Nanotechnology and malaria: Evaluation of efficacy and toxicity of green nanoparticles.

Malaria is a global health problem that causes 1.5-2.7 million deaths worldwide each year. Resistance to antimalarial drugs in malaria parasites and to insecticides in vectors is one of the most serious issues in the fight against the disease. Moreover, the lack of an effective vaccine against malaria is still a major concern. Recent developments in nanotechnology have resulted in new prospects for the fight against malaria, especially by obtaining metal nanoparticles (NPs) that are less toxic, highly biocompatible, environmentally friendly, and less expensive. Numerous studies have been conducted on the synthesis of green NPs using plants and microorganisms (bacteria, fungi, algae, actinomycetes, and viruses). To our knowledge, there is no literature review that compares toxicities and antimalarial effects of some existing metallic nanoparticles revealing their advantages and disadvantages. The purpose of this review is to assess the metal NPs obtained through various green synthesis processes, to display the worth of future malaria research, and to determine future strategies. The literature review revealed that there are very limited studies on green NPs covering all stages of malaria parasites. Additionally, green metal nanoparticles have yet to be studied for their possible toxic effects on infected as well as healthy erythrocytes. Moreover, the toxicities of green metal NPs obtained from various sources differed according to concentration, size, shape, synthesis method, and surface charge, indicating the necessity of optimizing the methods used in future studies. This work has investigated the effectiveness of green metal nanoparticles synthesized from different sources against malaria, as well as their advantages and disadvantages. It was concluded that studies on the toxic properties of green nanoparticles would be very important for future stages.

Particulate and non-particle adjuvants in Leishmaniasis vaccine designs: A review.

Leishmaniasis is a parasitic disease with different clinical forms caused by protozoan parasites of the genus Leishmania and transmitted by the bite of an infected female sandfly. According to the World Health Organization (WHO), it is the second most common parasitic disease after malaria and it is known that approximately 350 million people are at risk. The disease manifests itself in different clinical forms. In addition to asymptomatic cases, cutaneous leishmaniasis (CL), which creates large lesions on the skin, and visceral leishmaniasis (VL), which causes death if not treated, especially affecting the abdominal organs, are two important clinical forms. When the studies were examined, it was seen that a clinically used vaccine against any form of human leishmaniasis has not been developed yet. In some studies, it was stated that the lack of appropriate adjuvant was responsible for the failure to develop an effective Leishmania vaccine. We can say that strong adjuvants are needed to achieve successful vaccines. In this article, adjuvants and adjuvant candidates used in vaccine studies against leishmaniasis are discussed.

Resuscitation of the Helicobacter pylori Coccoid Forms by Resuscitation Promoter Factor Obtained from Micrococcus Luteus.

Helicobacter pylori is a gram negative, spiral-shaped, and microaerophilic bacteria which can cause life-threatening diseases. It is known that more than 55% of the human population in the world is already infected by this bacterium. The traditional treatment of H. pylori infection consists of a combination of two or more antibiotics. However, H. pylori has evolved to turning its shape from spiral to coccoid form in the presence of antibiotics and this decreases the therapeutic efficacies of conventional antibiotic applications. Resuscitation promoter factor (RPF) is a protein secreted by Micrococcus luteus have significant resuscitation effects on some bacteria especially in the group of viable but non-culturable (VBNC) pathogens. However, there is no study in the literature investigating the resuscitation effects of RPF derived from M. luteus on H. pylori in order to change its form from coccoid to spiral. The purpose of this study is to investigate the resuscitation effect of RPF-containing metabolites isolated from M. luteus on the morphological transformation of H. pylori coccoid forms to spiral forms in order to increase their susceptibilities to antibiotic treatments. Rpf-containing metabolites were primarily obtained from M. luteus culture supernatants. H. pylori was exposed to five different conditions such as prolonged culture, incubation at + 4 °C, incubation at + 22 °C, cultivation in PBS and treatment with kanamycin in order to induce transformations of bacteria to coccoid forms. Induced H.pylori coccoids were characterized by inverted microscope, UV spectrophotometer, SEM imaging, and flow-cytometer. As a result, it was found that the most suitable condition for inducing coccoid forms was cultivation of bacteria with kanamycin. Followingly, different concentrations of RPF-containing metabolites were applied on H. pylori coccoids induced by kanamycin. For the first time in this study, it was determined that the Rpf-containing metabolites obtained from M. luteus demonstrated very high resuscitation effect on kanamycin-induced H. pylori coccoid forms. This new approach for resuscitation of H. pylori coccoids is thought to play an important role in increasing the treatment effectiveness of the conventional antibiotics against the infection.

