No one would have predicted that the nature of our technological identity would be a threat to an era without it, however many of our own generation are now calling into question life without futuristic innovation, a world without nanotechnology.
The term “nano” means one-billionth of a meter. Now, if we really take a moment to think about what that term constitutes, it is only fitting to be secure in encompassing the science behind manipulating matter and nanostructured materials within technological dynamism.
As a result, one-billionth of a meter doesn’t only suggest what it is referring to, but also how a nanoscale is not only measured by one-billionth of a meter, rather one billionth of our world, what we as humans are used to seeing, used to observing with our naked eyes.
Since our human race has adapted to sustainable life on a scale of meters and kilometers, it is difficult to fathom a world that is 1000 times smaller than the world we already live in, a world even more infinitesimal than the microscopic scale.
Imagine stepping out into a world where your backyard did not consist of a patio, barbeque or chairs, but instead minuscule atoms, molecules, proteins or cells. Now suppose you could configure these atoms in any way, shape or form you wish, almost like tiny puzzle pieces coming together in different patterns.
With these atoms being shrunk down to what is referred to as the “nanoscale,” your naked eye wouldn’t only be observing what the molecules are made up of, but how they move and interact with each other as well. This concept of making something out of what appears to be nothing to the human eye, or configuring these “puzzle pieces” in innovative methods, is called nanotechnology, one of the more foremost precursors to groundbreaking science as well as technology in our societal era.
Why Is Nanotechnology So Popular?
Technological Sustainability & Growth:
- I don’t believe our generation can process or fathom an era in which we lived with the convenience of technology or devices. This is because we as a society have inclined ourselves to adapt to the use of technological pieces on a daily basis. To uphold the reputation of technology and how it plays a prominent role in our daily lives, we must realize how nanotechnology specifically advanced energy storage, products on the market as well as applying nanotechnological solutions to everyday situations.
Commercialization & Growth Of Technological Market:
- Since nanotechnology & generation of carbon nanotubes are an advancing field in the era of technology, it opens doors for economic sustainability. Nanosensors don’t only contribute to the financial status of our international market, but also are cost-efficient, as manufacturing products that require reduced amounts of materials are more ideal and affordable for the purpose of conserving resources.
Application To Different Fields:
- In today’s day and age, specialties targeted towards certain fields can also be applied to different career paths as well as areas of study. For example; being an engineer is versatile to fields in medicine that require bioengineering skills for the purpose of using these principles for the basis of biological technology/systems. Much like that example, nanotechnology is subjective to many fields of study including nanomedicine, electrical engineering, environmental studies or mechanical engineering.
- To uphold the expectations of how a society operates, it is essential to understand how exactly nanoscience connects to multiple career paths to revolutionize the concepts behind nanotechnology itself.
Now you may be asking, is there a certain device or sensor that can detect the presence of nanomaterials or molecules on the “nano” scale? Well, yes, in fact, there is. These devices are referred to as “nanosensors,”
and are chemical or mechanical devices used to discover an array of parameters in relation to physical factors such as climate change on a minute scale, or blood-borne diseases in medical technology. Our application of sensors used on a daily basis, possibly to detect pollution or even oncoming traffic fuels our need to apply this learning to nanoparticles and arrangement of molecules on a molecular or atomic scale.
Applications & Significance Of Nanosensors
Nanosensing technology has seen much promise in terms of applications within the medical field, technological era, and consumerism. While nanosensors and conventional sensors operate in the same way, with the same goal to detect changes and concentration of quantities, except what differs these microsensors from conventional ones, include their defining ability to use a different active sensing element to detect minute particles.
There are many different classifications and categories that nanosensors can be placed in. Active nanosensors are components that require forced from outside environments to function, while Absolute nanosensors have certain requirements also known as “reference points” that they refer to based on the absolute sensors type (absolute pressure nanosensors).
These sensors are considered to be of innovative significance, as it constitutes a platform for not only emerging technology in chemical species or minute scales but also the beginning of entrenching a technological based revolution. Uses are listed in the following.
