NANOMATERIALS

Reading Time: 10 minutes

INTRODUCTION

Nano means one billionth that means 10^-9 times in scientific notation. Have you ever thought how small it is? Avg human height is around 1.5-2m, size of ants are about 2mm, the diameter of a human hair is around 100mm and size of our DNA is around 2nm that means it is 10^-9 times smaller than average human height. To imagine how small is one-billionth let’s go on the other side and see how big an object would be if we are one billionth time larger than the humans. The diameter of the sun is about one billionth times larger than a human. That’s pretty big. So our DNA is as small as humans as humans are from the sun.

What are nanomaterials?? What is its importance? Where are they used? Let’s dive into the world of smallness!!!

Nanomaterials include a broad class of materials, which has at least one dimension less than 100nm. Depending on their shape, they can be 0-D, 1-D, 2-D or 3-D. You may be thinking what this small piece of material can do?? Nanomaterials have an extensive range of applications. The importance of these materials was realized when it was found that size can influence the physicochemical properties of a substance. Nanoparticles have biomedical, environmental, agricultural and industrial based applications.

Nanoparticles are composed of 3 layers-

  • The Surface Layer- It may be functionalized with a variety of small molecules, metal ions, surfactants and polymers.

  • The Shell Layer- It is a chemically different material from the core in all aspects.

  • The Core- It is the central portion of the nanoparticle and usually referred to as nanoparticle itself.

These materials got immense interest from researchers in multidisciplinary fields due to their exceptional characteristics.

CLASSIFICATION OF NANOPARTICLES

Based on the physical and chemical characteristics, some of the well-known classes of NPs are-

  1. CARBON-BASED NPs

  • FULLERENES- It contains nanomaterials that are made up of globular hollow cage such as allotropic forms of carbon. They have properties like electrical conductivity, high strength, structure, electron affinity and versatility. They possess pentagonal and hexagonal carbon units, while each carbon is sp2 hybridized. The structure of C-60 is called Buckminsterfullerene

  • CARBON NANOTUBES(CNTs)- They have elongated, tubular structure, 1-2nm in diameter. They structurally resemble graphite sheets rolling upon itself, which can have single double and many walls and therefore are named as single-walled (SWNTs), double-walled (DWNTs) and multi-walled carbon nanotubes (MWNTs) respectively. They are widely synthesized by decomposition of carbon, especially atomic carbons, vaporized from graphite by laser or by an electric arc to metal particles. Chemical Vapour Deposition (CVD) technique is also used to synthesize CNTs. They can be used as fillers, efficient gas absorbents and as a support medium for different inorganic and organic catalysts.

NANOMATERIALS

  1. METAL NPs

They are purely made up of metal precursors. Due to Localized Surface Plasmon Resonance (LSPR) characteristic, they possess unique optoelectrical properties. Due to excellent optical properties, they find their application in various research areas. For example, gold nanoparticles are used to coat the sample before analyzing in SEM.

  1. CERAMIC NPs

They are inorganic, nonmetallic solids, synthesized via heat and continuous cooling. They are made up of oxides, carbides, carbonates and phosphates. They can be found in amorphous, polycrystalline, dense, porous or hollow forms. They found their application in catalysis, photocatalysis, photodegradation of dyes and imaging application.

  1. SEMICONDUCTOR NPs

They possess wide band gaps and therefore show significant alteration in their properties with bandgap tuning. They are used in photocatalysis, photo optics and electronic devices. Some of the examples of semiconductor NPs are GaN, GaP, InP, InAs.

  1. POLYMERIC NPs

They are organic-based NPs, mostly nanospheres and nanocapsules in shape. They are readily functionalized and therefore have a wide range of applications.

  1. LIPID NPs

They contain liquid moieties and are effectively used in many biomedical applications. They are generally spheres with diameters ranging from 10 to 1000nm. They have a solid core made of lipid, and a matrix contains soluble lipophilic molecules.

