A Robust pH Sensing Module Utilizing Reproducible Structural Colour Fabricated by Two-Photon PolymerisationJing Qian, Yekaterina Tskhe, A. Louise Bradley, Larisa Florea and Colm DelaneyEPJ Web Conf., 335 (2025) 08001DOI: https://doi.org/10.1051/epjconf/202533508001