Functionalized Borophene Quantum Dots for Fluorescence Sensing of Folic Acid

Borophene has undergone extensive exploration in recent years for potential applications in sensing, electronics, optoelectronics, and energy storage due to its promising properties. However, the existing synthesis methods, such as molecular beam epitaxy, chemical vapor deposition, and physical vapor deposition, are expensive and challenging to implement. Therefore, it is important to establish simple and scalable synthesis approaches for borophene nanosheets to realize their diverse applications. In this study, we utilized a mixed-solvent-based liquid phase exfoliation strategy using a solvent mixture containing 50% ethanol and 50% water for borophene nanosheet synthesis. Furthermore, we performed surface modifications of these nanosheets using arginine (Arg) molecules, leading to the formation of Arg-functionalized borophene quantum dots (B-Arg). These B-Arg quantum dots were used as a fluorescent probe for detecting folic acid (FA) in various media, including aqueous solutions, human blood serum (HBS), artificial urine (AU), and FA tablet solutions. The observed detection limits were approximately 14.91 nM, 14.22 nM, 14.32 nM, and 14.94 nM for aqueous media, HBS, AU, and FA tablets, respectively, for the linear concentration range of 0–6.66 μM.