Construction And Property Of The Ferrocene-Modified Zr-MOFs As Biosensors

Traditional sensors generally only have one signal,which is easily affected by sensor preparation,detection environment and operation methods.The dual-signal sensors refer to each other to reduce the influence of errors and improve the accuracy of detection;a calibration system is established inside the proportional sensor to overcome the interference of environmental and personal factors,thereby improving the sensitivity and reliability of detection.Metal-organic frameworks（MOFs）are often used as signal sources,carriers and catalysts in the field of biosensing due to their large specific surface area,abundant functional groups,variable composition and tunable pore environment.In this paper,the sensitive detection of the drug inhibitor galantamine（GH）was realized from the aspects of fluorescence and electrochemistry through UiO-67-Fc,enzyme inhibitor/signal molecule,and UiO-67-Fc as the organophosphorus hydrolysis of mimetic enzymes along with ratiometric electrochemical sensors were used for realizing sensitive detection of pesticide paraoxon.The main research contents and conclusions are as follows:1.Using UiO-67-NH₂with good fluorescent signal as the parent,ferrocenecarboxaldehyde（Fc-CHO）with strong electron withdrawing ability was covalently modified on the surface of MOF by Schiff base reaction to form weakly fluorescent UiO-67-Fc.The acetic acid generated by the enzymatic reaction promotes the decomposition of UiO-67-Fc to release UiO-67-NH₂and with the recovery of the fluorescence signal,in the presence of the inhibitor,the generated acetic acid decreases and the fluorescence intensity decreases;acetylcholinesterase（ACh E）is used to decompose acetylcholine（ACh）to produce acetic acid,acetic acid disrupting the Schiff base in UiO-67-Fc,UiO-67-Fc decomposes into UiO-67-NH₂and Fc-CHO,where UiO-67-NH₂acts as a carrier without structural collapse,and Fc-CHO has an electrical signal.Using the inhibitory effect of UiO-67-NH₂bonded Fc-CHO molecule and GH on ACh E activity,this strategy can sensitively detect GH with a detection limit of 14.6 ng m L^-1for the fluorescence sensor and 1.5 ng m L^-1for electrochemical detection.The dual-signal sensor has a fluorescent signal and an electrochemical signal,which can be referred to each other to reduce the influence of errors and improve the accuracy of detection.2.Using the nanozyme UiO-67-NH₂as the parent,Fc-CHO was covalently modified on the surface of MOF by Schiff base reaction to form UiO-67-Fc.When paraoxon is present,UiO-67-Fc acts as an organophosphorus hydrolysis mimetic enzyme to catalyze the decomposition of paraoxon into p-nitrophenol（p-NPh）and diethyl phosphite.P-NPh has an electrical signal,and acidic diethyl phosphite destroys Schiff base in UiO-67-Fc,resulting in UiO-67-NH₂and Fc-CHO electrical signaling molecules.With the increase of paraoxon concentration,the I_p-NPh/I_Fc-CHOvalue(I_p-NPhand I_Fc-CHOare the peak currents of p-NPh and Fc-CHO,respectively)decreased.Based on this strategy,the designed ratiometric electrochemical sensor has a detection limit of 2u M.The ratiometric electrochemical sensor outputs the Fc-CHO electrical signal and the p-NPh electrical signal,and an internal correction system is established,which can effectively overcome the influence of external factors.interference,thereby improving the sensitivity and reliability of detection.