Preparation, characterization and immunological evaluation: canine parvovirus synthetic peptide loaded PLGA nanoparticles.

BACKGROUND: Canine parvovirus 2 (CPV-2) remains a significant worldwide canine pathogen and the most common cause of viral enteritis in dogs. The 1 L15 and 7 L15 peptides overlap each other with QPDGGQPAV residues (7-15 of VP2 capsid protein of CPV) is shown to produce high immune response. PLGA nanoparticles were demonstrated to have special properties such as; controlled antigen release, protection from degradation, elimination of booster-dose and enhancing the cellular uptake by antigen presenting cells. Nevertheless, there is no study available in literature, about developing vaccine based on PLGA nanoparticles with adjuvant properties against CPV. Thus, the aim of the present study was to synthesize and characterize high immunogenic W-1 L19 peptide (from the VP2 capsid protein of CPV) loaded PLGA nanoparticle and to evaluate their in vitro immunogenic activity. RESULTS: PLGA nanoparticles were produced with 5.26 ± 0.05 % loading capacity and high encapsulation efficiency with 81.2 ± 3.1 %. Additionally, it was evaluated that free NPs and W-1 L19 peptide encapsulated PLGA nanoparticles have Z-ave of 183.9 ± 12.1 nm, 221.7 ± 15.8 nm and polydispersity index of 0.107 ± 0.08, 0.135 ± 0.12 respectively. It was determined that peptide loaded PLGA nanoparticles were successfully phagocytized by macrophage cells and increased NO production at 2-folds (*P < 0.05) in contrast to free peptide, and 3-folds (*P < 0.01) in contrast to control. CONCLUSION: In conclusion, for the first time, W-1 L19 peptide loaded PLGA nanoparticles were successfully synthesized and immunogenic properties evaluated. Obtained results showed that PLGA nanoparticles enhanced the capacity of W-1 L19 peptide to induce nitric oxide production in vitro due to its adjuvant properties. Depend on the obtained results, these nanoparticles can be accepted as potential vaccine candidate against Canine Parvovirus. Studies targeting PLGA nanoparticles based delivery system must be maintained in near future in order to develop new and more effective nano-vaccine formulations.

Investigation of metal-polyelectrolyte complex toxicity.

Water-soluble binary and ternary copper complexes of polyelectrolytes were synthesized, and the toxicity of these complexes was tested in mouse fibroblast cell line (L929) in vitro. Both the binary and ternary complexes were prepared at the ratio of 0.4 mole copper(II) ions per monomer of acrylic acid and 0.5 mole copper(II) ions per monomer of methyl vinyl ether maleic anhydride, furthermore at the ratio of 1 and 2 mole bovine serum albumin per mole of polyacrylic acid and poly(methyl vinyl ether-co-maleic anhydride), respectively. Compared to binary copper(II)-polyelectrolyte complexes, these ternary complexes have been determined to be of least toxicity.

Conjugation, characterization and toxicity of lipophosphoglycan-polyacrylic acid conjugate for vaccination against leishmaniasis.

