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Cost-effective optical probe for Haemoglobin detection

Dielectica traverses through the literature on this topic – and summarizes as they appear.

Correspondence prepared by: Dr. Md Palashuddin Sk, Assistant Professor of Aligarh Muslim University, Uttar Pradesh, India, email: palashuddin.ch@amu.ac.in (12:10:2020, 17:30)

Key Words: Haemoglobin, Carbogenic Dots, luminescence, nanocrystals

Aligarh: Haemoglobin (Hb) is an essential iron-containing protein, which exists in the red blood corpuscles. Hb consists of four iron-porphyrin units (heme) together with the globular protein moiety. Atomic iron encaged into the heme moiety plays a crucial role in transporting molecular oxygen (O2) from the respiratory organs to the different parts of our body through blood and carrying the major portion of carbon dioxide from these parts to the lungs at the same time. The Hb level in blood to the well-functioning of the organism in the human body is 13.0-18.0 g/dL and 12.0- 16.0 g/dL for male and female, respectively [1]. On the contrary, Hb amount below this level solely causes several blood disorder diseases (even fatality) such as thalassemia, anaemia, and leukaemia. Approximately, two billion people (mainly women and children), worldwide suffer from particular anaemia due to the lower level of Hb in blood. The lower level of Hb thus becomes a major issue and hence is of substantial significance for clinical diagnosis purposes. In this regard, the sensitive detection and determination of Hb in clinical diagnostics is essential to assess the extent of blood disorder diseases and to evaluate various intervention programs aimed at control of the same.

There are quite a few analytical methods like electrochemical, colorimetric, and various spectroscopic techniques are generally employed for the detection of Hb in the blood. Unfortunately, most of these techniques require harsh, expensive chemicals, tedious and complicated probe preparation and of low sensitivity detection ability as well.  In this scenario, the luminescent carbogenic dots (Cdots) are paid great attention due to their higher water solubility, biocompatibility, high quantum yield, and excellent optical (stability towards the chemical/physical environment changes such as pH, ionic strength, etc.) and well enough chemical stability.

Following this trend, our Research Group at Aligarh Muslim University, India, has recently developed a Hb sensor from the reaction by-product, which is accidentally isolated during the synthesis of tin oxide (SnO2) nanocrystals [1]. The purified by-product is confirmed as luminescent carbogenic dots which is again produced due to the polymerization and consequent carbonization of the excess of 4,7,10-trioxa-1,13-tridecanediamine (TTDDA). Yet, TTDDA is a hazardous reagent, it is used as a stabilizing agent in metal nanocrystals synthesis [1]. The advantage of such synthesis lies in the fact that the obtained product SnO2 nanocrystals and the reaction side product are environmentally friendly and are produced through the sustainable way. Our Research Group has actually employed the principle of luminescence turn-off property of Cdots with the interaction of Hb to develop a diagnostic method for qualitative and quantitative detection of Hb in the blood. The observed luminescence property of the Cdots remains highly selective towards the detection of a trace amount of Hb. Efficient ground state complexation between Cdots and Hb is solely responsible for the unprecedented selectivity of Cdots towards Hb detection. Keeping in mind the issues of accuracy in the visual detection, economic factors and the portability, we have further developed a fluorescent test strip-based sensing method. The rapid sensing experiment by using the fluorescent test strip has also been studied with the voluntary collection of blood samples, and various interfering chemical substances, proteins, amino acids, metal ions, anions, etc at pH ~7.4 in order to realize the selectivity as well. Upon addition of Hb, the emission intensity of Cdots is drastically reduced; while, in the case of other analytes addition, hardly any reasonable change in the intensity observed, validating the accuracy of the test strip. Test strip-based luminescence turn-off property of Cdots in the presence of Hb further defines their applicability in fabricating portable and inexpensive sensing devices. Even the trace amount of blood present in the human urine is also possible to be detected by this paper-based method, the author stated. The present paper strips based detection technique has advantages over conventional methods (absorption-based spectroscopic methods) because of the portability, cost-effectiveness, time-saving, high sensitivity, ease to measuring Hb, requiring minimum instrumentation and so forth. The user-friendly nature of this technique is quite desirable and beneficial mainly in the remote areas or primary health care centres to monitor the Hb level of patients.

Sources:
[1] F. Arshad et. al., New J. Chem., 44, 6213 (2020)
https://pubs.rsc.org/en/content/articlelanding/2020/nj/d0nj00401d#!divAbstract

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The Nobel Prize in Physiology or Medicine 2020

By Dr. Amaresh Kumar Sahoo, Assistant Professor,Department of Applied Sciences, IIIT Allahabad, India; Email:asahoo@iiita.ac.in

The 2020 Nobel Prize in Physiology or Medicine is awarded to Prof.Harvey J. Alter, Prof.Michael Houghton and Prof.Charles M. Rice “for the discovery of Hepatitis C virus“. This is a blood-borne disease that has been the reason for more than a million deaths and caused a major health problem around the globe. The viral infection is the leading cause of different types of Hepatitis, with some of its forms that remained dormant for years until developed life-threatening symptoms. Much appreciation to Prof. Harvey J. Alter, Prof.Michael Houghton and Prof.Charles M. Rice for their groundbreaking discoveries that led to the identification of causative agent of this blood-borne disease, a novel virus, Hepatitis C Virus. The committee members of the Nobel Assembly at Karolinsky Institute in Stockholm, Sweden issued several statements regarding the revolutionary impact of this pioneering discovery in understanding the causes and cure for chronic Hepatitis. They added, “for the first time in the history, the disease can now be cured and it also raises hope of eradicating the disease caused by Hepatitis C virus from the world population”.

Hepatitis has been a serious threat to human health from ancient times. Hepatitis causes a liver infection that may have serious health issues. This virus is having a longer incubation period within the human body- the time between first exposure and start of the disease – itvaries from 14 to 80 days, with an average incubation period of 45 days.

