Stephen L. Farias

The rapid growth of additive manufacturing technologies continues to drive the commercial development of standardized materials to streamline the process. Despite the growing range of available materials, few still achieve a balance between flexibility and biocompatibility. Here, we evaluated the cytotoxicity of Formlabs Biomed Elastic 50A, Biomed Flexible 80A, and Biomed Durable resin using normal human dermal fibroblasts and human mesenchymal stromal cells. The sol fraction of the crosslinked and uncrosslinked materials was measured to determine the amount of leachable components in the polymer network. Following ISO 10993‐5 guidelines, cytotoxicity was evaluated through direct, indirect, or extract testing for 24 h. All three materials did not elicit a cytotoxic response when assessed through fluorescence imaging and LDH assay. In each test, cells showed similar viability as cells cultured with a known noncytotoxic control, polycaprolactone, and showed significantly higher viability compared to a cytotoxic control, a polyurethane film containing 0.1% zinc diethyldithiocarbamate (ZDEC). Post‐processing parameters were shown to minimize the effects of cytotoxicity when post‐treated with an isopropyl alcohol wash, UV post‐curing, or ethanol sterilization. Overall, the Formlabs Biomed Elastic 50A, Biomed Flexible 80A, and Biomed Durable resins were shown to exhibit minimal cytotoxicity after printing and post‐processing. Further, the presented findings can be adapted to standardize in vitro testing of a wide range of commercial photocurable resins for tissue‐interfacing parts.

Tissue engineering is widely used in research for investigating cellular proliferation, behavior, and responses to various stimuli. However, the predictive value of preclinical studies using cell culture plates is limited by the inability to recapitulate the complexity of the physiological microenvironment. Synthetic three-dimensional (3D) scaffolds can be engineered to mimic the complex morphology of the extracellular matrix of native tissues and can serve as physiologically relevant platforms for preclinical studies. In this study, 3D electrospun scaffolds were characterized to aid in breast cancer research. Unlike previous studies that focused primarily on scaffold fabrication or cell viability, this work systematically evaluates how scaffold morphology influences breast epithelial and breast cancer cell behavior within three-dimensional microenvironments. Breast cancer cell lines and normal breast epithelial cells were seeded on scaffolds of different morphologies, on commercially available mesh scaffolds, and on standard tissue culture plates. Cells were treated with a fluorescent fructose mimic (ManCou-H) that targets the fructose-specific transporter GLUT5 to assess metabolic activity on different scaffolds. The study evaluated cell–cell and cell–matrix interactions through time-lapse experiments, cell metabolism, and variations in the expression of cytoskeletal protein (CK18) and GLUT5. Statistically relevant differences were observed between cells cultured on scaffolds and plates, and different scaffolds morphologies. Results from this study demonstrate that scaffold topology alone can significantly alter cellular phenotype and metabolic responses, highlighting the importance of scaffold selection in the development of predictive non-animal in vitro models and studies of the tumor microenvironment.