One Nanoregulation

... at least for combating and preventing nanopollution and nanotoxicity.

Preface

Advancing along the series of articles I have made ​​dedicated to "The Roots of Nano-Fear Decoded", I have pointed briefly which are the main roots of nano-fear (or at least some of them). Some of them have already been addressed in subsequent articles published by me in NanoMedRev Blog:

• Nanopollution. The articles dedicated to nanopollution are:
• "Nanopollution Revised";
• "Fighting & Preventing Nanopollution";
• Nanotoxicity. The articles dedicated to nanotoxicity are
• "Nanotoxicity in Humans";
• "Indicators of Nanotoxicity";
• "Some of The Main Types of Nanoengineered Nanoparticles Reported as Nanotoxic";
• "Nanoengineered Nanoparticles in Consumer Goods";
• "A World Without Nanotoxicity";
• Nanoregulation:
• "Why Nanoregulation Must be a Top Priority on Political Agendas";
• "Nanoregulation For The Future";
• and this current article;
• Nanoeducation. The article dedicated to nanoeducation is:
• "Nanoeducation 3.0";
• Ethics (no articles published in NanoMedRev Blog yet);
• Media Professionals (no articles published in NanoMedRev Blog yet).

This one more article I wrote about nanoregulation and the way I envision it must reposition to meet the challenges of the future. Again, my goal in this article is to contribute to make nanoregulation a real legal instrument to be used to its full potential by ALL Countries, thereby contributing to a better world for ourselves and our descendants.


Introduction

I advocate that nanoregulation must be unique.

Put this way, this point of view seems silly and sounds like an unreasonable thing. Therefore, I have to explain and develop my idea.

I recognize that recommending that nanoregulation must be unique in the entire world is at least controversial.

There is a whole diversity of Countries, each with their own features that give them their own identity and differentiate them from all others. This is about culture, nationality, independence, sovereignty, nation, people, identity, national pride, and many other values ​​that any Country hardly (or, better saying, never) abdicates. Therefore any unification of regulation (even in the nanoscience and nanotechnology field) is and will always be controversial.

But its implementation is not impossible. Better saying, its implementation is possible.

The Engagement of ALL Countries

I advocate that ALL Countries must urgently include nanoregulation in their political agendas.

When I explained "Why Nanoregulation Must be a Top Priority on Political Agendas", this was the idea that I advocated.

My goal is that every Country in the world must be, over time, developing (at a first stage) and implementing (at a later stage) nanoregulation.

Nanoregulation covers numerous and diverse areas of intervention. Follow just a few, among many examples:

• Nanopollution ("Fighting & Preventing Nanopollution");
• Nanotoxicity ("A World Without Nanotoxicity");
• Nanobiopharmaceuticals ("Why Nanoregulation Must be a Top Priority on Political Agendas");
• "Nanoengineered Nanoparticles in Consumer Goods".

Fields of Nanoregulation Common to ALL Countries

Moreover, the world is facing problems and threats that are common to ALL Countries. Following the alignment of the thematic scope of this article, I refer to:

• Combating and preventing nanopollution;
• Combating and preventing nanotoxicity.

On the other hand, I recognize that unifying these regulations in all their diverse fields are beyond controversial, a highly complex task (e.g. nanobiopharmaceuticals and nanoengineered nanoparticles in consumer goods).

Thus, what do I propose after all?

I propose that nanoregulation must be unique for ALL Countries at least in these two fields:

• Combating and preventing nanopollution;
• Combating and preventing nanotoxicity.

What Does Unique Mean in This Thematic Context?

In other words, what do I mean by unique?

There must be a worldwide organization with global legitimacy and mandate to exercise global uniformity or standardization of the various nanoregulations developed by ALL the different Countries, prior to its domestic implementation. This global uniformity or standardization of the various nanoregulations developed by ALL the different Countries, must cover, at least, the following fields: (a) combating and preventing nanopollution; (b) combating and preventing nanotoxicity.



Luís Bastos

Why Nanoregulation Must be a Top Priority on Political Agendas

... of ALL COUNTRIES

Preface

Following the alignment of my article "The Roots of Nano-Fear Decoded", I have pointed briefly which are the main roots of nano-fear (or at least some of them). Some of them have already been addressed in subsequent articles published by me in NanoMedRev Blog:

• Nanopollution. The articles dedicated to nanopollution are:
• "Nanopollution Revised";
• "Fighting & Preventing Nanopollution";
• Nanotoxicity. The articles dedicated to nanotoxicity are
• "Nanotoxicity in Humans";
• "Indicators of Nanotoxicity";
• "Some of The Main Types of Nanoengineered Nanoparticles Reported as Nanotoxic";
• "Nanoengineered Nanoparticles in Consumer Goods";
• "A World Without Nanotoxicity";
• Nanoregulation (addressed in this current article);
• Nanoeducation. The article dedicated to nanoeducation is:
• "Nanoeducation 3.0";
• Ethics (no article published in NanoMedRev Blog yet);
• Media Professionals (no article published in NanoMedRev Blog yet).

