Fig. 5
From: Laser-induced hierarchical carbon patterns on polyimide substrates for flexible urea sensors
a Urease activity on (I) the untreated carbon film, (II) coupled to glutaraldehyde; (III) after oxygen plasma treatment and (IV) coupled to glutaraldehyde; [urea] = 10−2 M in all cases. b Urea detection using chitosan–urease sensors. The film was exposed to a 1 mg/ml urease solution for immobilization and thoroughly washed before exposure to the urea solutions. c Urease activity in solution (black curves), and (I) the sensor with electrodeposited chitosan and (II) in the presence of the untreated film; (III, IV) control film, untreated with and without electrodeposited chitosan, respectively. Urea concentration is 10−2 M in all cases. d Urease activity of flat and rolled-up sensors; [urea] = 10−2 M. All measurements were performed in triplicate, and data points report the mean ± standard deviation
