CNTs are cylindrical molecules that comprise sheets of single-layer carbon atoms like graphene rolled up. CNTs can be either single or double-layered. CNTs have many remarkable properties and applications, but we will read mostly about their use in the health sector because of small dimensions and their high surface area, which has the capability of conjugating or absorbing with a broad range of diagnostic and therapeutic agents. CNTs have high thermal and electrical conductivity, and they are very elastic. The most common applications of CNTs in health are that they can deliver drugs to the targeted cell, help treatment against cancers, and helps in bone regeneration. CNTs only cures damaged cancerous cells but don’t affect normal healthy cells. This article delivers information about Carbon Nanotubes (CNTs) and their work in the diagnosis of several diseases and their effective treatment as the human body is made up of many carbon atoms.
In today's world, diseases are going through a fast evolution, the current diagnostics, delivery of drugs, and treatments are turning less operative. Therefore, now modern health care wants more sophisticated and operative carriers. CNTs offer normal detection or diagnosis of different diseases, for instance, leukemia, breast cancer, etc. Slowly nanotechnology's concept and materialization have reached a greater extent. CNTs are very strong, stiff, and flexible with excellent properties. Nanotechnology is the engineering of functional systems at the molecular scale. In the fields of precise drug delivery and methods of bio-sensing for monitoring of health or treating a disease, CNTs are highly researched. Carbon nanotubes can easily be changed with a broad range of molecules through various procedures. The real use of Carbon nanotubes in biotechnology and biomedical includes their use as channels for biosensors, drug delivery, neuron growth and regeneration, vascular stents, and enzymes sheathe, and DNA's transfection.
Truly, Carbon nanotubes are said to be the next generation of systems for the delivery of drugs for many reasons; the major one is its ability to transport drugs to the targeted tissues and cells. CNTs are also aiding in the manufacturing of materials and equipment pieces like, for cell and tissue engineering, scaffolds are being made. Also, for observing some aspects of human health, sensors are being manufactured to use. Carbon makes up a lot of the human body; that's why it is considered a very biocompatible material. CNTs have no toxic effect. Single-walled nanotubes (SWNTs) have enhanced solubility and allows effective drug delivery/tumor targeting without altering the function of immune cells. The ability to functionalize (chemically modify) the CNTs' sidewalls also give rise to biomedical applications. It is showed that a nanotube could be bonded to a single strand of DNA that can then be successfully introduced into the cell. This article makes an effort to talk about CNTs and their relevant work in the field of health and medicine.
CNTs are seamless graphite sheets tubes with the nano-sized diameter and contain Multi-walled carbon nanotubes (MWNTs) and Single-walled carbon nanotubes (SWNTs). Some nanotubes have opened terminal parts; some have closed with full fullerene caps. CNTs are also called as 'King of Nanomaterials.' This name Carbon nanotubes come from their nanometer-scale size. An ideal nanotubeis defined as a cylinder assembled by a network of carbon atoms and at the end covered by half a fullerene molecule.Depending on the diameter and direction of the sheet, it can be either metallic or semiconducting in nature. CNTs have the highest theoretical strength in comparison to natural materials. CNTs are 100 times stronger than steel. CNTs have advantages in absorbing electromagnetic radiation, thermal conducting, field emission, storing of hydrogen, catalyzing, and absorbing. Graphene sheet can also be rolled in more ways than one, thus making different types of CNTs with remarkable electronic properties and other unique properties, which makes them stiffest and strongest fibers known. Therefore, CNTs have gained huge attention and been learned for different applications. Literature hopes that CNTs would be useful one day in the treatment of cancer, gene therapies, and in delivery of vaccines. There are many CNTs characteristics and usages which takes full advantage of unique properties of CNTs like, mechanical strength, aspect ratio, thermal and electrical conductivity. CNTs are used in many applications like energy storage, fibers and fabrics, Air & Water Filtration, biomedical applications, CNTs catalyst supports, and many other applications, but in this article, we will be looking at the medical application of Carbon Nanotubes in Health.
Carbon Nanotubes have properties like high in thermal conductivity, high electrical current density, and conductivity because of graphene's symmetry and its unique electronic structure. Other properties are aspect ratio, very elastic, very high tensile strength because of the sp2 covalent bonds made in-between the single carbon atoms, Perfect linear or rational bearing, high flexibility (can be bent greatly without breakdown), a low thermal expansion coefficient and good electron field emitters.
CNTs also have many exclusive electrical, optical, chemical, and structural characteristics that make them eye-catching as the transporter of drug and bio-sensing for the diagnosis, treatment of numerous diseases, and the noninvasive monitoring of the levels of blood and other body's chemical properties.