- Discovering airborne pathogens & bloodborne diseases: Nanosensors are accustomed to control or detect high concentrations of hazardous substances released through chemical spills or when materials gain chemical exposure. The small size of nanowires and tubes can harness shifts in electrical conductivity to make it more resistant to bacterial agents. In industrial settings, these sensors can be utilized to detect chemical pathogens released by industrial plants
With regards to bloodborne diseases (pathogens that are transported within human blood which can cause serious illness/disease), nanosensors assist in diagnosing the patient and extracting the source of the bloodborne pathogens. The delivery of diagnosis, medical treatments, and patient prognosis can be sustainable with the use of nanosensors, which enables “lab-on-a-chip” (LOC) technology, a device that combines laboratory functions on a single chip, to ensure quality within the healthcare system.
- Tracking the temperature of live cells & nanofluids: Recently, research teams at the Princeton University & UC Berkley constructed noninvasive devices by the name of “nano thermometers” that can be inserted in singular cells to measure their temperatures. This approach allows for semiconductor crystals which indicate a color change according to shifts in temperature of the cells.
In contrast, to control the effects of excess heat from electronic devices, studies are being researched to cultivate substances such as “nano fluids” which have characteristics to manage thermal energy from these devices. Nanosensors are used to assess effects brought on by the fluids.
- In today’s developing era, we are consistently looking for new ways to innovate already existing technology, for the purpose of convenience or being a building block for other creations as well. Nanosensors encompass and practice these values, as they do not only produce more efficient and faster results or responses but also hold more power than large-sized computers.
These materials hold the dexterity to improve their speed of detection towards nanoparticles and due to them being much smaller than conventional sensors, they can be placed on smaller materials such as test strips of paper. Micro-sized particles can do what normal sized particles can’t-use their larger surface area to be more reactive & efficient with other molecules, producing a more reliable, coordinated and faster version of already existing conventional materials.
- Within our everyday life, we don’t realize the multiple devices we have to use to rid stains on clothing or make fabric more fire resistant and durable. Fabric and clothing that contain nanofibers or particles can be used to rid these issues, without causing stiffness, damaging or thickening of fabric.
- More accurate & increased data density are benefits initiated through the process of utilizing nanosensors to extract information. Along with the capabilities that nanosensors have to convey data and characteristics about nanoparticles, the measure of information to be stored in these devices amount to far more than the data density levels of other technological pieces
- Monitoring water distribution & quality, especially in developing countries creates a gateway for favorable outcomes regarding water supply as well as infrastructure to be produced by these microsensors. A “smart pipe” prototype system was developed to detect pipe leakage water pressure and dormant water sections using the sensors, including the advancement of a wireless-based infrastructure for public water systems.
By extension, carbon nanotubes also play an efficient role in fields such as electronics, for the purpose of building integrated circuits from the semiconductor material, which holds the potential inaugurate a new generation of technological pieces that are more efficient with energy usage, rather than electronics made from silicon chips.
Within the field of dentistry & healthcare, researchers are currently advancing the effects of titanium dental implants (surgically implanted into the jawbone to improve dental lifespan or prosthesis- the percentage of implants need to be removed). Studies have conveyed that the jawbone reacts more efficiently with titanium dioxide nanotubes than the typical titanium implants.
How Do Nanosensors Operate?
First off, to determine how nanosensors work and the end result, we must go back to how different types of nanosensors operate and their functions.
One of the greatest examples to this day of nanosensors pertains to using calcium selenide quantum dots (semiconductor fluorescent nanoparticles that can be ingrained in organisms to explore abnormalities) to detect cancer and growing tumors within the body, as well as medical imaging, to pinpoint the stage of the tumor and whether it is malignant (invasive) or benign.
Nanosensors hold unique abilities as they have receptive signals (mechanisms) which can recognize and store information from nanomaterials. When comparing these microsized devices to regular sized sensors, it is vital to keep in mind that they operate in the same relative way and also hold the same type of configuration, but as mentioned before, nanosensors are developed based on the nanoscale units as well as dimensions of nanometers (1 nanometer is equal to 1 billionth of a meter).