This article is dedicated to nanoregulation. I'll try to do my best to point and suggest paths for the future, with regard to nanoregulation. My goal in this article is to contribute to the nanoregulation to become a real legal instrument to be used to its full potential by ALL COUNTRIES, thereby contributing to a better world for ourselves, our children, our grandchildren and so on.


Introduction

Nanoregulation is already underway. Obviously those differences at the level of attitudes are abyssal, when making a comparison between different Countries:

• A minority of  pioneer Countries are already working at full speed;
• The majority of Countries is divided into two groups:
• The Countries that are waiting for the pioneering Countries in pursuing nanoregulation, so that they may decide to imitate them or affirm themselves by the difference;
• The Countries that are fully asleep, regarding nanoregulation; never heard of such a thing or if heard, it is a low-priority issue on their political agendas.

What Nanoregulation has to do With Priority on The Political Agendas of All Countries?

An interesting question. Though this question sounds simple, an appropriate and quite enlightening response is complex. I'll try to do my best to be clear and at the same time correct and synthetic.

There are several reasons. I'm going to address the ones I consider more critical.


01. Nanopollution

Problem: Humans and the environment spread nanoparticles to the entire Biosphere.

As I explained in my article "Nanopollution Revised", nanoparticles are present:

• In the air (atmosphere);
• In water (hydrosphere)
• In the soil (lithosphere).

They are thus gathered all the requirements necessary for the entire biosphere being contaminated with presence of nanoparticles. It can therefore be said that the nanoparticles tend to be ubiquitous.
Just as an example, nanoparticles that are present in the air (atmosphere):

• Mix well with the humidity in the air. As a consequence, when precipitation occurs (e.g. rain, sleet and snow) this gets contaminated with nanoparticles. The precipitation reaches the soil and open water (e.g. oceans, seas, rivers, lakes);
• Contaminate drinking water exposed to air;
• Contaminate open water (e.g. oceans, rivers, streams, lakes);
• Contaminate the surface of the soils;
• Contaminate the groundwater through infiltration;
• Contaminate the inner part of soils (trough groundwater);
• Enter into the plants through their aerial components (involved in the process of photosynthesis, respiration and transpiration);
• Enter into the animals through respiration, eyes, skin, etc.;
• Contaminate foods exposed to air.

Again, just as an example, nanoparticles that are present in the water (hydrosphere):

• Return to the air (atmosphere), ascending together with the water vapour during the evaporation process of water;
• Are absorbed by the roots of aquatic plants, entering this way into these;
• Enter into the aquatic, underwater, marine animals as well as amphibians;
• Contaminate food during washing with water (supposedly drinking water);
• Contaminate food during the cooking process, when water is used (presumably drinking water).

Once again, and just as a third example, nanoparticles present in soils:

• Return to the air (atmosphere), ascending together with the water vapour during the evaporation process of water;
• Are absorbed by the roots of terrestrial plants, entering this way into these;
• Enter into the underground and terrestrial animals; 
• Contaminate groundwater.

On the other hand, nanoparticles present into plants and animals traverse the entire food chain until reach Humans.

Fact: Countries in general occupy the entire (or almost all) of the surface of the lithosphere (nanopolluted) of the planet Earth. Due to reasons of sovereignty, most countries hold territorial waters (hydrosphere, nanopolluted, by the way) and airspace (atmosphere, also nanopolluted, by the way).

Therefore, it starts to become quite clear that nanopollution affects ALL Countries of planet Earth.

By consequence, it is also clearly explained why the regulation has to do (a lot) with the priorities defined in the policy agendas of all countries.

The pollution itself is a reason more than enough to justify the engagement of ALL countries in the nanoregulation

02. Nanotoxicity

Therefore, since nanoparticles are present into the entire environment (which includes ALL COUNTRIES) these easily enter into the Human body of ALL POPULATIONS OF ALL COUNTRIES.

