Prussian blue (PB) and its analogs (PBA) are widely used for modifying flexible electrochemical sensors due to their excellent electrocatalytic activity and low cost. However, traditional electrodeposition methods often result in uneven films with poor crystallinity and weak adhesion, compromising sensor stability and reproducibility. Herein, we propose a lignosulfonate (LS)‐assisted solution‐phase in situ growth strategy to achieve uniform nucleation and high‐loading growth of PBA nanocrystals on laser‐induced graphene (LIG) under mild conditions (45°C, atmospheric pressure). Leveraging the three‐dimensional porous structure and high surface area of LIG, combined with the dispersion and regulatory functions of LS, PBA crystals grow directly on the graphene framework, forming a tightly bound, highly crystalline active interface. Compared to electrodeposited PB, this approach enhances interfacial adhesion, prevents delamination, and simplifies the fabrication process, making it suitable for scalable, low‐cost flexible devices. Integrated with molecular imprinting technology (MIP), the resulting RE‐PBA@LIG@MIP electrode exhibits a peak current density of −5.29 mA cm −2 (12% higher than PB) and retains 88.48% activity after 2000 cycles. The sensor achieves a detection limit of 0.28 μM for leucine, with excellent selectivity against histidine, isoleucine, lysine, and uric acid (signal fluctuations <5% in the presence of 10 μM interferents; <4% with uric acid). This work demonstrates the potential of the in situ growth strategy for high‐performance wearable sensors in health monitoring. Specifically, this device targets a challenging niche application: the noninvasive monitoring of branched‐chain amino acids (BCAAs) like leucine. This capability is critical for the early screening of metabolic disorders (e.g., Maple Syrup Urine Disease) and the real‐time management of muscle recovery in sports nutrition, offering a distinct advantage over traditional rigid analytical tools.
Tang et al. (Sun,) studied this question.