Applications of Nanotechnology in Veterinary Science
Nanotechnology is an emerging technology that allows us to work at an atomic and macromolecular level of structures and materials. It is considered a new discipline of science that has led to novel and innovative approaches that crosses all industrial sectors and scientific disciplines. Nanotechnology is no more a concept or theory, rather, it is an enabling technology with tremendous potential to revolutionize agriculture and livestock sector in India as well all over the globe. In medical sciences, they are used for diagnostic or therapeutic purposes, in the preparation of nanovaccines and nanoadjuvants etc. Moreover, the works in the treatment of cancer and in gene therapy has opened the door for a new era in medicine. Recently, various applications of nanotechnology started to find their way in the veterinary sector- animal therapeutics, diagnostics, production of veterinary vaccines, farm disinfectants, for animal breeding and reproduction, and even the field of animal nutrition. Nanotechnology has provided new tools for molecular and cellular biology, biotechnology, veterinary physiology, reproduction and many more which could be applied to the science and engineering of agriculture, animal and food systems.
The National Science and Technology Council of United States of America (2004) defined nanotechnology as “research and development (R&D) aimed at understanding and working with – seeing, measuring and constructing materials at atomic, molecular or at an even deeper level of matter. This correlates to length scales of roughly 1 to 100 nanometers. At this scale, the physical, chemical and biological properties of materials differ fundamentally and often unexpectedly from those of the corresponding bulk materials.’’ In a layman’s term it is engineering at atomic and molecular level. Naturally existing nano-scaled biological materials include, for example, the DNA (2.5 nm width) and protein molecules (in average 5 nm). This technology applies the principles and techniques of nanoscales to understand living and non-living biosystems and use their principles to create new devices integrated from the nanoscale.
Types Of Nanoparticles Used:
Liposomes- These are spherical nanoparticles having a lipid bilayer, mostly. They can be used as effective drug delivery system. Cancer therapeutic drugs and highly toxic drugs like actinomycin are seen to have higher efficacy and safety when used with liposomes, compared to the conventional systems. They are optimised to be used as topical, intravenous and intramuscular use.
Fullerenes a.k.a. Bucky Balls- These are a carbon allotrope that are being investigated as drug delivery system of antibiotics, antivirals etc. since they are hollow structures pharmacological drugs can be delivered easilyThese are also used as free-radical scavengers and have potential to stimulate host immune response.
Nanotubes- These are tubular structures like a sheet of graphite rolled and capped with Bucky ball. Also used as drug delivery system mediated by endocytosis or insertion into cell-membrane.
Quantum Dots- These are nano-crystals that can be made to fluorescence when stimulated by light. These can be used for imaging of sentinel nodes of cancer patients to determine the tumor stage and planning of treatment. Also for various immune asaays.
Nanoshells- These are spherical particles on a non-conducting material coated with a metallic shell, mostly gold. These can be used in diagnostic assays and non-invasive detection of tumours.
Micelles- These are nanostructures characterised by having a hydrophobic core and a hydrophilic shell. These have a long circulation time. The drugs are in the hydrophobic core that protects the drug from enzyme degradation. Micelles have low toxicity and high versatility in drug delivery system.
Metallic nanomaterials- Various metals like gold, copper and silver have been used. Metal nanoparticles are mostly used in bio-sensing, bio-imaging and cancer thermotherapy. However, the use of metallic nanoparticle(eg. Silver) is restricted as pet care shampoos and other topical preparations(eg: AgCu Nanoparticle formulations as mastitis treatment dip). This is due to the fact that nanotechnology is still in its early stages and toxicity is a major problem.
Ceramic nanomaterials- Ceramic nanoparticles are made up of materials such as silica, alumina and titania. They have several advantages over polymeric nanoparticle systems as they are easy to prepare and can be designed to a desired shape, size and porosity. They are biocompatible, with large surface to volume ratios and are extremely inert. They provide protection to the adsorbed particles they carry against denaturation induced by extreme pH and temperature.