Nanotoxicity and nanotoxicology are highly complex subjects. It falls out of my objective a full coverage of this topic on this article. I will address two only:

• Routes for entry of nanotoxic nanoengineered nanoparticles into the Human body;
• Destinations of nanotoxic nanoengineered nanoparticles, after entering the Human body.

Regarding the routes for entry of nanotoxic nanoengineered nanoparticles into the Human body, as I explained in my article "Nanotoxicity in Humans", in general terms, nanotoxic nanoengineered nanoparticles may enter into the human body via different routes. This entry of nanotoxic nanoengineered nanoparticles into the Hyman body happens through episodes usually incidental and/or involuntary. For example, Humans may:

• Inspire accidentally and/or involuntarily air (previously contaminated with nanotoxic nanoengineered nanoparticles);
• Absorb casually and/or involuntarily through their skin (through the skin breathing process) air (previously contaminated with nanotoxic nanoengineered nanoparticles);
• Absorb accidentally and/or involuntarily, through the eyes, air, raindrops
  dew droplets, droplets humidity or water vapour or other impurities (previously contaminated with nanotoxic nanoengineered nanoparticles);
• Accidentally and/or involuntarily eat food (previously contaminated with toxic nanoengineered particles);
• Drinking accidentally and/or involuntarily, water (supposedly drinking water) and consumption beverages (previously contaminated with nanotoxic nanoengineered nanoparticles).

These incidental and/or involuntary episodes are associated with a lack of knowledge, information, awareness and nanoeducation by populations of ALL COUNTRIES. Therefore, through episodes of incidental and/or involuntary nature, the nanoparticles can enter the Human body via (not necessarily by this order):

• Inhalation;
• Cutaneous and eyes;
• Ingestion;
• Other.

Regarding the destinations of nanotoxic nanoengineered nanoparticles, after entering the Human body, these can undergo different fates:

• Can be totally or partially excreted;
• Can be totally or partially metabolized;
• Can be totally or partially cumulated into cells, tissues and organs.

Regarding excretion, follow some different examples of excretion of nanoengineered nanoparticles:

• Through the kidneys, during the blood filtration in which the nanotoxic nanoengineered nanoparticles are to be a product of excretion (a constituent of the urine);
• Through the intestines, during the formation of faeces and excreted through the anus;
• Through the sweat glands in order to be excreted in sweat during perspiration;
• Through the lungs (after venous blood having executed gas exchanges with the lung alveoli) being released into the environment during the exhalation.

In what concerns to metabolism, follow two examples of where nanotoxic nanoengineered nanoparticles can be metabolized:

• In the liver; 
• In the spleen.

Regarding total or partial bioaccumulation into cells, tissues and organs, nanotoxic nanoengineered nanoparticles which are insoluble or poorly soluble in biological fluids are of great concern in terms of public health:

1. Some nanotoxic nanoengineered nano particles which are insoluble or of low solubility can pass through the various defence mechanisms of the body. Thus, these nanotoxic nanoengineered nanoparticles which are insoluble or low solubility can be transported along the human body in an insoluble form: passing into the blood stream (blood and/or lymphatic vessels) after passing through the respiratory membranes (lung alveoli via gas exchanges) and/or gastrointestinal membranes. These nanotoxic nanoengineered nanoparticles which are insoluble or low solubility are then distributed to the various organs and eventually may accumulate at specific sites.
2. Other nanotoxic nanoengineered nanoparticles which are insoluble or poorly soluble can still find a direct link to the brain: after they are inhaled, they can travel through the olfactory nerves and penetrate directly into brain neurons.

As a consequence of what I explained above, it is easy to conclude that nanotoxicity is or should be a concern of ALL COUNTRIES.


03. Nanobiopharmaceuticals

Pharmaceuticals, biopharmaceuticals and nanobiopharmaceuticals are allowed to enter into the commercial channels after approval by regulatory authorities.

As a rule base, it can be stated that the regulatory authorities have as jurisdiction territory the Country where they belong. In other words, regulatory authorities operate in their own country and only in their own country.

As far as I know, there may be regional agreements in Organizations of Countries regarding some aspects of regulation.

If a pharmaceutical, for example, is approved in one country A, this fact does not necessarily imply that other country B adopts the introduction into their commercial channels, just because it was approved in the country A.

This general concept, described to pharmaceuticals, also applies to biopharmaceuticals and nanobiopharmaceuticals.

Since the nanomedicine is relatively new, these nanobiopharmaceuticals are also relatively new. They present a whole series of challenges in terms of legislation and regulation to the diverse regulatory authorities of ALL COUNTRIES around the globe. Most of these Countries are not yet ready to face these challenges, but one day will be.

