Spatially Patterned Grid Optodes for Simultaneous Multiparameter Chemical Imaging

High-resolution imaging of chemical gradients is critical for studying complex microscale environments, but conventional planar optodes face limitations in simultaneous multiparameter sensing due to spectral crosstalk and signal overlap. Here, we present a modular alternative using grid optodes─arrays of discrete, selectively responsive sensor spots printed in a checkerboard layout via a custom 3D-printed dispensing system. Each spot responds to either oxygen or pH, enabling parallel detection with minimal optical interference and achieving spatial resolution below 650 μm. Optical readout was performed using standard RGB cameras, and multiple spatial interpolation methods were evaluated to reconstruct continuous 2D analyte maps from discrete spot data. Nearest-neighbor interpolation followed by mean filtering provided robust image reconstruction. The grid optodes were validated in structured agar matrices and sulfidic sediment, demonstrating imaging performance comparable to conventional planar optodes. This approach offers a scalable, low-cost platform for high-resolution, multiparameter chemical imaging compatible with accessible RGB detection systems and adaptable to diverse sensing applications.