A highly flexible, physically stable, and selective hydrogel-based hydrogen peroxide sensor

Sensitive, rapid, and continuous detection of hydrogen peroxide (H2O2) is of great importance in many systems for quality control, healthcare products, medical diagnostics, food safety, and environmental protection. Yet, the continuous monitoring of H2O2 remains challenging due to the cost, lack of specificity, and bulkiness of current H2O2 sensor technologies. These challenges are exacerbated for applications where the sensor must be fully submerged in a liquid media. In this work, a highly flexible hydrogel-based electrochemical sensor is constructed for reliable and ultrasensitive detection of H2O2 in liquid environments. The hydrogel-based H2O2 sensors are based on poly(3,4-ethylenedioxythiophene):polystyrene sulfonate (PEDOT:PSS) as the transducer, hydrophilic polyurethane (HPU) as the hydrogel matrix, and horseradish peroxide (HRP) as the H2O2 specific redox enzyme. The sensors have a dual-mode sensing mechanism, namely amperometric and chemiresistive sensing. Benefited from co-redoxing of PEDOT:PSS and HRP, the sensors exhibit high stability, fast response (< 6 s), and high selectivity against common interferences, as well as a detection range from 100 mu M to 101.6 mM in amperometric mode or 613 nM to 6.13 mM in chemiresistive mode. The hydrogel-based sensors are stable in liquid environments without leaching of PEDOT:PSS after a 2-month storage period in an aqueous media.

Automated summary

Sensitive, rapid, and continuous detection of hydrogen peroxide (H2O2) is important in many systems. However, current H2O2 sensor technologies are costly, lack specificity, and are bulky, making continuous monitoring challenging. In this study, a highly flexible hydrogel-based electrochemical sensor was developed for reliable and ultrasensitive detection of H2O2 in liquid environments.