What is so special about nanotechnology? To some it is the technology of the 21st century while for others it is the most potentially damaging technology of the future. According to Franz Brandstetter, BASF president, polymer research, it is an enabling technology that links chemistry, physics and biology to produce a whole range of products, from transparent sunscreens to drug delivery, and from self-cleaning and sterilising textiles to flat screen displays and alternatives to barcodes.
But is nanotechnology really a technology? ‘Yes,’ said Stefan Marcinowski, BASF’s research director. ‘All the analytical tools and skills needed to look at the nano scale level cross all sectors from scratch resistant coatings to marine antifouling products. But it is also a very wide field ranging from nanoparticles to molecular architecture – a real mix of chemistry, physics and biology.’
Nanotechnology is one of the five growth clusters that have been established at BASF as important drivers for growth. BASF’s nanoresearch is ‘not so different from our general approach,’ said Marcinowski. With an annual R&D expenditure of around €60m, it operates through a global network with more than 150 R&D cooperations, a BASF laboratory at ISIS, the University of Strasbourg and its Global Research Center Singapore.
There is huge market potential for nanomaterial-based products that cover a broad range of applications spanning across vast industries like environment, energy, medical, construction, textile, automotive, household and personal care. Nanotechnology is already a €250m/yr business for BASF, with commercial vitamin and packaging products already available, and other products, for example, offering dirt resistance in textiles and paint, and UV protection in cosmetics, at launch stage. In the development stage, there are insulation and OLED lighting products.
‘Nanotechnology gives opportunities for new revolutionary products. Innovations are critical to the profitable growth of BASF,’ said Marcinowski. It is ‘not a question of no market need’, he added. ‘The markets are very abundant but they need solutions. We need to put the technology push on green. This conference will serve as an excellent platform for the scientists from research institutes, universities, industry partners and customers to interact and further collaborate on innovations that are highly customised for the market.’
And why nanotechnology in Singapore? Lim Chuan Poh, chairman of the Singapore Agency for Science, Technology and Research (A*STAR), who opened the conference together with BASF’s Brandstetter, said: ‘The BASF Global Research Centre, which opened in April 2006, was the first BASF research centre in Asia to focus on nanotechnology. BASF’s choice of Singapore to hold its first nanomaterials conference in the South-East Asia region reaffirms the considerations behind the decision that Singapore is the choice location for nanotechnology R&D, underscoring the quality of nanotechnology research and talent that Singapore offers.’
‘The establishment of the Global Research Center Singapore is a strategic and timely move, as we see a strengthening of the research community in Asia Pacific, primarily in China, Japan, Singapore and India. There is great potential in the R&D talent pool in the region and the ideas and innovations that emerge are world-class,’ said BASF’s Marcinowski.
Established as the Competence Center for Nanostructured Surfaces in April 2006, it gained the laboratory for organic photovoltaics in December 2006, and further expanded to incorporate the Organic Electronics R&D Center in May 2007. Between 2006 and 2009, total research expenditure for the Center is expected to be S$30 million (€15 million).
‘Nanotechnology is one of the five future growth clusters of BASF R&D, it is also one of A*STAR’s key R&D focus areas. We are therefore happy to partner BASF through our research institutes and their R&D in nanomaterials to impact society and the economy,’ said Lim.
Ideas & applications
An unlikely industrial sector for nano-biotechnology is aerospace but as Shawn Park, from Boeing’s Phantom Works − the ‘catalyst for the Boeing enterprise’ as Park described it − demonstrated, there are many applications that have relevance to other market segments. ‘Aerospace is involved in lifting, moving and placing payloads, from people to munitions,’ said Park, ‘Therefore nanobiotech can be applied to sensors, materials, advanced filtration, self decontamination and biomechanics.’
Boeing has 12 ongoing nano-technology projects, looking to provide passenger comfort, a healthier environment and improved fuel efficiency, he added. A key area is smart environmental control systems, including filtration and sensors. ‘In the Boeing 777, for example, the air quality is better than in buses, trains and the subway,’ he said, ‘despite the number of possible contaminants ranging from anti-icing fluids to engine oils and hydraulic fluids.’ High levels of air quality can be achieved using carbon nanofibres and tubes for filtration and odour removal, and with coatings on the tubes and fibres, it is possible to capture and destroy airborne spores and bacteria, and even prevent viral transmission. The materials used must, however, meet the stringent non-flammable and toxic requirements applied in aerospace systems, said Park, but along with air sampling sensor developments, in the form of lab-on-a-chip developments, these solutions are equally applicable in other systems. Other areas of interest for Boeing include the bioassisted repair of small cracks in airframe components and biomimetic optical sensing.
As Subodh Mhaisalkar, from the Institute of Materials Research & Engineering, in the School of Materials Science & Engineering at Singapore’s Nanyang Technological University, pointed out, carbon nanotubes have attracted attention for sensor applications because they are highly sensitive to molecular adsorption both within the tube and
on the tube wall. ‘Nanotubes are one-dimensional conducting wires. The current flows at the surface therefore the sensing medium is in contact with the gas or liquid environment. A nanotube network on a flexible substrate can therefore be used to make a monitor,’ he said.
