The present application relates to biosensors, for example comprising an high-molecular weight, tandem repeating, structure-switching nucleic acid aptamers (concatemeric aptamers) to rapidly create patterned sensors via, for example, inkjet printing. These concatemeric aptamer reporters remain immobilized at the point of printing through strong adsorption but retain sufficient segmental mobility to undergo structure switching and reporter signalling to provide both qualitative and quantitative detection of one or more analytes. In certain embodiments, inkjet printing allows for the patterning of internally referenced sensors with multiplexed detection, and provides a generic platform for on-demand printing of sensors even in remote locations.