Research on the conjugates of synthetic polyelectrolytes with antigenic molecules, such as proteins, peptides, or carbohydrates, is an attractive area due to their highly immunogenic character in comparison to classical adjuvants. For example, polyacrylic acid (PAA) is a weak polyelectrolyte and has been used in several biomedical applications such as immunological studies, drug delivery, and enzyme immobilization. However, to our knowledge, there are no studies that document immune-stimulant properties of PAA in Leishmania infection. Therefore, we aimed to develop a potential vaccine candidate against leishmaniasis by covalently conjugating PAA with an immunologically vital molecule of lipophosphoglycan (LPG) found in Leishmania parasites. In the study, LPG and PAA were conjugated by a multi-step procedure, and final products were analyzed with GPC and MALDI-TOF MS techniques. In cytotoxicity experiments, LPG-PAA conjugates did not indicate toxic effects on L929 and J774 murine macrophage cells. We assume that LPG-PAA conjugate can be a potential vaccine candidate, and will be immunologically characterized in further studies to prove its potential.

Investigation of antileishmanial activities of Tio2@Ag nanoparticles on biological properties of L. tropica and L. infantum parasites, in vitro.

Leishmaniasis is a public health problem which is caused by protozoon parasites belonging to Leishmania species. The disease threatens approximately 350 million people in 98 countries all over the world. Cutaneous Leishmaniasis (CL) and Visceral Leishmaniasis (VL) are the mostly commonly seen forms of the disease. Treatment of the disease has remained insufficient since current antileishmanial drugs have several disadvantages such as toxicity, costliness and drug-resistance. Therefore, there is an immediate need to search for new antileishmanial compounds. TiO2@Ag nanoparticles (TiAg-Nps) have been demonstrated as promising antimicrobial agents since they provide inhibition of several types of bacteria. The basic antimicrobial mechanism of TiAg-Nps is the generation of reactive oxygen species (ROS). Even though Leishmania parasites are sensitive to ROS, there is no study in literature indicating antileishmanial activities of TiAg-Nps. Herein, in this study, TiAg-Nps are shown to possess antileishmanial effects on Leishmania tropica and Leishmania infantum parasites by inhibiting their biological properties such as viability, metabolic activity, and survival within host cells both in the dark and under visible light. The results indicate that TiAg-Nps decreased viability values of L. tropica, and L. infantum promastigotes 3- and 10-fold, respectively, in the dark, while these rates diminished approximately 20-fold for each species in the presence of visible light, in contrast to control. On the other hand, non-visible light-exposed TiAg-Nps inhibited survival of amastigotes nearly 2- and 2.5-fold; while visible light-exposed TiAg-Nps inhibited 4- and 4.5-fold for L. tropica and L. infantum parasites, respectively. Consequently, it was determined that non-visible light-exposed TiAg-Nps were more effective against L. infantum parasites while visible light-exposed TiAg-Nps exhibited nearly the same antileishmanial effect against both species. Therefore, we think that a combination of TiAg-Nps and visible light can be further used for treatment of CL, while application of TiAg-Nps alone can be a promising alternative in VL treatment.

Preparation and Characterization of Graphene-Based 3D Biohybrid Hydrogel Bioink for Peripheral Neuroengineering.

Peripheral neuropathies can occur as a result of axonal damage, and occasionally due to demyelinating diseases. Peripheral nerve damage is a global problem that occurs in 1.5%-5% of emergency patients and may lead to significant job losses. Today, tissue engineering-based approaches, consisting of scaffolds, appropriate cell lines, and biosignals, have become more applicable with the development of three-dimensional (3D) bioprinting technologies. The combination of various hydrogel biomaterials with stem cells, exosomes, or bio-signaling molecules is frequently studied to overcome the existing problems in peripheral nerve regeneration. Accordingly, the production of injectable systems, such as hydrogels, or implantable conduit structures formed by various bioprinting methods has gained importance in peripheral neuro-engineering. Under normal conditions, stem cells are the regenerative cells of the body, and their number and functions do not decrease with time to protect their populations; these are not specialized cells but can differentiate upon appropriate stimulation in response to injury. The stem cell system is under the influence of its microenvironment, called the stem cell niche. In peripheral nerve injuries, especially in neurotmesis, this microenvironment cannot be fully rescued even after surgically binding severed nerve endings together. The composite biomaterials and combined cellular therapies approach increases the functionality and applicability of materials in terms of various properties such as biodegradability, biocompatibility, and processability. Accordingly, this study aims to demonstrate the preparation and use of graphene-based biohybrid hydrogel patterning and to examine the differentiation efficiency of stem cells into nerve cells, which can be an effective solution in nerve regeneration.