SYNTHESIS OF NPs

There are various methods used for the synthesis of NPs, which are broadly classified into two main classes-

  1. TOP-DOWN APPROACH

Top-down routes are included in the typical solid-state processing of the materials. It is based on bulk materials and makes it smaller, thus using physical processes like crushing, milling and grinding to break large particles. It is a destructive approach, and it is not suitable for preparing uniformly shaped materials. The biggest drawback in this approach is the imperfections of the surface structure, which has a significant impact on physical properties and surface chemistry of nanoparticles. Examples of this approach include grinding/milling, CVD, PVD and other decomposition techniques.

NANOMATERIALS

  1. BOTTOM-UP APPROACH

As the name suggests, it refers to the build-up of materials from the bottom: atom by atom, molecule by molecule or cluster by cluster. They are more often used for preparing most of the nanoscale materials which have the ability to generate uniform size, shape and distribution. It effectively covers chemical synthesis and precisely controls the reaction to inhibit further particle growth. Examples are sedimentation and reduction techniques. It includes sol-gel, green synthesis, spinning and biochemical synthesis.

CHARACTERIZATION OF NPs

Analysis of different physicochemical properties of NPs is done using various characterization techniques. It includes techniques such as X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Infrared (IR), SEM, TEM and particle size analysis.

  1. MORPHOLOGICAL CHARACTERIZATION

Morphology always influences most of the properties of the NPs. Microscopic techniques are used for characterization for morphological studies such as a polarized optical microscope, SEM and TEM.

SEM technique is based on electron scanning principle. It uses a focused beam of high energy electrons to generate a variety of signals at the surface of solid specimens. It is not only used to study the morphology of nanomaterials, but also the dispersion of NPs in the bulk or matrix.

TEM is based on electron transmission principle so that it can provide information on bulk material from very low to higher magnification. In TEM a high energy beam of electrons is shone through a skinny sample. This technique is used to study different morphologies of gold NPs. It also provides essential information about two or more layer materials.

NANOMATERIALS

  1. STRUCTURAL CHARACTERIZATION

Structural characteristics are of primary importance to study the composition and nature of bonding materials. It provides diverse information about the bulk properties of the subject material. XRD, Energy dispersive X-ray (EDX), XPS, IR, Raman and BET are the techniques used to study the structural properties of NPs.

XRD is one of the most used characterization techniques to disclose the structural properties of NPs. Crystallinity and phases of nanoparticles can be determined using this technique. Particle size can also be determined by using this technique. It worked well in identification of both single and multiphase NPs.

EDX is usually fixed with field emission-SEM or TEM device is widely used to know about the elemental composition with a rough idea of per cent weight. Nanoparticles comprise constituent elements, and each of them emits characteristic energy X-rays by electron beam eradication.

XPS is one of the most sensitive techniques used to determine the exact elemental ratio and exact bonding nature of elements in nanoparticles materials. It is a surface-sensitive technique used in-depth profiling studies to know the overall composition and the compositional variation with depth.

  1. PARTICLE SIZE AND SURFACE AREA CHARACTERIZATION

Size of the particle can be estimated by using SEM, TEM, XRD and dynamic light scattering (DLS). Zeta potential size analyzer/DLS can be used to find the size of NPs at a deficient level.

NTA is another new and exclusive technique which allows us to find the size distribution profile of NPs with a diameter ranging from 10 to 1000nm in a liquid medium. By using this technique, we can visualize and analyze the NPs in a liquid medium that relates the Brownian motion rate to particle size. It can be helpful in biological systems such as protein and DNA.

NPs have large surface areas, so it offers excellent room for various applications. BET is the most used technique to determine the surface area of nanoparticles material. Principle of this technique is adsorption and desorption and Brunauer-Emmett-Teller (BET) theorem.

  1. OPTICAL CHARACTERIZATION

Optical properties are of great concern in photocatalytic applications. These characterizations are based on Beer-lambert law and basic light principles. The techniques used to give information about absorption, luminescence and phosphorescence properties of NPs. The optical properties of NPs materials can be studied by well-known equipment like Ultraviolet-visible, photoluminescence and the ellipsometer.

