In comparison to bulk materials, nanomaterials are characterized by significantly distinct defect dynamics, and as a result, they exhibit distinctive structural and functional features. Because nanoparticles have a high surface area to volume ratio, they have a higher level of chemical and biological activity. This is because the surface atoms of nanomaterials are unsaturated in their chemical bonds. Nanomaterials are capable of exhibiting unusually high levels of reactivity due to the fact that almost one quarter or more of their atoms are located at the surface.
The use of nanotechnology can either be considered to be passive or active. Applications are considered passive when the nanomaterial or its structure does not change in either form or function during the application. When it comes to nanostructures or nanomaterials, activity is defined as the ability to change either the structure or function of the nanoparticle.
Nanotechnology is bound to have an impact due to large-scale applications in industry and household products
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Impacts of nanotechnology
The environment and ecological systems are in danger as scientific and technological progress disrupts the natural balance of forces. From the early humans’ discovery of fire to today’s sophisticated air transportation networks, it’s clear that all technological advancement can be used for evil by malicious individuals or organizations. The issues with nanotechnology are comparable.
For example, certain carbon nanotube manufacturing methods necessitate the use of harmful raw materials and generate toxic by-products. Since the degree of influence is species-specific and often depends on the size and geometry of the particle, this needs to be thoroughly explored to understand the extent of the negative effects of manufactured nanoparticles. The nanotoxicological impact of various nanoparticles on aquatic and animal species is currently the subject of intensive study.
The dangers associated with unwanted exposure during production or service exploitation of nanoparticles can be mitigated by taking steps once the safe limits of various nanomaterials have been analyzed and tabulated. Waste management for nano-enhanced items and their potential to contribute to pollution are further sources of concern. Human and environmental dangers posed by GMOs (genetically modified organisms) in food production and related industries require the collection of quantitative data, followed by deep scientific understanding. In response to these worries, the discipline of nano (eco-)toxicology has developed over the past decade.
Nanotoxicology is the study of how man-made nanoparticles react in living systems. We will then attempt to paint a clear picture of what is happening to reduce the dangers to human health and the environment that are associated with the usage of engineered nanomaterials in the following sections.
Negative Impacts of Nanotechnology
Even when they are present in their bulk form, certain chemical compounds have been the subject of extensive research into their potentially harmful effects for several centuries. Paracelsus , who is commonly considered as the father of toxicology, had the opinion that the majority of substances are toxic when their quantity in the human system exceeds a crucial acceptable level. He stated this position in his writings. Because of this, determining the maximum safe dose of a substance or the highest concentration that may be used of a variety of materials without causing harmful consequences is of the utmost importance, particularly in the field of nanomaterials.
In the field of nanotoxicology, the most important issue to ask is, “Which characteristics of particles are essential in initiating and causing adverse effects?” As a result of the pioneering animal research that was done on particle deposition and retention in the lung, it is now common knowledge that nanoparticles possess a greater surface area-to-volume ratio than larger particles, which boosts the chemical and biological reactivity of the nanoparticles. Because selective nanoparticles exhibit both chemical and biological reactivity, the risk factor associated with them is significantly increased.
When nanoparticles interact with biological systems, certain other foreign entities and hazardous molecules may bind to the places where the nanomaterials are chemically active, which may further exacerbate the negative effects of the interaction. Nanomaterials not only have the capability of penetrating cell membranes, which would normally prevent the admission of foreign entities, but they also have the potential to translocate themselves to other tissues and organs, which presents a concern.
In order to mitigate the negative consequences of manufactured nanoparticles, it is essential to conduct in-depth research with the goal of better comprehending the fundamental mechanisms involved.
Impacts of nanomaterials on human and environment
Since synthetic nanoparticles are being used more and more, it is likely that there will be more of them in the earth, water, and air in the future. Nanoparticles are made in the same way that bigger airborne particles are made, such as when a volcano erupts or when a forest burns. Nanoparticles that come from nature have a wide range of sizes, shapes, and materials.
On the other hand, manufactured or “deliberately” made nanoparticles are all made the same way so that they have the qualities that are wanted. The behavior and effects of nanoparticles on the environment can be estimated by looking at how they form naturally or how they are made by burning. But these figures aren’t enough to know for sure how dangerous manufactured nanoparticles are. Nanotechnology has a lot of uses, and the different nanomaterials are very different from each other. Because of this, their possible risks need to be looked at differently.
Nanotechnology is still in its early stages, so most ideas about how nanotechnology and biology interact have been guesses that need to be proven by controlled experiments. A lot of papers show that detailed research is being done on how nanoparticles affect aquatic, plant, and animal species. But a lot of work needs to be done in this way before regulations can be put in place.