These structural and electrical characteristics best serve Carbon Nanotubes as much as bio-sensing is concerned because the change of current in carbon nanotubes can indicate specific biological beings they are made to detect. Carbon Nanotubes being small enables them to transfer small drugs doses to selective diseased cells inside the body, thereby lessening the negative effects and damage to healthy cells, unlike other drugs.
CNTs, when being functionalized with lipids, have shown enhancement in solubility that would make its movement smooth so that it will not block any organ and also move easily through the body. Carbon Nanotubes also displays strong optical absorbance in specific spectral windows such as near-infrared light. When CNTs are functionalized with tumor cells, specific binding entities have permitted the specific damage of tumor cells with Near-infrared light in the application of drug delivery.
1. Controlled drug delivery
Carbon Nanotubes have shown applications in targeting specific unhealthy or cancer cells to kill them. However, it doesn't harm normal cells and considerably lessens the side effects. An anti-cancer molecule like methotrexate was discussed where a fluorescent probe was connected to MWNTs. The connected probe permits the monitoring of the cancer cell's nanotubes uptake. Fluorescent signal from cells was proportional to the nanotube's dose. While using CNT like a delivery system for drugs, a specific targeting ligand (small peptides or antibodies) should also be connected like the drug. These targeting ligands bind to the selective molecules and can help narrow down the cells that get the delivered drug. Targeting ligands severely enhances the action of the drug bounded by ensuring that more amount of the drug reaches the targeted cells.
In comparison to other drugs, CNTs show good cell penetration, administers more drug to cells, thus more antimicrobial effect but no negative side effect, low toxicity in the body, and highest strength to weight ratio. Molecules encapsulation provides controlled release and protection. All this results in a good drug delivery basis.
2. Vaccine Delivery
CNTs that are Peptide functionalized can penetrate the cell membrane of mammalian and translocates to the nucleus. The main aim of vaccine delivery through Carbon nanotubes is to link CNTs to an antigen while regaining its conformation and with right specificity convincing an antibody response.
3. Treatment of broken bones
A broad range of materials, such as peptide fibers or polymers, makes scaffolds that may face rejection from the body. The natural combination of hydroxyapatite crystals and collagen fibers makes bone tissue. Research reveals that nanotubes can imitate collagen's role as the formation material of scaffold for hydroxyapatite growth into the bone. CNTs may transport the drugs to weak bones, safely without any toxicity.
Researchers have enfolded SWNTs with double-stranded DNA as a pencil wrapped with electric wire, which then acts as a biosensor and permits the detection of intracellular contaminants. An aligned CNT ultrasensitive biosensor was developed for the detection of DNA.
5. Laser mediated killing of cancer cells
Researchers placed CNTs solutions under an infrared laser beam that was capable of heating the solution above 1580 F within 2 minutes. The heat will destroy the cells quickly when the nanotubes were placed inside the cells and radiated by the laser beam. This CNTs behavior is credited because of absorbing near-infrared, which are a bit longer than visible light rays. This near-infrared goes safely through normal cells without any harm. Also, CNTs surface has been coated with antigens that are also expressed by the cancer cells, acting as an 'artificial antigen-presenting cell,' therefore triggering an immune response and, therefore, the production of T cells that specifically target that antigen.
6. Tumor therapy
Nanotubes with folate commonly target unhealthy cancer cells using folate receptor that's present on its surface. Fullerene resists getting broken down by the body. The structural strength of CNT is specifically required for containing compounds that are likely to do damage if released in normal healthy cells.
7. Neurons Regeneration
Carbon Nanotubes are excellent conductors of electricity that make them very beneficial in neuron regeneration, which can happen well on Carbon nanotube beds; 4-hydroxyonoenal modifies the surface and helps in the growth of neuron, enhancing the length of neuron and degree of branching over CNTs.
8. Monitoring of Glucose
One way is a glucose sensor continuously being integrated into a small needle that must be implanted under the skin to monitor levels of glucose after a few days.
The second way is in which the blood should be applied on strips. Both of these ways aren't only invasive but also yield wrong results.
9. Antitumor drug sensitivity test
MWNTs- modified glass carbon electrode (GCE) detected change in tumor cells electrochemical behavior, which was induced by antitumor drugs. This method could serve as a convenient means to learn about tumor cells' sensitivity to antitumor drugs.
Some other applications are
- X-ray aimed at in-vivo imaging Osteoporosis
- Blood test for early detection of breast cancer
- In dialysis because of High compatibility with blood
- Binding of Plasmid DNA and condensation into the functionalized CNTs
- As protein(<80 KDa weight) carriers
- As vectors in gene delivery due to small size
Currently, available drug carriers possess certain limitations like cell penetration which could be overcome by the utilization of CNTs because of its large surface area capable of absorbing, nano-pores having compatibility with blood, destroys the damaged cells, and delivers drugs to specific receptors without affecting the normal cells in the way. CNTs have many remarkable properties and applications that make it different than any other known material.