View the latest medical engineering news

Dr Xianghong Ma, Aston University, offers a brief view on the current developments on nanotechnology and its applications in medical fields.

Nanotechnology is defined as the creation of materials and devices by the control of matter at the nano (10-9 of a metric unit) scale and the exploitation of novel properties and phenomena developed at that scale. In the biological world, a cell is at the scale of a few to tens of micrometers in diameter. Viruses, ribosomes and antibodies are at the scale of tens and hundreds of nanometers. Nature has created many efficient nano systems. Chromosomes are nano data storage devices. Proteins such as actin and myosin behave as a molecular mechanical mechanism to enable muscle contraction. Living cells are nanomachines that can fulfil complex functions in a highly controlled fashion.

Nanotechnology certainly is the one of the most funded research fields in developed countries. Global governmental research spending on nanotechnologies was 6.4 billion US dollars in 2006 and corporations spent an additional 5.3 billion on nanotechnology research and development. In the knowledge-based economy, technology equates to advantage in terms of profits, health and wealth of the population and country. The US National Science Foundation predicts a trillion-dollar world-wide market for nanotechnology products in 2015.

Currently two approaches are being pursued in nanotechnology research. The ‘Top-down’ approach is a further miniaturization of microfabrication techniques based on semiconductor manufacturing processes, in which one builds from large to small. It is often viewed as a further extension of microtechnology. Using this approach, Micro Mechanical and Electrical Systems (MEMS) can be made with features on a scale from 30 nano-metres to a few hundred micro-metres. These dimensions are similar to that of biological molecules and cells and therefore various bio-MEMS have been designed to manipulate and monitor biological functions. In the recent special issue “Microtechnology and Nanotechnology in Medicine” published in the Journal of Engineering in Medicine (part H of the IMechE Proceedings, No H2, 2007), examples of micro-robotic manipulators for genetic manipulation of embryos, micro-fluidic devices for cell filtration and diagnosis, and a valveless micropump for the detection of biomolecular binding and cell adhesion are discussed, showing the current wide range of applications of Micro/Nano scale devices in medicine and biotechnology.

The alternative ‘Bottom-up’ approach is to build nanostructures using atoms, molecules, proteins and DNA by bio/chemical synthesis, self-assembly and/or nano-manipulators/assemblers. There are many examples of creating functionalized nano-structured layers on surfaces to make biosensors and building tissue scaffolds through self-assembly. Another area of nanotechnology is molecular engineering, in which one aims to build larger and more complex systems by precisely controlling molecular structures. While research in the ‘Top-down’ approach tends to be led by mechanical and electrical engineers, scientists in Chemistry, Biology and Pharmacology tend to lead in the ‘Bottom-up’ approach. A successful nano-system will undoubtedly be a joint effort of a multi-disciplinary investigation.

Nanotechnology has and will continuously offer the most amazing discoveries in medicine. Diseases are caused mainly by damage at the cellular and molecular level. With the prospect of creating systems and machines on a comparable scale to that of the cellular and subcellular level, nanotechnology will offer powerful tools for the treatment of human diseases and the improvement of health and well being. The following areas are just the beginning, in terms of possibilities:
New biomaterials based on nano structures will improve the quality and biocompatibility of medical devices and implants. Current research activities include nanocoating on surfaces for guided migration, spreading, growth and differentiation of cells in vivo and in vitro; active surface functionalisation and surface topography at the nanoscale providing selective surface matrices for cells to either facilitate or prevent adhesion, as required; nanofibre materials being produced for wound dressing and drug delivery systems. The integration of novel nano scale phenomenon with biological functions has created a series of very active medical research fields in nanomaterials.

Micro/nano scale surgical tools will improve medical procedures involving delicate surgery on individual cells and the understanding of biological and body functions. Microfabrication can provide analytical tools such as submicrometer mechanical probes and integrated fluid circuits for investigating biomolecules (in genomics, proteomics and high throughput screening for drug leads), for exploring the interior structure and function of cells, as well as for manipulating cells and performing cellular surgery and therapy, genome synthesis and diagnostics. As surgeons today rely on the spontaneous, self-organizing ability of cells and tissues to join and heal the parts they manipulate, so cell-surgery devices will rely on the spontaneous self-organizing capabilities of molecules to join and heal the parts that they place together.

Medical Micro/Nano electromechanical systems for early diagnosis of disease and for disease prevention have the key advantages of small size, low power demand, and low cost per function. MEMS can be fabricated to create a complete diagnosis system, including sensors to discriminate biological functions, actuators to move and manipulate the samples, electronics to analyze and transmit information and to execute control functions. In many examples of novel biosensors for diagnosis, biotechnology and drug development, the handling of biological samples is achieved by microfabricated structures and the analytical functionality of the sensors is given by specific functionalised surface, using nanotechnological processes that can sense the biological/chemical properties of the samples.

A most promising future of nanotechnology is to produce durable, rejection-resistant artificial tissues and organs. The smallest, most successful, artificial organ of modern medical practice certainly is the pace maker for the heart. This is an integrated system that can be further miniaturized by using Micro/Nano techniques. There are many applications for sensor prostheses, such as retinal and hearing implants.

The exciting current activities and the future potential of nanotechnology will be able to revolutionise medicine and healthcare in the 21st century. Many engineers, scientists, clinicians and researchers are working together to realise new goals for the benefit of society. One can see that there is a need for more graduate education in this emerging multi-disciplinary field to provide guidance and leadership in developing nanotechnology to the next level of exploitation.

Back to top