Sandhanasamy Devanesan

In vivo and in vitro effectiveness of Azadirachta indica-synthesized silver nanocrystals against Plasmodium berghei and Plasmodium falciparum, and their potential against malaria mosquitoes

Malaria transmission is a serious emergence in urban and semiurban areas worldwide, becoming a major international public health concern. Malaria is transmitted through the bites of Anopheles mosquitoes. The extensive employ of synthetic pesticides leads to negative effects on human health and the environment. Recently, plant-synthesized nanoparticles have been proposed as highly effective mosquitocides. In this research, we synthesized silver nanoparticles (AgNP) using the Azadirachta indica seed kernel extract as reducing and stabilizing agent. AgNP were characterized by UV-vis spectrophotometry, SEM, EDX, XRD and FTIR spectroscopy. The A. indica seed kernel extract was toxic against Anopheles stephensi larvae and pupae, LC50 were 232.8ppm (larva I), 260.6ppm (II), 290.3ppm (III), 323.4ppm (IV), and 348.4ppm (pupa). AgNP LC50 were 3.9ppm (I), 4.9ppm (II), 5.6ppm (III), 6.5ppm (IV), and 8.2ppm (pupa). The antiplasmodial activity of A. indica seed kernel extract and AgNP was evaluated against CQ-resistant (CQ-r) and CQ-sensitive (CQ-s) strains of Plasmodium falciparum. IC50 of A. indica seed kernel extract were 63.18μg/ml (CQ-s) and 69.24μg/ml (CQ-r). A. indica seed kernel-synthesized AgNP achieved IC50, of 82.41μg/ml (CQ-s) and 86.12μg/ml (CQ-r). However, in vivo anti-plasmodial experiments conducted on Plasmodium berghei infecting albino mice showed moderate activity of the A. indica extract and AgNP. Overall, this study showed that the A. indica-mediated fabrication of AgNP is of interest for a wide array of purposes, ranging from IPM of mosquito vectors to the development of novel and cheap antimalarial drugs.

Fabrication of nano-mosquitocides using chitosan from crab shells: Impact on non-target organisms in the aquatic environment

Mosquitoes are arthropods of huge medical and veterinary relevance, since they vector pathogens and parasites of public health importance, including malaria, dengue and Zika virus. Currently, nanotechnology is considered a potential eco-friendly approach in mosquito control research. We proposed a novel method of biofabrication of silver nanoparticles (AgNP) using chitosan (Ch) from crab shells. Ch-AgNP nanocomposite was characterized by UV-vis spectroscopy, FTIR, SEM, EDX and XRD. Ch-AgNP were tested against larvae and pupae of the malaria vector Anopheles stephensi obtaining LC50 ranging from 3.18 ppm (I) to 6.54 ppm (pupae). The antibacterial properties of Ch-AgNP were proved against Bacillus subtilis, Klebsiella pneumoniae and Salmonella typhi, while no growth inhibition was reported in assays conducted on Proteus vulgaris. Concerning non-target effects, in standard laboratory considtions the predation efficiency of Danio rerio zebrafishes was 68.8% and 61.6% against I and II instar larvae of A. stephensi, respectively. In a Ch-AgNP-contaminated environment, fish predation was boosted to 89.5% and 77.3%, respectively. Quantitative analysis of antioxidant enzymes SOD, CAT and LPO from hepatopancreas of fresh water crabs Paratelphusa hydrodromous exposed for 16 days to a Ch-AgNP-contaminated aquatic environment were conducted. Notably, deleterious effects of Ch-AgNP contaminating aquatic enviroment on the non-target crab P. hydrodromous were observed, particularly when doses higher than 8-10ppm are tested. Overall, this research highlights the potential of Ch-AGNP for the development of newer control tools against young instar populations of malaria mosquitoes, also highlighting some risks concerned the employ of nanoparticles in aquatic environments.

