Abstract 2637: The use of 3D-printed Polylactic acid scaffolds (PLA) as a substrate for growth of MCF7 human breast cancer cells
Authors: McAllister Brenna , Mustafa Mohammed , Sundarram Sriharsha , Phelan Shelley A. 
Published: July 2021

Abstract
This study focuses on fabrication of large-scale tissue scaffolds from Polylactic acid (PLA) and their feasibility as a substrate for cell growth. The scaffolds were fabricated via combined additive manufacturing and microwave foaming. The benefit of this approach is the ability to generate scaffolds with specific architectures and controllable pore size and porosity. The resulting scaffolds have dual pore networks with porosity in excess of 80% which provide a pathway for both cell growth and circulation of culture media. We sought to determine the capability of these scaffolds to support attachment, growth and viability of the MCF7 human breast cancer cell line, as well as drug sensitivity. For these experiments the PLA scaffolds were sterilized in 24-well plates and 1 x 105 MCF7 cells were seeded into each well and cultured for up to 7 days. Scaffolds were then used for SEM imaging, hoescht-staining, or cell counting and viability measurements after trypsinization. Comparisons of cell numbers detached from the scaffolds vs. the remaining well suggest a proportionally small percentage of cells (less than 5%) attached to the PLA, which is not surprising since the scaffolds lack a solid bottom. However, our imaging data using hoescht-staining of PLA-attached cells pre- and post- trypsinization suggest that traditional trypsinization does not effectively detach cells from the PLA material, and therefore this method cannot be used to accurately determine the proportion of cells growing on the scaffolds. This also reveals a potential limitation for application. SEM imaging confirmed cell attachment, with cell growth in the form of sheets along the struts on the bottom layer, and clusters elsewhere with a size of around 50 micron. Analysis of viability using trypan blue exclusion shows no effect of the PLA material on cell viability. To determine the drug sensitivity of cells grown with the PLA material, we treated MCF7 cells grown in the presence or absence of oleuropein, the main phenolic compound found in olive leaves. Media was collected at 48 hours and 7 days and released LDH measured by a cytotoxicity assay. Our data showed that the PLA material itself did not increase cellular toxicity in the absence of oleuropein treatment. It also confirmed that treatment with 200 ug/ml oleuropein induces the expected cytotoxicity in MCF7 cells grown in the absence of PLA, with no significant difference in oleuropein-susceptibility for cells grown in the presence of PLA scaffolds. Together, our results suggest that PLA scaffolds can support MCF7 cell attachment and growth, with no effect on cell viability or drug-induced cytotoxicity. This provides support for the promise of PLA scaffolds for physiologically relevant cell and tissue culture work.
Citation Format: Brenna McAllister, Mohammed Mustafa, Sriharsha Sundarram, Shelley A. Phelan. The use of 3D-printed Polylactic acid scaffolds (PLA) as a substrate for growth of MCF7 human breast cancer cells [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 2637.