PHYSICOCHEMICAL PROPERTIES OF NPs

So it’s all about the size, isn’t it? Yes and no. When a material becomes a nanomaterial is not so simple. A nanomaterial may have different properties compared to the same substance in bulk form. That means that a material could change when it goes from bulk to nanoform, but at what size that happens varies depending on the substance.Nanoparticles are used in various applications due to their unique properties such as large surface area, strength, optically active and chemically reactive.

  1. ELECTRONIC AND OPTICAL PROPERTIES

The optical and electronic properties of nanoparticles are dependent on each other. For example, gold colloidal nanoparticles are the reason for the rusty colours seen in blemished glass windows, while Ag NPs are typically yellow. The free electrons on the surface of nanomaterials are free to move across the material. The mean free path of Ag and gold is ~50nm, which is greater than the NPs size of these materials. Therefore, no scattering is expected from the bulk, when light interacts. Instead, they set into a standing resonance condition, which is responsible for LSPR in the NPs.

  1. MAGNETIC PROPERTIES

There is a class of nanoparticles known as magnetic nanoparticles that can be manipulated using magnetic fields. Such particles consist of two components- a magnetic material and chemical component that has functionality. These types of materials have a wide range of applications which includes heterogeneous and homogeneous catalysis, biomedicine, magnetic fluids, MRI and also in water decontamination. Magnetic properties of NPs dominate when its size is less than the critical value, i.e. 10-20nm. The reason for these magnetic properties is the uneven electronic distribution in NPs.

  1. MECHANICAL PROPERTIES

To know the exact mechanical nature of NPs different mechanical parameters such as elastic modulus, hardness, stress and strain, adhesion and friction are surveyed. Due to distant mechanical properties of NPs, it finds its application in fields like tribology, surface engineering, nanofabrication and nanomanufacturing. NPs shows different mechanical properties as compared to microparticles and their bulk materials.

  1. THERMAL PROPERTIES

It is well known that metals have better thermal conductivities than that of fluids. Same is the case of NPs. Thermal conductivity of copper is much higher than water and engine oil. Thermal conductivity of fluids can be increased by dispersing solid particles in them. Using the same way nanofluids are produced which have nanometric scales solid particles dispersed into a liquid such as water, ethylene glycol or oils. They are expected to exhibit superior properties relative to those of conventional heat transfer fluids and fluids containing microscopic solid particles. As heat transfer takes place at the surface of the particles, it is better to use the particles with large surface area, and it also increases the stability suspension.

APPLICATIONS

As discussed above the nanoparticles have various unique properties. Due to their properties, they find their applications in multiple fields, including drugs, medication, manufacturing, electronics, multiple industries and also in the environment.

NANOMATERIALS

Nano-sized inorganic particles have unique, physical and chemical properties. They are an essential material in the development of various nanodevices which can be used in multiple physical, biological, biomedical and pharmaceutical applications. Particles of an iron oxide such as magnetite (Fe3O4) or its oxides from maghemite (Fe2O3) are used in biomedical applications. Polyethene oxide (PEO) and polylactic acid (PLA) NPs have been revealed as up-and-coming systems for the intravenous administration of drugs. Biomedical applications require NPs with high magnetization value, a size smaller than 100nm and a narrow particle size distribution. Most of the semiconductor and metal NPs have immense potential cancer diagnosis and therapy.

Image shows the bamboo-like structure of nitrogen-doped carbon nanotubes for the treatment of cancer.

NANOMATERIALS

In specific applications within the medical, commercial and ecological sectors manufacturing NPs are used which show physicochemical characteristics that induce unique electrical, mechanical, optical and imaging properties. Nanotechnology is used in various industries, including food processing and packaging. The unique plasmon absorbance features of the noble metals NPs have been used for a wide variety of applications including chemical sensors and biosensors.

