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Background: Modern science in drug delivery systems has long been paid to effectively design drug delivery systems, to reduce side effects, increasing bioavailability, targeted drug delivery, and passing through blood-brain barriers. Nanoparticles are very important as carriers because they  carry different types of drugs to different parts of the body at the right time. Method: In the present study, thiolated nano chitosan loaded with Biperiden was synthesized by ion gel method using two types of crosslinkers (tripolyphosphate and genipin) and their efficiency was investigated. Results: FTIR analysis confirmed the successful synthesis of various stages of thiolated nano chitosan loaded with Biperiden by both crosslinkers. SEM images showed that as-synthesized nano-carriers have a nanorod structure and nanocarriers crosslinked by genipin had a more regular structure with a size of about 150 nm than nanocarrier crosslinked by TPP with a size of approximately 200 nm. In vitro drug release and cytotoxicity studies showed nano-carriers crosslinked by genipin have had a higher release and less cytotoxicity than nano-carriers crosslinked by TPP. Conclusion: Considering the lower toxicity and delayed release of nanoparticles synthesized with genipine than nanocarriers synthesized with TPP, the use of this nanocarrier increases the bioavailability of the drug and can be used as a suitable drug delivery system.

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​Escherichia coli O157:H7 is one of the most important and common foodborne pathogens in the world which is being resistant against some current synthetic antimicrobials. The aim of this study was to determine the minimum inhibitory concentration (MIC) and the minimum bacterial concentration (MBC) of Artemisia dracunculus (tarragon) essential oil and its nanoemulsion for enterohemorrhagic strain of Escherichia coli and then the effect of sub-MIC concentrations on growth rate and gene expression of virulence genes (stx1A and stx2A). Nanoemulsion of tarragon essential oil was prepared by the ultrasound method and the droplet size and zeta potential were determined. MIC and MBC of essential oil and nanoemulsion were determined using the broth microdilution method. The growth rate and expression of stx1A and stx2A genes in Escherichia coli were assessed after treatment with different concentrations of sub-MICs of essential oil and nanoemulsion. Estragol was identified as the main component in the essential oil. The average diameter of nanoemulsion particle was 50 nm and the zeta potential was -30mV. The MIC values ​​ of essential oil and nanoemulsion were 0.58±0.11 and 0.33±0.07mg/ml, respectively, and their MBC were 0.65 ± 0.20 and 0.38 ± 0.15 mg/ml, respectively. Nanoamulsion had a greater inhibitory effect against bacterial growth than free essential oil. At the end of the 72-hour period, nanoemulsion treatment at 75% MIC resulted in a reduction in stx1A and stx2A transcription of 3.75 and 4.10 folds, while at 75% MIC of essential oil stx1A and stx2A transcripts were reduced 1.91 and 2.02 folds compared with control, respectively. Higher activity of nanoemulsion of tarragon essential oil to reduce the growth and shigatoxin production of E. coli compared to pure EO, reveals its potential to be used as a natural food preservative and a solution to the global problem of emergence of antibiotic-resistant microbes.