Nanotechnology in Food.

One definition of nanoscience and nanotechnology is that they are concerned with understanding and applying atomic or molecular level manipulation and assembly of structures. In this case food science and technology already embraces such methods and is likely to continue to do so.

Protein engineering provides one of the earliest examples of molecular manipulation of biopolymers. Microbial, plant and animal systems have evolved to synthesise polymeric systems and the atomic structure is regulated genetically. Cloning and expression in a wide variety of microbial systems has been used to produce a large variety of new protein structures. Proteins are primary gene products and there is a growing interest in the production and manipulation of secondary products of biosynthesis. If such products are altered or generated by positive changes in the structure of biosynthetic enzymes, or the insertion of new enzymes into the pathway, rather than deletion of genes, then they are the classic examples of the use of protein design as a pathway to molecular manufacture as described in the seminal KE Drexler PNAS paper in 1981. There are a wide range of products that can be manipulated. As an example, carbohydrates and, in particular polysaccharides, are difficult to synthesise by synthetic chemical, or combined chemical and enzymatic routes. Cellular systems offer a route to producing such structures. Cells have evolved to modify such structures in response to external stimuli, and the possibility exists to engineer such pathways to produce new structures. Strategies for disrupting the assembly of such structures for certain bacterial pathogens may provide a route for allowing the immune system to combat these micro-organisms. Higher order structures or assemblages, such as starch or plant cell walls, are likely to arise through the partial self-assembly of smaller nanostructures. The growing availability of genomic sequences in plants offers the possibility to target and design such structures. At present the detailed molecular structures and the mode of assembly are still unclear. The physical techniques developed to probe materials at the nanometer scale provide a basis for answering these types of questions. These include scattering methods particularly involving spallation or synchrotron sources, and new developments in electron and probe microscopies. Probe microscopes have revolutionalised the characterisation of nanostructures, and are already producing new molecular information and mechanisms in a number of areas in food science for the first time. Genetic engineering provides a tool for manipulating structure and deducing structure-function relationships in these complex systems. This combined approach provides a basis for setting targets for design of molecular assemblies.

Many of the molecular structures that confer function in food systems are in the nanometer range. These materials have traditionally been studied by established colloid and interface science methods. New molecular information on these structures and, in particular, the structure present at interfaces, is suggesting the possibility for designing interfaces to control the stability of a wide range of foods. This approach has been claimed to be the use of nanotechnology in food science. There are new opportunities for colloid scientists in the design and production of nanocrystals and nanoparticles. Semiconductor nanocrystals are finding unexpected applications as fluorescence labels for biological tagging. There are potential uses in food analysis and microscopy. Nanoparticles are finding new applications as non-viral gene vectors and as molecular delivery systems.

Modern microchip array methods, which are becoming increasingly used in food microbiology and food safety, rely on molecular fabrication adapted from the lithographic patterning methods, developed for the integrated circuit industry. Array methods are starting to be applied in other areas such as nutrition, in the investigation of the role that food macromolecules play in controlling, or preventing disease, or in promoting health. Nanoscience may permit other related analysis methods, such as gel electrophoresis, to be miniaturised through developments of nanofabricated artificial gel systems. This could lead to higher density arrays, increased analytical throughputs, and the possibility of integrated interrogation and interpretation of the collected data. Such nanofabricated tools in genomics and proteomics would lead to higher throughput screening of biological structures or validation of genetically modified structures. The likely benefits from nanoscience in future computing applications might be expected to ease and improve the processing of these vast amounts of biological data.

Many modern biosensors and assays used by the food industry are based on molecular arrays assembled on surfaces. Nanoscience is likely to lead to improvements in the production of patterned surfaces, higher denser arrays of molecules and more reproducible structures. Probe microscopies can be used to image the molecular structures of these areas. Affinity mapping of such structures can be used to map the functional efficiency of sectors of the surface, and can be used to engineer more regular and reproducible devices. The expected contributions of nanoscience to computing should lead to enhanced interrogation and interpretation of the data from such systems. Miniaturisation could lead to multifunctional sensors. The coupling of sensors to nanofabricated release systems offer the possibility of controlled release in response to programmed stimuli. Such devices may have probiotic type functions in areas such as the control of the gut microflora.

The ability to design materials at the atomic or molecular level is likely to impact the food industry through the development of coatings, barriers, release devices and novel packaging materials. In the synthetic polymer field novel barriers are starting to be produced through the use of composite structures (fuzzy nanoassemblies) formed from successive molecular layers of different polymers, and this approach may be adaptable to the food area. The drive to develop bio-compatible surfaces for medical or pharmaceutical applications may lead to novel surfaces or coatings that repel or combat bacterial adhesion and biofilm formation. Nanofabrication of surfaces allows imprinting methods to be used to create novel catalytic structures or alternatives to naturally occurring enzymes.

If nanoscience and nanotechnology embody biological manipulation then the major impact to food is likely to come from genetic engineering. Genetic engineering will certainly become an increasingly important tool in food science. Whether products from such studies are commercialised will depend on consumer preference and need. The protocols and committees for evaluating the risks and benefits of this technology are well established. Nanoscience would be expected to contribute better methods and tools for evaluating and validating genetic modification.

If nanoscience and nanotechnology is restricted to manipulation through physical sciences then the food industry will still benefit from this work. Benefits are likely to arise from advanced materials, tools for nanoscience such probe microscopies, improved analytical tools and the expected advantages from advanced computers in information technology.

The food industry is most likely to benefit from nanoscience and nanotechnology if strong links can be developed between physical scientists engaged in nanosciences and molecular biologists. This type of collaboration appears to be consistent with the future strategic plans of the BBSRC and EPSRC, and should be encouraged by the IFST. The views expressed in the above document are personal and may not coincide with the opinions of the Institute of Food Research or the IFST.

Dr VJ Morris, 18/06/2003.