Infection sources of liver dysfunction and other health issues like fatigue and vomiting. This also causes jaundice characterized by yellow pigmentation of eyes and skin. Moreover, it may cause acute and chronic infections to lead to serious health complications like liver cancer or Cirrhosis. The cases of Hepatitis were seen upsurge rapidly since 1960 due to the increased number of surgeries and multiple blood transfusions. In World Health Organization (WHO) report around 1.34 million deaths mainly due to Hepatitis C virus infections were reported in 2015, which is approximately 63% increase in cases since 1990. Originally only Hepatitis Type A and Hepatitis Type B were known. The discovery of a vaccine for Hepatitis type B partially reduced the risk but chronic liver damage and liver cancer persisted. In the 1970s, Harvey Alter, a senior investigator for the National Institutes of Health in Maryland discovered a new type of Hepatitis Virus while studying the blood transfusion among the patients at the U.S. National Institutes of Health. Later, Michael Houghton, a British Scientist while working for a pharmaceutical firm Chiron then, dedicatedly put the strenuous effort in isolating the genetic sequence of the virus and given a name to this unknown virus as Hepatitis C Virus in 1989. Subsequently, Professor Charles M. Rice consistently worked at the Center for the Study of Hepatitis C as Scientific and Executive Director from 2001 to 2018 at Rockefeller University at New York and provided the final pieces of evidence stating that Hepatitis C Virus alone could cause Hepatitis. This is a RNA virus, which is having envelope glycoproteins such as E1 and E2 on the outside of the viral surface. The hepatitis C virus (HCV) causes hepatitis C, which is contagious in nature, and an infected person may transmit it to a non-infected person via blood contact. Therefore, the transfusions of unscreened blood and blood products or unsterilized medical setups have been found to be the major route of the transmission of HCV infections. It would be mentioned here that different genetic variations (genotypes) are present in the case of HCV strains. Thus, the prescription of the medicines is done based on the genotype of infection of HCV.  Use of combination therapy of recombinant interferon (IFNα) and the nucleoside analogue ribavirin was being recommended initially. However, several side effects and risks factors limit their widespread usages. In this line of interest, the development of drugs was proposed by specifically targeting the viral RNA-dependent RNA polymerase or other vital proteins.

The work of these three Nobel Laureates distinctively characterizes this form of Hepatitis from other clinical entity and found to be caused by an RNA virus of the Flavivirus family, termed as Hepatitis B virus. It is a milestone achievement that paved the way for the introduction of a new screening technique and an effective antiviral drug in medicine that could dramatically reduce the risk of Hepatitis C infection. 

Ref : https://www.nobelprize.org/prizes/medicine/2020/summary/#main-navigation-js

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Earth’s Radiation Belts – What is it and Why do we need to study?

Dielectica traverses through the literature on this topic– and summarizes as they appear.

Correspondence prepared by: Suman Chakraborty, Physical Research Laboratory, Ahmadabad, Gujrat, India, email: suman.chakrabarty37@gmail.com (05:10:2020, 18:30 IST)

Key Words: Magnetosphere, Radiation belts, Space environment, Radiation Belt Storm Probes

Ahmedabad, India: Any planet that has a magnetic field is capable of deflecting charged particles travelling towards it and forms a protective cavity around itself called the magnetosphere. Besides shielding the planet from charged particles, the magnetosphere is also capable of trapping charged particles along magnetic field lines, forming a region called the radiation belts. The Earth’s radiation belts were discovered in 1958 by James Van Allen, a physicist at the University of Iowa using a simple cosmic ray experiment consisting of a Geiger counter and a tape recorder on the first US satellite, Explorer 1. During the flight, radiation levels seemed to increase and then suddenly drop to zero and then again to increase followed by a further sudden drop to zero. What the team soon realized was that regions appearing as zero were really off the scale! These high-radiation regions were mapped and identified as the radiation belts which are now often dubbed as the “Van Allen Radiation Belts” after the name of James Van Allen [1].

So, what are the radiation belts?
The Earth’s radiation belts are two giant donut-shaped regions of magnetically trapped, highly energetic charged particles with the Earth sitting at the center of the “donut hole”. It comprises of an inner belt and an outer belt with a “slot region” separating the two belts [1,2].

The figure shows the Van Allen Radiation Belts with the Earth at its center. We can clearly see a two-belt structure with a region of depleted charged particles in between the two belts. Although numerous studies have been conducted for the past several decades, the most prominent outcomes came since the launch of the Van Allen Probes in 2012. The Van Allen Probes (VAP; 2012 – 2019), initially known as the Radiation Belt Storm Probes (RBSP), were two identical spacecrafts that were deployed to study the Van Allen Radiation Belts. NASA conducted the VAP mission as part of the “Living with a Star” program. It was initially planned for 2 years, but eventually operated for 7 years. The probes showed that the radiation belts are even more complex than previously imagined and the shape of the belts depends on what particles are being studied. Such observations are more important today as our society now relies on more than 800 satellites operating in the radiation belts for communication and navigation. Dr. David Sibeck, VAP mission scientist at NASA’s Goddard Space Flight Center in Maryland, in a 2018 statement said, “Our current technology is ever more susceptible to these accelerated particles because even a single hit from a particle can upset our even smaller instruments and electronics. As technology advances, it’s actually becoming even more pressing to understand and predict our space environment“[1].

Part of interest to study the radiation belts came from its location. It is known that the radiation belts can expand and contract depending on solar activity. During intense solar activity, the belt can expand and even extend over the orbit of the International Space Station (ISS; Orbit height: 408 km). The ISS has been permanently inhabited since 2000, with typical astronauts staying there for six months at a time. In 2015 – 2016, NASA astronaut Scott Kelly and Russian cosmonaut Mikhail Kornienko remained there for almost a year. As astronauts stay in orbit for longer duration, their radiation exposure may also increase, leading to concerns about long-term habitation for astronauts in space. The knowledge of space environment is also necessary to design future spacecrafts in order to prevent them from short out due to an electrical overload that may lead to disruption of communication. All these aspects make the radiation belts a hot topic of research for the space science community. In an August 2016 NASA statement, Dr. Sibeck said, “We study radiation belts because they pose a hazard to spacecraft and astronauts. If you knew how bad the radiation could get, you would build a better spacecraft to accommodate that” [1].