Nanomaterials are also used in some environmental applications like green chemistry, pollution prevention, the recommendation of contaminated materials and sensors for ecological stages.

NPs such as metallic NPs, organic electronic molecules, CNTs and ceramic NPs are expected to flow as a mass production process for new types of electronic equipment.

NPs can also offer applications in mechanical industries, especially in coating, lubricants and adhesive applications. Its mechanical strength can be used to produce mechanically more reliable nanodevices.

CONCLUSION

Nanomaterials are no doubt the future of technology, being the smallest material they have a wide range of applications due to their unique physical and chemical properties. Due to their small size, NPs have a large surface area which also makes them suitable candidates for many applications. Even at that size, optical properties dominate, which further increase their importance in photocatalytic applications. Though NPs are used for various applications, still they have some health hazard concerns due to their uncontrollable use and discharge to the natural environment, which should be considered to make the use of NPs more convenient and environmentally friendly.

WONDER, THINK, CREATE!!!

Keep Learning!, Keep Growing!

Team CEV

CORONA VIRUS

Reading Time: 5 minutes

What is a virus?

A virus is a small infectious agent that replicates only inside the living cells of an organism. 

While not inside an infected cell or in the process of infecting a cell, viruses exist in the form of independent particles, consisting of Genetic material, i.e. long molecules of DNA or RNA that encode the structure of the proteins by which the virus acts. The shapes of these virus particles range from simple helical forms for some species to more complex structures for others.The origins of viruses in the are unclear. Viruses undergo genetic change by several mechanisms.

Viruses are basically classified under two categories

  • DNA Virus

The genome replication of most DNA viruses takes place in the cell’s nucleas.

  • RNA Virus

 Replication usually takes place in the cytoplasm.

CORONA VIRUS

This is structure of Chicken Pox virus

What is coronavirus?

 

Coronaviruses (CoV) are a large family of viruses  out of which only 6 viruses that cause illness ranging from the common cold to more severe diseases such as Middle East Respiratory Syndrome (MERS-CoV) and Severe Acute Respiratory Syndrome (SARS-CoV). The name corona was given due to the shape of the of the outer covering which resembles to a crown. Corona is the Latin name for “Crown”.

A novel coronavirus (nCoV) is a new strain that has not been previously identified in humans.  

How it is spread?

Coronaviruses are zoonotic, meaning they are transmitted between animals and people. 

 Detailed investigations found that SARS-CoV was transmitted from civet cats to humans and MERS-CoV from dromedary camels to humans.

 Several known coronaviruses are circulating in animals that have not yet infected humans. 

 

Symptoms of coronavirus:

Common signs of infection include respiratory symptoms, fever, cough, runny nose, headache seasonal flu shortness of breath and breathing difficulties.

 In more severe cases, infection can cause pneumonia, severe acute respiratory syndrome, kidney failure and even death. 

The incubation period of the coronavirus is 2-11 days so it means that if you are affected with the coronavirus main take 2 to 11 days show the symptoms.

Standard recommendations to prevent infection spread include regular hand washing, covering mouth and nose when coughing and sneezing, thoroughly cooking meat and eggs.

 Avoid close contact with anyone showing symptoms of respiratory illness such as coughing and sneezing.

If you are infected with symptoms showing presence of  coronavirus ,it is advised to wear a mask but if you are not, infected with coronavirus the only wearing mask is not going to protect you.

 

Cure of the coronavirus:

Till date there is no vaccine available for coronavirusIt is expected that it will take one year to develop vaccine for coronavirus.

In 2001 when SARS virus was spread in  China it took 20 months to develop vaccine.It is also said that if your immune system is strong you will be able to recover it.

 

What is the effect of  corona virus across the globe?

