Lab News

Matt presented his preliminary research results at the 25th Annual Teaching and Learning Innovations Conference on May 1, 2012 at Rozanski Hall, University of Guelph. Alex is in the Right.

 

 

 

 

 

Matt Presents a Poster

April 2012: FDA’s Approach to Regulation of Nanotechnology Products

http://tinyurl.com/794uzcm


Media:  What do you make of these new guidelines?

Sureshlab:  The benefits of nanotechnologies in food packaging over conventional technologies are undeniably tremendous. These new guidelines are not a surprise for nano-researchers and we have been expecting these. I guess FDA's guidelines can be taken as a strong precautionary tone on safety risks of food packaging applications of nanotechnology.  However, big players such as Kraft, Nestle and even academic and scientific researchers will NOT consider this announcement as a step to jeopardize the benefits of nano food-packaging. Rather, one should remind and acknowledge that there are deficiencies in the current regulations, and a huge knowledge gap exists in terms of the public awareness and information on the impact of nanotechnology on food packaging. It is nice and advisable to take a proactive approach to avoid any unpredictable health hazard. I believe FDA is doing exactly the proactive approach.

Media:  What is the current common practice for nanotech use in food packaging? Why are they necessary? What is the advantage to nanotech applications in packaging?

Sureshlab:  Nanotechnology offers higher hopes in food packaging by promising longer shelf life, safer packaging, better traceability of food products, and healthier food. Polymer nanocomposite technology holds the key to future advances in flexible, intelligent, and active packaging. Intelligent, smart, and active packaging systems produced by nanotechnology would be able to repair the tears and leakages (self-healing property), and respond to environmental conditions (e.g., change in temperature and moisture). Intelligent food packaging can sense when its contents are spoiling, and alert the consumer, while active packaging will release a preservative such as antimicrobials, flavors, colors, or nutritional supplements into the food when it begins to spoil. Antimicrobial nanoparticle coatings in the matrix of the packaging material can reduce the development of bacteria on or near the food product, inhibiting the microbial growth on nonsterilized foods and maintain the sterility of pasteurized foods by preventing the post-contamination. Foods such as cheese, sliced meat, and bakery that are prone to spoiling on the surface can be protected by contact packaging imbued with antimicrobial nanoparticles. Nanotechnology can effectively produce oxygen scavengers in packaging for sliced processed meat, beer, beverages, cooked pastas, and ready-to-eat snacks; moisture absorber sheets for fresh meat, poultry, and fish; and ethylene-scavenging bags for packaging of fruit and vegetables.

It is even possible to produce intelligent smart packaging for providing authentication, and track and trace features of a food product for avoiding counter-feiting; preventing adulteration and diversion of products destined for a specific market. Complex invisible nanobarcodes with batch information can be encrypted directly onto the food products and packaging. This barcode technology could offer food safety by allowing the brand owners to monitor their supply chains without having to share company information to distributors and wholesalers.

Media: Is FDA ahead of the curve, or behind?

SureshLab:  The regulations put forward by the European Union (about two years ago) seems to be way ahead in the nanotechnology related food applications compared to us here in North America. The guidelines by FDA are only voluntary. I personally think, EU is more conservative than us in adopting the food nanotechnology. FDA is behind the curve on this issue.

Media: What effects will these guidelines have?

SureshLab:  These guidelines are indeed essential as they will aid in sustaining the growth of food industry in the longer term, and will help to avoid unpredictable health hazards. These will also change and influence the tangent of nanotechnology research towards safety and toxicology. Industries will be compelled to use clear labelling for ingredients present in the form of nanoparticles. Food manufacturing industries might be obligated to conduct the risk assessment. As such there are no standard protocols for testing the toxicology effects of nanomaterials. Further research into human exposure to nanomaterials and their toxicology and biokinetics will add more challenges.

Media: What revisions, if any, would you like to see?

SureshLab:  There is no consensus among the nanotechnology researchers regarding the definition of 'NANO', and more particularly the size as well. Although 1 to 200 nm range is commonly accepted as a nano-particle, 150 nm and above may not have as serious implications in terms of health risks. Some environmental groups’ claim that nanoparticles is in the range of 50 to 70 nm can enter cells. The definitions and the size range between 1 to 100 nm, put forward by the National Nanotechnology initiative of US is predominantly based on the non-food materials of nanoscience. Absence and lack of clear formal globally accepted definition about the term 'nano' and the legally accepted size range for nano would cause a political and technical challenge in terms of implementing these guidelines of FDA. Along with the voluntary disclosure mandate from the industries, FDA could possibly put forward a platform or web source to inform the public about the list of products that are commercially available in the market that are made using nanotechnology. The new legislation should be explicit with specific provisions for various nanomaterials. FDA could release a list of authorized substances that could be used as components of intelligent, smart and active packaging.

Bionanotechnology - What is it?