Sources:
[1] https://www.space.com/33948-van-allen-radiation-belts.html
[2] https://www.nasa.gov/mission_pages/rbsp/mission/fun-facts.html

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Nanobot: Futuristic Intelligent Doctor

Dielectica traverses through the literature on this device – and summarizes as they appear.

Correspondence prepared by: Priyanka Bhadra and Chandra Kishore, email: himimimi2006@gmail.com (28th September, 2020 10:20 JST)

Tokyo, Japan: In the year of 1966, the future of nanobots (nano-robot) was first featured in a popular Hollywood Sci-Fi movie, “Fantastic Voyage”. The concept of the movie was a submarine and its crew was shrunken to the size of a microbe in such a way that they can be injected into the bloodstream of an injured scientist whose brain was blocked and stopped working by a deadly blood clot. Based on the reel man’s imagination, the real life scientists have been fascinated by the advancement of technology to do revolutionary innovations in the medical science. The best example is to treat inoperable tumours in the brains with the help of nanobots. Meanwhile, the concept of these nanobots was also introduced in the story lines of other popular Hollywood movies, such as Seven of Nine in Star Trek: Voyager, Innerspace, I Robot, Hulk, Iron Man, Terminator 3, G.I joe-The Rise of Cobra, Ghost in a Shell, The Avengar-Infinity War. Prof. Gao Wei of Carolina Institute of Technology inspired a lot based on the movie “Fantastic Voyage” and developed a microbot that can be guided towards specific parts of the digestive tract to treat the tumours. Even he stated, in the future, a tiny machine would be able to travel inside the human body to sense the particular diseased area, deliver the drugs with high precision, and perform surgery or stimulate the neuron in the brain [1]. The idea of the nanobot was again influenced by a novel “Prey” by Michael Crichton in 2002 where he had mentioned two important terms, “Nanobots” and “Assembler”. Nanobot is a miniaturised robot that performs certain functions, whereas “Assembler” can build new structures and is able to multiply himself if he knows the right blueprint. Soon both of these ideas were merged to form a new thought named as “Grey Goo” which extinguishes all life on earth by multiplying themselves in an uncontrolled manner. The scientific discussions of the novel were essentially argued by two well renowned scientists, Erik Drexler and the Nobel laureate Richard Smalley. Their controversial discussions even gave more in-depth findings on the function of nano machines. Drexler claimed that depending on the equipment this tiny nanomachines could be assembled themselves to move like an organism to do different work properly and could even allow to reproduce further on the addition of a definite mechanism. On the other hand, his hypothesis was strongly opposed by Richard Smalley who had stated the fact that these tiny machines would not work because of Van der Waals forces between the atoms would not allow the machine parts to move. The strong gravitational forces between the matters would not allow independent nanobots to be assembled in small structure, although it could be possible within micro or millimetre sized structures.

There are various components required to build a nanobot including, “shell” (principle component of the machinery system),  “motor” (driving machine), “energy source” (to operate the machine),“sensor” (detect the environment to navigate the machine), and “payload” (a chamber built inside the machine to load the drugs for targeted delivery approach). In current scenario, there are plenty of technological developments are going on throughout the world’s top most research laboratories and it is reasonable to expect that use of nanobots may take a pivotal role for human disease cure in next decade. Prof. Sun and his team from Beijing’s Tsinghua University have developed a 3D printed nanoscale robot (trial version) to repair the meniscus, the thin fibrous cartilage in between knee joints. By targeting drug delivery approach, a small dose of drugs can be reached to the injured knee than a bigger dose of medicine swallowed by mouth [2]. Dr Jinxing Li, Post Doctorate Fellow at Standford University developed a drug delivery system based on micromotors powered by stomach acid [3]. In a recent work, scientists from the Arizona State University in collaboration with researchers from the National Center for Nanoscience and Technology (NCNST), of the Chinese Academy of Sciences, have successfully developed a DNA nanobot name as “DNA Origami”. In this study, they have fabricated thrombin (anticoagulating agent) loaded DNA nanobot and injected into the blood stream to shrink the cancer cell by blocking tumour blood flow and ultimately cause cancer cell death [4]. Researchers from Massachusetts Institute of Technology have created cell-sized nanobots that can sense their environment, form cluster together. Moreover, this can be controlled by magnetic field operated from outside. [5] Scientists from the University of Pennsylvania have designed catalytic antimicrobial robots (CARs) which could even eliminate dental plaque via magnetic field operating system [6]. Even many of these nano designs inspired by nature to swim, crawl or walk and they could be powered by heat or electricity within the body. [7] A group of researchers from ITMO University, Russia has discovered a new concept of a drug delivery approach against cancer. Their innovative concept is based on an idea in a “theranostic” approaches (combined effect of therapeutic and diagnostic) on simultaneous diagnostic of a disease [8]. Such DNA based nanobots consist of two parts: a detection one and a therapeutic one. Detection part of the nanobot detects the pathogenic cells in terms of incorrect RNA molecule by chemically binding with substance artificially introduced into the cell. Whereas, the therapeutic part destroys the pathogenic RNA strand to prevent the production of harmful proteins, which inhibits the multiplication of the cancerous cells. In India, a research team from both Maharashtra Institute of Medical Education and Research and MIT World Peace University, Pune have done an excellent in-vitro study on multi component magnetic nanobot designed with chemically

conjugating magnetic Fe3O4 nanoparticles (NPs), anti-epithelial cell adhesion molecule antibody (anti-EpCAM mAb) to multi-walled carbon nanotubes (CNT) loaded with an anticancer drug, doxorubicin hydrochloride (DOX). Their work reveals that the multicomponent nanobot’s design represents a promising strategy in targeted cancer therapy [9]. In other hand, medical professionals/ Surgeons are also constantly looking for minimal invasive ways to treat their patients with faster recovery, as there are usually fewer complications in the postoperative methods. The potential of these nanobots in surgery is huge. Eye surgeons can perform eye surgeries by tiny microneedles injected through a standard needle into the eye and this whole process can be directed by using a specialised magnetic field [10]. For the treatment of cardio vascular diseases, corkscrew chain of iron oxide beads are injected into the bloodstream to clear the blocked arteries (work done by engineers of Drexel University) [11]. Nanobots resembling unfolded cubes made of