In addition to the aerospace applications outlined by Park, this approach can be used for in vitro diagnostics for detecting biomarkers. ‘Biological molecules change the conductance when on the surface of transistors and desired biomarkers can attach themselves to an attached antibody, for example.’ Such an application for the detection of prostate cancer can detect the relevant biomarker at up to ten times lower levels than current tests, while NO and CO biomarkers, useful in cardiovascular diseases, can be detected at 50ppb.
Lightweight, flexible and robust electronics have applications across most major industrial and consumer markets, according to Beng Ong, also from the Institute of Materials Research & Engineering in Singapore. Ong described current work that is focused on organic polymers, which have long side chains for processability and appropriate
spacing for interdigitisation, and can be formed as layered structurally ordered nanoparticles that can be ink-jet printed.
Compared with silicon-based electronics, which are costly, brittle and fragile, organic/polymer-based transistors are a critical platform technology for low-cost plastic electronics. However, plastic-based semiconductors suffer from a lack of stability and can be sensitive to light and oxygen while offering low conductivity. If they can be formed by low-cost liquid patterning and deposition, or even ink-jet printing, then despite not being high-performing like silicon-based circuitry they are functionally adequate for a whole range of high value applications becoming available. These range from smart cards and labels to replace bar-coding, a market estimated as being worth $10bn/yr, through printed solar cells, to wireless signage and large area products, like flat panel displays estimated to be worth over $80bn/yr, and disposable phones and toys.
Drug delivery is another key area for nanomaterials and a project at the Australian national nuclear research and development organisation (ANSTO) into controlled release has resulted in the spin-out of company CeramiSphere, which aims to work with drug companies to develop new products like wound healing and oncology therapies, vaccine delivery and oral insulin delivery.
The technology, based on sol-gel silica matrices, can also be used for ‘smart’ pigments that release corrosion inhibitors or biocides.
Combining emulsion synthesis with sol-gel technology enables the carrier to be produced in the form of mono-dispersed spherical particles, with an average size that can be varied from 10nm to 100µm. The bioactive ingredient is incorporated into the matrix during gelation at, or near, ambient temperature and remains entrapped until the gels are immersed in solution. The release profile can be tailored by controlling the internal structure of the gels – pore volume, size and tortuosity, and surface chemistry. The gel structure itself can be tailored by varying sol-gel parameters including water-to-alkoxide ratio, pH, ageing, drying time and temperature.
The temperature responsive block copolymer poly(ethylene oxide)-poly(propylene oxide)-poly(ethylene oxide) has been used as the basis for studies by Liu Hui-Zhou from the State Key Laboratory of Biochemical Engineering, Chinese Academy of Sciences, Beijing, China, into magnetic ‘smart’ nanoparticles that can act as drug delivery systems. The self-assembling particles can even cross the blood-brain barrier and also sensitise multidrug resistant cells to delivered anticancer agents, as well as providing a hyperthermia treatment and in imaging applications.
Takashi Oka from the Japanese cosmetics company Shiseido reported the use of a novel inverse micro-emulsion polymerisation to produce water-swellable microgels that can be used as viscosity thickeners for cosmetics, with high viscosity-enhancing ability even in 100% ethanol. Additionally the micro-gels show a high salt resistance, impossible to achieve by conventional hydro- or ionic-gel viscosity enhancers, and high ph resistance in the range ph3-10.
Anti-fouling for body implants, boat hulls and water purification systems is also another nanomaterial application being investigated by Hans Griesser from the Ian Wark research Institute, University of South Australia and other Australian researchers. ‘Biological “things” stick to materials where we don’t want them,’ said Griesser, noting that many antibacterial coatings for hip replacements, for example, utilise silver. Such coatings have a limited lifespan, around two years, so a coating with a much longer lifespan would be very beneficial. Griesser also pointed out that there are two possible types of antifouling: passive, as with such hip replacements, stents, and contact lenses, as well as active antifouling applications that have different ‘stickinesses’.
Addressing public concerns
Before being able to address public concerns about nanotechnology, Marcinowski said the industry must do its utmost to gather information on whether nanomaterials can be used like other chemicals, citing safety programmes around the world like Nanosafe in Europe. ‘We want to make money from nanotechnology,’ said Marcinowski, ‘ but before we can, we need to know what we are doing safely…And one of the key areas for safety is employee health, as those working with nanomaterials are at the greatest risk.
Once the industry is fully aware of any safety issues, or the lack of them, then there is a need to educate the public. ‘We need to show the benefits for mankind. As long as we are talking about theory then this is difficult. We need real information to demonstrate safety,’ he added.
‘We need to differentiate between the “risky” part of nanomaterials and the safe part. And that risky part is most likely to be nanoparticles. Most nanomaterials are not a problem as generally, particles are not free but bound up in the structure of the materials. Even with nanoparticles of TiO2 in sunscreens, a lot of studies have been done that show the particles do not penetrate the skin,’ he said.
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