2D disposable stochastic sensors for molecular recognition and quantification of maspin in biological samples

Three disposable stochastic sensors using nanolayer deposition of a graphene nanocomposite comprising graphene nanoparticles and gold nanoparticles, on different supports: silk, plastic, and paper, and modified with chitosan, were characterized and validated for molecular recognition and quantification of maspin in biological samples. Very low limits of determination (of pg mL−1 magnitude order) were recorded (5.12 pg mL−1 for the sensor based on silk at pH 7.40 and on copy paper at pHs 3.00 and 7.40; 16 ng mL−1 at pH 7.40 for the sensor based on plastic, 41.00 pg mL−1 for the sensor based on silk at pH 3.00, and 204.00 pg mL−1 for the sensor based on plastic, at pH 3.00), with wide linear concentration ranges (5.12 × 10−12–2.00 × 10−6 g mL−1 for the sensors based on silk at pH 7.40, and on copy paper at pH 3.00; 5.12 × 10−12–8.00 × 10−7 g mL−1 for the sensor based on copy paper at pH 7.40; 1.60 × 10−8–2.00 × 10−6 g mL−1 for the sensor based on plastic at pH 7.40; 4.10 × 10−14–2.00 × 10−6 g mL−1 for the sensor based on silk, at pH 3.00; and 2.04 × 10−13–8.00 × 10−7 g mL−1 for the sensor based on plastic at pH 3.00) allowing the molecular recognition and quantification of maspin in healthy people and patients with gastric cancer, when a potential of 125 mV vs. Ag/AgCl was applied. The recoveries of maspin in whole blood, saliva, urine, and tissue samples were higher than 95.00%, with a relative standard deviation lower than 1.0%. Graphical abstract: [Figure not available: see fulltext.]. © 2022, The Author(s), under exclusive licence to Springer-Verlag GmbH Austria, part of Springer Nature.