Investigation of Melphalan interaction as an alkylating agent with nucleotides by using surface enhanced Raman spectroscopy (SERS).

SERS (Surface Enhanced Raman Spectroscopy) is a new Raman spectroscopy which relies on Surface Plasmon Resonance (SPR) of metal nanoparticles. We have applied colloidal silver and gold nanoparticles as amplifier agents to enhance nucleotide Raman signals. It is observed that without these enhancing agents, it is impossible to investigate nucleotide spectrum due to weak Raman signals. Interaction mechanism of Melphalan, an anticancer drug with four nucleotides (Adenine, Cytosine, Guanine, Thymine) was investigated using SERS to detect and identify changes due to alkylating process in Raman spectra. After incubating Melphalan drug with nucleotides for 24 h at 37 °C, some changes occurred in SERS spectrum and interpretation of SERS spectra revealed the influence of the alkyl substitution on peaks and Raman shifts. After incubation of Melphalan with each nucleotide, intensity of relevant SERS signals assigned to Amid III group of Cytosine and Amid I of Thymine decreased significantly, confirming alkylating taking place. In this study, we also investigated the effect of nanoparticles type on nucleotide spectrum. We could not obtain useful information in the cases of guanine nucleotide. The SERS spectrum of Cytosine as an example of nucleotides in aqueous solution compared to solid state and results demonstrated that in solid state better signals were obtained than in liquid state.

Chitosan nanoparticles improve the effectivity of miltefosine against Acanthamoeba.

BACKGROUND: Acanthamoeba keratitis (AK) is a corneal sight-threatening infection caused by the free-living amoebae of the genus Acanthamoeba. Early and appropriate treatment significantly impacts visual outcomes. Mucoadhesive polymers such as chitosan are a potential strategy to prolong the residence time and bioavailability of the encapsulated drugs in the cornea. Regarding the recent administration of miltefosine (MF) for treating resistant AK, in the present study, we synthesized miltefosine-loaded chitosan nanoparticles (MF-CS-NPs) and evaluated them against Acanthamoeba. METHODOLOGY/PRINCIPAL FINDINGS: Chitosan nanoparticles (CNPs) were prepared using the ionic gelation method with negatively charged tripolyphosphate (TPP). The zeta-potential (ZP) and the particle size of MF-CS-NPs were 21.8±3.2 mV and 46.61±18.16 nm, respectively. The release profile of MF-CS-NPs indicated linearity with sustained drug release. The cytotoxicity of MF-CS-NPs on the Vero cell line was 2.67 and 1.64 times lower than free MF at 24 and 48 hours. This formulation exhibited no hemolytic activity in vitro and ocular irritation in rabbit eyes. The IC50 of MF-CS-NPs showed a significant reduction by 2.06 and 1.69-fold in trophozoites at 24 and 48 hours compared to free MF. Also, the MF-CS-NPs IC50 in the cysts form was slightly decreased by 1.26 and 1.21-fold at 24 and 48 hours compared to free MF. CONCLUSIONS: The MF-CS-NPs were more effective against the trophozoites and cysts than free MF. The nano-chitosan formulation was more effective on trophozoites than the cysts form. MF-CS-NPs reduced toxicity and improved the amoebicidal effect of MF. Nano-chitosan could be an ideal carrier that decreases the cytotoxicity of miltefosine. Further analysis in animal settings is needed to evaluate this nano-formulation for clinical ocular drug delivery.

Fabrication, characterization and wound-healing properties of core-shell SF@chitosan/ZnO/Astragalus arbusculinus gum nanofibers.

Aim: Silk fibroin/chitosan/ZnO/Astragalus arbusculinus (Ast) gum fibrous scaffolds along with adipose-derived mesenchymal stem cells (ADSCs) were investigated for accelerating diabetic wound healing. Methods: Scaffolds with a core-shell structure and different compositions were synthesized using the electrospinning method. Biological in vitro investigations included antibacterial testing, cell viability analysis and cell attachment evaluation. In vivo experiments, including the chicken chorioallantoic membrane (CAM) test, were conducted to assess wound-healing efficacy and histopathological changes. Results: The incorporation of Ast to the silk fibroin@ chitosan/ZnO scaffold improved wound healing in diabetic mice. In addition, seeding of ADSCs on the scaffold accelerated wound healing. Conclusion: These findings suggest that the designed scaffold can be useful for skin regeneration applications.

