Enzyme‐conjugated nanosensors with tunable detection limits for small biomolecule determination

Polymeric nanosensors are more appealing than electrochemical sensors for advanced biological imaging applications, but more development is required before polymeric nanosensors can achieve widespread application. The detection of small biomolecules without a suitable ionophore, such as the detection of glucose, depends on enzymatic recognition by mixing oxidase enzymes with nanosensors. However, conjugation schemes and response control methods are needed to make polymeric nanosensors suitable for real‐world applications. In this work, we develop enzyme‐conjugated nanosensors based on the biotin/avidin interaction with two unique structures. The response of the first structure is controllable through changes to the concentrations of enzyme and avidin as well as surface biotinylation level during synthesis, while the second structure requires a simpler synthesis and has a controllable response through changes to the surface biotinylation level. We also report findings about optimal avidin concentration and separation of unbound enzyme from the enzyme‐nanosensor conjugates through a magnetic purification approach.