These sensors can precisely distinguish healthy cells within the body versus the ones cause certain abnormalities, deficiency or lack of functional bodily growth, which why they are currently popular in the field of medicine, specifically relating to cancer research and tumor imaging. Within the body specifically, these sensors are able to measure any forces of pressure, temperatures & concentration/volume of live cells and displacements or fixations. With regards to electronics and technological pieces, different sensors types can be utilized in different ways, to perform accurate function of measuring electrical conductivity levels.
That being said, both chemical & mechanical methods play an active role in monitoring the electrical energy of nanomaterials, except electrochemical sensors recognize changes in the material if contracted by an analyte (a chemical substance that is used in analytical chemistry-otherwise separated or divided through analytical methods) based on the accumulation or deficiency in electric charges. Nanosensors are also equipped to identify changes that are large in scale (macroscopic changes), as they assist in determining the external environment/interaction from which they came and confer these shifts to other nanodevices or elements.
Types Of Nanosensors:
- These sensors are constructed from silicon, nanowires and carbon nanotubes. They hold the capacity to detect molecules as well as atoms at extremely low concentrations and can be used to detect early onset cancer types, genome mapping, diagnosis of metabolic conditions and environmental forecasting or estimation of food quality. Many nanomaterials have been explored based on their electronic and mechanical properties used to improve biological sensing.
Materials that help biosensors to perform biomolecular disclosure or using them as amperometric devices to test for glucose through enzymatic detection include nanowires, particles, oxide or rods made up of nanocrystalline matter (polycrystalline/crystallite material with a size of a few nanometers). The surface of the sensor is composed of receptors that can sense or target types of biological molecules and as soon as a molecule is captured on the sensor’s surface, the changes in the agent are known.
- These nanosensors function through identifying changes in a material’s electrical conductivity on the basis of the nanoscale region and mechanical forces of the object. As a result, nanomaterials used in or as mechanical sensors provide a shift in the electrical conductivity of the material, when it is physically altered, which enforces a noticeable or perceptible response.
- For example; combining nanosensors with microelectromechanical systems (MEMS) can be useful for detecting the concentration of microorganisms in fluid samples or using minuscule, fluid base devices which contain gold nanowires to monitor cholesterol levels in the blood. A detectable response can be invoked using a capacitor (a double terminal electrical device used to store electrical energy in the form of an electrostatic field between its terminals), in which the physical shifts of the material initiates a change in the effect of a capacitor-known as the capacitance.
- Chemical nanosensors operate through also measuring differences in electrical energy and conductivity of nanomaterials or particles, once the chemical compound called analyte
- Nanotubes and nanowires are common examples of nanosensors due to their electrically compact figures can be flexibly applied to electrical components such as transducers (devices that can convert energy types such as light energy to electrical signals) and electric wires when an analyte is discovered
- Due to nanomaterials being high in their electrical conductivity properties, when being faced with the extraction of a molecule from the material, the conductivity will reduce. Carbon nanotubes also function in the same way. For example; if ammonia reacts with water and gives an electron to the carbon nanotube, it will make it more electrically conductive and hold a greater electric charge
- Built in the Georgia Institue Of Technology (Georgia Tech) during the late 1900s, these nanosensors contain specific particles at the end of the carbon nanotubes which help to calculate the “vibrational frequency” of the nanotube itself. These devices are used to monitor and detect chemical occurrences or reactions in nanoparticles.
How Are They Constructed (Nanofabrication):
What Is Nanofabrication?
Construction & design of nanomaterial-based devices that are measured in the nanoscale. It is known as a cost-effective method of using machinery and resources to create a smaller device/material.
- The nanofabrication process uses cutting edge technology to manufacture microchips and microcontrollers through structuring the properties or shapes of atoms and rearranging them to fabricate nanosensors.
- An example of revolutionizing regular sized devices through the process of nanofabrication are integrated circuits (a small chip that can function as electric components such as an amplifier, microprocessor or computer storage/memory and can perform calculations using digital or analog platforms). These circuits are built from analyzing each atom individually through nanomachinery components.