Nanoemulsion of Spiramycin against Tachyzoites of Toxoplasma gondii, RH Strain: Preparation, Toxicology, and Efficacy Studies.

Background: Toxoplasma infection is caused by Toxoplasma gondii, which is an intracellular protozoan parasite. This infection consequently lead various congenital disabilities during pregnancy in patients. Spiramycin (Spi), a macrolide antibiotic, is typically recommended for T. gondii infection in pregnant women. We aimed to prepare the nanoemulsion of spiramycin (NE-Spi) and to evaluate the activity of this formulation in tachyzoites of T. gondii, RH strain. Methods: This study was conducted in 2019-2021 at the School of Public Health, Tehran University of Medical Sciences, Tehran, Iran. NE-Spi was prepared by spontaneous emulsification. The effects of this nanoemulsion on the viability of cultured cells were measured using MTT assay. To estimate the effects of NE-Spi on tachyzoites of T. gondii, RH strain, different concentrations of NE-Spi, S-Spi (suspension of spiramycin), and NE (nanoemulsion without any spiramycin) were added to tachyzoites and then stored for 30, 60, 90, 120 min and 24 h in 250 µg/ml concentration at room temperature. Finally, Tachyzoites mortality rates were evaluated by trypan blue staining. Of note, flow cytometry was conducted to confirm the obtained results. Results: The final particle size of NE-Spi was calculated to be 11.3 nm by DLS and TEM. Thereafter, using MTT assay, in 62.5 µg/ml concentration of NE-Spi, the Vero cells viability was obtained as 82%. The highest mortality rates of tachyzoites of T.gondii, RH strain were observed at 250 µg/ml concentration and after 120 min of exposure, but it was not significantly different from 24 h of exposure. Conclusion: NE-Spi has lethal efficacy on T. gondii RH strain in-vitro.

Current challenges ahead in preparation, characterization, and pharmaceutical applications of nanoemulsions.

Nanoemulsions (NEs) are emulsions with particle size of less than around 100 nm. Reviewing the literature, several reports are available on NEs, including preparation, characterization, and applications of them. This review aims to brief challenges that researchers or formulators may encounter when working with NEs. For instance, when selecting NE components and identifying their concentrations, stability and safety of the preparation should be evaluated. When preparing an NE, issues over scale-up of the preparation as well as possible effects of the preparation process on the active ingredient need to be considered. When characterizing the NEs, the two major concerns are accuracy of the method and accessibility of the characterizing instrument. Also a highly efficient NE for clinical use to deliver the active ingredient to the target tissue with maximum safety profile is commonly sought. Throughout the review we also have tried to suggest approaches to overcome the challenges. This article is categorized under: Therapeutic Approaches and Drug Discovery > Emerging Technologies.

Effect of folate-targeted Erlotinib loaded human serum albumin nanoparticles on tumor size and survival rate in a rat model of glioblastoma.

The aim of this study was to prepare folate-targeted Erlotinib loaded human serum albumin nanoparticles (FA-ERL-HSA NPs) and investigate in vitro cytotoxic and apoptotic effects using cell lines (U87MG and C6 cells) and an in vivo rat bearing C6 glioma model. The mean size of the FA-ERL-HSA NPs prepared using a desolvation method was 135 nm. In vitro MTT assays demonstrated that FA-ERL-HSA NPs had an IC50 value of 52.18 µg/mL and 17.53 µg/mL compared to free ERL which had an IC50 value of 119.8 µg/mL and 103.2 µg/mL for U87MG and C6 cells for 72 h, respectively. Flow cytometry results showed the apoptosis rate with FA-ERL-HSA NPs (100 µg/mL, 72 h) was higher compared to free ERL for both U87MG and C6 cells. Experiments using a rat glioblastoma model via TUNEL assay indicated that the apoptosis index of FA-ERL-HSA NPs was 48 % compared to 21 % for free ERL and the tumor size effectively decreased after a daily injection of 220 µg (2.5 mg/kg) from 87.45 mm3 (19th day) to 1.28 mm3 (60th day). The median survival rate of the rats increased after treatment to >100 days which was greater than controls.

