4-Jul-2020: A non-caloric natural sweetener that can make cancer therapy using magnetic nano particles more efficient
Stevioside (STE), isolated from the leaves of Honey yerba and widely used as the non-caloric natural sweeteners, can sweeten our lives in more ways than one, say scientists.
Researchers at the Institute of Nano Science & Technology an autonomous institute of Department of Science and Technology (INST), Government of India in their recent study have found that Stevioside, a natural plant-based glycoside found in leaves of Honey yerba (‘Stevia rebaudiana Bertoni’) when coated on nanoparticles can increase the efficiency of Magnetic hyperthermia-mediated cancer therapy (MHCT).
MHCT method of cancer therapy is based on heating the tumor tissues using magnetic nanoparticles in comparison to the routinely used surfactant moieties (oleic acid and polysorbate-80) and is based on generation of localised heat at the tumour site on exposure to AMF (alternating magnetic field) in the presence of magnetic nanoparticles.
Ruby Gupta and Deepika Sharma in their research published in the International Journal of Hyperthermia showed that coating the nanoparticles with the Stevioside, a biosurfactant not only improved the cellular uptake of the nano-magnets in glioma C6 cancer cells (one of the most common and aggressive form of glial cancer cells) but also enhanced its retention time. The researchers have modified the Stevioside structure to make it more effective as a biosurfactant for magnetic nanoclusters synthesized in the Lab. The Manuscript related to the same was submitted to the Journal of ACS Molecular Pharmaceutics.
The Stevioside coating exhibited significant improvement in the calorimetric hyperthermia activity, through particle size reduction of magnetic nanoparticles, thereby intensifying the magnetic hyperthermia-mediated cancer therapy. Exposure of magnetic nanoparticles to alternating magnetic field leads to temperature rise from 37 to 42−45°C inducing tumour cell death by triggering activation of certain intracellular and extracellular degradation mechanisms.
Controlling the magnetic properties of a nanoparticle efficiently via its particle size to achieve optimized heat under AMF is the critical point for magnetic hyperthermia-mediated cancer therapy. The INST team has shown that the use of stevioside as a promising biosurfactant controls the magnetic properties of Fe3O4 nanoparticles by controlling the particle size.
The hyperthermia output measured in terms of specific absorption rate (SAR), defined as the power dissipation per unit mass of magnetic content (W/g), for Stevioside-coated nanoparticles obtained was 3913.55 W/g Fe which was significantly higher than those for other existing Nano systems at a field strength of 405 kHz and 168 Oe. Stevioside coating increases the switching speed of magnetic spin of synthesized nanomaterial, increasing the thermal fluctuations and resulting in a higher amount of heat generated in comparison to other Nano systems.
Hyperthermia output of nano-magnets reduces dramatically on the agglomeration of nanoparticles. Hence, the INST team developed water-stable nanomaterial with a biomolecule as the surfactant to address two of the main concerns regarding translation of nanotechnology-based strategies to clinical applications -- biocompatibility of the material used and therapeutic response of these nano-systems. Stevioside stands out for being antihyperglycemic, immunomodulatory, and sports antitumor action. Therefore, surface modification of magnetite nanoparticles with stevioside may provide dual targeting of cancer cells, namely with magnetite nanoparticles based cancer therapy and antitumor effect of the stevioside coating onto the particles.
Stevioside-coated nanoparticles also demonstrated successful uptake and highest cellular persistence inside the glioma cells upto 72 h. Thus the research suggests that the nano-magnets are capable of being available inside the cells for a sufficient period (upto at least 72 h) during which further treatment strategies can be employed for cancer therapy, this avoiding the need to re-administer the nanomaterials.
22-May-2020: IASST develops electrochemical sensing platform for detecting carcinogenic & mutagenic compounds in food
Institute of Advanced Study in Science and Technology (IASST), Guwahati, has developed an electrochemical sensing platform for detecting carcinogenic or mutagenic compound N-nitrosodimethylamine (NDMA) and N-nitrosodiethanolamine (NDEA) sometimes found in food items like cured meat, bacon, some cheese, and low-fat milk. It was achieved by developing a modified electrode by immobilizing carbon nanomaterials (carbon dots) in DNA.