25 countries across the world has been reported the the coronavirus infection . The first three case was reported in Kerala state of India also. According to NDTV news six cities in China has been quarantined.50 million peoples in China are quarantined. Australia and Singapore banned Chinese tourist in their country. Russia,Mongolia and Nepal closed border with China. It is estimated that China will loss nearly 60 billion due to the temporary trade Hault. Thus 5 trillion economy will become nearly  3.8 trillion economy and Chinese GDP will be slowed down by 1.5 %.

 

 Is coronavirus is that much dangerous?

 

Below data available as per date of the February 5 2020

China’s National Health Commission reported that there were 2009 new confirmed cases and 142 additional deaths as of Feb. 15. That brings the total number of cases in mainland China to 68,500, and the total deaths so far to 1665,  according the latest statistics from the commission released Sunday.

An American passenger tested positive for a second time after the cruise ship operator for MS Westerdam requested another test.

China sends more than 25,000 medical workers to Hubei, state-owned Xinhua reported.

Mortality and Contagious

CORONA VIRUSCORONA VIRUS

The mortality rate of the coronavirus is about 2 %that means if you are affected with coronavirus 98% chance that you will survive. But still it is early to predict the and state the mortality rate as of now.

The people who died due to infection of the coronavirus most of them were having weak immune system or aged people.

Contagious is the term which is defined that how much fast virus will spread. In nature, in most of the cases it is observed that the virus which is more contagious has low mortality rate. The ebola virus which was spread in Africa has 70 % mortality rate. Virus was not that contagious but it killed nearly 3500 people in Africa. The common cold  has mortality rate of the 0.01% it means out of the 10,000 people infected there is a chance that one person will die due to this infection. SARS virus which affected China had 10 percentage mortality rate. The number of people affected by the virus was around 8k. And due to novel coronavirus is more than 45k. It is observed that the novel corona virus is 6  times more contagious then SARS virus.

Here one thing to be clarified that less mortality rate that doesn’t mean the number of people died is less. The Spanish flu which occurred during 1918-20. The number of the people affected by that virus was around 500 million and its mortality rate was around 10% so nearly 50 million peoples were killed.

 

Keep Reading, keep learning

AANTARAK DIVISION

TEAM CEV!!

CIRCADIAN RHYTHM : The Inner Engineering

Reading Time: 6 minutesSo, first of all, I want to share the motivation behind the topic. The Nobel prize of 2017 in Physiology (medicine) was shared by three American scientists Jeffrey C. Hall, Michael Rosbash and Michael W. Young for the discovery of molecular mechanism behind Circadian Rhythm.

CIRCADIAN RHYTHM : The Inner Engineering Circadian Rhythm

For introduction: Circadian Rhythm is phenomena that leads all biological process to display an oscillation of about 24 hours and work in sync with each other for optimum health. These rhythms are tuned by a circadian clock and apply to nearly all the organisms. In simple words, the routine of our anatomy is controlled by a body clock.

Here is the proof that the clock is genetically controlled :

There was an experiment in which a healthy adult was shifted to an underground apartment for 40 days to check whether he could maintain his sleep-wake cycle without the aid of sunlight or any external means.

Here is are the recordings of his sleep-wake cycle –

CIRCADIAN RHYTHM : The Inner Engineering Circadian Rhythm

Blue represents wake and yellow represents sleep. As the days go on only sleeping timing moves towards midnight but the time period of sleep almost remain constant, hence it can be easily deduced that time-period of body clock is not altered by external factors, the time period remains close to 24 hrs. It has taken decade-long medical researchers to establish that genes control the circadian clock.

Here is what happens in our body to maintain sleep-wake cycle-

If it is assumed that the circadian clock rightly synchronized to earth day and night then it will make you go to sleep by 11 o’clock, will reach deep sleep by 3 o’clock and to anticipate waking body will begin warming up at around 5 o’clock, as soon as you wake up the hormone called melatonin hurtle down and stress hormone called cortisol will rise, brain will reach its peak performance time by noon, athletic performance get its peak in late afternoon and as evening sets the level of melatonin again begin to increase and by 11 o’clock sufficient melatonin is acquired to get a sound sleep.