This is therefore a reason per se more than sufficient to justify that ALL COUNTRIES include the nanoregulation subject as a top priority in their political agendas.


04. Nanoengineered Nanoparticles Present in Consumer Goods

As I explained in my article "Nanoengineered Nanoparticles in Consumer Goods", there are consumer goods being sold as commercial products containing nanoengineered nanoparticles in their composition.

As we can naturally imagine, the trade relations between countries are highly dynamic:

• New business relationships are always flourishing among the most diverse and distant countries;
• Import and export flows are developed or are changed;
• New distribution networks and channels are constantly created, so that a good produced in a country can be sold in other countries across the globe.

I want to emphasize that this dynamics also covers consumer goods being sold as commercial products containing nanoengineered nanoparticles in their composition.

These consumer goods are divided into several categories, regarding the use that consumers give them and the intended purpose. Nevertheless, there is a group of consumer goods already released into the commercial channels, which has been a particular target of debate: cosmetics, sunscreens and personal care products. Follow some examples: deodorants, soaps, toothpastes, shampoos, hair conditioners, sunscreens, anti-wrinkle creams, lipsticks, blushes, eye shadows, nail polishes, perfumes and after-shave lotions (just to mention a few).

Regarding the possible beneficial, harmless or nanotoxic effects of these nanoparticles to consumers, the information available to consumers is, in some cases, none, a bit vague or enlightening.

Personally, I am convinced of the presence of nanoengineered particles in consumer goods is not necessarily harmful, as was published in the sensationalist and non-specialized press.

I even admit that:

• A significant percentage of (or even most) of these manufacturers have performed quality and safety tests into their laboratories, in order to determine the beneficial, harmless or nanotoxic effects of these nanoengineered nanoparticles and the results have confirmed that they were safe;
• A significant percentage (or even most) of these manufacturers have hired independent external laboratories (outsourcing) to perform laboratory tests in order to  determine the beneficial, harmless or nanotoxic effects of these nanoengineered nanoparticles and the results have confirmed that they were safe.

However, given (a) the enlightening information (or absent) provided to consumers about the nanosafety of these nanoengineered particles in some consumer goods and given (b) the background noise made ​​by some sensationalist and not specialized media, the atmosphere of suspicion and fear was gradually settling into a few layers of populations.

Therefore, how consumers can rely on the results of laboratory tests? How can consumers trust the quality of these products?

In my personal opinion, there is only one answer: nanoregulation.

As we can naturally imagine, the trade relations between countries are highly dynamic:

• New business relationships are always flourishing among the most diverse and distant countries;
• Import and export flows are developed or are changed;
• New distribution networks and channels are constantly created, so that a good produced in a country can be sold in other countries across the globe.

Is therefore once again demonstrated ALL COUNTRIES must include nanoregulation as a top priority on their political agendas, with the objective of putting some order regarding this subject of the presence of nanoparticles into consumer goods.

Again, The Great Spiral of Sustainability (Now With ALL COUNTRIES Involved)

As I described in several pprevious articles, there is a phenomenon that has already been triggered - it's what I call "the great spiral of sustainability". Entities, organizations and players (in the world of nanotechnology, science, science-related, academia, industries) already started to compete with each other to see which is the one that applies and implements the best of the practices. Now, whith the advice I presented in this article - nanoregulation must be a top Priority on political agendas of ALL COUNTRIES - Countries will start to compete with each other to see which is going to develop the best nanoregulation.

In fact, this competition already started. In other words, some Countries have already joined (even without taking aware of it) to the big spiral of sustainability.

Again, this whole competition of best practices is highly positive and beneficial to the entire world.

Conclusion

I could have presented a lot more reasons for ALL COUNTRIES include nanoregulation as a top priority on their political agendas. However, I am absolutely sure that the four topics I presented above fully justify it.

The Countries that are waiting for the pioneer Countries in nanoregulation to proceed further (in order that they can then decide to imitate them or affirm themselves by the difference) don't need to do it. They can change of attitude and be proactive - by starting their own home work.

The Countries that are fully asleep in what regards nanoregulation can also change their attitude. They can start to be proactive - by starting their own home work.

Besides, there is a world trend to let it happen.

Nanoengineered Nanoparticles in Consumer Goods

Through regulation, all players win and nobody loses.

