MoS₂‐Polyaniline Based Flexible Electrochemical Biosensor: Toward pH Monitoring in Human Sweat

Abstract

Wearable pH sensors for sweat analysis have garnered significant scientific attention for the detection of early signs of many physiological diseases. In this study, a MoS2‐polyaniline (PANI) modified screen‐printed carbon electrode (SPCE) is fabricated and used as a sweat biosensor. The exfoliated MoS2 nanosheets are drop casted over an SPCE and are functionalized by a conducting polymer, polyaniline (PANI) via the electropolymerization technique. The as‐fabricated biosensor exhibits high super‐Nernstian sensitivity of −70.4 ± 1.7 mV pH−1 in the linear range of pH 4 to 8 of 0.1 m standard phosphate buffer solution (PBS), with outstanding reproducibility. The sensor exhibits excellent selectivity against the common sweat ions including Na+, Cl−, K+, and NH4+ with tremendous long‐term stability over 180 min from pH 4 to 6. The enhanced active surface area and better electrical conductivity as a consequence of the synergistic effect between MoS2 and PANI are correlated with the boosted performance of the as‐produced biosensor. The feasibility of the sensor is further examined using an artificial sweat specimen and the successful detection confirms the potential of the biosensor for a real‐time noninvasive, skin attachable, and flexible wearable pH sensor.

Desenvolvimento de sensor ótico de ambientes ácidos a partir de compósitos do tipo Pani/HDLs

“…A Pani é conhecida por sua capacidade de mudar a sua cor de acordo com o pH do meio [10], essa alteração de cor está associada à uma conversão reversível da Pani entre suas formas ácida (sal esmeraldina -verde) e básica (base esmeraldina -azul). Essa propriedade tem sido muito explorada na construção de sensores óticos de pH, utilizando tanto a Pani pura quanto seus compósitos com os mais diversos materiais [1,10,[29][30][31][32]. A grande maioria desses sensores tratam do controle da cor, pela mudança do sal esmeraldina para a base esmeraldina, ou seja, tratam de sensores de ambientes básicos.…”

Printable and flexible integrated sensing systems for wireless healthcare

“…131 One of their most frequent applications is for pH sensing. 132–135 For instance, Monsalve et al demonstrated a pH sensor based on screen printed carbon electrodes functionalized with inkjet printed PANI for sweat analysis. The sensor exhibited a sensitivity of 69.1 mV pH −1 that fits with the Nernst equation.…”