A glucose-responsive microgel-based soft etalon as an epidermal glucose colorimetric sensor

Nam S., Kim H., Lee S., DURUKAN M. B., ÜNALAN H. E., Lee H. J.

Sensors and Actuators B: Chemical, vol.396, 2023 (SCI-Expanded) identifier identifier

  • Publication Type: Article / Article
  • Volume: 396
  • Publication Date: 2023
  • Doi Number: 10.1016/j.snb.2023.134554
  • Journal Name: Sensors and Actuators B: Chemical
  • Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus, Academic Search Premier, Aerospace Database, Analytical Abstracts, Biotechnology Research Abstracts, Chemical Abstracts Core, Chimica, Communication Abstracts, Compendex, INSPEC, Metadex, Pollution Abstracts, Civil Engineering Abstracts
  • Keywords: Epidermal sensor, Glucose colorimetric sensors, Glucose-responsive poly (N-isopropylacrylamide) microgels, Soft Fabry-Pérot etalon, Soft sensing chamber
  • Middle East Technical University Affiliated: Yes

Abstract

Colorimetric sensors are promising candidates for convenient monitoring of changes in glucose concentration via a wearable platform. Here, poly(N-isopropylacrylamide) (pNIPAm) microgels are used as a glucose-responsive layer in a soft Fabry-Pérot etalon structure, which is incorporated in a sensing chamber for colorimetric on-body measurements. The sensing mechanism is based on dimensional changes of pNIPAm microgels in response to changes in glucose concentration, which cause spectral shifts of the reflected light in etalons. Using feed-type microgels for glucose-responsive etalon, we successfully observe distinguishable redshifts in the visible spectrum for the sweat glucose concentration of diabetic patients (0.01 ∼ 1 mM). Additionally, we introduce grid-shaped slits within the etalon structure to improve reaction time. The etalon sensor is also fabricated on a flexible substrate and is integrated into a soft sensing chamber to maintain high sensitivity during on-body measurement. The proposed non-invasive colorimetric sensor based on soft etalon suggests the possibility of simple on-body glucose measurements.