Green synthesis of silver nanoparticles using Pimpinella anisum seeds: antimicrobial activity and cytotoxicity on human neonatal skin stromal cells and colon cancer cells

Background The present study focused on a simple and eco-friendly method for the synthesis of silver nanoparticles (AgNPs) with multipurpose anticancer and antimicrobial activities. Materials and methods We studied a green synthesis route to produce AgNPs by using an aqueous extract of Pimpinella anisum seeds (3 mM). Their antimicrobial activity and cytotoxicity on human neonatal skin stromal cells (hSSCs) and colon cancer cells (HT115) were assessed. Results A biophysical characterization of the synthesized AgNPs was realized: the morphology of AgNPs was determined by transmission electron microscopy, energy dispersive spectroscopy, X-ray powder diffraction, and ultraviolet-vis absorption spectroscopy. Transmission electron microscopy showed spherical shapes of AgNPs of P. anisum seed extracts with a 3.2 nm minimum diameter and average diameter ranging from 3.2 to 16 nm. X-ray powder diffraction highlighted the crystalline nature of the nanoparticles, ultraviolet-vis absorption spectroscopy was used to monitor their synthesis, and Fourier transform infrared spectroscopy showed the main reducing groups from the seed extract. Energy dispersive spectroscopy was used to confirm the presence of elemental silver. We evaluated the antimicrobial potential of green-synthesized AgNPs against five infectious bacteria: Staphylococcus pyogenes (29213), Acinetobacter baumannii (4436), Klebsiella pneumoniae (G455), Salmonella typhi, and Pseudomonas aeruginosa. In addition, we focused on the toxicological effects of AgNPs against hSSC cells and HT115 cells by using in vitro proliferation tests and cell viability assays. Among the different tested concentrations of nanoparticles, doses < 10 µg showed few adverse effects on cell proliferation without variations in viability, whereas doses >10 µg led to increased cytotoxicity. Conclusion Overall, our results highlighted the capacity of P. anisum-synthesized AgNPs as novel and cheap bioreducing agents for eco-friendly nanosynthetical routes. The data confirm the multipurpose potential of plant-borne reducing and stabilizing agents in nanotechnology.

Genetic deviation in geographically close populations of the dengue vector Aedes aegypti (Diptera: Culicidae): influence of environmental barriers in South India

Mosquitoes are vectors of devastating pathogens and parasites, causing millions of deaths every year. Dengue is a mosquito-borne viral infection found in tropical and subtropical regions around the world. Recently, dengue transmission has strongly increased in urban and semiurban areas, becoming a major international public health concern. Aedes aegypti (Diptera: Culicidae) is a primary vector of dengue. Shedding light on genetic deviation in A. aegypti populations is of crucial importance to fully understand their molecular ecology and evolution. In this research, haplotype and genetic analyses were conducted using individuals of A. aegypti from 31 localities in the north, southeast, northeast and central regions of Tamil Nadu (South India). The mitochondrial DNA region of cytochrome c oxidase 1 (CO1) gene was used as marker for the analyses. Thirty-one haplotypes sequences were submitted to GenBank and authenticated. The complete haplotype set included 64 haplotypes from various geographical regions clustered into three groups (lineages) separated by three fixed mutational steps, suggesting that the South Indian Ae. aegypti populations were pooled and are linked with West Africa, Columbian and Southeast Asian lineages. The genetic and haplotype diversity was low, indicating reduced gene flow among close populations of the vector, due to geographical barriers such as water bodies. Lastly, the negative values for neutrality tests indicated a bottle-neck effect and supported for low frequency of polymorphism among the haplotypes. Overall, our results add basic knowledge to molecular ecology of the dengue vector A. aegypti, providing the first evidence for multiple introductions of Ae. aegypti populations from Columbia and West Africa in South India.

Fluorescence spectral classification of iron deficiency anemia and thalassemia

Abstract. Thalassemia (Thal), sickle cell anemia, and iron deficiency anemia (IDA) are the most common blood disorders in many parts of the world, particularly in developing countries like India and Bangladesh. The well-established diagnostic procedure for them is the complete blood count (CBC); however, there is substantial confusion in discrimination between Thal and IDA blood samples based on such CBC. We propose a new spectral technique for reliable classification between the above two anemias. This is based on the identification and quantification of a certain set of fluorescent metabolites found in the blood samples of patients of Thal and IDA.

