibility and Mechanical Stability of PVA/alginate Composite Scaffolds." Doctoral dissertation, University of Toledo, 2021. http://rave.ohiolink.edu/etdc/view?acc_num=toledo1639925307628226

    Chicago Manual of Style (17th edition)

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This open access ETD is published by University of Toledo and OhioLINK.