CIRCADIAN RHYTHM : The Inner Engineering Circadian Rhythm

So humans and other organism developed their body clock in synchronization to day-night cycle i.e. 24 hrs as of our planet earth to anticipate daily life. Evolution of body clocks took place through developing adaptation to external stimuli of warm, bright days and cool, dark nights, through genes. And we all must be feel thankful for inheriting this life-sustaining feature by virtue of our primitives or past generations. In the coming part of the blog, I will prove to you how this gift can be taped to become the healthiest version of ourselves, maximize our productivity and do greater feats.

HOW GENES WORK?

Now every cell in our body has the 24-hour cycle and here is how it operates.

This video beautifully explains the molecular mechanism of the genes to run the body clock.

Till now we have an overview of how the circadian clock works now let’s talk how do we relate this with our lives after all an engineer is far more interested in practical applications and theory behind.CIRCADIAN RHYTHM : The Inner Engineering Circadian Rhythm

We have seen that the time period of this clock is 24 hours but point to be noted is that every organ in our body has its own cycle and work in sync with cycle of other organs to form a single system like blood supply to liver peaks in midnight during deep sleep, lungs gets its peak blood supply in early morning, large intestine in late morning, and so on, so what we need to take care is that this synchronization among organs of body system remain in harmony as they are very well subjected to external stimuli.

HOW LIGHT AFFECTS THIS SYNCHRONICITY?

CIRCADIAN RHYTHM : The Inner Engineering Circadian Rhythm

Basically the clock of our brain, the master clock, gets activated by blue light, if natural cycle is followed the blue color rich light of morning sunset melatonin to lowest, as the evening sets the natural light becomes less rich in blue and appears red and orange, for which our master clock has evolved to response by instructing to increase melatonin. Now problem is that most part of day-time we live indoors the light of which is not rich in blue color and brains receives a confusing signal, at night when we use our electronic gadgets blue light content is much more than outside hence again a confusing signal and hence melatonin is not controlled properly. If continued for longer duration give rise to problems like migraine, ASD, ADHD, Depression, etc. This is the reason why comps people get sleep late in night and these days devices, when operated at night mode, shifts its color to orange, eliminating blue. On the other hand, owls have evolved to respond differently.

HOW FOOD AFFECT SYNCHRONICITY?

CIRCADIAN RHYTHM : The Inner Engineering Circadian Rhythm

Normal functioning of the digestive system is as follows- during the day time our body runs on carbohydrates provided by diet and stores fats, at night time no carbohydrates input is there and hence body works on fat. Consider if you give carbohydrates to the body at late night then the body cannot burn the fats, hence chances of becoming obese are increased. The solution to this problem is that eat the same amount of food you generally do but avoid taking input late night, it will surely hammer on circadian rhythm by offsetting stomach from the sync with the system.

Now the last part of the blog, the healing power of circadian rhythm. So you must have noticed that the medicines prescribed to you are also instructed to be taken at a particular time of day. The circadian clock tunes the potency of every drug we take, so taking the drug at the instructed time of day can cure you as well as taking it at the wrong time can have adverse effects also. Schedule of flu shots, surgery of liver or heart, radiation therapy of cancer patients all these things depends on the time of day.

Conclusion: We can analyze that in earlier days human died due to diseases like malaria, dengue, chickenpox, polio, pneumonia, mumps, rabies, Ebola, etc. until proper sanitation, vaccination, and antibiotics came into existence, but now the scenario has changed. Now, most common diseases are chronic kidney diseases, asthma, hypertension, anxiety, diabetes, lung cancer, breast cancer, liver cancer, insomnia, bipolar, acid reflux, etc. These diseases are directly or indirectly related with our ignorant attitude towards our lifestyles and to be more precise hampering the Circadian Rhythm has bought this havoc to us.

In the end, thanks for time and patience and whole CEV team wishes you a happy Diwali.

Stay healthy, Enjoy reading!

Regards,

TEAM CEV.

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