- Nanofabrication processes to produce nanosensors provides an evolutionary platform for engineers to utilize high-density microprocessors and sensors/chips.
How Are Nanosensors Built?
Basic materials used to build nanosensors include zinc oxide, silver, iron, metal (copper) & silicon.
- This is a technique of nanofabrication where parts of the sensor and device are built at the same time, so no assembly line is needed to cater to individual parts, which holds great advantage to integrated circuits. The material (atoms and molecules), as well as nanoparticles, are arranged in the desired format/shape. This process is responsible for ensuring that all materials are aligned with nanoscale measurements & can lead to increased waste as it requires large portions of materials.
- Nanolithography, optical lithography, and NIL (Nanoimprint Lithography) are approaches to the top-down method that are currently dominating the market. Since many top-down approaches involve etching (a process used to remove exposed material from the surface, or in this case, the material protected by a mask), there are a multitude of chemical and mechanical methods available to etching in nanofabrication.
- Based on the resolution levels for the nanosensors, the etching of the base product can be performed through acid-base substances or electronic lasers/beams.
- This type of nanofabrication involves atoms and molecules being carefully placed individually to form a nanostructure, which is why it might not be the most time-efficient method but does utilize fewer materials and by extension, less economic resources. As a result, this approach to nanofabrication uses chemical/physical forces residing at the nanoscale, to arrange smaller units of nanoparticles and sensors into greater structures.
- Many top-down methods have been used to fabricate nanoparticles such as atomic vapours on different material surfaces. An example would be how liquid techniques dealing with “inverse micelles” (micelle formed when nonpolar & polar phases of a substance have reversed roles), developed to create nanoparticles with magnetic and semiconductor properties.
- Common bottom-up methods include; scanning probe manipulation techniques and “self-assembly”. The probe manipulation tactic allows molecules/atoms to build structures one at a time but requires more efficiency, attention to detail and is a more intensive method than most. The self-assembly process involves molecules and atoms to organize themselves into nanostructures through measurements on the nanoscale, initiated by either chemical or physical factors.
- Tools used in the manufacturing of nanosensors through the bottom up method includes; carbon nanotubes, quantum dots, chemical synthesis, and metallic based nanowires.
- In contrast to the self-assembly approach, “molecular assembly”, another arising and evolving method for nanofabrication, includes how molecules more specifically can adapt into a defined arrangement on the nanoscale. The 2 types of molecular self-assembly are; intramolecular self-assembly & intermolecular self-assembly.
While there are more current and advanced ways listed as to how we are now developing nanosensors, there are a great number of emerging processes within the top-down & bottom-up categories.
- Chemical vapour deposition: This process entails chemicals reacting with each other to produce high-quality solid material and films, while also being used to deposit materials in the form of polycrystalline or monocrystalline.
- Atomic layer epitaxy: Enables depositing thick layers of one-atom bases on material surfaces.
- Dip-pen lithography: The atomic force microscope is placed into a chemical substance & transferred to writing on a surface (comparable to ink on paper).
- The 2 different types of nanofabrication processes (top-down nanofabrication & bottom-up nanofabrication) both have factors that question the effectiveness of resources such as time and money. As a result, the top-down nanofabrication method is much more resourceful when it comes to time spent on constructing nanosensors, although equipment used to build these devices such as etching and removal tools, packaging tools as well as lithography & pattern transfer tools are much more expensive (less resourceful when it comes to financial strains). This technique for nanofabrication is not feasible nor practical in the eyes of the industrial or commercial industry (not possible to extract material to produce nanofeatures; due to the size of sensors).
- On the other hand, while the bottom-up nanofabrication method is much more efficient when it comes to saving money with resources, it takes much more time to construct nanosensor devices than it would if the top-down method was utilized.
