A Self-Powered Glucose Biosensor Operated Underwater to Monitor Physiological Status of Free-Swimming Fish
A Self-Powered Glucose Biosensor Operated Underwater to Monitor Physiological Status of Free-Swimming Fish
Blog Article
The changes in blood glucose levels are a key indicator of fish health conditions and are closely correlated to their stress levels.Here, we developed a self-powered glucose biosensor (SPGB) consisting of a needle-type enzymatic biofuel cell (N-EFC), which was operated underwater and connected to a charge pump integrated circuit (IC) and a light emitting diode (LED) as the indicator.The N-EFC consisted of a needle bioanode, which Piano Stool was inserted into the caudal area of a living fish (Tilapia) to access biofuels, and a gas-diffusion biocathode sealed in an airtight bag.
The N-EFC was immersed entirely in the water and connected to a charge pump IC with a capacitor, which enabled charging and discharging of the bioelectricity generated from the N-EFC to blink an LED.Using a smartphone, the glucose concentration can be determined by observing the LED blinking frequencies that are linearly proportional to the blood glucose concentration within a detection range of 10–180 mg/dL.We have successfully demonstrated the feasibility of the SPGB used to Hats continuously monitor the physiological status of free-swimming fish treated with cold shock in real time.
The power generated by a free-swimming fish with an N-EFC inserted into its caudal area, swimming in a fish tank with a water temperature (Tw) of 25 °C, exhibited an open circuit voltage of 0.41 V and a maximum power density of 6.3 μW/cm2 at 0.
25 V with a current density of 25 μA/cm2.By gradually decreasing Tw from 25 °C to 15 °C, the power generation increased to a maximum power density of 8.6 μW/cm2 at 0.
27 V with a current density of 31 μA/cm2.The blood glucose levels of the free-swimming fish at 25 °C and 15 °C determined by the blinking frequencies were 44 mg/dL and 98 mg/dL, respectively.Our proposed SPGB provides an effective power-free method for stress visualization and evaluation of fish health by monitoring a blinking LED through a smartphone.