Cost-efficient and ultrasensitive hydrogel-based visual point-of-care sensor integrated with surface patterning and strongly emissive carbon dots directly from Prunus mume Carbonisatus

Point-of-care (POC) sensors possess significant potential for various applications such as environmental monitoring and clinical diagnosis. However, POC sensors often encounter challenges regarding accuracy and sensitivity. Herein, we present a facile, cost-efficient and high-yield synthesis strategy of strongly blue-emitting carbon dots (CDs) from Prunus mume Carbonisatus (PMC) for fabricating surface patterned fluorescent hydrogel POC sensors with ultra-high sensitivity and accuracy. By rationally integrating Fe3+-responsive PMC-CDs with surface patterning enhanced visualization (SPEV) strategy, we achieve accurate POC detection of Fe3+ ions with a visual detection limit of 0.1 μM using the pseudo-color-assisted patterned POC sensors. Benefiting from more diverse and well-controlled visual information provided by the pseudo-color images of patterned hydrogels, the ultrasensitive and accurate visual POC detection of Fe3+ in iron supplements and human serum samples could be easily achieved without using any expensive instruments. This single emitting fluorophore-based surface patterned hydrogel sensing platform exhibits exceptional visual quantitative capability and remarkable convenience, thus holding great promise for visual POC testing.