Electrochemical detection of parathyroid hormone using graphene-incorporated conductive polymer decorated with MoS₂ nanoparticles

In this work, we have developed an electrochemical biosensor using reduced graphene oxide (rGO) incorporated onto a conductive polymer poly(3,4-ethoxylenedioxythiophene) (PEDOT) and decorated with molybdenum disulfide (MoS₂) nanoparticles for the detection of parathyroid hormone (PTH). Our analysis revealed that a ternary composite containing rGO, MoS₂, and PEDOT with 1:5:60 (weight ratio) exhibits acceptable sensitivity toward PTH and enables superior adhesion between the sensing materials and the screen-printed carbon electrodes (SPCEs). The sensitivity of as-prepared SPCEs was 0.0011 (μA·mL)/pg for the PTH concentration ranging from 1 to 500 pg/mL with the detection limit of 1.457 pg/mL. Moreover, the high selectivity of the as-prepared sensors was confirmed toward PTH (i.e., 95.26%, 96.87%, 97.41%, 98.93%, and 99.73% with the existence of interfering substances (p-cresol, urea, and creatinine) diluted to 5, 10, 50, 100, and 200 times, respectively). The design parameters were finally optimized by the Taguchi method for the SPCE sensors to reliably detect PTH (reliability factor > 95%).