Formulating and Characterizing an Exosome-based Dopamine Carrier System.

Exosomes between 40 and 200 nm in size constitute the smallest subgroup of extracellular vesicles. These bioactive vesicles secreted by cells play an active role in intercellular cargo and communication. Exosomes are mostly found in body fluids such as plasma, cerebrospinal fluid, urine, saliva, amniotic fluid, colostrum, breast milk, joint fluid, semen, and pleural acid. Considering the size of exosomes, it is thought that they may play an important role in central nervous system diseases because they can pass through the blood-brain barrier (BBB). Hence, this study aimed to develop an exosome-based nanocarrier system by encapsulating dopamine into exosomes isolated from Wharton's jelly mesenchymal stem cells (WJ-MSCs). Exosomes that passed the characterization process were incubated with dopamine. The dopamine-loaded exosomes were recharacterized at the end of incubation. Dopamine-loaded exosomes were investigated in drug release and cytotoxicity assays. The results showed that dopamine could be successfully encapsulated within the exosomes and that the dopamine-loaded exosomes did not affect fibroblast viability.

Polymeric Approach to Adjuvant System in Antibody Production against Leishmaniasis Based on Hybridoma Technology.

Background: Leishmaniasis is a zoonotic disease, which is one of the serious public health problems in the world. Nowadays, antibody production using hybridoma technology may be a correct approach in terms of sensitivity in the diagnosis of diseases such as leishmaniasis. The aim of this study was investigation of the effectiveness of different adjuvants on polyclonal antibody production against L. tropica based on hybridoma technique. Methods: Accordingly, Freund's adjuvant (1956, M. tuberculosis), as a classic adjuvant in studies, was used comparatively with the non-toxic polymeric based Polyoxidonium adjuvant. All animal immunization procedures were conducted at Bezm-i Alem University Experimental Animal Research Center. The adjuvant response was tested both in the serum sample and in the antibodies produced by the hybridomas. The antibody titers were determined with ELISA. Results: Freund's and Polyoxidonium (PO) group blood titer's increased approximately 5.5 fold compared to control after the 6th and 8th immunization. Hybridomas produced from mice immunized with PO adjuvant induced only antigen-specific antibody response and did not develop an immune response against the adjuvant. Conclusion: Adjuvant selection is very important in terms of the specificity of antibody responses of cells produced in hybridoma technology. Therefore, PO is recommended as a new adjuvant system in this study.

Nano-co-delivery of lipophosphoglycan with soluble and autoclaved leishmania antigens into PLGA nanoparticles: Evaluation of in vitro and in vivo immunostimulatory effects against visceral leishmaniasis.

