Lecture XXXVI. Applications of Nanobiotechnology in Food Contaminant Detection

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1 Lecture XXXVI Applications of Nanobiotechnology in Food Contaminant Detection ABSTRACT Nanotechnology is an emerging field of science which deals with the study and manipulation of particles which have atleast one dimension in the scale of nanometers. By exploiting the intrinsic and extrinsic properties of nano-sized particles, researchers have created a vivid plethora of devices and techniques. The most conspicuous factor that led to the in depth study of nano particles is the fact that the properties of particles change drastically at nanometer levels. Nanotechnology is applied in various areas like pharmaceuticals and cosmetics, biosensing, electronics and many others. One of the main areas of interest is agriculture and food industry. First addressed by United States, it is now a rapidly evolving sector which has an imminent potential to revolutionize the entire agriculture and food systems. Nanobiotechnology is the portmanteau of biotechnology and nanotechnology which when combined together is an important option for enhancing the food productivity and to complement the current methodologies. It finds applicability in food industry in events like food processing and packaging, food pathogen detection, quality control and enhancement.

2 INTRODUCTION Nanotechnology is the understanding and control of matter at dimensions of roughly 1 to 100 nm, where unique phenomena enable novel applicationss (Roco et al.,2003). The application of nanotechnology (NT) to the food and agricultural industries was firstt addressed by the United States Department of Agriculture in its roadmap published in September 2003.Nanobiotechnology is evolving as the technologica al scaffold for the future development and transformation of food and agricultural systems. Nanotechnology is enticing large-scale investment from global food corporations, is backed by academic science, and has captured financial and ideological support from many governments around the globe (Sandler et al., 2002). Nanobiotechn nologyhas moved from laboratories to the marketplace because of its large applications. Advanced nanotechnology techniques may make it possible to alter the nutritional constituents, preferred flavour and other impart various other salubrious aspects to the food to match market desiress and demand. Similarly, nanoparticles are employed in smart-food packaging to be able to detect harmful food pathogens. Nanobiotechnology is a promising field in food industry as described in this review. The following diagram illustrates the holistic view of applicability of nanosciences and technology in food industry.

3 As outlined in the abovefigure(1),contribution of nanoscience research in agriculture will be in the following areas: 1. Food safety and biosecurity 2. Detection of food borne pathogens FOOD SAFETY AND BIOSECURITY Fresh produces and foods which are either degraded or unpalatable exhibit smells, colors or other sensory features which can be easily apprehended by consumers. Intake of such unhealthy food can prove detrimental to human health and hence prominent detection methods to indicate contamination or degradation of food particles are the need of the hour. Here s where the unique chemical and electro-optical properties of nanoscale particles can be used as a possible solution to this problem. Through bottom-up and top-down engineering, nanomaterials can be manufactured which are capable to detect the presence of gases, aromas, chemical contaminants and pathogens, or respond to changes in environmental conditions. This not only is useful for quality control to ensure that consumers are able to purchase products which are at their peak of freshness and flavor, but it also has the potential to improve food safety and reduce the frequency of food-borne illnesses. Such technology would obviously benefit consumers, food corporations and food regulators. Some companies (e.g., Ripesense [ and OnVu[ already market nanotechnology products that help consumers determine whether certain foodsare likely to be eatable, but most of the work on nanosensorsor assays for food-related analytesis still in the rudimentary phase of development. Nanosensors for the detection of pathogens andcontaminants could make manufacturing, processing, and shipment of food products moresecure. Specific nanodevices could enable accurate tracking and recording of the environmental conditions and shipment history of a particular product. Smart systems capable of providing integrated sensing, localization, reporting and remote controlof food products could increase the efficacy and security of food processing and transportation.

4 Array Biosensors Detection of food borne contaminants Carbon nanotube based sensors Measurement of nutrient level in a food Nanobiosensors Detection of pathogens by NEMS Wine discrimination using electronic nose. In detection of presence of small organic molecules in food responsible for contamination, the following three broad approaches are followed. The first approach is based on color change in the nanoparticle on interacting with the small molecules.for example, gold nanoparticles (AuNPs) functionalized with cyanuric acid groups selectively bind to melamine, an adulterant usedto artificially inflate the measured protein content of pet foods and infant formulas; the interaction of melamine with the goldparticles causes AuNPs to undergo a reproducible, analyteconcentration-dependent color change from red to blue, which can be used to precisely measure the melamine content in raw milk and infant formula at concentrations as low as 2.5 ppb with the naked eye (K Ai et al., 2009). A similar approach examined test samples for the presence of melamine by adding in sequential fashion separate solutions of gold ions and a chemical reductant(q.a. Cao et al,2010). In this system, when melamine is present in a sample, it binds to the reductant and prevents AuNP formation;thus, test samples with no melamine turn fully redduring the assay due to AuNP formation via reaction between thegold ions and the reductant. Colorimetric detection of melaminein raw milk using AuNPs and crown-ether-modified thiols with a limit of detection of 6 ppb has also been report

5 Fig. 2. (a) Schematicc showing colorimetric detection of melamine in solution using modified gold nanoparticles (AuNPs). AuNPs are conjugated to a cyanuric acid derivative, which selectively binds to melamine by hydrogen bonding interactions. When bound to melamine, aggregated AuNPs (blue) exhibit different absorptive properties than free AuNPs (red). (b) Visualcolor changes of AuNP melamine sensor in real milk samples: (1) AuNP solution without any addition; (2) with the addition of the extract from blank raw milk; (3), (4) and (5) with the addition of the extract containing 1 ppm (final concentration: 8 ppb) melamine, 2.5 ppm The second approach is fluorescent based technique.in this case,we use a a sensor based on a detection technique called enhanced fluorescence linked immuno-sorbent assay (EFLISA) which is employed for the detection ofpresence of gliadin, one of the primary food proteins that is the agent of inflammation in patients suffering from Celiac disease; this system utilizes metal- to silver nanofilms.this technique can be used to determine the gluten level of gluten-free foods It can also be easily adaptedd for the selective detection of otherr protein-basedanalytes. The third approach is based onelectrochemical detection; compared to optical (colorimetric or enhanced fluorescence from rhodaminelabeledanti-gliadin antibodiess in close proximity fluorimetric) methods, electrochemical approaches may be more useful for food matrices because the problem of light scattering and absorption from the various food components can be avoided. Many electrochemical sensors operate by binding selective antibodies to a conductive nanomaterial (e.g., carbon nanotube) and then monitoringg changes to the material s conductivity when the targetanalytebinds to the antibodies. High moisture and oxygen conten is leading cause of spoilage of food products especially meat and animal fats, to detect this spoilage photoactivated indicator ink for in-package oxygen

6 detection based upon nanosizedtio2 or SnO2 particles and a redox-active dye (methylene blue) is promising; this detector gradually changes color in response to even minute quantities of oxygen.one example of a sensor for moisture content,is based upon carbon-coated copper nanoparticles dispersed in a tenside film (Loher S et al.,2007). In humid environments, swelling of the polymer matrix results in larger degrees of internanoparticleseparation; these changes cause sensor strips to reflect or absorb different colorsof light which can be monitored easily for quick and accurate determination of package moisture levels without invasive sampling.