Preface

Proceeding with the approach initiated in my article "The Roots of Nano-Fear Decoded", I will address in this article other nanotoxicology topic: consumer goods containing nanoengineered nanoparticles. Later on, I will attempt to point out ways and propose solutions in order fight and prevent nanotoxicity.


Introduction

This theme is vast.

It has been developed numerous, responsible and meritorious studies in the field of scientific research in nanotoxicology. However, the need for knowledge in this field is enormous. What has been done is too little when compared with what is still needed.

Since there is a large gap in scientific knowledge concerning nanotoxicology and nanotoxicity, the emergence of new nanoengineered nanoparticles introduced many and new questions and challenges regarding the risks and benefits:

• To the living organisms (including Humans);
• And to the environment.

The nanoscale size of those nanoparticles, associated with their highly increased surface area available for reactions allows them to penetrate the biological structures, enventually interfering with their normal function. Of course, this interference, when occurs may be nanotoxic or beneficial. 

Scientifically evidence-based proofs are the only way to demonstrate the nanotoxicological or benefical effets of each specific nanoengineered nanoparticle, for each specific set of physiological conditions.

Nanoengineered Nanoparticles in Consumer Goods

There are consumer goods being sold as commercial products containing nanoengineered nanoparticles in their composition.

Regarding the possible toxic, harmless or beneficial effect of these nanoparticles to users, the information available to the general public is, in some cases absent or poor and vague.

These consumer products fall into several categories, regarding the use by consumers and the intended purposes.

However, there is a group of consumer goods already introduced into the commercial channels that has been a particular target of debate: cosmetics, sunscreens and personal care products. Follow some examples: 

• Deodorants;
• Soaps;
• Toothpastes;
• Shampoos;
• Hair conditioners;
• Sunscreens;
• Anti-wrinkle creams;
• Lipsticks;
• Blushes;
• Eye shadows; 
• Nail polishes;
• Perfumes;
• After-shave lotions.

At this point, I want to express my personal opinion on this subject (and I want to make my position clear): the presence of nanoengineered nanoparticles in consumer goods is not necessarily harmful, as has been published in a sensationalist way in non-specialized press (especially in a minority of non-specialized press).

I even admit that a significant percentage (or even the most) of these manufacturers have conducted tests in their laboratories in order to ascertain the nanotoxicity or the beneficial effects of these nanoengineered nanoparticles and the results have confirmed its safety. it is common to hear in television ads a phrase like "after tests conducted in our laboratories ...".

I even admit that a significant percentage (or even the most) of these manufacturers has contracted independent external laboratories to carry out tests in order to determine the nanotoxicity or the beneficial effects of these nanoengineered nanoparticles and the results have confirmed its safety. It is also common to hear in television ads a phrase like "after tests conducted by independent laboratories highly accredited ...".

However, given the poor and vague (or totally nonexistent) information provided to consumers about the safety of these nanoengineered nanoparticles in some products and given the noise made by some non-specialized media, the climate of suspicion and fear was installed in a few layers of populations.

Therefore, two questions arise:

• How can consumers rely on the laboratory test results?
• How can consumers rely on the quality of these products?

In my personal opinion, there is only one answer: through regulation.

These products will inevitably need to be tested in the laboratory, being these tests closely monitored by regulatory authorities.

If the different tests are supervised by regulators and the results are approved, then consumers can use these products safely and confidently.

If the different tests - monitored by regulators - are disapproved, then the products must be removed immediately from the market. These manufacturers must reformulate their not approved consumer goods, in order to improve them to the point of being beneficial for consumers. Again, new tests, once approved, will give credibility and confidence to their use by consumers.

Thereby, through regulation, ends the climate of suspicion and fear regarding the introduction of nanotoxic nanoengineered nanoparticles into the skin of consumers and into the environment.

Regulation will put an end to all doubts that perhaps exist: everything will be crystal clear and transparent with regard to this subject. Through regulation, all players win and nobody loses. I highlight here some of the many advantages:

• Citizens are reassured and start to consume these products with confidence;
• This sector is no longer subject to debate and its credibility rises to an even higher level;
• Regulatory authorities demonstrate once again that they are actively monitoring the toxicity risks of society and respond positively and in accordance;
• The nano-fear decreases significantly, walking this way to fade (if additional measures are taken in other fields).

Personally, I admit that these nanoengineered nanoparticles are quite beneficial. But there is nothing like demonstrating this fact to consumers around the world, with the guarantee of the accuracy of regulatory authorities.