elastic polymer grab tissue samples by folding up and collect the sample for biopsies [12]. Nanopatch vaccines made up of thousands of silicon microneedles which offer similar immune response with a smaller dose of vaccine can eliminate the need for refrigeration. Smart bandage made from hydrogel, can be left on infected area until they dissolve and release the antibiotics as needed to heal. Vibrant capsules promote muscle contraction to quick start digestion. Even it treats IBS (irritable bowel syndrome) patients to recover from constipation without any laxatives. In 2001, the first FDA (US. Food and Drug Administration) approved ingestible camera attached smart pill name as PillCam has been launched. Another smart pill developed in US, contains a sensor which fetches the data through a patch worn by the patient. The imprinted App tracks the drug, dosage and time, which can be shared with both doctors and patients. Atmo gas capsules diagnose Gastrointestinal disorder and colon cancer by detecting the levels of oxygen, hydrogen and carbon dioxide, which may enter the capsules through an outsider permeable membrane surrounded it. Even this level of oxygen allows the researchers to navigate the capsule’s location.   It is highly mentioned that by 2024, the global market for nanotech will exceed $125B and by 2025, the global smart pill market will reach $650M [13]. The scenario of medical science is expected to completely change in next decades where indigestible capsules, nanobots containing sensors, cameras, and microprocessor units will be used as a therapeutic approach. In future, surgical nanobots, programmed by a human, may act as an autonomous on-site surgeon inside the human body. These nanobots will help the surgeon’s life easier from the use of surgical tools and may lead to planned treatment with more precision and better execution.

Sources:

  1. Micro/nanorobots for biomedicine: Delivery, surgery, sensing, and detoxification, Jinxing Li, Berta Esteban-Fernández de Ávila, Wei Gao, Liangfang Zhang* and Joseph Wang*, Science Robotics  01 Mar 2017:Vol. 2, Issue 4, eaam6431, DOI: 10.1126/scirobotics.aam6431
  2. https://www.todayonline.com/these-tiny-robots-are-turning-science-fiction-medical-reality
  3. Micromotor-enabled active drug delivery for in vivo treatment of stomach infection BEF de Ávila, P Angsantikul, J Li, MA Lopez-Ramirez, Nature communications 8 (1), 1-9
  4. Tasciotti, E. Smart cancer therapy with DNA origami. Nat Biotechnol 36, 234–235 (2018). https://doi.org/10.1038/nbt.4095
  5. Nanoparticles take a fantastic, magnetic voyage Tiny robots powered by magnetic fields could help drug-delivery nanoparticles reach their targets. Anne Trafton | MIT News Office Publication Date:April 26, 2019, https://news.mit.edu/2019/nanoparticles-magnetic-robots-0426
  6. Catalytic antimicrobial robots for biofilm eradication, Geelsu Hwang1,*,Amauri J. Paula1,2,*, Elizabeth E. Hunter3, Yuan Liu1, Alaa Babeer1,4, Bekir Karabucak4, Kathleen Stebe5, Vijay Kumar3, Edward Steager3,† and Hyun Koo1,†, Science Robotics  24 Apr 2019: Vol. 4, Issue 29, eaaw2388, DOI: 10.1126/scirobotics.aaw2388
  7. Palagi, S., Fischer, P. Bioinspired microrobots. Nat Rev Mater 3, 113–124 (2018). https://doi.org/10.1038/s41578-018-0016-9
  8. Aleksandr A. Spelkov  Ekaterina A. Goncharova  Artemii M. Savin  Dr. Dmitry M. Kolpashchikov, Bifunctional RNA‐Targeting Deoxyribozyme Nanodevice as a Potential Theranostic Agent,13 January 2020 https://doi.org/10.1002/chem.201905528
  9. Andhari, S.S., Wavhale, R.D., Dhobale, K.D. et al. Self-Propelling Targeted Magneto-Nanobots for Deep Tumor Penetration and pH-Responsive Intracellular Drug Delivery. Sci Rep 10, 4703 (2020). https://doi.org/10.1038/s41598-020-61586-y
  10. https://www.intelligentliving.co/nanobots-swim-eye/
  11. https://www.smithsonianmag.com/innovation/tiny-robots-can-clear-clogged-arteries-180955774/
  12. Yaari, Z., da Silva, D., Zinger, A. et al. Theranostic barcoded nanoparticles for personalized cancer medicine. Nat Commun 7, 13325 (2016). https://doi.org/10.1038/ncomms13325
  13. https://www.roboticsbusinessreview.com/news/infographic-nanobots-and-nanotech-deliver-medicines-future/

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Molecular materials for future solar energetics

Dielectica traverses through the literature on this device – and summarizes as they appear.

Correspondence prepared by: Sourabh Pal, Indian Institute of Technology, Kharagpur, India. Email id: sourabhelt92@gmail.com (24th September, 2020 08:30 IST)

KOLKATA: Portable electronic devices have now become an indispensable part of our life. The conventional electronic systems pervade in every aspect of human life, whether it is mobile phones, televisions, computers, or medical instruments, and many more. Most of electronic devices has been conquered by optoelectronics which can offer the purposes that are not possible with simple electronics. They can transmit information to a much longer distance at a significantly higher rate. Optoelectronic devices engage those electronic devices that engender light, control light, and convert optical signals into electrical ones. Optoelectronics has become the subject matter of extensive research in recent years, leading to the development of various commercial products, such as light emitting diodes (LEDs) for home lightning and display panel in television, semiconductor lasers as emitters, and photodiodes as detectors for application in communication, medical and defense and solar cells as a renewable energy source for electricity production.

While many of these optoelectronic devices are very well developed and industrially feasible, more fundamental research is required to improve their efficiency and reduce the cost. In the past few decades, inorganic materials such as silicon and III-V compound semiconductors are widely used in manufacturing the aforementioned optoelectronic devices. However, complex manufacturing processes of such devices lead to a higher production cost. Additionally, the high temperature fabrication steps required in the manufacturing process of inorganic devices creates several difficulties for industrializations. Hence, as a savior of current research society, the researchers have discovered a new class of semiconducting materials: the hybrid organic inorganic metal halide perovskites which have been extensively explored for application in optoelectronic devices owing to the extraordinary electrical and optical properties. These materials are expected to benefit from the striking features of both inorganic and organic materials, such as high charge carrier mobility and low temperature processing possibility. The research on perovskite based devices has experienced rapid growth since the last decade.

