A high-performance wearable microneedle sensor based on a prussian blue-carbon nanotube composite electrode for the detection of hydrogen peroxide and glucose

Hydrogen peroxide (H 2 O 2 ) plays an important role in biology, and biomarker detection in skin interstitial fluid (ISF) has recently shown great promise. However, limited sensors were designed for H 2 O 2 detection in ISF. Therefore, a high-performance wearable H 2 O 2 microneedle sensor with a Prussian blue (PB)/carbon nanotube (CNT) composite electrode and a glucose microneedle sensor based on this electrode were developed. Two types of H 2 O 2 microneedle sensors with different CNT and PB ratios were prepared with ultra-wide detection ranges (1 μΜ–2800 mM/100 nΜ–2200 mM) in accordance with the Hill equation. Ultra-high sensitivity (954.1 μA mM −1 cm −2 and 451 μA mM −1 cm −2 ) and excellent linearity (R 2 =0.999) were exhibited in linear ranges of 1 μM to 10 mM and 100 nM to 10 mM, respectively·H 2 O 2 sensors exhibit good selectivity and essentially unattenuated detection signals in artificial ISF. The glucose enzyme-catalyzed microneedle sensor based on the CNT/PB composite electrode also exhibited a great detection range (0.5 mM–180 mM) in accordance with the Hill equation and ultra-wide linear range (0.5 mM–40 mM) with high sensitivity (16.56 μA mM −1 cm −2 ) and linearity (R 2 =0.995) in artificial ISF. To verify the practical applicability of the sensors, H 2 O 2 levels in normal and tumor cells were successfully detected by the H 2 O 2 sensor. The glucose levels in ISF before and after eating were successfully detected by the glucose sensor in vivo . The present work developed a low-cost, easy-to-prepare H 2 O 2 sensor and a related enzyme-catalyzed sensor with excellent performance, which hold promising prospects for application across diverse fields.