The aim of the present study was to encapsulate lipophosphoglycan molecule (LPG) which is one of the most immunogenic antigens of Leishmania parasites into PLGA nanoparticles with autoclaved or soluble leishmanial antigens, characterize synthetized nanoparticles with different methods and evaluate their in vitro/in vivo immunostimulatory activities to develop new vaccine candidates. PLGA nanoparticles including LPG and autoclaved leishmania antigen (ALA) or soluble leishmania antigen (ALA) were synthetized by double emulsion solvent evaporation method. The synthetized nanoparticles were characterized by SEM and Zeta-sizer instruments for determination of size, zeta potentials and polydispersity index (PDI) values. The antigen release profiles and encapsulation efficiencies were determined by UV-Vis spectroscopy. Griess reaction and ELISA tests were used for measurements of produced nitric oxide (NO) and cytokine levels of macrophages and splenocytes treated with nanoparticles. For determination of protective effects of nanoparticles, parasite reduction in livers and spleens of immunized mice were calculated by LDU values post-infection. According to results, (SLA-LPG) PLGA NPs and (ALA-LPG) PLGA NPs possessed the sizes of 253 and 307 nm respectively. Antigen-loaded nanoparticles elevated the released NO amounts from macrophages for 14 and 18-folds in contrast to control. Furthermore, synthetized nanoparticles significantly triggered macrophages to produce excessive levels of IFN-γ and IL-12 cytokines. Besides it was detected that vaccination of mice with (SLA-LPG) PLGA NPs and (ALA-LPG) PLGA NPs elicited approximately 80% protection from Visceral Leishmaniasis. Furthermore, (SLA-LPG) PLGA NPs and (ALA-LPG) PLGA NPs lead to 10 to 14-folds increase in secreted Th1 cytokine levels from splenocytes than control demonstrating abundantly stimulation of T cell response following to vaccination with nano-vaccine formulations. These results reveal that both (SLA-LPG) PLGA NPs and (ALA-LPG) PLGA NPs have excellent immunostimulatory activities and they are promising nanovaccine formulations for the prevention of leishmaniasis in near future.

Investigation of antileshmanial activities of Cuminum cyminum based green silver nanoparticles on L. tropica promastigotes and amastigotes in vitro.

Leishmaniasis is one of the most important parasitic diseases, which is caused by Leishmania species. Nowadays; although pentavalent antimonials are used as the basic treatment option for Cutaneous Leishmaniasis, high cost, toxicity and resistance of the parasites to the medication over time are some important limitations causing several problems in the treatment. In recent years, the progress in the field of green nanotechnology provides the development of green nanoparticle-based treatment methods for Cutaneous Leishmaniasis. The importance of green nanoparticles has gradually increased due to their special reductive, stabilizing, antioxidant and non-toxic properties. Although there are many studies based on green nanoparticles against Leishmania parasites, we have not found any research about antileishmanial activities of biosynthesized silver nanoparticles (Bio-AgNPs) using Cuminum cyminum L (Cumin) seed extract. Therefore for the first time in this study in vitro antileishmanial effects of Bio-AgNPs prepared from Cumin seed extract were examined on L. tropica promastigote and amastigote forms and their efficacies were compared with chemically synthetized AgNPs. During the experiments, antileishmanial effects of synthetized nanoparticles were determined on both promastigote and amastigote forms of Leishmania parasites by detecting different parameters such as proliferation, infection index and produced nitric oxide (NO) amounts from macrophages. According to the results, it was shown that Bio-AgNPs and AgNPs excessively inhibited L. tropica promastigotes and amastigotes by significantly decreasing proliferation rates of promastigotes and metabolic activities of amastigotes, as well. Moreover, infection index rates of macrophages revealed remarkable anti-amastigote performances of Bio-AgNPs. Besides, Bio-AgNPs stimulated macrophages to release NO to kill Leishmania parasites. Consequently, for the first time, Bio-AgNPs were found to be more effective on both forms of Leishmania parasites than AgNPs. Obtained results indicated high antileishmanial potential of green nanoparticles on L. tropica parasites, causative agents of Cutaneous Leishmaniasis. Thus, obtained results demonstrated that green nanoparticles can lead to the development of new, safer, stable and more effective antileishmanial formulations against Cutaneous Leishmaniasis.

A nanotechnology-based new approach in the treatment of breast cancer: Biosynthesized silver nanoparticles using Cuminum cyminum L. seed extract.