Cytotoxicity and Anti-Plasmodium berghei Activity of Emodin Loaded Nanoemulsion.

Background: Malaria parasites cause a tremendous burden of disease in both the tropics and subtropics areas. Growing of drugs resistance in parasites is one of the most threats to malaria control. The aim of study was to investigate the anti-malarial activity of nano-emodin isolated from Rhamnus cathartica on Plasmodium berghei in mice to evaluate parasites inhibition rate using in-vivo test. Methods: The study was conducted in the School of Public Health, Tehran University of Medical Sciences, during 2020. Nano-emodin particles were prepared from Rhamnus cathartica, and confirmed by Zeta Potential Analyzer, DLS and electron microscopy techniques. Mice were infected with P. berghei and treated by emodin nano-particles. Parasitemia was evaluated in each group in comparison with control group. Toxicity test was done using twice the highest concentration of emodin extract on a separate group of mice and ED50 was calculated. Results: Emodin extract was significantly effective in all concentrations on D4 (P<0.05). The most effective on parasitemia was observed in 400 mg/kg of Liquid Nano-emodin and solid (non-Nano) emodin. ED50 for emodin extract was determined 220 mg/kg. Toxicity test showed no toxic effect on the subjects. Conclusion: The emodin extract is safe, lack of side effects. So, it can be used for more and longer period of time and in higher doses. Emodin extract, either in form of liquid and nanoparticle or in a solid form, has the same therapeutic effect on P. berghei in infected Balb/c mice.

COVID-19 Death Rates in Iran and Iraq: Possible Relations Between Iraq's Pre-COVID-19 Mass Gatherings and Its Low Death Rate.

In recent years, COVD-19 has made millions of death worldwide. When reviewing the death rate, we encountered a very notable difference in death rate of Iran and Iraq, which are two neighboring countries. Investigating the COVID-19 risk factors, parameters, such as ethnicity and vaccination, do not appear not to be affecting our observation. We also could not find important differences in mortality rate being under-reported in the two countries. In this letter, we tried to discuss the possible effect of Iraq pre-COVID-19 mass gatherings on the death rate. The authors would like to highlight the effect of immune system on COVID-19.

Immobilization of urease enzyme on chitosan/polyvinyl alcohol electrospun nanofibers.

Electrospun nanofibers have gained much attention for enzyme immobilization due to their high surface-to-volume ratio. In this study, urease was immobilized on chitosan/poly(vinyl alcohol) (PVA) nanofibers by both adsorption and crosslinking methods. In order to obtain nanofibers with more desirable properties, solutions with different ratios of chitosan and PVA were electrospun and crosslinked using glutaraldehyde. Comparing SEM images of the nanofibers, before and after immersing them in phosphate buffer, it was shown that higher chitosan content leads to more stable fibers. So, the solution with the chitosan to PVA ratio of 40:60 was used for enzyme immobilization. Then, the effects of initial protein concentration, temperature, incubation time, and method of immobilization were investigated to reach the highest enzyme activity. Under similar immobilization conditions, covalently immobilized urease showed higher activity, compared to uncrosslinked immobilized enzyme. Besides, it retained 30% of its initial activity after 10 times usage. So, this method was chosen for further investigation. Not only the activity of the immobilized enzyme was much higher than the free enzyme in a wide range of pH and temperature, but also stability of the immobilized enzyme was improved. Immobilized urease was then used to remove thiourea which is a toxic compound. Findings indicated 60% hydrolysis of initial thiourea in 12 h. In conclusion, the findings showed that chitosan/PVA nanofibers are suitable candidates for the immobilization of urease.