Rapid Biological Synthesis of Silver Nanoparticles Using Plant Seed Extracts and Their Cytotoxicity on Colorectal Cancer Cell Lines

In this research we focused on the green synthesis of silver nanoparticles (AgNPs) using Pimpinella anisum seed extract. Furthermore, we evaluated their cytotoxicity on colorectal cancer (CRC) cell lines. Our results revealed the anti-cancerous cytotoxic potential of green synthesized AgNPs. Green synthesized AgNPs exhibited high cytotoxicity on colorectal adenocarcinoma CRC cells. They selectively killed cancer cells through suppression of proliferation, cell cycle arrest at the G2/M phase, and induction of apoptosis. Interestingly, between the two different clones, SW620 cells were more sensitive than HCT8 cells. Overall, our findings suggest that AgNPs could be effective cancer chemotherapeutic agents or a combination nano-drug in future anti-cancer therapy.

Spectral detection of sickle cell anemia and thalassemia.

Sickle cell disease (SCD) and thalassemia (Thal) are the most common inherited, autosomal, recessive blood disorders which lead to complications such as vasoocclusion and splenomegaly. Patients who suffer from these diseases have poor quality of life and shorter life span. The most common techniques for detection of these diseases are complete blood cell count, followed by electrophoresis and high performance liquid chromatography. In this connection, the results of this paper indicate the potential of a new technique, based on spectral analysis of blood plasma and cellular components, to detect SCD and Thal with accuracy of 90% and above. To the best of our knowledge this would be the first report on spectral pathology of hemoglobinopathy.

Smoking Induced Hemolysis: Spectral and microscopic investigations

Smoking is one of the major causes of lifestyle associated mortality and morbidity such as cancer of the oral cavity and lungs, and also cardiovascular diseases. In this study, we have provided evidences for the smoking-induced hemolysis using two methods: spectra of blood components and atomic force microscopic analysis of surface morphology. A total of 62 subjects (control = 31; smoker = 31: 21 male; 10 female in each set) were considered for the study. The findings indicate that smoking leads to potholes on the surface, swelling of shape, rupturing of erythrocytes, removal of hematoporphyrin and flushing into the plasma as metabolites of the erythrocyte. The overall morphology of the erythrocytes of the smoker group appears more like a Mexican hat. The mean surface roughness was 5.5 ± 3 nm for the smoker group, but 1.2 ± 0.2 nm for the control group. Such damages might help the toxins, (CO, peroxidants, aldehydes etc.,) to gain easy access and get strongly absorbed by the hemoglobin, leading to enhanced rates of hemolysis as shown by the spectral features of metabolites. This indicates that the average life span of the smoker’s erythrocytes is significantly less than that of the control group.

Optical Biopsy of Benign and Malignant Tissue by Time Resolved Spectroscopy

Pathological condition of malignant tissue could be analyzed by spectral domain or time domain spectroscopy, the two being the complementary to each other in optical biopsy (OB) of cancer. This paper reports results of time resolved emission spectroscopy (TRS) of 24 excised tissue samples of breast and prostate (normal control = 12; benign = 4; malignant = 8), employing a 390 nm, 100 fs, Ti-Sapphire laser pulses. The fluorescence decay times were measured using streak camera and the resultant data were fitted for single and bi-exponential decays with reliability of 97%. Our results show the distinct difference between normal, benign and malignant tissues mostly due to the emission spectra of Nicotinamide Adenine Dinucleotide (NADH), Flavin Mononucleotide (FAD) and also due to the heterogeneity of micro environments associated with the diseased tissues. In this short report, fit is also shown that TRS of breast tissues are similar to those of prostate tissues.

Optical biopsy of breast cancer tissue

In this paper, we report results of Fluorescence Emission Spectra (FES) and Stokes Shift Spectra (SSS) of 19 cancer tissue of invasive ductal carcinoma of different grades in comparison with normal breast tissues (obtained away from tumor regions). We were able to get distinct differences in the spectral features of normal and malignant tissues in terms of the ratios of concentrations of biomolecules like tryptophan, collagen and NADH. The sensitivity and specificity were in the range of 75%. What was all the more important was the parallelism in the spectral features of normal and malignant breast tissue pieces of above set of subjects. The objective of our research is to evolve one such protocol and the first step is the spectral characterization of in vitro optical analyses of excised tumor tissues.