Skip to main content
2025 BMES Annual Meeting Main banner
Icon Legend
This session is not in your schedule.
This session is in your schedule. Click again to remove it.

Drug Delivery

Drug Delivery - Poster Session E

V40 - Characterization of CASP Hydrogels for the Delivery of TMZ and siRNA to Treat Glioblastoma

Saturday, October 11, 2025
10:00 AM - 11:00 AM PDT
Location: Exhibit Hall F, G & H

Introduction: : Glioblastoma (GBM), a grade IV brain tumor, is the most common malignant central nervous system (CNS) tumor, accounting for 47% of cases. Current treatment options are limited, leading to poor prognosis. Temozolomide (TMZ), a hydrophobic prodrug, is the only FDA-approved chemotherapeutic to treat GBM, but it has limited bioactivity due to its physicochemical properties and biological barriers, like the blood-brain barrier (BBB). Gene therapies, such as small interfering RNA (siRNA), can regulate the expression of oncogenes and genes that contribute to chemoresistance by blocking the translation of mRNA into protein. When used together, siRNA and TMZ combination therapy allows both treatments to work synergistically, potentially resulting in a more favorable response to treatment. Due to barriers of delivery inherent to both treatment modalities, such as cargo degradation and limited crossing of the BBB, advanced delivery strategies are needed for effective combination TMZ and siRNA gene therapy for GBM treatment. This study aims to characterize cationic amphiphilic self-assembling peptide (CASP) hydrogels as a vehicle for local co-delivery of siRNA and TMZ to improve GBM therapeutic response. CASP hydrogels are biocompatible, tunable, and self-healing, making them suitable for use as an injectable macroscale drug delivery system. We hypothesize that these co-loaded peptide hydrogels will promote the long-term release of cargos and facilitate bioactive delivery of cargo to GBM cells, thereby improving treatment and anticancer efficacy.

Materials and

Methods: : CASP hydrogels flanked with arginine (R2) or lysine (K2) were formed via self-assembly in salt solutions, including NaCl and PBS, with TMZ and peptide-siRNA nanocomplexes added prior to gelation. Coumarin 6 (C6), a fluorescent hydrophobic dye, was substituted for TMZ for the purpose of visualization, and DY547- or Cy5-tagged siRNA was used for imaging and detection of siRNA. Fluorescent microscopy was conducted to examine the loading of cargo in vehicle-only gels, single-loaded gels with either peptide-siRNA-Cy5 complexes or C6 (TMZ), and coloaded gels with both C6 and peptide-siRNA complexes. To investigate the rate of cargo release from CASP hydrogels, supernatant was collected daily from single and co-loaded CASP hydrogels over a 30-day period. siRNA release was quantified via fluorescence intensity and TMZ release and conversion was evaluated via absorbance using a plate reader. The R2 and K2 CASP hydrogels were tested in both 2D monolayer and 3D spheroid models of the U87MG and U118MG cell lines. To determine whether the R2 and K2 hydrogels exhibited a cytotoxic effect in GBM cells, 2D cells were treated with hydrogels, and viability was measured after 48 hours using an MTS assay. Fluorescent microscopy was used to examine the internalization of cargo into GBM cells following release from the hydrogels over the course of 8 days, with imaging conducted every 2 days.

Results, Conclusions, and Discussions:: Fluorescent microscopy demonstrated successful loading of peptide-siRNA complexes and TMZ in both single and co-loaded R2 and K2 hydrogels. In all gel formulations, homogenous loading was observed throughout, indicating minimal interference between the cargos. Both hydrogels demonstrated continuous release of cargo over the course of 30 days, with R2 exhibiting an initial burst release of cargo followed by linear release, and K2 demonstrating a linear release. Concentrations up to 0.25 mg/mL of both R2 and K2 unloaded hydrogels were cytocompatible with GBM cell lines. Altogether, we demonstrated that R2 and K2 CASP peptide hydrogels successfully load and release therapeutic cargo, an important characteristic of an effective macroscale drug delivery system. Future work will investigate GBM oncogene silencing through PCR and western blots to confirm gene and protein knockdown and anticancer efficacy through viability and apoptosis studies.

Acknowledgements and/or References (Optional): : This project was supported by: The National Science Foundation EPSCoR Program under NSF Award # OIA-1655740 and NSF Career Award #2046694. Further funding was provided by SCBioCRAFT NIH #P30 GM131959, and Clemson Creative Inquiry and Undergraduate Research.