Photodynamic therapy-mediated extirpation of cutaneous-resistant dermatophytosis with Ag@ZnO nanoparticles: an efficient therapeutic approach for onychomycosis.

Aim: The aim of this study was to determine whether photodynamic therapy of resistant onychomycosis with Ag@ZnO nanoparticles can promote the treatment procedure and extirpates the recurrence of fungal infection. Methods: Ag@ZnO nanoparticles (NPs) under UVB-radiation were applied to treat T. rubrum and T. mentagrophytes in vitro through photodynamic therapy. In vivo therapeutic efficacy, biocompatibility and biodistribution of Ag@ZnO NPs were studied. Results: 40 µg/ml of UVB-activated Ag@ZnO NPs showed 100% antifungal activity against dermatophytosis in vitro and in vivo followed by complete growth prevention by degeneration of spores and mycelium after 180 days, while posed biocompatibility. Conclusion: This study showed the superiority of photodynamic therapy with Ag@ZnO NPs followed by proper regeneration of the skin with Zinc ion of the shell.

Anti-rheumatic activity of topical nanoemulsion containing bee venom in rats.

PURPOSE: Bee Venom (BV) has been used to treat rheumatoid arthritis (RA) for many centuries. However, its clinical use is limited by pain and fear of bee stings/injection. Nanoemulsions (NEs) are nanocarriers that are able to help their content(s) penetrate through the skin. They also act as drug reservoirs on the skin to provide an efficient, sustained-release vehicle. METHODS: In this paper, we present the development of a stable water-in-oil NE to help passing BV through the animal skin when used topically. RESULTS: Particle size of NE was 12.7 to 29.8 nm for NEs containing 0 to 150 µg/ml BV. Also, its anti-inflammatory effects were evaluated in rat models of type II collagen-induced arthritis. Topical administration of NEs containing 18.75 or 9.37 µg/ml BV were able to significantly (p < 0.05) reduce inflammation in the rat paws compared to the blank and control groups. CONCLUSION: Our findings demonstrated the efficacy of NEs containing BV to reduce inflammation caused by RA animal model.

Use of antioxidant nanoparticles to reduce oxidative stress in blood storage.

Oxidative damage by free radicals has a negative effect on blood quality during storage. Antioxidant nanoparticles can prevent oxidative stress. We use SOD-CAT-Alb-PEG-PLGA- nanoparticles to reduce the effects of oxidative stress in blood storage. Electrospray was employed to prepare nanoparticles. Nanoparticles entered the test bags and were kept for 35 days from the time of donation under standard conditions. On target days, experiments were performed on the samples taken. The examination included blood smear, red blood cells count, hemoglobin, hematocrit, K, Fe, glutathione peroxidase, glutathion reductase, glucose-6-phosphate dehydrogenase, prooxidant-antioxidant balance, malondialdehyde, and flow cytometric assay for phosphatidylserine. The repeated measures analysis was performed on samples every week. Morphological changes were less in the test group compared to the control. The quantitative hemolysis profile test showed significant changes in the test and control groups (p < 0.05) in consecutive weeks except for K and Fe. Oxidative stress parameters too showed a significant change during the target days of the examination (p < 0.05). Also, the phosphatidylserine expression was increased in control groups more than test in consecutive weeks (p < 0.05). It seems that the use of antioxidant nanoparticles improves the quality of stored red blood cells and can prevent posttransfusion complications and blood loss by reducing oxidative stress.

A topical gel of tea tree oil nanoemulsion containing adapalene versus adapalene marketed gel in patients with acne vulgaris: a randomized clinical trial.