"The Wonders and Worries of NANOTECHNOLOGY" Video

On February 7, 2012 was published on YouTube a video titled "The Wonders and Worries of NANOTECHNOLOGY". This great video was directed and produced jointly by:

• Nanoscale Informal Science Education Network (NISE Net); 
• National Science Foundation (NSF);
• www.whatisnano.org.

This video is simply a "must". "The Wonders and Worries of NANOTECHNOLOGY" is a short video (4 min. and 33 sec.) which aims (according to its co-directors and co-producers - and I agree) to aid in the discussion of the societal and ethical implications of nanotechnology.

In my opinion is well worth watching this video several times, due to the extremely important message that transmits. In order to present a practical example of real life, face creams and skin care products as a whole are referred. The video also focuses on promoting debate of the societal and ethical implication of nanotechnology. As the narrator states, "whenever a new technology emerges, it is necessary to evaluate the risks against the benefits".

Some of The Main Types of Nanoengineered Nanoparticles Reported as Nanotoxic

Some of the main types of nanoengineered nanoparticles reported as toxic are (among others) fullerenes, carbon nanotubes (CNTs), inorganic nanoparticles, organic nanoparticles and quantum dots (QDs).

Introduction

Following up the approach initiated in my article "The Roots of Nano-Fear Decoded", and continuing with the approach taken in my previous article - "Indicators of Nanotoxicity" - I will now address another nanotoxicity topic: some of the main types of nanoengineered nanoparticles reported as nanotoxic. Later on, I will attempt to point out ways and propose solutions in order fight and prevent nanotoxicity.

Some of the main types of nanoengineered nanoparticles reported as toxic are (among others):

• Fullerenes; 
• Carbon nanotubes (CNTs);
• Inorganic nanoparticles;
• Organic nanoparticles;
• Quantum dots (QDs).

Fullerenes

Fullerenes are nanoparticles in the form of spherical cages containing 28 to 100+ carbon atoms.

The most studied fullerene contains 60 carbon atoms. This particular type of fullerene is a hollow sphere and its atomic arrangement consists of pentagons and hexagons of carbon interconnected.

The fullerenes show the capability of being subjected to extreme pressures and regain its original shape when pressure is no longer applied - something equal or identical to resilience, I would say.

When the fullerenes are not modified, these molecules do not react with each other.

However, when fullerenes are engineered, some specific carbon atoms may be replaced by other atoms. Consequently, the nanoengineered fullerenes show the capacity of establishing bonds with other molecule. The physical result obtained is a material hard and elastic at the same time.



Carbon nanotubes

Carbon nanotubes (CTNs) are hollow cylinders consisting of a crystalline form of carbon molecules arranged into a hexagonal network of carbon atoms. CNTs can have diameters around 0.7 nm.

Regarding the CNTs length, this can vary between a few nanometres to several millimetres. Each end of a CTN can be opened or closed by a fullerene half-molecule. 

Regarding the complexity of the CNTs wall, there are two main groups of CTNs. These CNTs can have:

• A wall consisting of a single layer: Single-Walled Carbon NanoTubes (SWCNTs);
• A wall consisting of several layers: Multi-Walled Carbon NanoTubes (MWCNTs). MWCNTs can also be perceived as a coaxial arrangement of carbon cylinders of increasing diameters having a common axis.

The diameter of MWCNTs can reach values such as 20 nm. MWCNTs are chemically and thermally very stable. The nanofabrication of MWCNTs normally requires the presence of metals. The presence of these metals (e.g. Co, Fe, Ni, and Mo) can play a significant role on the toxicity of these MWCNTs.

It is considered that a CNT having the dimensions 20 nm width x 2.000 nm length may have 100 x more surface area than a spherical nanoparticle with a diameter of 20 nm. Under specific conditions, this can interpreted as an indicator of high toxicity of the CNTs.

On the other hand, CNTs show a great tendency to agglomerate. This fact may be a cause for a significant reduction of the total area of CNTs capable of interacting with Human cells or their components.


Inorganic Nanoparticles

Inorganic nanoparticles are frequently insoluble or show a poor solubility. Inorganic nanoparticles can be composed of pure metals or various inorganic alloys.

Among the inorganic nanoparticles, nano-titanium dioxide (nano-TiO2) is one of the most studied due to their nanotoxic effects.


Organic Nanoparticles

Organic nanoparticles are also frequently insoluble or show a poor solubility. Organic nanoparticles can be composed of various organic substances. These various organic substances are commonly insoluble polymers. Different organic radicals can be grafted to these insoluble polymers.However, organic nanoparticles can also be materials involving entrapment, encapsulation or surface adsorption of a bioactive substance.


