Abstract 1861: A study of the effects of sodium alginate concentration on the physical properties of injectable alginate scaffolds for the treatment of glioblastoma

Glioblastoma Multiforme (GBM) is a Grade IV malignant brain cancer with a high recurrence and low survival rate. Despite advances in various therapeutic methods, prognosis has not improved much, thus, alternative treatment methods are needed. Minocycline (MINO), an antibiotic, has been shown to have anti-angiogenic properties useful for GBM treatment. Alginate is a biodegradable polysaccharide that can be used for the fabrication of injectable hydrogels for drug delivery. The objective of this study was to investigate the effects of sodium alginate (SA) concentrations (i.e., 1.00, 1.50, and 2.00 wt./vol.%) on scaffold pH, gelation time, dimensions, weight, and cell viability. Scaffolds were fabricated by dissolving SA and calcium carbonate (CaCO3) in water, homogenizing with glucono-delta lactone (GDL), then injecting the solution into a 24-well plate to form uniform scaffolds. Scaffold properties were evaluated by determining pH values with a pH meter, gelation time using a tilt test with a digital timer, dimensions with a digital caliper and wet and dry weight (after lyophilization) using an analytical scale. To determine cell viability, U87 GBM cells were treated with 24 hr scaffold release solution, and an MTT assay was performed after 48 hrs. Scaffolds made with the different SA concentrations reached similar pH values after 60 min. (∼6.0). They had workable gelation time (∼15-36 min.) and were able to conform to the topography of the mold. The increase in SA concentration resulted in a decrease in gelation time and a significant increase in diameter, height, dry weight, and overall stability of the scaffold. The increase in SA polymer chains (with higher concentration of SA), allowed for more cross-linking which could have led to the sturdier scaffolds with a significant increase in scaffold height. As expected, as the concentration of SA increases, more components make up the scaffold structure, resulting in a significant increase in scaffold dry weight. The wet weights were not significantly different, probably due to the high-water content of the hydrogels masking the difference in the weight of the scaffold components. Increasing the concentration of SA had no significant effect on the cell viability of the blank scaffolds. The blank and minocycline-loaded scaffolds resulted in 65-70% and 40-45% cell viability, respectively. The drug-loaded scaffolds were able to enhance cell death compared to the control and blank scaffolds. In conclusion, the concentration of SA can be optimized to tune the physical properties of the scaffolds (which may lead to different scaffold degradation rates and drug release kinetics). The alginate scaffolds fabricated in this study may be a promising adjuvant therapy for GBM treatment and future studies will focus on evaluating the effects of the SA concentration on scaffold degradation rate and drug release kinetics. Citation Format: Serenade N. Trevino, Dorina A. Madrid, Samantha Davila, Marco A. Arriaga, Sue Anne Chew. A study of the effects of sodium alginate concentration on the physical properties of injectable alginate scaffolds for the treatment of glioblastoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2025; Part 1 (Regular Abstracts); 2025 Apr 25-30; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2025;85(8_Suppl_1):Abstract nr 1861.