Adapalene is used for treatment of acne vulgaris, a common dermatological disease. Nano-based carriers have been developed to improve solubility and bioavailability of adapalene and other acne treatment drugs. In our previous report, tea tree oil nanoemulsion containing adapalene gel (TTO NE + ADA Gel) showed appropriate physical and biological properties such as stability, viscosity, pH, size, morphology and biocompatibility in an animal model. The present study was designed to assess efficacy and safety of the TTO NE + ADA Gel in comparison with 0.1% adapalene marketed gel (ADA Marketed Gel). A total of 100 patients were randomized to receive TTO NE + ADA Gel or ADA Marketed Gel, once daily at night, for 12 weeks. Analysis for efficacy was conducted by acne lesion count (total, inflammatory and non-inflammatory) and acne severity index at weeks 4, 8 and 12 using generalized estimating equation along with the safety assessments in each measurement for assessing dryness, erythema, burning sensation and irritation. Significantly better reduction in total, inflammatory, and non-inflammatory acne lesions were reported for TTO NE + ADA Gel as compared to the ADA Marketed Gel overall and on each measurement occasion (p value < 0.001 for all). Mean acne severity index also reduced with TTO NE + ADA Gel significantly in comparison with ADA Marketed Gel (p value < 0.001). Dryness was the most common adverse effect reported in both groups and it was higher in TTO NE + ADA Gel group. In conclusion, TTO NE + ADA Gel compared to ADA Marketed Gel appears more effective in the treatment of acne vulgaris, with no important change in adverse effects.

Repellent Efficacy of Eucalyptus globulus and Syzygium aromaticum Essential Oils against Malaria Vector, Anopheles stephensi (Diptera: Culicidae).

BACKGROUND: Mosquito species are highly considering as disease transmission as well as nuisance insects. One of the principal strategy to protect human from the mosquito bites is repellent agents. This study aimed to assess repellency of two organic essential oils, Eucalyptus globulus and Syzygium aromaticum from bites of malaria vector, Anopheles stephensi. METHODS: The study was conducted in 2019-2020. The components of essential oils of E. globulus and S. aromaticum was determined using gas chromatography/mass spectrometry. The unfed female mosquitoes aged 2-5 d old were used in all experiments. In vivo Klun and Debboun module bioassays were utilized on human-volunteer skin. The essential oils at serial concentrations were used to find repellent efficacy against Anopheles landings and bites. To find the synergistic effect, four combinations of the essential oils were tested. RESULTS: The main composition of E. globulus essential oil was 1,8-Cineol (78.20%), whereas that of S. aromaticum essential oil was 2-methoxy-3-(2-propenyl) (77.04%). Based on minimum effective dose (≤1% biting), 10% (v/v) of E. globulus showed high landing repellency (77.78%), whereas minimum effective dose of S. aromaticum at concentration of 1% had high landing repellency (88.89%). Among four combinations, the ratio of 1:1 of E. globulus (10%):S. aromaticum (1%) showed the most landing repellency (94.44%). CONCLUSION: The combinations of two essential oils had the most potential repellency effect against landing of mosquitoes. As essential oils are eco-friendly with less irritation for human skin, E. globulus and S. aromaticum essential oils are recommended as effective and safe mosquito repellents.

Dose-dependent efficacy of antioxidant nanoparticles on red blood cells storage.