The present study reports the anticancer activities of Cuminum cyminum L. (Cumin) seed extract, chemically synthetized silver nanoparticles (AgNPs) and biosynthesized silver nanoparticles (Bio-AgNPs) from Cumin seeds on human breast adenocarcinoma cell line (MCF-7) and human breast adenocarcinoma metastatic cell line (AU565). The synthetized nanoparticles were characterized by dynamic light scattering (DLS), UV-visible spectroscopy (UV-Vis), X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR) and Scanning electron microscopy (SEM). The cytotoxic and anticancer effects of AgNPs and Bio-AgNPs were determined by MTT assay. According to the cytotoxicity analysis, Bio-AgNPs appears to be less toxic against J774 macrophage cells than AgNPs since IC50 values were measured as 0.75 and 1.25 µg/ml for AgNPs and Bio-AgNPs, respectively. On the other hand, Bio-AgNPs demonstrated significant inhibitory effects on human breast cancer cells at non-toxic concentrations such as 0.25 and 0.5 µg/ml. However, at increased concentrations, the lethal effects of AgNPs on breast cancer cells were higher than Bio-AgNPs. When cytotoxic and anticancer characteristics of Cumin extract were investigated, it was established that it did not show any inhibitory effect on J774 cells, while killing the half of MCF-7 cells at investigated concentrations. Interestingly, Cumin extract gave rise to no inhibitory effects against AU565 cells. On the other hand, AgNPs and Bio-AgNPs exhibited considerable anticancer activities on both cell lines. The inhibition percentages of AgNPs on MCF-7 and AU565 cell lines were respectively evaluated as 95% and 97% at the highest concentrations applied (12.5 µg/ml). Similarly, we determined that 87.5% and 96% of MCF-7 and AU565 cells were respectively inhibited when they were exposed to the highest concentrations of Bio-AgNPs. Considering relatively toxic-free features of Bio-AgNPs prepared from Cuminum cyminum L. seed extracts, it can be thought that this formulation will be a pioneer in development of nanotechnology-based new anticancer drug for the treatment of breast cancer in near future.

An overview of nanotechnology-based treatment approaches against Helicobacter Pylori.

Introduction: Helicobacter Pylori (H.Pylori) is a pathogen that infects about 50% of the world's population and is known to be responsible for gastroduodenal diseases such as atrophic gastritis, peptic ulcer and stomach cancer. Nowadays, there is no treatment that ensures complete eradication. In addition, resistance to antibiotics used in the current treatment adversely affects the success rates in the fight against infection. Areas covered: This article take attention to treatment approaches using nanoparticles as an alternative to H.Pylori treatment to cope with increased antibiotic resistance. The purpose of this review is to provide an overview of the current limitations and new promising altenatives in treatment of H.Pylori, to highlight the location of nanotechnology to overcome treatment failures, and to emphasize the advantages of using membrane-coated nanoparticles for the first time. Expert opinion: Because of the current problems in the treatment of H.Pylori, there is increasing interest in alternative approaches including nanotechnology. The strong antibacterial effects of metallic nanoparticles, the advantages of polymeric nanoparticles in drug delivery and drug protection, and the prominent properties of membrane-coated nanoparticles in direct targeting demonstrate the significance of nanotechnology in developing new approaches for treatment of H.Pylori infection.

Current Approaches in Development of Immunotherapeutic Vaccines for Breast Cancer.

Cancer is the leading cause of death worldwide. In developed as well as developing countries, breast cancer is the most common cancer found among women. Currently, treatment of breast cancer consists mainly of surgery, chemotherapy, hormone therapy, and radiotherapy. In recent years, because of increased understanding of the therapeutic potential of immunotherapy in cancer prevention, cancer vaccines have gained importance. Here, we review various immunotherapeutic breast cancer vaccines including peptide-based vaccines, whole tumor cell vaccines, gene-based vaccines, and dendritic cell vaccines. We also discuss novel nanotechnology-based approaches to improving breast cancer vaccine efficiency.

Current aspects in treatment of breast cancer based of nanodrug delivery systems and future prospects.

