Here, a carbon paste modified electrode (CPME) with Zn/Al-layered double hydroxide (Zn/Al-LDH) was developed for the simultaneous electrochemical detection of dopamine (DA) and uric acid (UA). The surface morphology and structural features of the synthesized Zn/Al-LDH were analyzed using scanning electron microscopy and X-ray diffraction analysis. The LDH-modified sensor exhibited enhanced adsorptive properties, significantly improving the preconcentration and detection of the targets. Electrochemical characterization using square wave voltammetry demonstrated that the Zn/Al-LDH structure plays a crucial role in increasing sensitivity due to its high surface area and favorable electrostatic interactions by adsorptive preconcentration separate from the electrochemical cell. Under optimized conditions (preconcentration pH of 6.0 and an electrochemical cell pH of 7.0), the sensor demonstrated excellent linearity across biologically relevant concentrations, ranging from 0.2 to 20 μM, in phosphate-buffered saline (PBS), synthetic urine, and synthetic cerebrospinal fluid, with limits of detection of 68 nM for UA and 71 nM for DA. Recovery studies confirmed the sensor’s reliability in complex biological matrices, with recoveries ranging from 90% to 120%. Compared to existing electrochemical sensors, the Zn/Al LDH-modified CPE offers a promising, selective, and efficient platform for neurotransmitter and metabolite analysis in biological samples.

ITIC’s superior electron-accepting capacity and efficient oxygen reduction motivated the design of a sensor to enhance sensitivity, selectivity, and stability over conventional oxygen-dependent or fullerene-based systems. As oxygen acts as the terminal reagent in enzymatic glucose oxidation, we developed an ITIC-mediated glucose oxidase (GOx) biosensor on glassy carbon (GCE) and screen-printed carbon electrodes (SPCE). ITIC, a non-fullerene organic semiconductor, was drop-cast onto the electrode to catalyze oxygen reduction, followed by GOx immobilization in a chitosan matrix. Scanning electron microscopy (SEM) confirmed uniform, ultrathin coatings without significant morphological changes upon ITIC and GOx deposition. Electrochemical studies (cyclic (CV) and differential pulse voltammetry (DPV)) revealed a distinct ITIC reduction peak at –0.7 V (vs. Ag/AgCl) and a glucose-dependent current decrease, consistent with mediated electron transfer during enzymatic oxidation. Under optimized conditions, the GCE-based biosensor showed a sensitivity of 10.7 μA L mmol⁻¹, a linear dynamic range (LDR) of 0.10–1.00 mmol L⁻¹, and detection (LOD)/quantification (LOQ) limits of 0.02 and 0.06 mmol L⁻¹, respectively. The SPCE device displayed sensitivity (3.8 μA L mmol⁻¹) and maintained excellent linearity (R² > 0.99) with LOD and LOQ of 0.05 and 0.16 mmol L⁻¹. Both platforms showed good precision (RSD < 5%) and reliable recovery in deproteinized plasma and artificial tears (90–104%). The superior performance of the GCE is attributed to higher ITIC loading, faster electron transfer, and reduced background current, while the SPCE offers a low-cost, disposable format with sufficient analytical performance for point-of-care glucose monitoring.