Real time biochemical monitoring is crucial in personalized medicine and disease diagnosis. Fiber electrochemical sensors have become an ideal carrier for wearable devices due to their advantages of miniaturization and biocompatibility. However, the traditional surface functionalization preparation strategy has led to two major bottlenecks: firstly, the active material is easily peeled off from the high curvature fiber surface, resulting in mechanical degradation in dynamic biological environments (such as tissue deformation and fluid immersion), leading to monitoring failure; Secondly, the uniformity of the coating is difficult to control, with batch performance differences of up to 80%, which hinders large-scale applications.

The team led by Academician Peng Huisheng and Associate Professor Sun Xuemei from Fudan University has developed a universal co extrusion strategy, which achieves continuous preparation of flexible fiber electrochemical sensors by co extruding active materials with conductive polymer PEDOT: PSS suspension. This technology enables the active material to be uniformly embedded in the interpenetrating conductive polymer network, forming a stable interface structure. The obtained sensor exhibits excellent stability and consistency (performance deviation₂ O ₂) in mice and continuous tracking of ascorbic acid (AA) in the brain for up to 14 days

Figure 1 reveals the innovative structure of the co extruded fiber sensor (EFS). The active material of traditional coated sensors (Figure 1a-i) is prone to detachment due to bending or friction, while EFS (Figure 1a-II) solves the problem of structural instability from the root by uniformly fusing the active material with the polymer network. The preparation process (Figure 1b) shows that the active material (such as MnO ₂ nanoparticles) PEDOT:PSS、 Dimethyl sulfoxide (DMSO) and dodecyl benzene sulfonic acid (DBSA) are mixed and extruded into the silicone tube. After spontaneous gelling, water washing and drying, continuous fibers with a diameter of 42.31 ± 0.52 μ m are formed (Fig. 1c). The diameter and bending stiffness deviation of 50 groups of EFS were all less than 5% (Figure 1d). SEM images (Figures 1f-g) and manganese element distribution maps (Figure 1h) confirmed that the active material was uniformly dispersed in the fiber cross-section, and a stable porous electrochemical active interface was constructed.

Source: Sensor Expert Network