Biocompatible Electrochemical Sensor Based on Platinum-Nickel Alloy Nanoparticles for In Situ Monitoring of Hydrogen Sulfide in Breast Cancer Cells.

Hydrogen sulfide (H 2 S), an endogenous gasotransmitter, is produced in mammalian systems and is closely associated with pathological and physiological functions. Nevertheless, the complete conversion of H 2 S is still unpredictable owing to the limited number of sensors for accurate and quantitative detection of H 2 S in biological samples. In this study, we constructed a disposable electrochemical sensor based on PtNi alloy nanoparticles (PtNi NPs) for sensitive and specific in situ monitoring of H 2 S released by human breast cancer cells. PtNi alloy NPs with an average size of 5.6 nm were prepared by a simple hydrothermal approach. The conversion of different forms of sulfides (e.g., H 2 S, HS - , and S 2- ) under various physiological conditions hindered the direct detection of H 2 S in live cells. PtNi NPs catalyze the electrochemical oxidation of H 2 S in a neutral phosphate buffer (PB, pH 7.0). The PtNi-based sensing platform demonstrated a linear detection range of 0.013-1031 µM and the limit of detection was 0.004 µM (S/N = 3). Moreover, the PtNi sensor exhibited a sensitivity of 0.323 μA μM -1 cm -2 . In addition, the stability, repeatability, reproducibility, and anti-interference ability of the PtNi sensor exhibited satisfactory results. The PtNi sensor was able to successfully quantify H 2 S in pond water, urine, and saliva samples. Finally, the biocompatible PtNi electrode was effectively employed for the real-time quantification of H 2 S released from breast cancer cells and mouse fibroblasts.