Construction Of Self-assembly Probe Based On Fe 3 O 4 And Its Application In Hydrogen Sulfide Detection

Hydrogen sulphide?H₂S?joins the club of gasotransmitters as a third gaseous molecule following carbon monoxide?CO?and nitric oxide?NO?,with the functions of regulating the cardiovascular system,central nervous system,respiratory system,and gastrointestinal system.Although many of the physiological roles of H₂S have been confirmed,there are still many functions that need to be further explored.Therefore,the detection of hydrogen sulfide is particularly important.Based on this,hydrogen sulfide was detected by magnetic relaxation switching?MRSw?assay single mode and magnetic and optical dual mode detection in this paper.The work of this paper is divided into the following three parts:1.Construction of Fe@Fe₃O₄ Nanoparticles Self-Assembled Probe and Its Application in Hydrogen Sulfide DetectionDue to the high saturation susceptibility of Fe@Fe₃O₄ nanoparticles,two strong coordination of phenolic hydroxy groups of 3,4-dihydroxyphenylpropionic acid with iron and carboxyl groups with lead ions,the Fe@Fe₃O₄ nanoparticles self-assembled probe was constructed for the detection of hydrogen sulfide.The probe could effectively detect H₂S in solution and the assay can be quantified with a detection limit of 1.55?M.The competitive experiments demonstrate that common interferences and abundant thiols in tumors do not interfere with the detection.2.Construction of Flower-like Au-Fe₃O₄ Nanoparticles Self-Assembly Probe and Its Application in Hydrogen Sulfide DetectionAlthough the Fe@Fe₃O₄ nanoparticles self-assembled probe can detect hydrogen sulfide effectively,there are many limitations of a single model when facing a complex biological system.Therefore,it is of great significance to develop dual-mode assay.Based on the absorption of Au nanoparticles,the magnetic properties of Fe₃O₄,and the strong coordination of the two phenolic hydroxyl groups of3,4-dihydroxyphenylpropionic acid with iron and carboxyl groups with lead ions,the Au-Fe3O4 nanoparticles optical-magnetic dual-mode self-assembly probes were constructed for the detection of hydrogen sulfide.The advantages of dual-mode detection are the accuracy and rich information.The experimental results show that UV-visible optical detection can achieve qualitative detection of hydrogen sulfide,while MRSw assay could realize quantification,with a detection limit of 2.13?M.Common interferences and abundant thiols in tumors do not interfere with detection.The transverse relaxivities?r₂?of flower-like Au-Fe₃O₄ nanoparticles was 200 s^-1mM^-1,r₂/r₁=13.Thus,it was suitable for use as a T₂ imaging contrast agent.We hope that the probe could be applied in vivo to detect tumor endogenous hydrogen sulfide by magnetic resonance imaging.3.Construction of Janus Au-Fe₃O₄ Nanoparticle Self-Assembly Probe and Its Application in Hydrogen Sulfide DetectionTo further utilize the optical properties of Au and the magnetic properties of Fe₃O₄,we explored the application of Janus Au-Fe₃O₄ nanoparticles self-assembly probe in the detection of hydrogen sulfide.The experimental results show that the probe not only has the dual-mode function and anti-interference ability of the flower-like Au-Fe₃O₄ nanoparticles self-assembly probe,but also has the advantages of smaller measurement error and a lower detection limit?1.24?M?.