▎ 摘　　要

NOVELTY - Sensor unit configured for use in an electrochemical-sensor system having a reader module and a microfluidic unit, comprises a distal portion configured to connect with the microfluidic unit for receiving a sample, a proximal portion configured to connect with the reader module for measuring electrochemical properties of the sample, a substrate extending from the distal portion to the proximal portion and enabling fluid to flow on it, a first working electrode distributed on the substrate and extending from the distal portion to the proximal portion and a control electrode distributed on the substrate and extending from the distal portion to the proximal portion. USE - The sensor unit is useful in electrochemical-sensor system for quantitative and digital detection of target biomolecules and bioparticles. ADVANTAGE - The system allows for rapid detection of target biomolecules e.g. DNAs or RNAs and target bioparticles e.g. cells or virus by one or more detection routes, simultaneously from biological samples e.g. tissues and bodily fluids. The system is portable, does not require expensive laboratory equipment, elaborate multi-step processes and reagents and skilled personnel, provides timely and reliable results. DETAILED DESCRIPTION - Sensor unit (104) configured for use in an electrochemical-sensor system having a reader module and a microfluidic unit, comprises a distal portion (116) configured to connect with the microfluidic unit for receiving a sample, a proximal portion (114) configured to connect with the reader module for measuring electrochemical properties of the sample, a substrate (128) extending from the distal portion to the proximal portion and enabling fluid to flow on it, a first working electrode (124) distributed on the substrate and extending from the distal portion to the proximal portion, where the first working electrode has a sampling end in the distal portion and a connecting end in the proximal portion, a second working electrode (125) distributed on the substrate and extending from the distal portion to the proximal portion, the second working electrode has a sampling end in the distal portion and a connecting end in the proximal portion and a control electrode distributed on the substrate and extending from the distal portion to the proximal portion. The control electrode has a connecting end in the proximal portion and wraps around the first working electrode and the second working electrode in the distal portion. The sampling end of the first working electrode and the sampling end of the second working electrode are separated from each other by a defined distance of 125-750 μ m. The first working electrode and the second working electrode have a combined surface area, and the control electrode has a defined surface area, where a ratio of the combined surface area of the working electrodes to the defined surface area of the control electrode is 0.2-1.25. INDEPENDENT CLAIMS are included for the following: combination comprising a microfluidic unit and the sensor unit; method involves applying conductive ink onto a substrate such that, upon the conductive ink drying, an electrode having a nanostructured-sensing surface is formed on the substrate, where the conductive ink comprises 0.2-0.3 mg/ml poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS) mixed with 1-2 mg/ml electrochemically exfoliated graphene; conductive ink comprising 0.2-0.3 mg/ml PEDOT:PSS mixed with 1-2 mg/ml electrochemically exfoliated graphene; and microfluidic unit comprising a microchannel comprising a sample-receiving section configured to receive a sample, an electrodes-interface section configured to supply the sample to electrodes of a sensor unit, and a gap between the sample-receiving section and the electrodes-interface section configured to slow down movement of the sample and delay the supplying of the sample to the electrodes. DESCRIPTION OF DRAWING(S) - The drawing shows a schematic view of the sensor unit of the electrochemical-sensor system. 104Sensor unit 114Proximal portion 116Distal portion 124First working electrode 125Second working electrode 128Substrate