"Bionanotechnology is essentially the study of biological ideas with nanotechnology...a miniaturized version of biotechnology, a field that centers on the use of living organisms and bioprocesses in engineering...an emerging interdisciplinary field..."Got that? Read on...

E-Magazine Link

*(PDF)*

Bionanotechnology – New Frontiers

Bionanotechnology is essentially the study of biological ideas with nanotechnology. To put it in different terms, bionanotechnology is a miniaturized version of biotechnology, a field that centers on the use of living organisms and bioprocesses in engineering, technology, medicine, and other fields. Bionanotechnology is an emerging interdisciplinary field at the interface of biotechnology and nanotechnology. Because it’s still in the early stages, the topical areas of bionanotechnology research cover a wide range. In particular, bionanotechnology is ideally suited for understanding the interfaces between organisms in systems biology.

To help understand bionanotechnology, it is important to know what biofilms are. Biofilms are organized structures, primarily made of exopolysaccharides, water, and microbes,that are formed by one or several species of bacteria attached to solid surfaces. Biofilms affect many aspects of human life, including industry, medicine, and biosystems. In particular, biofilms play a major role in plant-microbe interactions, biofouling, and biocorrosion. 

The challenges associated with characterizing the diverse organisms involved in plant-microbe interfaces and dissecting their molecular exchanges are being addressed in collaborative research with my fellow scientists at Oak Ridge National Laboratory. Together, we have developed a variety of analytical tools for use in bionanotechnology, including microfluidic devices to sort bacteria, as well as image processing tools and nanoscale analytical techniques.

Microfluidics

Microfluidics is the science of constructing tiny (or microminiaturized) devices with tunnels and chambers for the precise control and manipulation of fluids. Within the 10 to 100 micron channels of these devices, fluid flow is dominated by surface tension and laminar effects. Since biofilm processes are initiated in confined microscopic spaces, and the size of bacterial cells is on the micron scale, microfluidic systems provide major advantages in studying biofilms. In particular, these systems have unique capabilities for applying stimuli to individual cells or to groups of cells and observing the responses. 

Unlike conventional benchtop systems, microfluidic systems allow efficient control of concentration gradients and avoid mechanical stresses in characterizing biofilms. For example, microfluidic devices have been designed and fabricated to study the influences of hydrodynamics in the bacterial environment, which helps us understand biofilm formation and adhesion kinetics. Combined with nanoscale features, microfluidic devices also aid in functionally assaying bacteria to investigate species variation. 

Our work in microfluidics has been innovative, and it has provided some new developments. For example, we have developed microfluidic methods to sort bacteria based on their affinity to chemo attractants. Using PDMS (polydimethyl siloxane) material, microchannels were created on a glass surface. The nanoporous barriers between the fluidic channels confined the bacteria in distinct compartments while allowing controlled delivery and exchange of molecular cues between the compartments.

An understanding of the complex chemical communications between plants and the bacteria that surround the plant roots was also achieved using microfluidic systems. The bacteria are attracted by chemicals that are produced by the plant roots and travel toward them for biofilm formation. Sometimes, for various reasons, the bacteria form colonies on the root surface. Without microfluidic systems, it would not be possible to understand the behaviour of these bacteria.

In addition, fabricated nanostructured microfluidic devices have helped us understand the effect of chemical cues on cellular processes, such as surface recognition, adhesion kinetics, cell-cell communication, and chemotaxis. Microfluidic devices are small and portable, which makes them suitable for screening field isolates of bacteria as well as for food quality monitoring. The devices can also be used to emulate drug delivery using tissues cultured inside the microfluidic compartments.

Image processing and nanoscale analysis Imaging studies of the colonization and surface adhesion kinetics of bacteria using atomic force microscopy (AFM) and confocal laser scanning can reveal the evolution of microbial biofilm morphologies and the structure of the bacterial pili (the hair-like appendages found on many bacteria). By understanding the way bacteria attach to different surfaces, it is possible to create nano-patterned surfaces so that biofouling and biocorrosion activity can be minimized or avoided. 

Quantitative imaging of live biological samples has also been achieved using AFM and confocal laser scanning. We quantified the pico-force with which the bacteria are attached to different surfaces using mica, polystyrene, polypropylene, and glass substrates. Non-intrusive investigation of single biomolecules is possible, and it is useful for screening and diagnostic purposes, as there are connections between biomarkers and genetic disorders. We have also been successful in producing nanowires from bacteria. These nanowires are 6 to 8 nm in diameter (fig. 3). They can conduct electrons and could be used as single-molecule electronic devices. To produce them, the growth conditions of bacteria were optimized to make the bacteria express nanowires from specific field isolates. The nanowires were then deposited on mica substrates and imaged using atomic force microscopy and transmission electron microscopy. In the near future, we will be able to grow nanowires in quantity, and researchers will create biological circuits with this new micro-material.

