In this thesis, a conductive hydrogel based on Gelatin Methacryloyl (GelMA) was developed and thoroughly characterised for its application in flexible strain sensors and advanced 3D printing using Digital Light Processing (DLP) technology. Mechanical testing under tensile and compressive loads was performed, along with additional assessments of bending resistance, durability, and general degradability, in order to evaluate the material’s structural integrity and long-term performance. The incorporation of tannic acid (TA) into the GelMA matrix significantly enhanced the mechanical properties, adhesion to various substrates, and printability of the hydrogel. Notably, the tensile strength of the hydrogel approximately doubled following TA addition, indicating a substantial improvement in robustness and resistance to failure under load.