Quantum Dots

Quantum dots (QDs) are nanoengineered nanoparticles.

The main properties of QDs are:

• High photostability;
• Strong light absorbance;
• Excitation by single-wavelength;
• Size-tunable emission.

Due to their physical properties, QDs are considered semiconductor nanocrystals.

QDs are usually composed of a core of a semiconductor material enclosed in a shell of another semiconductor material with a larger spectral band-gap. 

A typical QD has a diameter ranging from 2 to 8 nm.

QDs are extremely diversified. Therefore, the toxicity of QDs requires to be carefully characterized individually for each type of QD.

Indicators of Nanotoxicity

Despite being presented here some of the indicators of nanotoxicity of nanoparticles, there is still a wide gap of knowledge in regard to this specific topic and nanotoxicology as a whole. However, in spite of the wide gap of knowledge, many worthy efforts and a whole series of hard work in this field are underway already. Nevertheless, many challenges are still waiting to be overcome.

Preface

In the alignment of my article "The Roots of Nano-Fear Decoded", and preceding the approach taken in my previous article - "Nanotoxicity in Humans" - I will now address a nanotoxicity overview, dedicated to indicators of nanotoxicity. Later on, I will attempt to point out ways and propose solutions in order fight and prevent nanotoxicity.


Introduction

Traditionally, in toxicological studies carried out at macroscale or bulkscale, the toxic effects are normally correlated to the quantity of toxic product to which individuals are exposed.

This rule of the thumb means that "the greater the mass of toxic substance absorbed, the greater the toxic effect on individuals exposed".


Specific Surface

However, in the case of nanotoxic nanoengineered nanoparticles, once again the macroscale rules don’t apply. It has been demonstrated that the measured nanotoxic effects are not linked to the mass of the nanotoxic nanoengineered nanoparticles.

Several studies find a reasonable correlation between the specific surface of a nanotoxic nanoengineered nanoparticle and its nanotoxic effects.


Several Additional Parameters

On the other hand, several parameters can additionally contribute to the nanotoxicity of nanotoxic nanoengineered nanoparticles. Furthermore, with the currently limited existing scientific knowledge regarding nanotoxicity and nanotoxicology, it is extremely complex to weight the relative impact of each of these factors in order to predict accurately the toxicity of a new nanotoxic nanoengineered nanoparticle under study.

The published scientific literature links the observed nanotoxic effects of nanotoxic nanoengineered nanoparticles to a wide range of different chemical and physical parameters, such as, for example:

• Number of nanotoxic nanoengineered nanoparticles;
• Size of nanotoxic nanoengineered nanoparticles;
• Shape of nanotoxic nanoengineered nanoparticles;
• Surface charge of nanotoxic nanoengineered nanoparticles;
• Crystalline structure of nanotoxic nanoengineered nanoparticles;
• Concentration of nanotoxic nanoengineered nanoparticles;
• Porosity of nanotoxic nanoengineered nanoparticles;
• Electrostatic attraction potential of nanotoxic nanoengineered nanoparticles;
• Degree of agglomeration of the nanotoxic nanoengineered nanoparticles;
• Hydrophilic/hydrophobic behaviour of nanotoxic nanoengineered nanoparticles;
• Synthesis method employed on the nanotoxic nanoengineered nanoparticles;
• Post-synthesis modifications of nanotoxic nanoengineered nanoparticles.

Final Comments

Despite being presented here some of the indicators of nanotoxicity of nanoparticles, there is still a wide gap of knowledge in regard to this specific topic and nanotoxicology as a whole.

However, in spite of the wide gap of knowledge, many worthy efforts and a whole series of hard work in this field are underway already. 

Nevertheless, many challenges are still waiting to be overcome.

Nanotoxicity in Humans

Routes for entry of nanotoxic nanoengineered nanoparticles into the Human body. Destinations of nanotoxic nanoengineered nanoparticles, after entering the Human body.

Preface

Following my article "The Roots of Nano-Fear Decoded", I start here an attempt to approach nanotoxicology and nanotoxicity. Later on, I will attempt to point out ways and propose solutions in order fight and prevent nanotoxicity.



Introduction

As I wrote in "Nanopollution Revised", addressing nanopollution without addressing nanotoxicology is (theoretically and practically) an artificial effort, I would say. Nanopollution is present in the environment, which in turn affects the biosphere (including Humans). The biosphere is exposed to the nanotoxicity and thereby contaminates the environment. There is therefore a circle inseparable. However, due to space limitations, this article will try to address the nanotoxicology and nanotoxicity.

