Al₂O₃/Covalent Organic Framework on 3D-Printed Nanocarbon Electrodes for Enhanced Biomarker Detection

With the advantages of on-demand customization, 3D-printing techniques have elevated the horizon of various fields. The as-printed 3D structures often require postmodification to enhance their properties. Here, we describe the use of molecularly precise covalent framework modification in combination with atomic layer deposition (ALD) to construct advanced sensors. First, a high-stability electrode was obtained by covalent modification of porous nanomaterial [covalent organic frameworks, (COF)] on the activated 3D electrode for the first time. Subsequently, the Al2O3 nanomaterial was coated on the COF-based 3D electrode by the ALD technique. The constructed sensor termed Al2O3/COF/3DE was chosen for the determination of important biomarkers including ascorbic acid, catechol, and dopamine, which showed a high sensitivity for detecting these biomarkers. This work opens avenues for the covalent modification of porous materials on 3D-printed electrodes and deposition of functional material using the ALD technique on the modified 3D electrode surface.