Breast cancer is one of the most common diseases worldwide. The risk of getting this disease in female is 30% and the mortality rate is 14%. The breast cancer treatment is based on surgery, chemotherapy and radiotherapy. However, an effective treatment method has not been developed. The main cause of failure in the treatment is cancer stem cells metastasis and chemo-resistance. The use of nanocarrier systems against breast cancer stem cells has great importance. Not only advantages of polymeric drug delivery systems are increasing the stability and reduce the side effects of drugs, but also they have disadvantages such as biocompatibility and long-term potential safety. However, in recent years, studies on exosomes provide several advantages. Exosomes usage as nanocarrier do not cause immunological reactions also the drug effectively transport into the cytosol of targeted cell and have more stability characteristics. Although there are studies about various nanocarrier systems in literature against breast cancer but in general, we have not found any review that brings them together and develops a systematic approach to solving the problem. This review mentions prospective new strategies based on various nanocarrier systems and emphasize the importance of exosome based on drug delivery systems in the treatment of breast cancer.

Nigella sativa oil entrapped polycaprolactone nanoparticles for leishmaniasis treatment.

This study is the first to investigate the antileishmanial activities of Nigella sativa oil (NSO) entrapped poly-ɛ-caprolactone (PCL) nanoparticles on Leishmania infantum promastigotes and amastigotes in vitro. NSO molecules with variable initial doses of 50, 100, 150, and 200 mg were successfully encapsulated into PCL nanoparticles identified as formulations NSO1, NSO2, NSO3, and NSO4, respectively. This process was characterised by scanning electron microscope, dynamic light scattering, Fourier transform infrared, encapsulation efficiency measurements, and release profile evaluations. The resulting synthetised nanoparticles had sizes ranging between 200 and 390 nm. PCL nanoparticles encapsulated 98% to 80% of initial doses of NSO and after incubation released approximately 85% of entrapped oil molecules after 288 h. All investigated formulations demonstrated strong antileishmanial effects on L. infantum promastigotes by inhibiting up to 90% of parasites after 192 h. The tested formulations decreased infection indexes of macrophages in a range between 2.4- and 4.1-fold in contrast to control, thus indicating the strong anti-amastigote activities of NSO encapsulated PCL nanoparticles. Furthermore, NSO-loaded PCL nanoparticles showed immunomodulatory effects by increasing produced nitric oxide amounts within macrophages by 2-3.5-fold in contrast to use of free oil. The obtained data showed significant antileishmanial effects of NSO encapsulated PCL nanoparticles on L. infantum promastigotes and amastigotes.

Problems in Stem Cell Therapy for Cardiac Repair and Tissue Engineering Approaches Based on Graphene and Its Derivatives.

BACKGROUND: Today, coronary artery disease is still one of the most important causes of mortality despite advanced surgical methods, pharmacotherapies and organ transplantation. These treatment modalities are intended to prevent further progression of myocardial infarction and do not involve the repair of the damaged part. Therefore, stem cell therapy has emerged as a new approach for the treatment of coronary artery disease. However, there are some restrictions that limit the use of these cells for desired repair. The leading limitation is that newly formed cardiomyocytes do not provide electrical integrity with local cells. OBJECTIVE: In this paper, we review the difficulties that limit the use of stem cell therapy in cardiac repair and emphasize the importance of the integration of stem cell with tissue scaffolds with conductivity. Furthermore, significance of using graphene scaffolds in cardiac tissue engineering is highlighted due to its conductivity features. RESULT: Recently, the fabrication of tissue scaffoldings has made it possible to create a biomimetic cellular environment while providing a new approach to solving these problems in treatment. Especially, the integration of stem cell therapy with graphene-based tissue scaffolds with electrical conductivity, is one of the promising new strategies to turn the success of two approaches of tissue engineering into synergistic effect in cardiac repair. CONCLUSION: Literature analysis has demonstrated that there are some limitations in use of stem cell therapy for successful treatment of cardiac repair and graphene-based tissue engineering approaches which are promising to solve these problems in the near future.

Comparative study on the antileishmanial activities of chemically and biologically synthesized silver nanoparticles (AgNPs).