The perovskite (CaTiO3) is a kind of mineral, which was first identified by Russian mineralogist Gustav Rose in 1839 while performing mineralogical studies at Ural mountains. The mineral was named “perovskite” in the honor of Russian mineralogist Count Lev Aleksevich Von Perovski (1792–1856)[1]. Thereafter, the materials with the crystallographic structure similar to the CaTiO3, like ABX3 are referred to as perovskite. Here ‘A’ denote positively charged large atomic or molecular cations situated at the center of the cube, ‘B’ atoms also of positive charges located at the corners of the cube, and X is an anion (negatively charged) smaller in size, placed at the faces of the cube. The fascinating properties such as ambipolar charge transport, high charge mobility, large absorption coefficients, band-gap tunability, lower exciton binding energy, large diffusion length resulted in the incredible attention in perovskites and their promising applications, ranging from solar cell, novel lasers, photo detectors to field effect transistors among others. During the past few years, it has been observed that the conventional perovskite based materials exhibit excellent photoluminescence quantum yields with tunable light emission property over the entire visible spectral range. Utilizing these exciting luminescence properties, Prof. Zheng and his group from Nanjing University of Science and Technology, China fabricated highly efficient LED devices in 2015, from which the new era of quantum LEDs (QLED) has been commenced [2]. The gradual increment of the efficiency of electricity-driven LEDs has been updated every year, which makes the practical application much more feasible. Prof. Wang and a research team of Penn State researchers made the discovery while synthesizing perovskite materials for use in next generation solar cells [3]. Perovskites with a crystal structure good at absorbing visible light are an area of focus in developing both rigid and flexible solar cells that can compete commercially with traditional cells made with silicon. These 2D perovskite materials are cheaper to fabricate than silicon and can be equally efficient at absorbing sunlight. The material offers power conversion efficiencies similar to silicon solar cells but can also be used to develop flexible semi-transparent and light-weight cells appropriate for applications in buildings and a variety of urban spaces. In 2019, a group of Steve Albrecht from Helmholtz Young Investigator Group (YIG) at HZB (Helmholtz-Zentrum Berlin) and Bernd Stannowski from the HZB Institute PVcomB (Competence Centre Photovoltaics Berlin) have developed a tandem solar cell made of the semiconductors perovskite and silicon that converts 29.15 per cent of the incident light into electrical energy [4]. These are the highest recorded values reported for scalable perovskite solar cells. Recently, NASA stated that a quick way to secure a reliable supply of electricity for an extended stay on the Moon or Mars would use an ink-jet-like printer to make super-thin solar cells from perovskites [5]. This can undoubtedly open up a new pathway towards science and technology. Hence, the remarkable potential demonstrated by the perovskites could lead to a breakthrough in optoelectronics technology. Innovative research on perovskite based devices would further contribute towards the development of a sustainable and accessible electronic world.

Sources:

  1. “Perovskite: Name Puzzle and German-Russian Odyssey of Discovery” by Eugene A. Katz; DOI: 10.1002/hlca.202000061.
  2. “Quantum Dot Light-Emitting Diodes Based on Inorganic Perovskite Cesium Lead Halides (CsPbX3 )”, Adv. Mater. 2015, 27, 7162–7167; DOI: 10.1002/adma.201502567.
  3. “Distinct conducting layer edge states in two-dimensional (2D) halide perovskite”, Science Advances, 2019; 5 (7); DOI: 10.1126/sciadv.aau324.
  4. “Highly efficient monolithic perovskite silicon tandem solar cells: analyzing the influence of current mismatch on device performance”, Sustainable Energy & Fuels, 2019, 3, 1995–2005; DOI: 10.1039/c9se00120d.
  5. “Building Solar Panels in Space Might be as Easy as Clicking Print”, NASA; Website: www.nasa.gov/feature/glenn/2019/building-solar-panels-in-space-might-be-as-easy-as-clicking-print.
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Harnessing the Power of Atoms: India’s journey of pride and glory

Dielectica traverses through the literature on this device – and summarizes as they appear.

Correspondence prepared by: Aakash Hossain, School of Materials Sciences and Nanotechnology, Jadavpur University (23rd September, 2020 08:30 IST)

KOLKATA: The advent of nuclear science and production of atomic energy was started in India under the initiative of a group of scientists led by physicist Dr. Homi Jehangir Bhabha (often referred as “The Indian Oppenheimer”) shortly after the independence of India on 15th August’ 1947. This led to the formation of the Atomic Energy Act in 1948, which created the Indian Atomic Energy Commission, whose purpose was to develop and control the atomic energy to fulfil the necessities connected with it. During that time, the Prime Minister of India, Jawaharlal Nehru believed that India’s nuclear program primarily to be focussed on peaceful applications and not for the creation of any weapons [1]. Although, he later opened the doorway for using nuclear energy to create weapons, for which the nation was compelled to do so. India also opposed the Baruch Plan of the United States [2], which proposed an American monopoly on the control of nuclear energy, on the grounds that such a plan restricted national research and development of atomic energy.

In 1954, the construction of the Bhabha Atomic Research Centre (BARC) at Trombay led to the serious development of India as a nuclear power and eventually BARC became the primary research centre for India’s nuclear energy program. In 1955, Canada collaborated with India by providing a nuclear reactor based on the National Research Experimental Reactor (NRX) at Chalk river, Ontario[3]. The Canada-India Reactor Utility Services (CIRUS) was established thereafter, which completed the project in July 1960. However, most of the plutonium grade weapons, which were produced by CIRUS, were used for India’s first nuclear test. A further agreement was signed at that time with the United States government for providing 21 tons of heavy water for the reactor under the “Atoms for Peace” program [4]. Later on, India designed a pool type reactor in 1955, for which United Kingdom Atomic Energy Authority used to supply uranium fuel elements [5]. The reactor named as Apsara, was inaugurated by Jawaharlal Nehru in 20th January 1957 [6]. Finally, in 1958, a third reactor was designed in Trombay, named as ZERLINA (Zero Energy Reactor for Lattice Investigation and New Assemblies) which was commissioned in 1961[7].

