Amir Mirzaie

Curcumin, an important natural component of turmeric, has been known for a long time for its antimicrobial properties. This study aimed to investigate the anti-biofilm action of the niosome-encapsulated curcumin and explore the involved anti-biofilm mechanism. In silico investigations of ADME-Tox (absorption, distribution, metabolism, excretion, and toxicity) were first performed to predict the suitability of curcumin for pharmaceutical application. Curcumin showed low toxicity but at the same time, low solubility and low stability, which, in turn, might reduce its antimicrobial activity. To overcome these intrinsic limitations, curcumin was encapsulated using a biocompatible niosome system, and an encapsulation efficiency of 97% was achieved. The synthesized curcumin-containing niosomes had a spherical morphology with an average diameter of 178 nm. The niosomal curcumin was capable of reducing multi-drug resistant (MDR) Staphylococcus aureus biofilm 2–4-fold compared with the free curcumin. The encapsulated curcumin also demonstrated no significant cytotoxicity on the human foreskin fibroblasts. To understand the interaction between curcumin and S. aureus biofilm, several biofilm-related genes were analyzed for their expression. N-acetylglucosaminyl transferase (IcaD), a protein involved in the production of polysaccharide intercellular adhesion and known to play a function in biofilm development, was found to be downregulated by niosomal curcumin and showed high binding affinity (-8.3 kcal/mol) with curcumin based on molecular docking analysis. Our study suggests that the niosome-encapsulated curcumin is a promising approach for the treatment of MDR S. aureus biofilm and can be extended to biofilms caused by other pathogens.

Targeted drug delivery and increasing the biological activity of drugs is one of the recent challenges of pharmaceutical researchers. Niosomes are one of the new targeted drug delivery systems that enhances the biological properties of drugs. In this study, for the first time, the green synthesis of selenium nanoparticles (SeNPs), and its loading into niosome was carried out to increase the anti-bacterial and anti-cancer activity of SeNPs. Different formulations of noisome-loaded SeNPs were prepared, and the physical and chemical characteristics of the prepared niosomes were investigated. The antibacterial and anti-biofilm effects of synthesized niosomes loaded SeNPs and free SeNPs against standard pathogenic bacterial strains were studied, and also its anticancer activity was investigated against breast cancer cell lines. The expression level of apoptotic genes in breast cancer cell lines treated with niosome-loaded SeNPs and free SeNPs was measured. Also, to evaluate the biocompatibility of the synthesized niosomes, their cytotoxicity effects against the human foreskin fibroblasts normal cell line (HFF) were studied using the MTT (3-[4,5-dimethylthiazol-2-yl]-2,5 diphenyl tetrazolium bromide) assay. The results illustrated that the optimal formulation had an average size of 177.9 nm, a spherical shape, and an encapsulation efficiency of 37.58%. Also, the results revealed that the release rate of SeNPs from niosome-loaded SeNPs and free SeNPs was 61.26% and 100%, respectively, in 72 h. Also, our findings demonstrated that the niosome-loaded SeNPs have significant antibacterial, anti-biofilm, and anticancer effects compared to the free SeNPs. In addition, niosome-loaded SeNPs can upregulate the expression level of Bax, cas3, and cas9 apoptosis genes while the expression of the Bcl2 gene is down-regulated in all studied cell lines, significantly. Also, the results of the MTT test indicated that the free niosome has no significant cytotoxic effects against the HFF cell line which represents the biocompatibility of the synthesized niosomes. In general, based on the results of this study, it can be concluded that niosomes-loaded SeNPs have significant anti-microbial, anti-biofilm, and anti-cancer effects, which can be used as a suitable drug delivery system.

