Viral Nanotehnology (VNPs): An Emerging Field
Authors: Manpreet Kaur1, Dr. Anita Singh1, Neha2
1University College of Agriculture, Guru Kashi University, Talwandi Sabo, Punjab, India
2School of Agricultural Biotechnology, Punjab Agricultural University, Punjab, India



Nanobiotechnology is a field of nanotechnology which exploits biomaterials and devices on the nanoscale. It is a multidisciplinary field involving biology, chemistry, physics, material sciences, engineering and medicine.

Broadly, the work of nanobiotechnology is focused on two main areas. It aims at understanding the biological systems using nanobiotechnological devices and exploitation of biomaterials in fabrication of new nanomaterials.

Virus and Nanotechnology

A virus is a nanoscale particle that can infect the cells of a biological organism. Basically, it consists of genetic material (DNA, RNA) enclosed in a protective protein coat called 'capsid'. Viruses cannot reproduce on their own. They replicate themselves only by infecting a host cell. This property of virus of infecting, replicating and exiting from the host cell can be exploited for various uses. The field emerging from the exploitation of these properties is called viral engineering.

Materials at nanoscale (1-100 nm) have unusual but highly desirable electrical, mechanical, magnetic, thermal, dielectric, optical and catalytic properties. These properties enable their use in various sectors like electronics, material science, communication, medical sciences, pharmaceuticals and energy based sectors.

As viruses are nanoscale particles, they have following attracting features for use in nanobiotechnology:

• Size: Viruses range in size from 30 nm (ex: cowpea mosaic virus, CPMV) to 140 nm (ex: chilo iridescent virus, CIV).

• Ability to self- assemble into monodisperse nanoparticles (NP) of discrete shape and size with high degree of symmetry and polyvalency.

• The propensity for self organization. This enables easy production of 2-D and 3-D crystals of viruses by crystallization procedures.

• The viral capsid (protects genetic material) is extremely rigid and robust. It can tolerate high temperature(s) and remains intact at wide range of pH. Thus, it offers opportunities for chemical alterations that can be exploited for nanobiotechnology.

• The surface properties, charge and the amino acids available on the capsid surface can be altered.

• Viruses act as nanocomposities as they carry all the information for the production of their components. Their properties can be modified by engineering the nucleic acid sequences. This results in display of specific polypeptides on the viral surface. Also, viral chimeras could be constructed carrying proteins of different viral origins.

Viral Nanoparticles (VNPs):

VNPs are dynamic, self-assembling systems that form highly symmetrical, polyvalent and monodisperse structures. Ex: Tobacco mosaic virus (TMV), cowpea mosaic virus, CPMV, etc.

Advantages:

• Are exceptionally robust

• Can be produced in large quantities in short time

• Are biocompatible and biodegradable (as compared to synthetic NPs)

• VNPs derived from plant viruses are less likely to be pathogenic in humans and also less likely to induce side effects.

• VNPs present programmable scaffolds

• VNPs can be modified by chemical modification and genetic engineering to obtain desired functionality.

Applications of VNPs:

VNPs can be used as building blocks for fabrication of a composite material with required qualities. Ex: Tobacco mosaic virus (TMV) is used as a biotemplate for fabrication of a range of nanotubular inorganic materials via metal deposition. It is also used as a scaffold for the selective attachment of fluorescent dues and other small molecules. As compared to the traditionally produced NPs using chemical and physical processes, the deposition and coating of materials on the surfaces of viruses and their non-infectious counterparts allow the production of NPs having low batch to bath variation.

Plant extracts contain various chemicals, which reduce metal salts into metal NPs. The addition of plant viruses in these reactions increase NP formation. Thus, plant viruses are used to improve the "green" synthesis of metal NPs.

VNPs have diverse range of biomedical applications. VNPs can be programmed in a number of ways so that the internal cavity can be filled with drug molecules, imaging reagents and quantum dots; resulting in their use in disease prevention, diagnosis, monitoring and therapy. The external surface can be decorated with targeting ligands to allow cell-specific delivery.

VNPs can be used as nanocages for the entrapment of substances. Manipulation of the outer and inner surface of these nanocages by genetic engineering and in vitro chemical modification could result in encapsulation of exogenous molecules inside and further improve their potential as containment delivery devices.


Conclusion

Virues are a valuable addition to nanobiotechnology. Viral nanotechnology is an emerging field of nanotechnology. VNPs have taken great stride towards different fields such as biomedicine, pharmacology, separation science, catalytic chemistry, crop pest control and material science. A better understanding of natural viral pathogenesis including cell entry, gene expression and replication; and the use of genetic engineering and chemical modification could result in generation of safer, cheaper and more effacious viral particles having diverse applications. The engineered VNPs could open up more possibilities in medicine, industry and science.

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