BACKGROUND: Transfusion of healthy red blood cells (RBCs) after storage is important. One of the storage lesions on blood bags is oxidative stress. One way to prevent increased oxidative stress is to use antioxidant nanoparticles (NPs). Superoxide dismutase (SOD) and catalase (CAT) play an important role in antioxidant defense on RBC. poly lactic-co-glycolic acid (PLGA) is a nontoxic biodegradable polymer that is approved by the Food and Drug Administration for drug delivery. This study aimed to assess dose-dependent efficacy of SOD-CAT-polyethylene glycol -PLGA on RBCs storage. MATERIALS AND METHODS: Using a descriptive study, during 1 month, twenty donors from Bojnourd Blood Donation Center were selected. NPs with different concentrations were injected into the satellite bags after directing blood to them. On target days, experiments were performed on the samples taken. Electrospray was employed to prepare SOD-CAT-PLGA NPs. Twenty packed RBCs were isolated from the whole blood bags by the mechanical method, and certain amount of product was transferred to the satellite bags. On days 1, 7, 14, 21, 28, and 35, bags were sampled. Malondialdehyde (MDA), prooxidant-antioxidant balance (PAB), and Annexin V were performed on the samples taken. The repeated measures analysis with the help of SPSS software version 20 was performed on samples. RESULTS: MDA increased in both groups. The maximum increase in test group was seen in concentration 12 mg (MDA Day 14, test [1.93 ± 0.3], [P MDA < 0.001]). Maximum increase in PAB was seen in concentration 12 mg (from 444 ± 1.7 to 563 ± 2.5) (P PAB = 0.000). Furthermore, PS expression increased in the concentration of 12 mg greater than other concentration in consecutive (from 5.00 ± 0.8 to 22.26 ± 1.7, [P < 0.001]). CONCLUSION: Evaluation of dose dependency showed that different concentrations of antioxidant NPs affect RBC. This effect can be changed oxidative stress and apoptosis. Using both changes to evaluate functional and toxicity can be helpful.

Epinephrine-entrapped chitosan nanoparticles covered by gelatin nanofibers: A bi-layer nano-biomaterial for rapid hemostasis.

Uncontrolled hemorrhage accounts for significant death risk both in trauma and surgery. Various bleeding control techniques have been emerged to augment hemostasis, which still has several limitations and drawbacks. In this study, epinephrine-entrapped chitosan nanoparticles were electrosprayed on a base pad and covered by a gelatin nanofiber layer (E-CS-Gl. Physico-chemical characteristics, hemocompatibility, cytotoxicity, and blood coagulation tests were studied in-vitro, and blood coagulation and hemostasis potential tests were performed in-vivo. The in-vitro results showed that the prepared nano-biomaterial is cytocompatible against HuGu cells. Also, hemocompatibility studies showed that PT and aPTT times did not change in comparison with the controls. Further blood coagulation study indicated that E-CS-Gl provides an ultimate interface to induce red blood cell absorption and aggregation, resulting in augmented blood coagulation. E-CS-Gl also caused rapid clotting in rat models of ruptured femoral artery and liver compared to controls. Findings exhibited that E-CS-Gl is a safe and effective hemostatic agent and provides a new approach for fast and safe hemorrhage control.

Preparation of nanoemulsion of Cinnamomum zeylanicum oil and evaluation of its larvicidal activity against a main malaria vector Anopheles stephensi.

PURPOSE: There is a growing need to use green and efficient larvicidal as alternatives for conventional chemicals in vector control programs. Nanotechnology has provided a promising approach for research and development of new larvicides. Larvicidal potential of a nanoemulsion of Cinnamomum zeylanicum essential oil reports against Anopheles stephensi. METHODS: The nanoemulsion of was formulated in various ratios comprising of C. zeylanicum oil, tween 80, span 20 and water by stirrer. It was characterized by transmission electron microscopy (TEM) and dynamic light scattering (DLS). All components of C. zeylanicum essential oil were identified by GC-MS analysis. The larvicidal potential of the oil and its nanoformulation were evaluated against larvae of An. stephensi. The stability and durability of nanoemulsion was observed over a period of time. RESULTS: Sixty one components in the oil were identified, cinnamaldehyde (56.803%) was the main component. The LC90 and LC50 values of C. zeylanicum essential oil were calculated as 49 ppm and 37 ppm, respectively. The nanoemulsion droplets were found spherical in shape. It was able to kill 100% of larvae in up to 3 days. It was stable after dilution and increased its larvicidal activity up to 32% compared with the essential oil. CONCLUSIONS: A novel larvicide based on nanotechnology introduced. This experiment clearly showed increasing larvicidal activity and residual effect of the nanoformulation in comparison with the bulk essential oil. It could be concluded that this nanoemulsion may be considered as safe larvicide and should be subject of more research in this field.

State-of-the-Art of Nanodiagnostics and Nanotherapeutics against SARS-CoV-2.

