There is growing interest in reusable biosensors that can detect pathogens, particularly for disease diagnosis and environmental monitoring. It is difficult to implement a reusable biosensor for large biomolecules such as proteins because target molecules must be removed from sensor-surface-immobilized receptors without deteriorating their activity to restore the sensor to its initial state. While a high binding affinity generally improves the limit of detection (LOD), it also hinders recovery. In other words, the reusability and performance of a biosensor tend to be inversely proportional. To overcome this trade-off, we propose a combination of microbeads functionalized with enzyme-linked receptors and a solid-state electrochemical sensor that detects the signal of the electrochemical probe generated by the enzyme in a solution-phase reaction. In this study, 50 measurements of H1N1 nucleoprotein were achieved without affecting the femtomolar LOD of the biosensor.