Spheromatrix: a paper-based platform for scalable 3D tumor model generation, cryopreservation, and high-throughput drug assessment.

Three-dimensional in vitro tumor models are increasingly recognized for their value in preclinical oncology, offering enhanced physiological relevance compared to traditional two-dimensional cultures. These systems improve the reliability of drug response assessment and hold potential for advancing patient-specific treatment strategies. In this work, we introduce the Spheromatrix, a paper-based platform designed to support spheroid formation, long-term preservation, and parallelized drug evaluation. This scalable system maintains the viability, proliferation, and metabolic activity of tumor spheroids across a variety of cancer cell lines, including U87 glioblastoma. Importantly, it supports cryopreservation and subsequent re-culture, potentially enabling the generation of pre-formed, ready-to-use 3D tumor models. Drug testing on U87 spheroids revealed consistent cytotoxic effects of cisplatin and temozolomide (TMZ), both as single agents and in combination, before and after cryostorage. Combined treatment amplified cytotoxic outcomes, indicating a potentiating effect of cisplatin on TMZ-induced cell death. These results position the Spheromatrix as a practical and versatile platform for building 3D tumor model biobanks and addressing critical gaps in current model accessibility and reuse.