Supercapacitive Carbon‐Coated δ‐MnO 2 Nanosheets as a Solid‐Contact Material for Self‐Testing Potassium‐Ion Biosensors
Year: 2026
Type: article
Abstract: ABSTRACT Carbon‐coated δ‐MnO 2 nanosheets (δ‐MnO 2 @C) are developed as a solid‐contact material for all‐solid‐state potassium‐ion biosensors. The synthesis is designed to be facile and scalable: manganese(II) acetate and oxamide are coprecipitated and subsequently oxidized by persulfate treatment, achieving simultaneous crystallization of δ‐MnO 2 and carbon coating in a one‐pot process at room temperature. Benefiting from their large specific surface area, efficient redox activity, and good electrical conductivity, δ‐MnO 2 @C exhibits a high specific capacitance of 165.9 F g − 1 at 1.0 A g − 1 when used as an electrode material for supercapacitors. Practical biosensing applicability is demonstrated by employing δ‐MnO 2 @C as a solid‐contact material into a potassium‐ion sensing strip, enabling accurate detection of K + concentrations across a wide range (1.0 × 10 − 4 – 1.0 × 10 − 1 M). Notably, δ‐MnO 2 @C‐employed potentiometric potassium‐ion sensor achieved 1.4‐fold faster response time compared with conventional activated carbon contacts. Comparative studies reveal that sensor response time is governed primarily by the areal capacitance of the solid‐contact material rather than its surface area or porosity. Owing to the simplicity of the synthesis and the superior performance, δ‐MnO 2 @C provides a promising pathway toward portable self‐testing potassium‐ion biosensors for daily monitoring of blood potassium levels in patients with renal failure.
Source: Small
Institutions: Ewha Womans University, Seoul National University
Language: English
Subfield: Bioengineering
Field: Chemical Engineering
Domain: Physical Sciences
Open Access status: hybrid
Estimated APC paid: $5,790
OpenAlex ID: W7136395844