The pandemic outbreak of SARS-CoV-2, with millions of infected patients worldwide, has severely challenged all aspects of public health. In this regard, early and rapid detection of infected cases and providing effective therapeutics against the virus are in urgent demand. Along with conventional clinical protocols, nanomaterial-based diagnostics and therapeutics hold a great potential against coronavirus disease 2019 (COVID-19). Indeed, nanoparticles with their outstanding characteristics would render additional advantages to the current approaches for rapid and accurate diagnosis and also developing prophylactic vaccines or antiviral therapeutics. In this review, besides presenting an overview of the coronaviruses and SARS-CoV-2, we discuss the introduced nanomaterial-based detection assays and devices and also antiviral formulations and vaccines for coronaviruses.

Preparation of a Nanoemulsion of Essential Oil of Acroptilon repens Plant and Evaluation of Its Larvicidal Activity agianst Malaria Vector, Anopheles stephensi.

Background: Extensive use of chemical larvicides to control larvae, has led to resistance in vectors. More efforts have been conducted the use of natural products such as plant essential oils and their new formulations against disease vectors. Nanoformulation techniques are expected to reduce volatility and increase larvicidal efficacy of essential oils. In this study for the first time, a larvicide nanoemulsion from the essential oil of Acroptilon repens was developed and evaluated against Anopheles stephensi larvae under laboratory conditions. Methods: Fresh samples of A. repens plant were collected from Urmia, West Azarbaijan Province, Iran. A clevenger type apparatus was used for extracting oil. Components of A. repens essential oil (AEO) were identified by gas chromatography-mass spectrometry (GC-MS). All larvicidal bioassay tests were performed according to the method recommended by the World Health Organization under laboratory condition. Particle size and the morphologies of all prepared nanoformulations determined by DLS and TEM analysis. Results: A total of 111 compounds were identified in plant. The LC50 and LC90 values of AEO calculated as 7 ppm and 35 ppm respectively. AEO was able to kill 100% of the larvae in 4 days. Conclusion: The nanoemulsion of AEO showed a weak effect on the larvar mortality. It may therefore be suggested that this kind of nanoemulsion is not appropriate for the formulation as a larvicide. It is important to screen native plant natural products, search for new materials and prepare new formulations to develop alternative interventions with a long-lasting impact.

Evaluation of Nanoemulsion of Eucalyptus globulus Oil as Potent Botanical Larvicide against Malaria Vector, Anopheles stephensi and West Nile Vector, Culex pipiens Under Laboratory and Semi-Field Conditions.

Background: Due to undesired environmental impact of insecticides as well as resistant of vectors to them, the development of organic and natural insecticides has been more considered. In the current study, we developed nanoemulsion of eucalyptus and investigated lavicidal activity of it against malaria vector, Anopheles stephensi and Culex pipiens under laboratory as well as semi-field conditions. Methods: An optimized nanoemulsion was prepared by mixing Eucalyptus oil, Tween 80 and ethanol at ratio of 1:2:1.5 in distilled water, then, stirred for 20 minutes at room temperature. The product was then used for bioassay tests against 3-4th instar larvae of Anopheles stephensi as well as Culex pipiens. Furthermore, a semi-field trial was carried out to evaluate larvicidal activity of nanoemulsion of eucalyptus. Results: Nanoemulsion of eucalyptus showed significantly high lavicidal activity comparing with bulk eucalyptus essential oil. The LC50 and LC90 value of nanoemulsion against An. stephensi were 111.0 and 180.8 ppm respectively and 29.5 and 73.7 ppm for Cx. pipiens, respectively. In the semi field condition, the Nanoemulsion of eucalyptus decreased 1-2nd instar larval density of Culicines and Anophelines to 90.1% and 85.2%, respectively. Conclusion: The nano formulation of eucalyptus oil showed high larvicidal activity. Therefore, nanoemulsion of eucalyptus oil can be used as an eco-friendly larvicide against mosquitoes.