The present study was conducted to investigate the antileishmanial activity of biogenic silver nanoparticles (AgNPs) compared to chemically synthesized AgNPs. A nano dimension size (10-15 nm) biogenic AgNPs was produced and characterized by UV-Vis spectroscopy and X-rays diffraction. The chemically synthesized AgNPs was recovering from our previous study with a nanoparticle (NP) size in the range of 10-40 nm. The antileishmanial activities were investigated through 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide cell viability assay. The infectivity was determined by Giemsa staining of the infected macrophages cells. Nitric oxide (NO) accumulation was measured by Griess reagent using NaNO2 as a positive control. After 24 h of exposure with nanoparticles (NPs), a concentration-dependent growth inhibition was observed. The IC50 values were determined against promastigotes of L. infantum as 19.42 ± 2.76 µg/ml for leaves aqueous extract mediated AgNPs, 30.71 ± 1.91 µg/ml for stem mediated AgNPs and 51.23 ± 2.20 µg/ml for chemically synthesized AgNPs. It was also detected that all types of NPs produced NO at a significant level. However, the production of a high-level of NO in the biologically synthesized NPs activated macrophage cells, infected with L. infantum promastigotes indicates that NO radicals are mainly responsible for induced cell death and a decrease in the pathogenicity of the parasites. Since, biogenic nanoparticles are cost-effective, eco-friendly, simple to synthesize, and more effective than chemically synthesized silver nanoparticles, therefore, it could be used as a potential alternative for the development of antileishmanial drugs.

Meglumine antimoniate-TiO2@Ag nanoparticle combinations reduce toxicity of the drug while enhancing its antileishmanial effect.

Currently, the treatment of leishmaniasis is increasingly insufficient as current antileishmanial drugs have many disadvantages such as toxic side effects, high cost, and growing drug resistance. In order to overcome these disadvantages, researchers have recently focused on combination therapy by using pentavalent antimonials in conjunction with other antileihmanial compounds. Our previous study found that TiO2@Ag nanoparticles (TiAgNps) demonstrated significant antileishmanial effects. However, a lethal dose of TiAgNps on L. topica promastigotes was found to be toxic for macrophage cells. Moreover, non-toxic concentrations of TiAgNps were ineffective in inhibiting L. topica promastigotes and amastigotes. Thus, we propose the use of TiAgNps in combination with other antileishmanial compounds like meglumine antimoniate (MA) at non-toxic concentrations, which may increase the efficacies of both agents and decrease their toxicities. Therefore, the aim of this study was to determine in vitro and in vivo antileishmanial efficacies of TiAgNps-MA combinations at non-toxic concentrations and develop a new approach for treatment that lowers the toxicities of pentavalent antimonials to minimal levels and enhances their effectiveness. In vitro screening was performed on L. topica promastigote and amastigote-macropage culture by using MTT assay to determine proliferation, perform infection index analysis, and to conduct a Griess reaction for nitric oxide production, while in vivo antileishmanial assays were applied on Balb/c mice with CL models. The results demonstrated that combinations including TiAgNps and MA at non-toxic concentrations were highly efficacious against both promastigotes and amastigotes, while MA application alone did not show any inhibitory effects. It was determined that combination applications decreased the proliferation of L. topica promastigotes 2- to 5-fold in contrast to use of MA alone, and was dependent on concentrations. Moreover, the use of combinations led to inhibition of L. topica amastigotes at rates ranging between 80% and 95%. Additionally, combinations were found to decrease metabolic activities of each form of the parasite at ranges between 7- to 20-fold, causing programmed-cell death and stimulation of macrophages for intensive production of nitric oxide, which is accepted as an important antileishmanial agent (p<0.05). Furthermore, Σ FIC analysis demonstrated that the tested combinations composed little additive, but mostly synergistic effects for inhibition of promastigotes and amastigotes. According to in vivo screening results, the combinations displayed high antileishmanial activities by successfully healing lesions and significantly reducing parasite burdens. Combined, these results show that TiAgNps-MA combinations were much more effective than use of MA alone at non-toxic concentrations and they possess high potential for development of new antileishmanial drugs to fight against leishmaniasis.