Background In this study, the optimized niosomal formulation containing paclitaxel using non-ionic surfactants and cholesterol was designed and its cytotoxic effects against different breast cancer cell lines and apoptosis gene expression analysis were also investigated. Methods and results Due to enhancing equation variables, the Box–Behnken method has been applied. Lipid/drug molar ratio, the amounts of Span 60, and cholesterol were selected as the target for optimization. The particle size of niosome loaded paclitaxel and entrapment efficiency proportion have been considered in the role of dependent variables. Then the cytotoxic activity of the optimized formulation was evaluated using an MTT assay against different breast cancer cell lines including MCF-7, T-47D, SkBr3, and MDA-MB-231. The expression level of Bax and Bcl-2 apoptosis genes was determined by Real-Time PCR. In this study, the optimized niosomal formulation revealed that the synthesized niosomes had a spherical appearance and had an average size of 192.73 ± 5.50 nm so that the percentage of drug loading was 94.71 ± 1.56%. Moreover, this formulation showed a controlled and slowed release of paclitaxel at different pH (7.4, 6.5, and 5.4). The cytotoxicity results demonstrated that cell viability in all concentrations of niosome loaded paclitaxel had profound cytotoxic effects on all studied breast cancer cell lines compared to the free paclitaxel (p < 0.05). In addition, the expression of apoptosis genes was much higher than that of free paclitaxel indicating the susceptibility of cells to apoptosis. Conclusions As a result, niosomal formulations containing paclitaxel can be used as a new drug delivery system to increase cytotoxicity and treatment of breast cancer in the upcoming future.

Thymol is a monoterpene phenolic derivative extracted from the Thymus vulgaris which has antimicrobial effects. In the present study, thymol‐loaded chitosan nanogels were prepared and their physicochemical properties were characterized. The encapsulation efficiency of thymol into chitosan and its stability were determined. The in vitro antimicrobial and anti‐biofilm activities of thymol‐loaded chitosan nanogel (Ty‐CsNG), free thymol (Ty), and free chitosan nanogel (CsNG) were evaluated against both Gram‐negative and Gram‐positive multidrug‐resistant (MDR) bacteria including Staphylococcus aureus, Acinetobacter baumanii, and Pseudomonas aeruginosa strains using the broth microdilution and crystal violet assay, respectively. After treatment of MDR strains with sub‐minimum inhibitory concentration (Sub‐MIC) of Ty‐CsNG, free Ty and CsNG, biofilm gene expression analysis was studied. Moreover, cytotoxicity of Ty‐CsNG, free Ty, and CsNG against HEK‐293 normal cell line was determined using MTT (3‐(4,5‐dimethylthiazol‐2‐yl)‐2,5‐diphenyltetrazolium bromide) method. The average size of Ty‐CsNG was 82.71±9.6 nm, encapsulation efficiency was 76.54±0.62 % with stability up to 60 days at 4 °C. Antibacterial activity test revealed that Ty‐CsNG reduced the MIC by 4–6 times in comparison to free thymol. In addition, the expression of biofilm‐related genes including ompA, and pgaB were significantly down‐regulated after treatment of strains with Ty‐CsNG (P<0.05). In addition, free CsNG displayed negligible cytotoxicity against HEK‐293 normal cell lines and presented a biocompatible nanoscale delivery system. Based on the results, it can be concluded that Ty‐CsNG can be considered a promising candidate for enhancing antimicrobial and anti‐biofilm activities.

In this study, different formulations of amoxicillin-loaded niosomes were fabricated using the thin-film hydration method and their physicochemical properties were determined using scanning electron microscopy (SEM), dynamic light scattering (DLS), and Fourier-transform infrared (FTIR) spectroscopy. The optimum prepared niosomes had a spherical morphology with an average size of 170.6 ± 6.8 nm and encapsulation efficiency of 65.78 ± 1.45%. The drug release study showed that the release rate of amoxicillin from niosome containing amoxicillin was slow and 47 ± 1% of the drug was released within 8 h, while 97 ± 0.5% of the free drug was released. In addition, amoxicillin-loaded niosome increased the antimicrobial activity by 2–4 folds against multidrug-resistant (MDR) Staphylococcus aureus strains using broth microdilution assay. Moreover, at 1/2 minimum inhibitory concentrations, amoxicillin-loaded niosome significantly enhanced the anti-biofilm activity compared to free amoxicillin. Amoxicillin-loaded niosome had negligible cytotoxicity against HEK-293 normal cell line compared to free amoxicillin. The free niosomes exhibited no toxicity against HEK-293 cells and presented a biocompatible nanoscale delivery system. Based on the results, it can be concluded that amoxicillin-loaded niosome can be used as a promising candidate for enhancing antimicrobial and anti-biofilm effects against MDR strains of S. aureus.

