|SPOTLIGHTS ON NEW PUBLICATIONS
|Year : 2014 | Volume
| Issue : 2 | Page : 140-142
Spotlights on new publications
Sherif M Abaza MD
Department of Parasitology, Faculty of Medicine, Suez Canal University, Ismailia, Egypt
|Date of Submission||06-Nov-2014|
|Date of Acceptance||12-Nov-2014|
|Date of Web Publication||19-Jan-2015|
Sherif M Abaza
Department of Parasitology, Faculty of Medicine, Suez Canal University, Ismailia
Source of Support: None, Conflict of Interest: None
|How to cite this article:|
Abaza SM. Spotlights on new publications. Parasitol United J 2014;7:140-2
| Nanotechnology|| |
About 30 years ago, nanotechnology started with the birth of cluster science. Reduction of certain materials from the macroscale to the nanoscale radically changes some of their properties. For example, gold becomes a liquid at room temperature, silicon turns into a conductor instead of an insulator, and aluminum becomes combustible. The synthesis and properties of semiconductor nanocrystals were studied leading to discovery of a number of metal and metal oxide nanoparticles (NPs). This was followed by development of nanomedicine with its applications in diagnosis and monitoring as well as treatment and control of biological systems. In the last decade, a strong emphasis has been given to the research and applications in the area of nanomedicine to bring advancement in the diagnosis and treatment of multiple diseases including cancer. One of the focuses of nanotechnology is formulating therapeutic agents in biocompatible, polymeric, and submicron-sized nanocomposites such as NPs, nanocapsules, micellar systems, and conjugates. The use of NPs is gaining impetus in the present century as they possess defined chemical, optical, and mechanical properties.
In contrast, chitosan is a natural polysaccharide that has attracted significant scientific interest during the last two decades. It is a potential biologically compatible material that has chemically versatile NH 2 groups and various molecular weights. These two basic properties have been used by drug delivery and tissue engineering scientists to create a plethora of formulations and scaffolds that show promise in healthcare. There has been a growing interest in the modification and application of chitosan in medical and health fields. Chitosan has been the material of choice for the preparation of several NPs in various applications because of its biodegradable and nontoxic properties.
In parasitic diseases, nanotechnology has three main applications: diagnosis, treatment, and vaccination. (a) Diagnosis: with recent technology and determination of the atomic structure of many proteins, cellular nanometer domain became accessible, and cellular protein molecules were organized in complexes. Meanwhile, atomic force microscope, scanning tunneling microscope, and scanning acoustic microscope fastened the use of nanotechnology in diagnosis. Atomic force microscope is a very high-resolution microscopy (more than 1000 times better than the optical diffraction limit) and one of the foremost tools for imaging, measuring, and manipulating matter at the nanoscale. Scanning tunneling microscope is a powerful instrument for imaging surfaces at the atomic level. With its high resolution, individual atoms within materials are routinely imaged and manipulated. Scanning acoustic microscope is a powerful device in detection of voids, cracks, and delamination within microelectronic packages. Therefore, it provides data on cell and tissue elasticity, giving useful information on the physical forces holding structures in a particular shape. For example, diagnosis of malaria could be achieved by generated images that revealed hemoglobin degradation and also by loss of membrane elasticity in infected red blood corpuscles. (b) Treatment: liposomes and microspheres are considered the most extensively studied carriers for drug delivery systems. Liposomes are nanosize artificial vesicles of spherical shape that can be produced from natural phospholipids and cholesterol. NPs, such as liposomes, are of great importance for drug delivery as drug carriers. Parasitic diseases such as malaria, schistosomiasis, visceral leishmaniasis, African and American trypanosomiasis, filariasis, and toxoplasmosis represent a significant global burden and pose a great challenge to drug discovery due to their intracellular nature and/or disseminated locations. The available drugs are facing the problem of side effects, toxicity, unavailability, high cost as well as resistance of parasite due to high drug dose. For example, in toxoplasmosis, specific antibodies are coated with gold nanospheres, which are laser-irradiated causing the nanospheres to heat up and kill Toxoplasma gondii. (c) Vaccination: NPs are attractive tools to optimize vaccine development because design variables can be tested individually or in combination. Optimization of these variables is important for the development of NP-based vaccine systems against infectious diseases and cancer. Dendritic cells are responsible for representing an antigen to B and/or T cells to activate the immune response against the disease. The scientists used NPs to carry the antigen to dendritic cells for two important characters: its tiny size to cross the skin's extracellular matrix and its coating mimics bacteria cell wall, causing the complement system to be activated. For example, in visceral leishmaniasis, expression of an antigen or antigens from plasmid DNA elicited both humoral and cellular immune responses. Therefore, development of NPs as delivery systems for DNA vaccines is a hopeful approach in vaccine development.
