Extraction of type I collagen and development of collagen methacryloyl (ColMA)/PEGDA ink for digital light processing printing

The fabrication of three-dimensional (3D) biostructures through additive manufacturing relies on the critical role of ink development. With the growing demand for high-resolution manufacturing, digital light processing (DLP) technology has emerged as a promising technique requiring specialised photosensitive inks. Although gelatine methacryloyl (GelMA) has been the primary option for DLP, its mechanical properties, biocompatibility, and low stability still present limitations. The development of collagen-based ink is thus in high demand for a wider stiffness adjustment range, native bioactivities, and versatility in biomedical engineering applications. In this paper, we report a rapid and low-cost protocol for collagen methacryloyl (ColMA)/poly(ethylene glycol) diacrylate (PEGDA) ink for DLP printing. The ink demonstrated the highest printing resolution of similar to 50 mu m by using 405 nm visible light. The printability, mechanical properties and cell viability of the DLP-printed ColMA/PEGDA structures were comprehensively evaluated. The printed ColMA/PEGDA structures reached a compressive modulus over 100 kPa with 0.6 wt% collagen. The printed ColMA/PEGDA scaffolds promoted the attachment and proliferation of 3 T3 fibroblasts, demonstrating their potential in future applications in biomedical engineering.