Toxicity Of AgInS₂ Quantum Dots In Mice In Vivo And Their Applications In Drug Detection

Objectives:Water-soluble AgInS₂quantum dots（AIS QDs）were prepared and the toxicity of AIS QDs in mice in vivo was investigated.Based on the fluorescence quenching effect of trypsin on AIS QDs,a fluorescence detection method was established to detect the content of trypsin in urine.AIS QDs-Nafion-ITO electrochemical sensor was constructed using AIS QDs and their electrochemical properties were investigated.The electrochemical behavior of tetracycline on this electrode was studied through cyclic voltammetry（CV）and differential pulse voltammetrytechniques（DPV）.An electrochemical method for tetracycline content detection using modified electrodes was established.Methods:1.The prepared AIS QDs were characterized by X-ray diffraction（XRD）,X-ray photoelectron spectroscopy（XPS）,high resolution transmission electron microscope（HRTEM）,fluorescence spectrophotometer（PL）,ultraviolet spectrophotometer（UV-Vis）,dynamic light scattering（DLS）and Fourier transform infrared spectroscopy（FTIR）.2.6-week-old ICR mice was selected as an animal model,and high concentration(3mg?kg^-1)and low concentration(1 mg?kg^-1)AIS QDs were injected into mice through the tail vein,respectively.After the AIS QDs were injected,the mice were sacrificed on days 1,7,14,and 28.Body weight,hematology,blood biochemistry,organ histology and biodistribution were examined at different time.3.The optimal conditions of AIS QDs as a fluorescent probe for the detection of trypsinwere explored,and a method for the detection of trypsin by AIS QDs under the optimum conditions was established.4.The factors affecting the electrochemical behavior of tetracycline on the electrode surface were studied,and the sensitivity,stability and anti-interference performance of the prepared electrode materials for tetracycline detection were investigated.Results:1.The prepared QDs are tetragonal AIS QDs with uniform distribution.The average particle size is 2.8 nm.The oxidation valences of Ag,In and S are+1,+3 and-2,respectively.The band gap energy of AIS QDs is 1.87 e V.2.The LD₅₀of AIS QDs injected into tail vein was 3.451 mg?kg^-1.After tail vein injection of AIS QDs,the general condition of mice was worse than that of the normal group.Body weight increased slowly,significantly lower than the normal group;Blood routine results showed that WBC,GR,LY and MO of mice in AIS QDs group were significantly higher than those in normal group,while RBC,HGB and PLT of mice in AIS QDs group were significantly lower than those in normal group,suggesting that anemia,inflammatory reaction,tissue damage or acute poisoning might occur in mice.Serum biochemical results showed that the contents of LDH,CRE,AST and ALT in AIS QDs group were significantly increased,indicating that the tissues of heart,liver and kidney were damaged.Organ index calculation showed that the liver index,spleen index,lung index and kidney index of mice with low and high dose of AIS QDs were larger than those of the normal group.The results showed that AIS QDs mainly caused edema of liver,spleen,lung and kidney.Organ histopathological observation also confirmed the organ injury in miceby AIS QDs.The results of ICP-OES showed that Ag and In elements were mainly distributed and accumulated in lung,liver,spleen and kidney of mice,and the accumulation of Ag and In in serum and viscera decreased gradually with the passing of time.3.When 0.60 m L（0.40 m L）AIS QDs with a concentration of 40μg?m L^-1or 1.50 m L AIS QDs with a concentration of 20μg?m L^-1was used,the trypsin content in urine was quantitatively determined in phosphate buffer of p H=8.00 and under the condition of interaction time 90 min.The standard curve was established by relative fluorescence quenchingΔF/F₀versus the trypsin concentration C.The linear range was 0-4μg?m L^-1(0.40m L AIS QDs solution(40μg?m L^-1)),10-320μg?m L^-1(0.60 m L AIS QDs solution(40μg?m L^-1))and 0.0625-1.6 mg?m L^-1(1.50 m L AIS QDs solution(20μg?m L^-1)),and the correlation coefficients were 0.9943,0.9981 and 0.9976,respectively.The minimum detection limit is 0.014μg?m L^-1.The average recovery of trypsin in urine at various concentrations is between 96.7%and 105.3%.4.The AIS QDs-Nafion-ITO working electrode was prepared with 4 mg?m L^-1of AIS QDs and the coating amount of 40μL.The content of tetracycline in tap water was quantitatively determined by cyclic voltammetry and differential pulse voltammetry.The standard curve was established with the current value of oxidation peak versus tetracycline concentration.There is an obvious linear relationship between 0.1 m M-1.4 m M and 1.4 m M-8 m M.The lowest detection limits of CV and DPV are 0.075 m M and 0.060 m M,respectively.The average recoveries of tetracycline in tap water by CV and DPV were between 96.8%-100.7%and 100.8%-104.0%,respectively.Conclusions:In this experiment,aqueous AIS QDs were synthesized,and the experimental results showed that AIS QDs severely damaged organs in mice.A method for the determination of trypsin in urine by fluorescence quenching effect of trypsin on AIS QDs was established.An AIS QDs-Nafion-ITO electrochemical sensor was successfully constructed by AIS QDs to detect tetracycline in tap water.The sensor has the advantages of simplicity of operation high sensitivity and good stability.