Education & Experience:
- With any field regarding technology, highly skilled and trained candidates are needed to execute otherwise difficult tasks when it comes to manufacturing software or physically constructing electrical components. The field of nanotechnology specifically requires not only those who understand how sensors and processors work but also apply that knowledge to minute components. Since nanotechnology is still very much a developing field, many people who are taking initiative towards growing the study’s platform are those who work directly in that specific field of study (workers who are at the forefront of nanotechnology).
- Those who are being trained to work within nanotechnology must be versatile to constant technological change and new fundamental sciences. Along with adapting to an environment where knowledge might be limited and discoveries are still continuing, it might be difficult to recruit people who are willing to build resilience towards what the field holds
Difficulty With Construction:
- While there is a general consensus that constructing these devices are a difficult task, as they are quite small, thus the name “nano” sensors, that is not the only issue encountered when manufacturing these microsensors. As mentioned before, with the nanotechnology field still developing, there are still methods being used to make the process more efficient.
- Workers constructing these devices may run into technical difficulties such as dust particles or outside/external agents damaging the nanosensors and nanofabrication process by clogging the insides of these devices. This might compromise the different methods used in fabrication such as self-assembly or the probe technique, making them unreliable in the face of external factors threatening to disturb the process.
- Since attention to detail is highly noted within the process of nanofabrication, molecules/atoms need to be precisely arranged in their intended position while maintaining a thorough degree of accuracy. This method might not be feasible with every infrastructure created, as the need to manipulate singular/molecular features during the process is unequivocal.
How Do We Fix This?
To be quite frank, there is no simple solution that will solve problems towards nanofabrication issues. Although, there are a multitude of options we as a society can encourage to start changing now, in order to work on building a sustainable solution for the future.
- Raising awareness and gaining attention towards issues with the nanofabrication process, is the first step towards generating a positive outcome for any solution. Overall, our society plays an instrumental role in providing support and funding necessary resources that are essential for nanomanufacturing techniques.
- Educating youth starting from a young age through programs dedicated to aspects of nanotechnology, carve a pathway for the next generation of brilliant minds to revolutionize nanotechnology and combatting issues with it. To target youthful minds in the present, we should incorporate nanotechnology courses within departments in school-based communities, to spark the interest of nanotechnology nationwide and hopefully, internationally as well.
- These courses can provide opportunities for hands-on experiences for developing nanotechnological fields, therefore nurturing future nanotechnological engineers.
- Technological scientists are currently developing techniques through self-assembly processes that achieve better influence on production and time limits, through inviting external forces such as magnetism or electronic flow that allow atoms/molecules to structurally organize themselves into different patterns, on the nanoscale. This can be performed through physical forces, or chemical forces (crystal formation in solutions).
- Finding more efficient materials to construct these prototypes, also opens doors for improving the construction aspects of manufacturing nanostructures. Researchers at Yale University have recently created ultrasensitive nanosensors which according to them, are much simpler to manufacture.
- These sensors utilize semiconducting nanowires which hold the ability to detect infectious agents and low concentrations of particles. Using conventional tactics such as silicon and insulating material to lay a foundation for the placement of the nanowires, the researchers are able to remove the silicon substance and make multiple nanosensors on the same chip.
- Recent studies have also discovered that applying already learned methods not only from other areas of technology but nanotechnology specifically, details how the top down fabrication processes can be used to enhance the bottom-up fabrication techniques and vice versa. Having more elements in the top-down method that make it more time efficient, can be applied to the bottom-up tactic, and the bottom-up’s economical efficiency to the top-bottom.
Nanosensors are nothing but the product of a technological revolution, the way we view our goal regarding innovation. While the nanotechnology field is currently still developing in its entirety, we must not dismiss how the science behind today’s present is the technological impact of tomorrow's future.
As you can see, we as a human race perceive nanotechnology as a tool for convenience, a lesser burden of economic implications and most significantly, the result of our imagination, the risk behind pursuing our definition of innovation. But here’s the thing, innovation has no end-there is no finish line to our imagination and especially no conclusion to our introduction. Technology is constantly changing, constantly developing, and it is our responsibility to change with it.
The impact of nanotechnology is expected to exceed the impact that the electronic revolution has had on our lives -Richard Schwartz
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