Microstructure of food matrix determines the physical, textural and sensory properties of end products. For predicting moisture transport and viscoelastic stresses during sorption and drying of wheat grains it is crucial to determine the  precise internal structure of wheat. Lack of 3-dimensional morphology of the internal features of wheat kernel at the micro-nano scale is a constraint to understand the structure-function relationship, and the coupling between the heat and the mass-transfer processes during drying, cooking and processing. Micro X-ray computed tomography (X-ray CT) is a powerful tool for non-invasive high resolution 3-D visualisation and characterization of the internal micro-structure of cellular food products.

The goals of this study are:(i) to accurately investigate the 3-dimensional spatial distribution of the internal microstructure of insect and sprout damaged wheat kernels using X-ray micro CT images, and (ii) to determine the morphometric parameters such as porosity, anisotropy (3D symmetry) and absolute permeability of the matrix structures inside the insect and sprout damaged wheat kernels.

Nanomedicine is the technology that uses nanoscale or nanostructured materials such as bionanorobots in medicine that according to their structure have unique medical effects. A Nanorobot is defined as any smart structure which is capable of actuation, sensing, signaling, information processing, intelligence, manipulation and swarm behaviour at the nano scale. Bio-nanorobots are nanorobots designed and inspired by harnessing properties of biological materials such as DNAs and peptides. Bionanorobots made using bio-instrumentation have several clinical advantages including targeted drug delivery, nano sized hybrid therapeutics (low dosage) and early diagnosis at cellular level. Realizing Bionanorobots for biomedical applications raises several challenges. The objective of this project is to design an intelligent system using fuzzy logic and neural networks for diagnosis and treatment of tumours in humans using bionanorobots.

Bacterial biofilms have garnered much attention in recent years due to their importance in a wide range of both natural and engineered processes such as infection, water treatment, food processing, and oil pipelining. Here, we use a microfluidic device to quantify the effects of fluid shear force on the biofilm morphology of Shewanella oneidensis, a metal reducing bacteria of interest for several bioremediation and energy applications.

Collaborators: Ameet Singh and Scott Weese - Ontario Veterinary College

Surgical site infections (SSIs) are an inherent risk of any surgical procedure and SSIs caused by Staphylococcus pseudintermedius are becoming the most common nosocomial infections in canines at the Ontario Veterinary College. An important underlying pathogenic factor for the development of SSIs is the ability of the bacteria to form a biofilm. Bacterial biofilms are complex communities of bacteria embedded within a self-produced carbohydrate matrix attached to biological or non-biological surfaces that can greatly impact the ability to treat infections. Clarithromycin eliminates biofilms formed by a wide variety of bacteria and has an effective break-point of 8mg/l on methicillin-susceptible S.pseudintermedius strains. In this study, we investigated the in-vitro efficacy of clarithromycin on 20 methicillin-resistant S.pseudintermedius (MRSP) isolates in-order to test eradication therapies against SSI related infections. MRSP isolates were sub-cultured and inoculated into tryptic soy-broth before addition to microtiter plates. Biofilm formation was quantified first through removal of planktonic bacteria followed by staining, then heat fixing, and finally with elution of biofilm-embedded bacteria before completion of an OD570 reading. To characterize the adhesion, MRSP isolates were grown on stainless steel orthopaedic screws exposed to antibiotics at various time points using Scanning Electron Microscopy (SEM). Visual and image processing evaluation of the SEM images revealed the ability of the MRSPs to form biofilm on the surface and between the screw threads. The quantitative assay results (P > 0.5126) suggest that the influence of clarithromycin in the remediation of MRSP biofilms was insignificant after a 24h growth period. The results of our study indicate that the MRSP biofilms exhibits higher resistance to clarithromycin in therapeutic doses.

The attachment of bacteria to host roots is an initial step in colonization and is influenced by several factors including bacterial transport, surface recognition, and local shear forces. A quantitative understanding of the affinity of proteobacteria for root surfaces and a clear picture of the initial adhesion kinetics associated with attachment is essential to characterize biofilm formation and root colonization. The dual function of imaging and measuring interaction forces makes Atomic Force Microscopy (AFM) a unique tool for studying bacterial adhesion. The adhesion between the cell surface and the AFM tip can be measured from the extension and the retraction of the force curve cycle using functionalized cantilever tips. The mechanisms involved in the bacterial attachment and motility behavior were elucidated by force spectroscopy measurements and microfluidic systems. The developed analytical techniques quantified the adhesion forces which helped to explain the spatial and temporal dynamics of the colonization of Populus by proteobacteria. The role of the extracellular polymeric substance and the pili in facilitating the bacterial adhesion during biofilm formation are being analyzed.

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Bionanotechnology Laboratory
Suresh Neethirajan

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

Room 3513 - Richards Building
50 Stone Road East

Lab: THRN 2133 BioNano Lab

Phone: (519) 824-4120 Ext 53922
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