Fig. 2: Design and characterization of the synaptic biochemical sensors.
From: All-printed chip-less wearable neuromorphic system for multimodal physicochemical health monitoring
a Schematic design of the enzymatic synaptic biosensors. RE, reference electrode. b Redox reaction mechanism of the synaptic biosensors: oxidases catalyze the oxidation of target molecules, producing H2O2. This is subsequently catalyzed by Pt or Prussian blue (PB) nanoparticles, resulting in the formation of oxygen or hydroxide radicals, respectively. These reactions facilitate electron donation or withdrawal from Au electrodes, generating synaptic currents. c Optical microscopy image of the synaptic biochemical sensor. d Scanning electron microscopy (SEM) image of a PB nanoparticle-coated Au electrode. Similar morphological features are observed at more than five locations in each of the three independently prepared samples. Scale bar, 400 nm. e, f Responses of the lactate (e) and glucose (f) synaptic sensors in target analyte solutions. Redlines in (e and f) indicate a linear fit. The measure of center is represented as the mean, and the error bars indicate the standard deviation (s.d.) from three sensors. g, h Excitatory postsynaptic current (EPSC) response of the lactate (g) and glucose (h) synaptic sensors under varied target analyte concentrations. i, j Long-term potentiation/depression (LTP/D) response of the lactate (i) and glucose (j) synaptic sensors under varied target analyte concentrations. k EPSC response of lactate synaptic sensor in the presence of lactate (Lac) and biochemical interferences, including ascorbic acid (AA) (60 µM), uric acid (UA) (0.3 mM), urea (5 mM), and glucose (Glu) (4 mM). l EPSC response of the synaptic glucose sensor in the presence of glucose and biochemical interferences, including ascorbic acid (AA) (60 µM), uric acid (UA) (0.3 mM), urea (5 mM), and lactate (4 mM).