In February 1965, Dr. Bhabha visited Washington DC seeking for an American collaboration through the project Plowshare program, in which India could initiate peaceful nuclear explosions to test her nuclear weapons. But at the end, America went against this nuclear co-operation with India. In the year 1966, physicist Dr. Raja Ramanna took charge as the head of BARC after Dr. Bhabha’s death in a plane crash and became the principal designer behind India’s first nuclear device. India wanted to eliminate the western interference in her journey towards being a nuclear power. In the year 1968, India refused to sign the Nuclear Non-Proliferation Treaty (NPT) which could not differentiate between military and peaceful nuclear explosion and it only recognised the United States, Britain and Soviet Union as nuclear weapon states. In September 1972, under the leadership of Dr. Raja Ramanna and with the approval of Prime Minister, Indira Gandhi, India got the approval for testing her first nuclear device. Finally, on 18th May 1974, BARC tested the first nuclear explosive device weighing 3000 pounds and creating an energy surge equivalent to 8 kilotons of TNT. A team of 75 scientists were involved in the designing of the plutonium device. The test, officially known as Pokhran I, was very often referred as the “Smiling Buddha” [8]. After this test, India lost her support from Canada and the United States of America, who considered it as a violation of the “Atoms for Peace” program. After 1974, India had to face difficulties in procuring nuclear materials from a suddenly hostile international market. Almost two decades went by for preparing a nuclear arsenal which was capable of military deployment. The BARC leadership, after facing all the challenges, constructed its largest nuclear plant till date which is the Dhruva reactor in 1977 at Trombay which reached its full potential by 1988. Consequently, the Defence Research and Development Lab (DRDL) designed short range (Prithvi) and long range (Agni) missiles both of which were equipped with nuclear warheads. During the regime of Prime Minister Atal Behari Vajpayee, India officially became a nuclear state. Five nuclear devices were tested on May 11th 1998 under the Pokhran II series during the period of physicist Dr. Rajagopala Chidambaram as head of BARC. Although not all of them detonated, the energy surge created was equivalent to 45 kilotons of TNT (16 kilotons according to independent sources). After this massive success, India established the National Security Advisory Board, where a no first-use-policy was devised for Indian nuclear weapons. But it was later amended that if any biological or chemical attack initiated against India, these nuclear weapons can be used. In 2005, India signed a civil nuclear agreement with the United States of America, by which India got an access to buy nuclear materials through international suppliers in exchange of which India has to protect the civilian nuclear facilities, which also includes inspection by the International Atomic Energy Agency [9]. To this day, the prime minister of India, Narendra Damodar Modi chairs the Nuclear Command Authority to call for a nuclear strike. The estimated nuclear warheads possessed by India at present are 135. Henceforth, for every Indian it is a matter of pride that India has achieved and still continues to achieve milestones in nuclear research, which not only makes Indian military strong but is also playing an important role in the daily lives of ordinary civilians.

References- 

  1. International nuclear programs- Indian Nuclear program. Atomic Heritage Foundation
  2. The Baruch Plan by Bernard Baruch (June 1946). Atomic Heritage Foundation
  3. 50 year old Research N-Reactor shut down. Outlookindia.com/newswire
  4. Eisenhower’s Atoms for Peace program-Nuclear Power Today. Atomic Heritage Foundation
  5. “India’s First atomic reactor- Science Notes and News” . Current science. August 1956. Retrieved 3rd September 2017
  6. “Apsara Nuclear Reactor”- NTI Nuclear Security Index. Retrieved 12th April 2015. Archived 19th April 2015
  7. “Atomic Research for Asian Welfare”- Press Information Bureau of India. Archived from the original from August 8th 2017 
  8. “Bhabha’s quest for the bomb” by George Perkovich- Bulletin of the Atomic Scientists. Vol. 56 No. 3. Pages 54-63 
  9. U.S.- India: Civil Nuclear Cooperation. Archive of the U.S. Department of State.
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A new generation temperature sensor

Dielectica traverses through the literature on this device – and summarizes as they appear.

Correspondence prepared by: Sayan Bayan, S. N. Bose National Centre for Basic Sciences, Kolkata, sayan.bayan@gmail.com (19th September, 2020 08:30 IST)

KOLKATA: Although the detection of heat and temperature is a fundamental issue, human body temperature sensing has become an essential aspect to aspect of human civilization due to the ongoing COVID 19 pandemic. However, affording highly sensitive thermal scanners is often expensive due to the microfabrication of its sensors. In addition, the use of external power source (e.g. batteries) makes the system more complex as the frequent replacement of these power sources is an obligatory for the users. In this context, researchers have designed cost effective, self-powered heat sensors called electrolyte-assisted temperature sensor (EATS), similar to the conventional thermocouple based ones, but with higher sensitivity1. In the traditional thermocouple sensors, the temperature sensitivity is restricted to tens of microvolts per Kelvin, whereas EATS provides 300 times higher signals and can detect small temperature changes

(0.1 °C). The simple structure composed of concept two different metals connected by a printable gel-like electrolyte, endows EATS not only cost effectiveness but also provides the applicability on rigid as well as flexible platforms by manufacturing methods. These sensors are claimed to be very stable for long time usage. It is anticipated that in near future EATS can replace the commercial thermocouple based sensors following its improved features and performance over the later with low-cost large scale production.

Source: 1 npj Flexible Electronics (2020) 4:23; DOI:10.1038/s41528-020-00086-5

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Futuristic self-powered handwriting pad with handwriting recognition ability

Dielectica traverses through the literature on this device – and summarizes as they appear.

Correspondence prepared by: Sayan Bayan, S. N. Bose National Centre for Basic Sciences, Kolkata, sayan.bayan@gmail.com (14th September, 2020 08:30 IST)

KOLKATA: In everyday life for most of the inhabitant purposes, handwriting based signatures are used to authenticate individuals to maintain security as well as privacy. However, the forgery signature based scams have emerged as a common ground behind many of the big losses in monetary transactions or other security matters in daily life applications. Thus, signature authentication via handwriting recognition is a key challenge and must be addressed by the scientific community seriously.