Cytotoxicity means that something is toxic to cells. When a cytotoxic chemical is used on cells, there are many possible outcomes. The cells may go through necrosis, in which case their membranes break down and they die quickly from cell lysis. The cells can stop growing and splitting (which makes the cells less healthy) or they can turn on a genetic program that tells the cells to die. Apoptosis is the planned death of cells. Genotoxicity is when something bad happens to the genetic material of a cell and changes its structure.
Several researchers have found that carbon nanotubes are bad for the lungs of animals. Studies on rats have shown that when some nanomaterials are breathed in, they can move from the lungs to the brain cells and change the connections between neurons.
Moreover, nanomaterials that are used all over the world in recent scenario have both positive and negative impacts in human and environment. Thus, it will be very hard or even impossible to get rid of nanomaterials from the world.
Nanoparticles in living systems
When nanoparticles get into the body’s tissues and fluids, they tend to stick to macromolecules at the point where they enter. The amount of adsorption and other ways that cells connect will depend on many things, such as the chemistry and shape of the surface. The specifics of this adsorption process will depend on the shape and properties of the particles’ surfaces. By attaching certain biomolecular linkers to nanomaterials, scientists can figure out how they respond in different places. These kinds of studies can be used to label proteins with light and get drugs to the right place at the right time. During the process of generating nanoparticles, people can be exposed in a number of ways.
Dermal absorption
There are two possible ways for particles to get into the skin through dermal absorption: through the top layer of skin or through the hair roots. But not enough is known about healthy skin and skin that has already been damaged. It is also still not clear if toxic substances that stick to the particles can get into the body through the skin. Since nanoparticles are already in a lot of skincare products, it’s important to figure out how important this route of exposure is. Nanoparticles can be taken in through the mouth on purpose, like when they are used as ingredients in medicines. However, nanoparticles can also be taken in by accident, like when they are in certain foods.
Intestine
In general, even particles that don’t dissolve can be taken in through the intestines and end up in the lymphatic system. From there, these particles can get into the blood and spread to other parts of the body. At the moment, though, there are no studies that give enough information to make a fair assessment of the possible risks of eating nanoparticles.
Respiratory tract
Traditional methods of entering the body are through the lungs by means of inhalation, the skin by means of absorption, and the mouth by means of ingestion; however, exposure can also occur via a combination of these three methods. The inhalation of the substance into the body through the respiratory system is most likely the most significant method of exposure. It has been reported that nanomaterials on reaching the lungs through respiratory tract may causes asthma.
Bloodstream
The heart, liver, spleen, kidneys, and bone marrow may receive particles from the bloodstream. Studies show that nanoparticles can cross biological barriers like the blood–brain barrier. It’s also assumed that nanoparticles can cross the placenta into the foetus. These mechanisms may pose risks even if used therapeutically.
Ecological aspects of nanotechnology
The environmental implications of nanotechnology are quickly becoming an area of research that is becoming increasingly important from a sustainability perspective. There are currently only a small number of scientific studies available that examine the effect that nanoparticles have on the surrounding environment. However, it is necessary to make the assumption that, due to the exceptional qualities that they possess. There is no doubt that nanoparticles will cause damage to the surrounding environment.
The use of nanomaterials in everyday items like shampoo, electronics, etc., is on the rise. These are now being released into the natural world. Thus, nanoparticles can be transported both between biotic and abiotic levels, via distinct physiological mechanisms. Depending on the method of administration, water fleas, also known as Daphnia, might die in the presence of relatively low concentrations of C60 molecules, also known as buckminster fullerenes, and nanoscale titanium dioxide in the water.
Experiments carried out on juvenile largemouth bass (Micropterus salmoides) demonstrated that C60 nanoparticles are taken in through the gills of the fish. Even in low concentrations, they are able to cross the barrier that separates the bloodstream from the brain and cause damage there. It has been demonstrated that the presence of carbon nanotubes in zebrafish (Danio rerio) embryos results in a delay in the hatching of the offspring. In addition, the bactericidal activity of certain nanomaterials may result in unfavorable effects in sewage treatment works and may cause a shift in the make-up of the microbial population in water.
Similarly, there is a lack of research into how nanoparticles affect soil ecosystems. The findings of laboratory studies modeling the effect on human health can be extrapolated to the health of wild mammals. There are currently no available studies involving non-vertebrate organisms. Root development in several crops was inhibited in laboratory experiments using aluminum nanoparticles. For more substantial aluminum particles, this effect was not observed. Nanoparticles may alter the composition of the soil’s microbe population due to their biocidal action, or their ability to kill bacteria.
Likewise, it is harmful to the aquatic environment. Some algae, bacteria, and fish are extremely sensitive to their toxicity. Certain aquatic animals develop brain tumors after being exposed to carbon nanotubes. TiO2 nanoparticles impair growth and cause birth defects in exposed organisms. It kills phytoplankton and zooplankton, suggesting a biocidal effect.
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