In contrast, herbal medicine was not considered for development as novel formulations due to lack of scientific justification and processing difficulties. However, NPs, in synthesized natural products, can solve incorporation of herbal medicine in novel drug delivery system. Improving delivery techniques that minimize toxicity and improve efficacy offers new markets for pharmaceutical and drug delivery companies. Novel drug delivery systems not only reduce the repeated administration to overcome noncompliance, but also help to increase the therapeutic value by reducing toxicity and increasing the bioavailability. Besides, it will be of lower cost in case of using herbs. Finally, NPs using traditional alternative medicine represents an important and timely opportunity for progress in promoting integrative public health in both developed and developing nations.
The previous introduction was compiled from: (1) Bell IR, Schwartz GE, Boyer NN, Koithan M, Brooks AJ. Advances in integrative nanomedicine for improving infectious disease treatment in public health. Eur J Integr Med; 2013; 5(2): 126-140. (2) Devi VK, Jain N, Valli KS. Importance of novel drug delivery systems in herbal medicines. Pharmacogn Rev; 2010, 4(7): 27-31, and (3) El-Tonsy MMS. Nanotechnology and nanomedicine applications in parasitic diseases. PUJ; 2010; 3(1-2): 19-26.
The present spotlights compiles two recent publications that focus on the efficacy of the NPs on toxoplasmosis and green nanotechnology on mosquitoes control.
In the parasitological field, chitosan NPs have been studied for their antiparasitic effects against giardiasis with mild protection. It was also reported that it improved the antifilarial activity of ivermectin and prevented red blood corpuscle's invasion by malarial parasites in experimental models. Meanwhile, metallic NPs are most promising as they show good antibacterial properties due to their large surface area to volume ratio, which is coming up as the current interest for researchers due to the growing microbial resistance against metal ions, antibiotics, and the development of resistant strains. Different types of metallic NPs such as copper, zinc, titanium, magnesium, gold (Au), alginate, and silver (Ag) have come up. AgNPs have proved to be most effective as it has good antimicrobial efficacy against bacteria, viruses, and other eukaryotic microorganisms. Gaafar and colleagues from Alexandria University aimed at evaluating the antiparasitic effectiveness of chitosan and AgNPs singly or combined as prophylaxis and therapy in experimental toxoplasmosis. To achieve their objective, they tested both NPs in two doses (100 and 200 μg/ml) and evaluated three parameters: (a) Parasite density in impression smears of infected organs (liver and spleen), (b) T. gondii tachyzoites changes using light microscopy and scanning electron microscopy, and (c) Estimation of interferon-g. Moreover, the investigators assessed Ag weight in different organs (intestine, liver, kidneys, brain, and lungs) as Ag being a metal might be deposited in vital organs causing harmful effects.
Results revealed that both NPs showed promising anti-Toxoplasma spp. potentials, and combined therapy either preinfection or postinfection was superior to single therapy. The synergistic action between NPs showed the highest degree of effectiveness. In combined therapy, there was statistically significant decrease in parasite density, pronounced degree of deformity, and immobilization of T. gondii tachyzoites as shown from light microscopy and scanning electron microscopic studies, as well as increased interferon-g levels. These results were more or less similar in the used doses. With respect to the weight of tissue Ag, the highest weight was observed in the liver, but all values were within the safe range (less than 9 μg/g body weight). The researchers concluded that these NPs proved their effectiveness against experimental toxoplasmosis and recommended further studies to evaluate lower doses of AgNPs against toxoplasmosis and other parasitic infections.
Chitosan and Ag nanoparticles: promising anti-Toxoplasma agents. Exp Parasitol; 2014, 143: 30-38.
Cinnamon is a small evergreen tree and has both antioxidant and antimicrobial properties. The Indian investigators Namita Soni and Soam Prakash synthesized the AgNPs and AuNPs using the bark cinnamon extract (Cinnamomum zeylanicum) aiming for their use against mosquitoes species vectors for malaria and filarial diseases. After obtaining the bark aqueous extract, it was treated in aqueous solutions of AgNO 3 and HAuCl 4 . Larvae of Culex quinquefasciatus and Anopheles stephensi were collected, reared, and maintained in the laboratory at 25°C and 75 ± 5% humidity. The efficacy of AgNPs and AuNPs synthesized from C. zeylanicum was tested at different concentrations and time intervals for their killing activities against the collected larvae using ultraviolet-visible spectrophotometer and transmission electron microscope. The investigators found that A. stephensi larvae were highly susceptible to the synthesized AgNPs and AuNPs than those of C. quinquefasciatus.
Green nanoparticles for mosquito control. Sci World J; 2014.
| Acknowledgements|| |
I would like to thank Professor Dr. Manar El-Tonsy and Professor Dr. Maha Gaafar from Parasitology Departments, Faculty of Medicine, Ain Shams and Alexandria Universities for their help in preparation of spotlights on new publication of the present issue.
Conflicts of interest
There are no conflicts of interest.