Of course, what I write is in line with the way I understand this issue in the present.

Not all nanoparticles are nanotoxic. In my personal opinion, naturally occurring nanoparticles are not toxic. I can possibly consider some exceptions - if supported by scientific evidence (e.g. nanotoxic natural occurring nanoparticles released in forest fires). However, unfortunately not all forest fires are of natural origin. Nature has already demonstrated many times that knows how to ensure balance and harmony rather than the Mankind knows how. The Mankind must increasingly learn the lessons that nature has to teach us all.

Furthermore, even though some exceptions as valid, it does not seem to me that the nanotoxicity of naturally occurring nanoparticles has meaning when compared with the nanotoxicity (under study) on some nanoengineered nanoparticles.

Moreover, I believe that not all nanoengineered nanoparticles are toxic. In other words, I believe that:

• Only a part of them are nanotoxic;
• Some are harmless to the health;
• And others are beneficial to the health.

Of course that my personal opinion has to be demonstrated scientifically, based on evidences.

Nanotoxicity obviously affects all living beings (including of course Humans). I will focus this article on some aspects of nanotoxicity in Humans, caused by the nanoengineered nanoparticles which are nanotoxic.


Routes For Entry of Nanotoxic Nanoengineered Nanoparticles Into The Human Body

Generally, nanotoxic nanoengineered nanoparticles can enter into the Human body through incidental and/or involuntary episodes. These incidental and/or involuntary episodes may be associated with a lack of knowledge by Humans. Therefore, through episodes of incidental and involuntary nature, the nanoparticles can enter the human body via (not necessarily in that order):

• Inhalation;
• Cutaneous;
• Ingestion;
• Other.

As an example, Humans can:

• Inhale incidentally and/or involuntarily air contaminated with nanotoxic nanoengineered nanoparticles;
• Incorporate into their bodies incidentally and/or involuntarily, through their skin (via cutaneous respiration) air contaminated with nanotoxic nanoengineered nanoparticles;
• Eat incidentally and/or involuntarily food contaminated with nanotoxic nanoengineered nanoparticles; 
• Drink incidentally and/or involuntarily water and consumer drinks contaminated with nanotoxic nanoengineered nanoparticles.

Destinations of Nanotoxic Nanoengineered Nanoparticles, After Entering The Human Body

After entering the Human body, nanotoxic nanoengineered nanoparticles can undergo different fates:

1. Can be totally or partially excreted;
2. Can be totally or partially metabolized;
3. Can be totally or partially cumulated into cells, tissues and organs.

Nanotoxic nanoengineered nanoparticles can be excreted, for example:

• Through the kidneys, during the blood filtration in which the nanotoxic nanoengineered nanoparticles are to be a product of excretion (a constituent of the urine);
• Through the intestines, during the formation of faeces and excreted through the anus;
• Through the sweat glands in order to be excreted in sweat during perspiration;
• Through the lungs (after venous blood having executed gas exchanges with the lung alveoli) being released into the environment during the exhalation.

Nanotoxic nanoengineered nanoparticles can be metabolized: 

• In the liver; 
• In the spleen.

Nanotoxic nanoengineered nanoparticles can circulate in the blood stream and lymphatic vessels. Through this path, they can travel around the entire Human body and eventually accumulate into diverse organs (e.g. brain cells).

Insoluble or low solubility nanotoxic nanoengineered nanoparticles in biological fluids are a great cause for concern.

Some insoluble or low solubility nanotoxic nanoengineered nanoparticles can pass through the several defence mechanisms of the Human body. Thus, these insoluble or low solubility nanotoxic nanoengineered nanoparticles can then be transported through the body in insoluble form. Therefore, some insoluble or low solubility nanotoxic nanoengineered nanoparticles can pass to the bloodstream (blood vessels and/or lymphatic vessels) after passing through the respiratory membranes (pulmonary alveoli, through gas exchanges) and/or gastrointestinal membranes. These insoluble or low solubility nanotoxic nanoengineered nanoparticles are then distributed to various organs and eventually can accumulate at specific locations. 

Other insoluble or low solubility nanotoxic nanoengineered nanoparticles find a direct shortcut to the brain: after inhalation, travel along the olfactory nerves and penetrate directly into the brain neurons.


Final Comment

Given my personal belief that nanotoxicity of nanoparticles is practically caused only by nanotoxic nanoengineered nanoparticles, nanotoxicology and nanotoxicity are relatively new subjects that emerged after the appearance of nanofabrication.