The scientists pointed out that with changing food habits of urban Indians, they are exposed to harmful chemicals belonging to Nitrosamine family in cured meats, bacon, some cheese, low-fat dry milk, and fish. Such chemicals include carcinogenic ones like NDMA and NDEA, which may also alter the chemical composition of our DNA. Hence it is important to develop detection techniques to detect them.
Most of the techniques used for detection of Nitrosamine have detection limits in μM. In this study published in the journal ACS Appl. Bio Mater, the scientists, have fabricated an electrochemical biosensor using DNA immobilized on the surface of carbon dots for sensitive and selective detection of N-nitrosamine. The detection limit was determined to be 9.9×10−9 M and 9.6×10−9 M for NDMA and NDEA, respectively.
The electrochemical biosensor platform was developed using the ability of NDMA and NDEA, to alter the DNA. Carbon dots (CDs), a carbon-based nanomaterial, was used, which is already established as a biocompatible and environmentally friendly material. Naturally derived chitosan, (natural biopolymer obtained from the shells of shrimp, lobster, and crabs) is an environment-friendly sustainable material that was used to synthesize CDs.
As this is an electrochemical sensor, electrode was developed by depositing carbon dots (carbon nanoparticles) and then immobilizing bacterial DNA on them. This electrode system was used to measure the current peak. Both NDMA and NDEA alters the chemical structure of DNA present in the electrode, making it more conducting, which ultimately results in the increased current peak.
The scientists took advantage of the fact that out of the base pairs A, T, G, C, Guanine (G) is electrochemically active. In the presence of NDMA, guanine is modified to 6-Omethylguanine or 7-methyl guanine and with NDEA guanine changes to 8-oxoguanine to form DNA adducts. The DNA adducts formed are electrochemically active, which ultimately leads to an increase in peak current in electrochemical set-up, helping in the detection of the chemicals.
Some other structurally similar chemical compounds were also added to check if they can interfere with the system. But as these chemicals cannot alter the DNA sequence, hence they do not affect the system.
4-Jan-2020: Australia first to test new lithium batteries
Monash University researchers have developed the world’s most efficient lithium-Sulphur battery, capable of powering a smartphone for five continuous days. Prototype cells have been developed in Germany. Further testing in cars and solar grids to take place in Australia in 2020. Researchers have a filed patent on the manufacturing process, and will capture a large share of Australia’s lithium chain.
Monash University researchers are on the brink of commercialising the world’s most efficient lithium-Sulphur (Li-S) battery, which could outperform current market leaders by more than four times, and power Australia and other global markets well into the future.
Dr Mahdokht Shaibani from Monash University’s Department of Mechanical and Aerospace Engineering led an international research team that developed an ultra-high capacity Li-S battery that has better performance and less environmental impact than current lithium-ion products.
The researchers have an approved filed patent for their manufacturing process, and prototype cells have been successfully fabricated by German R&D partners Fraunhofer Institute for Material and Beam Technology.
Some of the world’s largest manufacturers of lithium batteries in China and Europe have expressed interest in upscaling production, with further testing to take place in Australia in early 2020.
Professor Mainak Majumder said this development was a breakthrough for Australian industry and could transform the way phones, cars, computers and solar grids are manufactured in the future.
Successful fabrication and implementation of Li-S batteries in cars and grids will capture a more significant part of the estimated $213 billion value chain of Australian lithium, and will revolutionise the Australian vehicle market and provide all Australians with a cleaner and more reliable energy marketed.
Researchers reconfigured the design of Sulphur cathodes so they could accommodate higher stress loads without a drop in overall capacity or performance.
Inspired by unique bridging architecture first recorded in processing detergent powders in the 1970s, the team engineered a method that created bonds between particles to accommodate stress and deliver a level of stability not seen in any battery to date.
Attractive performance, along with lower manufacturing costs, abundant supply of material, ease of processing and reduced environmental footprint make this new battery design attractive for future real-world applications.
This approach not only favours high performance metrics and long cycle life, but is also simple and extremely low-cost to manufacture, using water-based processes, and can lead to significant reductions in environmentally hazardous waste.