Nanoemulsion- Nanoemulsions are dispersions of oil and water where the dispersed droplets are stabilized with a surface film composed of surfactant and co-surfactant. When the oil nanodrops contact the membranes of bacteria or enveloped viruses the drops surface tension forces a merger with the membrane blowing it apart and killing the pathogen. A characteristic feature of the nanoemulsion is that they don't affect cell structures of higher organisms, which make it ideal to use be used as bactericidal and veridical, topically, in animals and humans. The advantages of nanoemulsions include simplicity, inexpensiveness, stability, versatility and the ability to solubilise lipophilic substances and to protect them from degradation.
Nanobubbles- Therapeutic drugs can be incorporated into nanoscaled bubble like structures called as nanobubbles. These nanobubbles remain stable at room temperature and coalesce to form microbubbles at physiological temperature. These have the advantages of targeting the tumour tissue and delivering the drug selectively under the influence of ultrasound exposure.
Nano-propolis- Nano-propolis is a nano-sized propolis particles tied together to make it more effective without changing its properties by changing the size of propolis by different methods. Propolis has many advantages such as anti-inflammatory, antioxidant, anticancer and antifungal activity, etc. The consumption of free form of propolis restricts these benefits due to low bioavailability, low solubility, low absorption, and untargeted release. Different nanoencapsulation technologies are used to obtain nano-propolis. Nano-propolis is more easily absorbed by the body and, therefore more effective, because of their smaller size.
Application in veterinary uses:
Treatment and Diagnosis- Gold nanoparticles have replaced the treatment for prostatic cancer in dogs and cats. Nanoshells are nanoparticles that are being used to detect tumour cells and to kill the diseased ones. Certain magnetic particles are also used to detect the cancer cells and release the anti-cancer drug near it. Nanochips are being used for disease diagnosis in early stages and determining the drug efficiencies. These biochiops(microassays) are also used to determine the abnormalities at DNA level and study the gene expressions. The most important application is the “smart” delivery system. For eg: binding gentamicin with a linker keeps it inactive for as long as the linker is intact. And the linker can be broken by the toxins produced by Pseudomonas aeruginosa. This ensures that the drug is released and activated only in presence of the bacteria. Nanoparticles like dendrimers, Buckyballs(Fullerenes), QuantumDots etc. are being used at contrast agent for biomedical imaging. The bactericidal property of silver particles is historically recognised. Using this knowledge, biosynthesized silk silver nanoparticles has emerged as a viable alternative for antibiotics. It has effective bactericidal activity against both G+ and G- bacteria. It was also seen that these nanoparticles have the ability to overcome antibiotic resistance making it a strong contender against MRSA and E.coli.
Preventives- Nanoparticles have fundamental immunomodulatory function i.e. it potentiates immunogenic responses. It acts as adjuvant by slowing down the release of the attached antigen and being highly tissue specific. These nano-vaccines come in different forms like nano-emulsion(eg. Recombinant Bacillus anthracis spore vaccine), polylactic-glycolic acid nanoparticles(eg. Tetanus toxoid), chitosan(eg. Recombinant Leishmania vaccine, TB vaccine), gold particle-based vaccine(FMD vaccines), nanocapsulation(Newcastle vaccine) etc. Also, recently a revolutionary product using nanobiotechnology has been formulated by Ariviya known as MammaryO. It is a NanoBio-Liquid foam that serves as a preventive post-milking teat dip solution. Added benefits include being washable, biodegradable and safe on mammary epithelial cells.
Animal Health and Nutrition- Nanominerals(nano-ZnO) are available for commercial use as they are found to promote growth, stimulate immune response and increase the reproductive status of farm animals and birds. Also, nano-sized nutrients are so produced that they pass the GIT without any degradation and deliver the nutrients directly into the blood stream. This increases their bioavailability and durability without the use of any preservatives. Microencapsulation of the feed additives protects them from degradation by digestive enzymes and inactivation by light and oxidation. This enables their better dispersion and extended shelf-life. Nano-mycotoxin binder of MgO-SiO2 binds aflatoxins efficiently which makes the toxin unavailable to cause toxicity. The nanomaterials also provide better packaging materials which have antimicrobial effect (e.g., nano-zinc oxide), protection from external environment and UV rays (nano-titanium dioxide) and extra strength (nano-titanium nitride). The development of nanosensors enables the detection of any biological or chemical contamination even in a very small concentration in food system.
Animal Breeding- After mapping the human genome, geneticists are now rapidly sequencing the genomes of cattle, sheep, poultry, pig and other livestock. By including probes for the traits, like disease resistance and leanness of meat on biochips, breeders will be able to speedily identify champion breeders and screen out genetic diseases.
