MXene functionalized whispering gallery mode microbubble resonator for Pb2+ sensing

This study proposes a novel optical fiber sensor that integrates two-dimensional MXene materials with a microbubble whispering gallery mode (WGM) resonator for the detection of lead ions (Pb 2+ ). Utilizing the inherent negative surface charge of MXene nanosheets, a uniform functionalized film was formed on the inner surface of the microbubble cavity, enabling specific binding to Pb 2+ . Experimental results demonstrated a nonlinear response ( R 2  > 0.99) over a Pb 2+ concentration range of 0–1000 mg/L, with a detection limit of 5 mg/L, meeting the standard requirements for monitoring lead ions in industrial wastewater. The sensor also exhibits high selectivity toward Pb 2+ in the presence of interfering ions such as Zn 2+ , Ni 2+ , and Cd 2+ . Furthermore, owing to the inherent microfluidic channel of the microbubble cavity, this structure is suitable for real-time monitoring in complex aqueous environments, highlighting the great potential of the MXene-microbubble resonator platform for environmental heavy metal detection.