| With the widespread use of antibiotics and other antibacterial drugs in medical care,animal husbandry and agriculture,large amounts of antibiotics accumulate in the environment,leading to the increasing resistance of pathogenic antibiotic resistance(AR).Antibiotic resistance is a global problem,posing a serious threat to human and animal health,food,ecology and the environment.In recent years,with the continuous expansion of the application of nanotechnology,the development of alternative antibiotics and the prevention of drug resistance have become the focus of current research.Different from traditional antibiotics,photoresponsive nanomaterials can kill pathogens by photothermal(PTT)and photodynamic(PDT).The synergistic effect of photothermal and photodynamic(PPT)has the advantage of high-efficiency sterilization.It has important application prospects in photocatalytic degradation of antibiotics,killing antibiotic resistant bacteria(ARBs),and inhibiting horizontal transfer of drug-resistant genes.Meanwhile,in order to combat ARBs and the spread of ARGs caused by antibiotics,it is urgent to develop multifunctional non-antibiotic nanomaterials that can eliminate residual antibiotics and inhibit the spread of ARGs.Therefore,in this paper,aiming at the pollution of antibiotics,antibiotic resistant bacteria and antibiotic resistant genes in the environment,from a variety of perspectives of comprehensive application,sodium dodecyl sulfate(SDS)was modified to Fe2O3@MoS2 surface by ultrasonic method,and a Z-type,multifunctional Fe2O3@MoS2@SDS nanocomposite material was obtained:(1)Fe2O3 and Fe2O3@MoS2 composites were synthesized by a simple hydrothermal method.Then SDS was modified on Fe2O3@MoS2 by ultrasonic method to obtain a Z-type heterogeneous composite nanomaterial.The characterization results showed that Fe2O3@MoS2 was completely covered by SDS.The dispersion of Fe2O3@MoS2@SDS in liquid was enhanced by SDS modification,and the band gap of nanomaterials in UV-visible light was decreased.(2)The near infrared response performance of Fe2O3@MoS2@SDS composite nanomaterial was studied.According to the experimental results,the optimal conditions were determined:When the concentration of nanomaterials is 120μg/mL,and the power of NIR irradiation is 0.7 W/cm2,the temperature of Fe2O3@MoS2@SDS suspension reaches 65℃after 300 s of NIR irradiation.At the same time,it has stable photothermal effect.The results of free radical capture experiment show that Fe2O3@MoS2@SDS can produce a large number of reactive oxygen species and free radicals under NIR irradiation,indicating that nanomaterials have photodynamic effects.Fe2O3@MoS2@SDS composite nanomaterial has 99.95%,99.97%and 99.58%antibacterial activity against Escherichia coli(E.coli),Methicillinresistant Staphylococcus aureus(MRSA)and Pseudomonas aeruginosa(P.aeruginosa)under the synergistic action of photothermal and photodynamic,and can also promote wound healing.(3)The photocatalytic degradation effect of Fe2O3@MoS2@SDS composite nanomaterial on tetracycline(Tet)was studied According to the results,the optimum conditions were determined as follow:When the concentration of nanomaterial was 240μg/mL,the concentration of Tet was 25 mg/L,pH=7,the removal rate of the Tet by Fe2O3@MoS2@SDS suspension reached the highest 92.3%after 120 min natural illumination.(4)The effect of Fe2O3@MoS2@SDS on horizontal gene transfer was studied.The experimental results showed that Fe2O3@MoS2@SDS had obvious inhibitory effect on the conjugation of antibiotic resistant bacteria.In the conjugation experiment:compared with the control,the engagement efficiency of RP4-7,F33:A-:B-and IncX4 were reduced by about 130 times,14 times and 43 times by adding Fe2O3@MoS2@SDS.The conjugation experiment of three different plasmids could effectively reduce the horizontal transfer(HGT)of antibiotic resistant genes and inhibit diffusion of antibiotic resistant genes. |
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