Considerations for using genetic material in medical nanotechnology.

• Author: Tyshenko, Michael G.

Introduction

"Nanotechnology" is a term used by scientists to describe the technologies and processes involving materials, devices and structures that occur on the scale of nanometres (a nanometer is one billionth of a metre), involving atoms or groups of atoms. The smallest nanostructures are more complex than man-made polymers like polyethylene, nylon or Teflon and more complex than natural objects like sugars, proteins and cellular membranes.

The nanotechnology market in 2003 was worth over $26 billion in sales worldwide, which demonstrates the widespread impact this new technology has had on development of consumer products. Products currently available that have been produced using nanotechnology include chemicals with microscopic catalytic particles, sun block lotions with zinc-oxide particles, paint emulsifiers and plastic resistant coatings to extend the life of industrial tools and eyeglass lenses. (1)

The use of nanotechnology to produce structures and products for medical therapeutics has so far been limited to gold nanoparticles for clinical trial cancer treatment, (2) quantum dots for photo-imaging of living tissue (3) and containers for delivery of drugs or materials to target cancer tumours. (4) However, the market for future therapeutics, molecular nanotechnology products, medical devices and diagnostic tools promises to be substantial. The use of DNA (Deoxyribonucleic acid) derived tools in the fields of molecular and medical nanotechnology promises a plethora of medical benefits with potential applications for drug delivery, health diagnostics and gene therapy. However, underlying the positive applications of this emerging technology is the potential for unknown hazards. As little has been mentioned of possible problems associated with using genetic material in the nanotechnology field to target drug delivery to specific cells and tissues so far, the technology should be regulated.

Just How "Nano" is Genetic Material?

DNA is composed of two strands that form a very stable double helix (much like a ladder) and acts as the physical carrier of genetic information. DNA is composed of many nucleotides that each consists of a sugar, a phosphate group and one of four bases (adenine, thymine, guanine or cytosine). (5) Molecular biologists have been working on a nanoscale to manipulate genetic material from a variety of organisms (human, animal, insect, plant, bacteria, virus) for over 25 years, with the ability to isolate, cut, move, join, splice together, synthesize and copy DNA. (6) In terms of scale, to better understand nanotechnology, most mammalian cells are between 20,000-30,000 nanometres (nm) in size, with some exceptions like neurons (brain cells, spinal cord) that can reach lengths up to 1 metre. The molecules in our body, including DNA and its component parts vary in size but range between 0.2 - 20 nanometres. (7) Each cell contains 3 billion nucleotide base pairs or 2 metres of DNA packed into the cell nucleus only 6,000 nm. (8)

Use of DNA in Nanotechnology to Create Drug Delivery Structures

The properties of DNA, including its size, structural stability and its ability to replicate combined with the pre-existing tools derived from molecular biology make it an ideal focus for nanotechnology applications. (9) DNA-dependent nanotechnology exploits the properties of DNA by harnessing it to act as a backbone to arrange ligands, proteins and gold particles (10), to form DNA-based nanowire (11), to...