The association of plants and microbes can often benefit plant health. Often, though, little is known about the specific organisms involved or the mechanisms through which these processes occur, particularly in natural ecosystems. Therefore, we examined the spatial and temporal dynamics of microbial colonization of Populus roots using microbial isolates that express green fluorescent protein (GFP). The association and attachment of bacteria to Populus roots is an initial step in microbial colonization and is influenced by numerous factors, including molecular signalling events, bacterial transport, and surface recognition. Standard molecular methods were used to introduce GFP into microbial isolates. Confocal and atomic force microscopy was then used to characterize the morphology, surface characteristics, and dynamics of biofilm formation of selected microbes isolated from the Populus rhizosphere. 

The gamma-proteobacteria isolate YR343 was observed to attach to the Populus roots (fig. 4) after approximately five hours of co-culture. The cells were observed to grow and form colonies on the surface of the root. Expression of pili during the biofilm formation and distinct morphotypes were revealed by the image analysis. These colonization studies provide direct evidence that microbes collected from the rhizosphere associate directly with Populus roots, and the dynamics of colonization were observed in real time using GFP-expressing microbes. The methods developed for this study will enable additional studies aimed at investigating plant and microbial responses to colonization.

To sum it up

Our research in the field of bionanotechnology has been highly productive. We have developed novel image processing tools and nanoscale analytical techniques to study systems biology, biofilms, and plant microbe interactions, and we have designed and fabricated microfluidic devices and systems for studying bacterial chemotaxis. In particular, we have been highly successful in studying how bacteria attach to root surfaces and in imaging live bacteria colonization on root surfaces. Last but not least, we have developed tools to create DNA templates and analyze chromosome structures using atomic force microscopy. All that, and the field of bionanotechnology is just beginning. 

ASABE Member Suresh Neethirajan, Assistant Professor

School of Engineering, University of Guelph, Ontario, Canada

Suresh presented a paper on '3D Imaging and Morphological Study of the Internal Structure of Cereal Grains Using X-ray Micro Computed Tomography' at the 46th ISAE Convention and International Grain Storage Symposium, Pant Nagar - India on Feb 28, 2012.

Internal structure of cereal grains were investigated using three-dimensional X-ray micro computed tomography images. Reconstruction of numerical samples of grain kernels aided in understanding the distribution of starch matrix and the intercellular path networks. Three dimensional quantitative analysis of internal structure of insect infested wheat kernel, sprout damaged durum wheat kernel, canola, corn and barley kernel revealed the inter-relationships between the structure and function. Stereological analyses using the developed algorithms helped to determine the void volume fraction, specific surface area and the connectivity between the tissues. The results suggests that the combination of computed tomography with image processing delivers geometric parameters of pore structure inside single cereal grain kernels for analysing and developing moisture diffusion models.


Keywords:  X-ray Micro CT; Image Processing; Grain Storage; Grain Geometry; Moisture Diffusivity

http://www.isae.in/sites/default/files/ISAE Schedule fi.pdf

Suresh delivered an invited talk at the 1st Biotechnology World Congress, at Dubai, February 14-15, 2012.

http://biotechworldcongress.com/abstracts/IL/IL-11-04-2011_005_Suresh Neethirajan.htm

Bionanotechnology - Emerging Trends for Agriculture, Food and Biosystems

Bionanotechnology is an emerging interdisciplinary field at the interface of biotechnology and nanotechnology. Being in the incipient stage, the topical areas of bionanotechnology research are in a wide spectrum. Nanoscale technology is well suited for understanding the interfaces between organisms in systems biology. The challenges associated in characterizing the diverse organisms involved in the plant-microbe interface and dissecting their molecular-based exchanges are being currently addressed by our developed analytical tools and devices. Microfluidic devices combined with nanoscale features aids in functionally assaying bacteria in investigating the species variation during motility. Imaging studies of colonization and surface adhesion kinetics of bacteria using confocal fluorescence and atomic force microscopy (AFM) reveals the evolution of distinct microbial biofilm morphologies and the ultra structure of the bacterial pili. Nonintrusive investigation of single biomolecules is challenging but useful for screening and diagnostic purposes as there are connections between biomarkers and genetic disorders. An accurate methodology for karyotyping of chromosomes and fabrication of DNA nanowire templates are being discussed. This presentation will highlight the uses of micro and nanotechnologies that have been developed for studying biomacromolecules as well as understanding the various aspects of plant-microbe interface.

Contact Us

Bionanotechnology Laboratory
Suresh Neethirajan

School of Engineering
University of Guelph
Guelph, Ontario
Canada N1G 2W1

Office:
Room 3513 - Richards Building
50 Stone Road East

Lab: THRN 2133 BioNano Lab

Phone: (519) 824-4120 Ext 53922
Fax: (519) 836-0227

E-mail: sneethir@uoguelph.ca

 
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