Novel plant extract-chitosan nanocomposite (SCE/ChNPs) biosensor for trace level arsenic sensing in water samples using quartz crystal microbalance with dissipation monitoring

Arsenic contamination in water poses a severe threat to human health and the environment, necessitating the development of sensitive, selective, and eco-friendly detection methods. This study unveils a groundbreaking approach for ultra-low arsenic detection in water by combining the unique properties of Saussurea costus ethanolic extract and chitosan nanoparticles in a Quartz Crystal Microbalance with Dissipation monitoring (QCM-D) based biosensor. The Saussurea costus extract, rich in bioactive compounds, was loaded onto chitosan nanoparticles to leverage their synergistic effects. The prepared Saussurea costus ethanolic extract loaded chitosan nanoparticles (SCE/ChNPs) were extensively characterized using various techniques, including atomic force microscopy (AFM), scanning electron microscopy (SEM), transmission electron microscopy (TEM), dynamic light scattering (DLS), and X-ray diffraction (XRD). The results revealed a mean particle size of 37.0 ± 2.0 nm, a spherical shape, a negative surface charge (-28.3 mV), a porous structure, and an amorphous crystalline nature. The QCM-D technique enabled real-time monitoring of mass changes on the quartz crystal sensor surface upon interaction with arsenic species. The biosensor's analytical performance was evaluated, demonstrating high sensitivity, selectivity, and repeatability for ultra-low arsenic detection. This innovative green biosensor technology offers a sustainable, efficient, and accessible solution for safeguarding public health and the environment from arsenic contamination.