With the increased occurrence of antibiotic-resistant bacteria, alternatives to classical antibiotics are urgently needed for treatment of various infectious diseases. Medicinal plant extracts are among the promising candidates due to their bioactive components. The aim of this study was to prepare niosome-encapsulated Echinacea angustifolia extract and study its efficacy against multidrug-resistant Klebsiella pneumoniae strains. Encapsulation was first optimized by Design of Experiments, followed by the empirical study. The obtained niosomes were further characterized for the size and morphology using dynamic light scattering (DLS), transmission electron microscopy (TEM), and scanning electron microscopy (SEM). Spherical niosomes had a diameter of 142.3 ± 5.1 nm, as measured by DLS. The entrapment efficiency (EE%) of E. angustifolia extract reached up to 77.1% ± 0.3%. The prepared niosomes showed a controlled drug release within the tested 72 h and a storage stability of at least 2 months at both 4 and 25 °C. The encapsulated E. angustifolia displayed up to 16-fold higher antibacterial activity against multidrug-resistant K.pneumoniae strains, compared to the free extract. Additionally, the niosome exhibited negligible cytotoxicity against human foreskin fibroblasts. We anticipate that the results presented herein could contribute to the preparation of other plant extracts with improved stability and antibacterial activity, and will help reduce the overuse of antibiotics by controlled release of natural-derived drugs.

In the current study, niosome‐encapsulated tobramycin based on Span 60 and Tween 60 was synthesized and its biological efficacies including anti‐bacterial, anti‐efflux, and anti‐biofilm activities were investigated against multidrug resistant (MDR) clinical strains of Pseudomonas aeruginosa. The niosomal formulations were characterized using scanning electron microscopy, transmission electron microscopy, and dynamic light scattering measurement. The encapsulation efficiency was found to be 69.54% ±; 0.67. The prepared niosomal formulations had a high storage stability to 60 days with small changes in size and drug entrapment, which indicates that it is a suitable candidate for pharmaceutical applications. The results of biological study showed the anti‐bacterial activity via reduction of antibiotic resistance, enhanced anti‐efflux and anti‐biofilm activities by more folds in comparison to free tobramycin. In addition, niosome encapsulated tobramycin down‐regulated the MexAB‐OprM efflux genes, pslA and pelA biofilm related genes in MDR P. aeruginosa strains. The anti‐proliferative activity of formulation was evaluated against HEK293 cell lines, which exhibited negligible cytotoxicity against HEK293 cells. The finding of our study shows that encapsulation of tobramycin in niosome enhanced the antibacterial activity and reduced antibiotic resistance in MDR strains of P. aeruginosa comparing to free tobramycin and it can be considered as a favorable drug delivery system.

In this study, the antibacterial, anti-efflux, anti-biofilm, anti-slime (exopolysaccharide) production and urease inhibitory efficacies of green synthesized gold nanoparticles (AuNPs) coated Anthemis atropatana extract against multidrug- resistant (MDR) Klebsiella pneumoniae strains were evaluated. The green synthesized AuNPs were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy-dispersive X-ray spectroscopy (EDX), X-ray diffractometer (XRD), particle size distribution, zeta potential and Fourier-transform infrared spectroscopy (FTIR). Then, antibacterial, anti-slime (exopolysaccharide) production, anti-biofilm and anti-efflux activities of AuNPs were investigated using micro-dilation, Congored agar, microtiter plate and MIC of ethidium bromide methods, respectively. Subsequently, the expression of mrkA, wzm and acrB genes was evaluated using quantitative Real-Time PCR (qRT-PCR). The synthesized AuNPs exhibited antibacterial activity against MDR strains of K. pneumoniae (minimum inhibitory concentration (MIC) of 6.25–50 µg/ml), as well as showed significant anti-slime (exopolysaccharide) production, anti-biofilm and anti-efflux activities against MDR strains. AuNPs showed significant inhibition against jack-bean urease and down-regulated the expression of mrkA, wzm and acrB genes. Moreover, the in vitro cytotoxic activity confirmed by MTT assay on the HEK-293 normal cell line showed negligible cytotoxicity. Thus, the present study suggests the potential use of AuNPs in the development of novel therapeutics for the prevention of biofilm-associated K. pneumoniae infections.