Living in a world where commercial products are continuously getting smarter and smaller, it’s no surprise that scientific research is moving towards the development of new materials on the nano-scale. Nature already accomplishes this extremely effectively.
For example, Geckos have complex nano-patterns imprinted on their feet, which allows them to stick to ceilings, and even butterfly wings are an exquisite assembly of natural photonic crystals. The field of Biomaterials includes biomimetic research that focuses on using or imitating molecular creations of Nature in order to create our own materials. In addition to this, biomaterials also encompasses work on synthetic materials for biological replacements in the body.
Although we consider biomaterials to be a relatively new field of research, more than 2000 years ago, the Romans, Chinese, and Aztecs were already using biomaterials such as gold for dental implants due to its good resistance to oxidative corrosion. The development of the biomaterials field only increased after synthetic polymer systems designed during the 1940’s became widely available for medical purposes.
Today, scientists in New Zealand, and worldwide, are working to develop “smart” biomaterials that can change their properties in a positive way in response to external stimuli, and are processed from sustainable resources before being recycled at the end of their usefulness.
Smart biomaterials
Biomaterials have become a wide-ranging field, encompassing aspects of basic biology, medicine, engineering and materials science. Because of the breadth of the field, confusion often exists about what a biomaterial is.
Medically, it can be defined as a molecular material intended to interface with biological systems to evaluate, treat, augment, or replace any tissue, organ or function of the body.
From a materials science perspective, the definition may be that biomaterials research is about the discovery and harnessing of unique properties of biopolymers and other extracts from biological resources to replace or improve current device fabrication or synthetic materials.
One of the major concerns of a biomaterial is the biocompatibility of a material to the task it is assigned to. Therefore, factors such as the materials nanostructure, degradation characteristics, surface chemical properties, and bulk chemical and mechanical properties must be understood in order to minimize the number of negative responses.
Biomaterials in New Zealand
Living in a world using less polluting renewable materials offers a more earth-friendly lifestyle solution – desirable for New Zealand in order to maintain our clean green image.
In New Zealand, a large number of research teams are working to find and understand the functional properties of biomaterials.
There have been recent advances in the development of electrospinning machines by teams at the University of Canterbury and Crop & Food Research Ltd. Electrospinning is a process developed to mimic the way a spider spins its web. The silk produced from a spider’s spinneret is light in weight, and greater in tensile strength than steel of the same diameter. However, unlike a real spider, the electrospinning machine uses a high voltage electrical potential to create a mat of nano-fibres with exceptional properties from resources such as proteins and cellulose. These fibres have applications in a number of fields, including tissue engineering, or new packaging materials, while at the same time creates a new way to keep our environment clean.
Researchers at the University of Waikato have found a way to turn waste products into new materials. Animal blood meal is a waste product from the meat industry, but can be used to create bioplastics. This is possible because of the large amounts of protein found in blood meal, and protein is made up of polymers, the basic ingredient needed to make plastic. The bioplastic developed is biodegradable, and has the same strength as plastic milk bottles or bags made from polyethylene available today.
Nature controls the precipitation of inorganic materials to high precision. In doing so it controls their growth such that the final materials have superior physical and chemical properties as compared with synthetically grown materials. Researchers working at Victoria University and the MacDiarmid Institute for Advanced Materials and Nanotechnology are looking at ways to harness the construction tips from biominerals controlled by sea urchins, which can make materials that are light, have incredible strength, and are able to regenerate themselves.
Human bones are made of calcium phosphate, which can wear or break as we age. This is simply because the human body wasn’t designed to live as long as we do today, compared to a few centuries ago. Sea urchins, however, have needle-like spines that are made up of a three-dimensional mixture of pores and solid calcium carbonate crystals, giving it the ability to withstand forces a thousand times stronger than standard calcium carbonate crystals. Understanding how the sea urchin can control its structure could ultimately lead to new ideas about how to trigger bone growth or create stronger bone implants for people.
One can envision a future of various designed functional materials, and we can expect biomaterials will become an increasingly influential part of our lifestyle.
Energy Crisis
In a nutshell, we all need energy to maintain our daily lifestyle. Ever since humans started using fossil fuels to heat homes, run cars and power factories, we have released over 400 billion tonnes of carbon into the atmosphere. The problem now is that our oil supplies are dwindling, the greenhouse gases in the atmosphere are threatening our life on Earth, and yet our demand for energy is expected to rise by 50 to 60% by 2030. Clearly, someone needs to find a sustainable solution to our energy needs as soon as possible.
For a small nation such as New Zealand, it’s easy to think that we can leave the other larger countries to develop the technology and a find a solution to save the world. But it’s also easy to see the opportunity it brings for New Zealand to find an energy solution that takes advantage of our relative geographic isolation, our environment and climate.
One possible solution describes the use of biomaterials extracted from biomass. Biomass is organic matter that can be used as a fuel and represents an abundant carbon-neutral renewable resource for the production of biomaterials and bioenergy. It is an abundant raw material consisting mostly of renewable polysaccharides and lignin – a glue-like chemical compound that keeps the cell walls of plants from falling apart.
The extraction of natural lignin can be used as a valuable biomaterial to begin replacing petrochemical-derived materials, as it contains long chains of sugars, which can be turned into simple sugars and converted to ethanol. This can be used in a mixture of products including transportation fuels, co-products, and direct energy.
Another solution has been developed at New Zealand’s Aquaflow Bionomic Corporation, which focuses on converting algae into biofuel. Commonly thought of as pond scum, around 50% of algae weight is lipid oil, and this can be used to make bio-diesel for cars, trucks, and airplanes. By growing algae in ponds, where it can capture sunlight through photosynthesis, it grows at one of the fastest rates in the world for a plant, so is readily available. A useful by-product is that the algae releases clean water that can be recycled for use in irrigation.
A small proportion of the world’s cars already run on biofuels such as ethanol and biodiesel, however energy derived from sustainable sources have enormous potential to provide a more significant supply of energy to the world’s transportation fuel needs.
Biofuel farming may also be well suited for New Zealand’s agricultural heritage and efficiency by using not only algae, but also tallow (animal fat by-product) or whey (dairy by-product), and offers New Zealand the chance to become a role model in the new renewable energy lifestyle.
References:
http://www.massey.ac.nz/~mwilliam/
http://www.macdiarmid.ac.nz/
http://www.aquaflowgroup.com/
http://www.crop.cri.nz/home/research/biomaterials/
http://www.waikatolink.ac.nz/
This Science Byte was reviewed by Dr. Bill (M.A.K.) Williams, Senior Lecturer in Physics, Massey University, Palmerston North.