Current non-enzymatic electrochemical biosensors rely heavily on transition metal-based nanomaterials, such as Pt, Ni, Co, and Cu, for molecule adsorption and charge transfer. Although high performance (sensitivity and selectivity) was usually demonstrated, these elements are generally toxic, making them less applicable for wearable/in vivo sensors.

Two general strategies are approached to address such drawbacks: minimizing their usage without sacrificing the activity and searching for other elements with lower toxicity. In this study, we demonstrated that the overlooked bismuth nanoparticles (NPs) could be used for non-enzymatic electrochemical glucose sensing with comparable performance [1]. Using a laser ablation approach (see Figure 1A), stabilizer-free Bi NPs (~10 nm diameter) were prepared, showing amperometric sensitivity of 127 µA mM⁻¹ cm⁻². The synthesis approach also enabled the one-step surface doping of the Bi NPs, producing Ni and Co-doped Bi NPs with an atomic doping ratio of ~10%, and led to further sensitivity boost to 677 and 2326 µA mM⁻¹ cm⁻² (see Figure 1B). Kinetic analysis revealed that the oxidation of Bi(III) to Bi(V) species was the key to enabling glucose electrooxidation on Bi NPs. Such results demonstrate the vast potential of the overlooked bismuth in electrochemical biosensing.

Figure 1 (A) Top: illustration of the laser ablation approach of preparing Bi and metal-doped Bi NPs; Bottom: TEM images of as-prepared Bi NPs and Co-Bi NPs; (B) Amperometric correlation between glucose concentration and the current density using Bi NPs and Co-Bi NPs as sensors.

Reference:

1. Zheng, W.; Li, Y.; Lee, L. Y. S., Bismuth and metal-doped bismuth nanoparticles produced by laser ablation for electrochemical glucose sensing, Sens. Actuators, B 2022, 357, 131334.