Animal Reproduction- Nanotechnology has many applications in this field. The “smart” drug delivery system enables a sustained hormone release(eg: gonadotropic hormone) along with protecting the said hormone from damage. Nanosensors are being used to detect reproductive disorders early on. Similarly, nanotubes are used to detect oestrus in real-time. They are implanted under the skin and have the capacity to bind and detect the estradiol at the time of oestrus. These signals can be centrally monitored to accurately identify oestrus in the herd. Even for fertilisation, nano-capsules loaded with bull semen has been devised that can be directed to ovary. Nanosystems are also used for cryopreservation of semen. Micro-injections of cryoprotectants having metallic nanoparticles that helps in fast freezing and, later on, fast and homogenous thawing. Thereafter, there is the use of microfluidics and nanofluidics to simplify the in vivo fertilisation in animal breeding. They analyse by controlling the flow of liquids through channels and valves, thereby sorting them. Nanoparticles of cadmium are used in low doses for animal sterilisation by directing the nanoparticles to the reproductive tract. Alternately, magnetic nanoparticles are delivered to the gonads which are externally heated by applying magnetic fields, in turn, sterilising the animal without any toxic chemical.
Meat and meat products- Nanotechnology in meat industry is generally in the form of nano-nutrients in food or nanomaterial that is used as packaging. Microencapsulation process can improve the dispersing ability of fat-soluble additives in the food products, enhances taste and reduces the use of fat, salt, sugar and other preservatives. Nanotechnology can be used to safeguard the micronutrients against chemical or physical damage during storage or transport. New advanced temperature tolerant packaging is developed for hot fills. Also, packaging that are very thin provides flexibility at the same have the functionality of anti-tamper, anti-microbial and anti-counterfeit. This packaging also supports freshness of meat, extends shelf-life and also reduces packaging waste simultaneously with food product waste.
Food safety through identity preservation- Identity preservation (IP) system is a system that provides consumers with information about the practices and activities used to produce an agricultural product. Today, through IP it is possible to provide stakeholders and consumers with access to information, records and supplier protocols regarding the farm of origin, environmental practices used in production, food safety and security, and information regarding animal welfare issues. Quality assurance of the safety and security of agricultural and animal products could be significantly improved through IP at the nanoscale, in turn, also increasing their value. Through IP it is possible to provide information regarding the records of the animal, food safety and security as well as the supplier’s protocol and animal welfare issues.
Nanobiotix technology for cancer treatment is recently gaining recognition. It is a nanoparticle with a treatment core which get accumulated in the tumour tissue when given intravenous. Thereafter, an external energy is applied to activate the nanoparticle to destroy the tumor cell.
Respirocytes and Microbivores are nanodevices that can function as RBCs and WBCS, respectively, with greater efficiency. Theoretically, respirocytes can detect the changes in the blood oxygen level and regulate the intake and output of oxygen as well as carbondioxide. Similarly, microbivores and expected to clear the blood stream in case of septicaemia by efficient phagocytosis and antigen trapping.
Existing researches have clearly shown their feasibility in introducing nanotubes and nanoshells into animal bodies to seek out and destroy the diseased cells. Therefore, it is reasonable to believe in the capability of the technology to develop in the next decade or so to meet all the applications hypothesized. Still in early stages, engineers, scientists and biologists are being recruited to work on cellular and molecular levels for significant benefits in healthcare.
Nanostructure are among the most impressive man-made materials that exhibit various physical, chemical and biological properties. These features allow nanotechnology to have innumerable applications in various sectors. In these recent years, nanotechnology has seen progressive research with promising results in every industry. More studies are needed to support the reliability of nanotechnology without any damage to animal, human and environmental health. There remains a huge gap to overcome in veterinary medicine; however, nanotechnology undoubtedly has potential tools for animal disease diagnostics and therapeutics. Therefore, it is necessary for intensive researches to continue, to bridge this gap. And the success will lead to a revolutionised and more advanced future where the treatment can be provided as soon as the diagnosis is done.
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Dr. Dibya Panda
BVSc. & AH, OUAT
Dr. Hemalatha Talluri
Dr. Amit Kumar Tripathy