Construction And Application Of Highly Sensitive And Anti-fouling Sensor Based On MXene Composite Material

Real-time online monitoring of ammonia nitrogen concentrations is an early warning indicator in terms of wastewater treatment and water pollution,and ammonium ion selective electrodes are the easiest of all ammonia nitrogen monitoring methods to achieve this effect.However,in practice ammonium ion selective electrodes can encounter problems with biological contamination,which can shorten the life of the sensor and lead to measurement errors.In the study,a surface-modified ammonium ion selective membrane based on Ag NPs@MXene is proposed to impart biological contamination resistance to ammonium ion selective electrodes.The use of hydrophilic polydopamine to modify sterile antimicrobial ions Ag NPs@MXene on the surface of ammonium ion-selective electrodes,which increases the hydrophilicity of the membrane surface,reduces the surface roughness and releases antimicrobial particles achieves the problem of biological contamination resistance of ammonium ion-selective electrodes.The surface-modified Ag NPs@MXene/PDA/NH₄⁺-ISEs responded well within 10^-1～10^-6 M with a response slope of 54.01 m V/dec and a lower limit of detection up to 10^-6.2 M,meeting the detection range of ammonia nitrogen in the wastewater environment.The selectivity coefficients for Na⁺and K⁺were also found to be better than those of commercial electrodes,and the detection process was not interfered with by common inorganic salt ions in water.In comparison with unmodified NH₄⁺-ISEs,Ag NPs@MXene/PDA/NH₄⁺-ISEs were found to inhibit up to 76.8%of Staphylococcus aureus and up to 97.9%of Pseudomonas aeruginosa.It is superior to unmodified NH₄⁺-ISEs with a service life of more than 10 days.Microbial blooms not only cause biological contamination problems and affect the sensing performance of some sensors,but there has also been a lot of interest in the study of their harmful effects on human infection.Pseudomonas aeruginosa is widely distributed as a drug-resistant bacterium in a variety of water environments.This bacterium can cause fatal bacterial infections in some immunocompromised people,intensive care unit patients and patients with cystic fibrosis（CF）.Pyocyanin is a redox-reactive biomolecule specifically secreted by Pseudomonas aeruginosa and plays an important role in biofilm formation.Indirect monitoring of pyocyanin can be used to analyse biofilm growth and also to provide a timely response to Pseudomonas aeruginosa infections.In this study,a novel electrochemical sensing material Co TAPc-MXene was synthesised and modified on the surface of a glassy carbon electrode to construct a novel pyocyanin electrochemical sensing platform,Co TAPc-MXene/GCE.Co TAPc-MXene/GCE was found to have good performance in the detection of pyocyanin with a wide linear detection range of 0.1-200μM（R²=0.9981）,a sensor sensitivity of 0.4793μA·μM^-1 and a detection limit of 39 n M（S/N=3）.The good electrochemical catalytic activity of the new Co TAPc-MXene composite offers the possibility of in situ monitoring of Pseudomonas aeruginosa and Pseudomonas aeruginosa biological contamination for timely warning.