Triclosan-based Nanoantibiotics For Combined Antibacterial Studies

At present,antibiotic-resistance of bacteria is an important issue causing international concern,which is a huge challenge of all over the world.In the 1930s and 1940s,penicillin,streptomycin and sulfonamides were widely used in clinical practice,which solved many routine infections.It wasn’t until the 1950s,when Japanese doctors first discovered and reported that Shigella,a strain isolated from endemic dysentery,was rapidly developing antibiotic resistance,causing resistance came to the forefront.In the treatment of infection,people adopt the method of increasing the dosage or concentration of drugs to overcome the bacterial resistance and improve the efficacy of antibiotics,but from another perspective,this also stimulates the bacteria to develop stronger resistance.Studies have shown that bacteria develop drug-resistance mainly through the production of inactivated enzyme or inactivating enzyme,efflux pump action of cell wall,target change and other mechanisms.With the development and clinical application of new antibiotics,new drug resistance mechanisms will emerge,and drug-resistant bacteria will become more and more extensive.In recent years,in addition to introducing new antibiotics for the treatment of drug-resistant bacteria,the combination of nano-materials and antibiotics has also been widely studied to inhibit the development of drug resistance in microbial pathogens.Recent studies have shown that some metal nano-materials have antibacterial activity and can effectively control infectious diseases.Compared with traditional antibiotics,antimicrobial nano-materials have many unique advantages in reducing acute toxicity,overcoming drug resistance and reducing cost.Various nano-carriers,which is loaded antibiotics,can improve the pharmacokinetic properties of drugs,increase the accumulation of drugs in the inflammation region,improve the bioavailability of antibiotics and reduce their toxic and side effects on the body.Antibacterial nano-materials are different from many antibacterial drugs currently used in clinic and will not cause direct and acute adverse reactions.Most importantly,antimicrobial nano-materials can effectively combat bacterial resistance by killing bacteria in a great variety of ways.Compared with synthetic antibiotics,the preparation of antimicrobial nanoparticles has the advantages of low cost,good stability and long-term storage.In addition,some nanoparticles can resist harsh conditions such as high temperatures that deactivate traditional antibiotics.Therefore,the use of nano-materials to deliver antibiotics for the treatment of bacterial infection has multiple advantages:1)the distribution in the target tissue is controllable and relatively uniform;2)the improvement of the water solubility of hydrophobic antibiotics;3)slow release and controlled release;4)can improve patient compliance;5)minimize side effects;6)enhanced cell internalization.In this research,silver,gold-nanoparticles,which was employed to be the carrier,respectively loaded antibacterial agent triclosan or antibacterial peptide to prepare triclosan-silver nanoparticles(TCS-Ag NPs)and antibacterial peptide-triclosan-gold nanoparticles(TCS-RW-Au NPs).At the same time,the structural characterization,antibacterial effect,biological compatibility and sterilization ability of TCS-Ag NPs and TCS-RW-Au NPs were evaluated.Results of anti-bacteria experiment of TCS-Ag NPs in vitro showed that TCS-Ag NPs had a better inhibitory effect on the proliferation of staphylococcus aureus than Ag NPs and free TCS.This is mainly due to the fact that TCS-Ag NPs can exert the synergistic antibacterial effect of broad-spectrum antibiotic Ag NPs and antibiotic TCS to jointly kill bacteria.TCS-RW-Au NPs in vitro anti-bacteria experiment performed a more obvious resistance to vancomycin-resistant staphylococcus aureus,compared with Au NPs,RW-Au NPs and TCS-Au NPs.The main reason for this phenomenon is that TCS-RW-Au NPs can simultaneously utilize the antibacterial effect of antibacterial peptides,which perform a positive charge combined with negatively charged surface of the bacteria,and sterilizing effect of triclosan to combat the bacteria.Therefore,the preparation of TCS-Ag NPs and TCS-RW-Au NPs is an effective nano-antibiotic,which provides a useful reference for the rational design of combined antimicrobial agents based on nano-materials and is worthy of further investigation.