In this context, the research group of Prof. Zhong Lin Wang from the Georgia Institute of Technology, USA, has come up with a signature identification platform that has promising ability in security defense, and private information protection applications. According to the report recently published in the scientific journal ‘Nano Energy’, Prof. Wang and coworkers have demonstrated the handwriting recognition ability of a device called ‘triboelectric nanogenerator’ that runs without any external power supply.1 Prof. Wang is regarded as the inventor of triboelectric nanogenerator which works in the coupled principle of contact electrification and electrostatic induction.2 In such nanogenerator system, mechanical stimulus induces a current flow and can power up small electronic gadgets.

It is quite obvious that any kind of writing or drawing exerts mechanical pressure on the writing platform and such mechanical pressure can be used to generate electric power leading to a self-powered system. Further, the combination of signal processing and machine learning technologies with a triboelectric nanogenerator endows the ability to recognize the handwriting of different people. The research group has demonstrated that such self-powered writing pads can recognize writings of English words, Chinese characters as well as Arabic numerals with classification accuracies of 99.66%, 91.36% and 93.63%, respectively. It is expected such triboelectric nanogenerator based smart systems can play a vital role for protecting personal information in various segments of modern life in the near future.

Sources:
1Nano Energy 77 (2020) 105174. DOI: 10.1016/j.nanoen.2020.105174
 2Nano Energy 1 (2012) 328. DOI: 10.1016/j.nanoen.2012.01.004

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A glorious journey of India to space: 50 years & ahead

Dielectica dives through India’s milestone events in space science – and summarizes as they appear

Correspondence prepared by: Ayan Dey (7th September, 2020 11:59 IST)

From a simple beginning in the early 1960s, India’s journey to the space has achieved several milestones. These include fabrications and launching of satellites, space vehicles, orbiter missions etc. This dream journey has started when Dr. Vikram Sarabhai, known to be the Father of Indian space programme formed an organization in 1962 named Indian National Committee for Space Research (INCOSPAR). In 1969 the INCOSPAR was renamed as Indian Space Research Organization (ISRO). The Indian Space Research Organizations has completed 50 years of its glorious journey, since its foundation on 15th August, 1969. Its journey started from ARYABHATTA, BALLON experiment, BHASKARA-I, APPLE (India’s first geostationary experimental communication satellite, 1977-83), INSAT-IA, INSAT-IB, PSLV to highly classified missions like Chandrayaan-1, 2 and Mangalyaan (India’s first deep space mission). Today, the annual budget of Indian Space Research Organization (ISRO) is more than 10 thousand crores ($1.45 billion). The people who made it happen with their extraordinary visions and sheer hard work were – Dr. Vikram Sarabhai, U.R. Rao (who had developed

18 satellites (including Bhaskara, APPLE, INSAT and many more)), Rakesh Sharma (the first Indian to venture into space), A.P.J. Abdul Kalam also known as ‘Missile Man of India’ and many others. The most interesting and biggest discovery among all expeditions conducted by ISRO was tracing water on the Moon. Chandrayaan’s Moon Mineralogy Mapper (M3) experiment (2008) has shown evidence of water on the Moon. An even bigger success was India’s first deep space mission to Mars: the “Mars orbiter mission (MOM)” (2014). With that, India became the first country to have ever succeeded in orbiting the Mars after the failures of the US, China and Russia. It was the first major breakthrough after the GSLV Fat Boy failure in 2010.
ISRO has announced its next 10 years plan, consisting of some new mega missions. The most notable one among these is: GAGANYAAN – India’s first ever manned mission, this project will make India the fourth nation in the world to achieve that benchmark. Approximate budget of this mission is INR 10,000 crore and it will be India’s biggest and boldest space mission till date. It is intended to send a maximum of 3 astronauts for a minimum of 7 days by the year of 2022.

This manned-mission spacecraft basically consists of service and crew module, which is collectively known as the orbital module. GSLV MK-III, the three-stage heavy lift launch vehicle will be used for the launch of GAGANYAAN, as it is capable of carrying a high payload capacity for different application fields. This spacecraft is designed to carry 4-ton class of satellites into the Geosynchronous Transfer Orbit (GTO) and about 10 tons to Low Earth Orbit (LEO). Its powerful cryogenic stages help it in placing heavy payloads into the Low Earth Orbit’s 600 km altitude. Due to the huge amount of payloads, it uses two very strong rocket boosters (S200), to produce huge amount of thrust to lift the Spacecraft. Some key points about the GAGAANYAAN are –

  • It consists of two models i.e. crew and service. The crew model, where the three astronauts will be staying, will have a mean diameter of 3.7 m and height 7 m.
  • It will take maximum of 15-16 mins for earth’s parking orbit insertion.
  • It will be placed 300-400 km off the low earth orbit (LEO).
  • The spacesuits for this mission are being developed at the Vikram Sarabhai Space Centre, Bengaluru, India which will be orange in colour.
  • The astronaut can breathe by these space suits for an hour, with the capacity of holding one oxygen cylinder.
  • The astronaut will be able to see the sunrise and sunset and also able to do some experiment about the microgravity with the help of the crew capsule module. This capsule will rotate around the earth for every 90 minutes.
  • After the accomplishment of whole mission, the capsule will land at the coast of Gujarat (maximum 36 hours to land).
  • French Space Agency CNES will assist ISRO in providing expert advice in various fields viz. space medicine, health monitoring of the astronauts etc.

Apart from this, ISRO has planned other classified missions for the near future –
ADITYA-L1: This is basically will going to be ISRO’s first planned mission to study the Sun’s corona and its atmosphere.
MANGALYAAN-2: India’s second mission again to the MARS as an Orbiter-2 (2022 – 23)
CHANDRAYAAN-3: This will be going to the India’s third lunar mission (late 2020s).

