visual and portable strategy for copperii detection based on a striplike polythyminecaged and microwellprinted hydrogel due to its importance to develop strategies for copperii cu2 detection we here report a visual and portable strategy for cu2 detection based on designing and using a striplike hydrogel the hydrogel is functionalized through caging polythymine as probes which can effectively template the formation of fluorescent copper nanoparticles cunps in the presence of the reductant ascorbate and cu2 on the hydrogels surface uniform wells of microliter volume microwells are printed for sampleinjection when the injected sample is stained by cu2 fluorescent cunps will be in situ templated by poly t in the hydrogel with ultraviolet uv irradiation the red fluorescence of cunps can be observed by nakedeye and recorded by a common camera without complicated instruments thus the strategy integrates sampleinjection reaction and indication with fast signal response providing an addandread manner for visual and portable detection of cu2 as well as a striplike strategy detection ability with a detectable minimum concentration of 20 m and practically applicable properties have been demonstrated such as resistance to environmental interference and good constancy indicating that the strategy holds great potential and significance for popular detection of cu2 especially in remote regions we believe that the striplike hydrogelbased methodology is also applicable to other targets by virtue of altering probes