Genipin-Crosslinked, Silane-Anchored 3D Tumor–Stroma Microtissues for High-Content On-Chip Drug Testing

Physiologically relevant 3D tumor models incorporating extracellular matrix (ECM) and cancer-associated fibroblasts (CAFs) are essential for studying tumor progression and drug resistance, yet often suffer from hydrogel contraction and instability—especially in microfluidic formats, where ECM deformation hampers long-term culture and quantitative imaging. Here, we present a microfluidic tumor–fibroblast co-culture platform for head and neck squamous cell carcinoma (HNSCC) that overcomes these limitations via a dual strategy: APTES-mediated surface silanization anchors the ECM to the chip, combined with Genipin-based crosslinking, which modestly increases hydrogel stiffness and progressively reinforces the network without compromising cell viability, as confirmed by time- and frequency-resolved rheology. Fourier-transform infrared spectroscopy (FTIR) verified successful collagen crosslinking while preserving reactive ─OH and ─NH₂ groups, enabling covalent bonding to the APTES-functionalized chip. The platform further integrates semi-automated segmentation and high-content imaging to quantify dynamic phenotypic drug responses at both single-cell and multicellular/tissue organization levels. Drug chemosensitivity assays, including co-culture with patient-derived CAFs, enabled quantitative assessment of clinically relevant chemoprotective effects. By combining biomaterial engineering with functional microfluidic design, this system enables reproducible, physiologically relevant modeling of tumor–fibroblast interactions, offering a scalable tool for preclinical drug chemosensitivity screening and clinical translation.