VENUS MISSION: It is basically a Venusian mission to study its surface and atmosphere which is Earth’s closest siblings due to their similarities in their sizes (2023 – 25). The proposed satellites for this mission will weight about 175 kg of payloads and 500 watts of power.
Another one, probably the most interesting yet challenging one as we may call it: a dream to have India’s own international space station. This will wind up by 2028. The proposed station will be about 15-20 tonnes hosting people for more than 15 days. As India is moving with the ‘Make in India’ dream, these missions are not very far off from reality. Right from the first launch from an old church at Kerala, India’s journey to space has been quite remarkable throughout the last 50 years and an a member of the Elite Space Club it will also set a milestone for all other developed countries across the globe who are yet to succeed in space.

Reference : INDIA IN SPACE : Harper Collins Publishers India 2020 JJ Imprints Pvt Ltd, Noida, P-ISBN- 978-935-357-641-7

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COVID 19: Another Threatening to Waste Management

By Suman Nandy
Caparica, Portugal.

2020, we are experiencing an unwanted situation that has changed our entire lifestyle. The whole world (more than 213 countries and territories) is affected, impacting all social areas and sectors, reaching from, health to economy.We are habituated with three phrases: “keep safe distance”, “wear your mask” and “sanitize yourself”. Because of the highly contagious parameters, we are concerned about the single use products such as personal protective kit, gloves, face mask and packaging. Right now, health and safety have taken priority over the environment. But this should not be a well practise for sustainable future. A civilization can only exist with their future thoughts.We can live better now, but we must think best for tomorrow.Coronavirus disease 2019 (COVID-19) situation is alarming us, to be careful and prepare for future. We are still not smart that we assume! There is no denying that already the world is in crisis due to overuse of un-recycled product that will end up in landfills and sustain over 100-1000 years. These kinds of unrecycled and unreacted products are affecting the soil, sea and river water that makes a negative effect in environment and living plants and animals. It was reported by European Union that in the Europe, 31kg of plastic packaging waste is produced per person per year in average that adds up to 15.8 million tonnes of plastic packaging waste generated in one year1.Waste plastics are a serious and growing environmental problem. In 2015, the Sustainable Development Goals (SDS) that are set by United Nation to achieve a better and more sustainable future for all by 2030, sustainability, waste management, recycling of product and environment are the concerning factors2.

But the present situation due to COVID-19 pandemic has led to a serious impedimentin waste management progress. Proper management of safety procedure will protect us in this crucial situation of pandemic. But mismanagement and misuse can also lead to another big crisis in environmental pollution. On 1st July 2020, the World Economic Forum reported an article entitled “The plastic pandemic is only getting worse during COVID-19”3. It raises the question of single-use plastics during the pandemic. Mostly, all the countries are facing mismanagement in waste product control. According to the report4,5 in China, medical waste from personal protective equipment like gloves, face masks and eye protection due to a surge in pandemic has raised tremendously from 40 tons per day in normal days to a peak of 247 tonswhich is about six fold.According to the Waste Agency of Catalonia report, the medical waste including masks, gloves, overalls, or davantals, has detected a 350% increment since mid-March which ismostly 925 tonnes more than usual6. According to the Thailand Environment Institute (TEI), plastic waste has increased from 1,500 tons to 6,300 tons per day, due to the frequent owing of home deliveries of food in pandemic situation which is 15%. TEI president Dr.Wijarn said, in Thailand each day, approximately 1.5 million face masks are being used and disposed. In Bangkok, the amount is about 150 tons per day7. With a same trend, in United Kingdom, there has been reported a huge spike in fly-tipping (illegal dumping) in some parts during the coronavirus lockdown.The Countryside Alliance reports approximately of 300% rise in fly-tipping after local authorities closed recycling centres amid the Covid-19 crisis8. Moreover, along with the increment of medical and protective kit wastage, COVID-19 pandemic situation also makes an obstruction on normal waste disposal and recycling system. According to the survey (on 18th May 2020from 95 surveyed communities) by AMORCE (French network for information, sharing of experiences and support for local authorities in the field of energy transition, territorial waste management and water cycle management), 42% of communities have noted a tendency to deposit non-conforming waste in the bins (mixed-waste or separate collections) and 48% noted an upsurge of illegal deposits. Also, an interruption has been noticed for selective waste (such as glass, paper, food waste, bulky waste) collections (door-to-door or bring-banks). Bulky waste and textile collections are the most interrupted which is about 41% 9. This situation is more or less similar in all over the world.

Therefore, specific plans and awareness programs should be carried out by all the countries and associations so that our fight against waste management and environment pollution will come in required track. People should be alerted to maintain selective waste management system. Also, we have to think about the use of biodegradable natural materials which will not make a negative impact on environment.

Author is currently a research investigator in CENIMAT, Department of Materials Science, FCT-Universidad Nova da Lisboa, Caparica, Portugal

References:

1. How much plastic packaging waste do you produce? 22 April 2018; https://ec.europa.eu/eurostat/web/products-eurostat-news/-/EDN-20180422-1?inheritRedirect=true

2. Sustainable Development Goals; https://www.un.org/sustainabledevelopment/sustainable-development-goals/

3. https://www.weforum.org/agenda/2020/07/plastic-waste-management-covid19-ppe/

4. Y. Ma, X. Lin, A. Wu, Q. Huang, X. Li, J. Yan, “Suggested guidelines for emergency treatment of medical waste during COVID-19: Chinese experience”, Waste Disposal & Sustainable Energy2020, 1.

5. Z. H. Si, Y. Li, “Medical waste treatment in Wuhan from emergency to stability,” Xin Hua Net (2020); www.xinhuanet.com/local/2020-04/01/c_1125796126.htm [in Chinese]

6. The Catalan Waste Agency has established different options to treat sanitary waste in the COVID-19 period; 15 April 2020;http://residus.gencat.cat/es/actualitat/noticies/detall/residus-sanitaris-COVID19-00001 [in Spanish]

7. COVID-19 has positive impact on ecosystem, 18 April 2020; National News Bureau & Public Relations
http://thainews.prd.go.th/en/news/detail/TCATG200418155259223

8. Coronavirus lockdown sees huge rise in fly-tipping across UK, 14 April 2020; https://www.itv.com/news/2020-04-14/coronavirus-lockdown-sees-huge-rise-in-fly-tipping-across-uk

9. Association of Cities and Regions for sustainable Resource management;https://www.acrplus.org/en/municipal-waste-management-covid-19#france