Current molecular techniques for the detection of microbial pathogens.

Traditionally the detection of microbial pathogens in clinical, environmental or food samples has commonly needed the prelevation of cells by culture before the application ofthe detection strategy. This is done to increase cell number thereby overcoming problems associated with the sensitivity of classical detection strategies. However, culture-based methods have the disadvantages of taking longer, usually are more complex and require skilled personnel as well as not being able to detect viable but non cultivable microbial species. A number of molecular methods have been developed in the last 10 to 15 years to overcome these issues and to facilitate the rapid, accurate, sensitive and cost effective identification and enumeration of microorganisms which are designed to replace and/or support classical approaches to microbial detection. Amongst these new methods, ones based on the polymerase chain reaction and nucleic acid hybridization have been shown to be particularly suitable for this purpose. This review generally summarizes some of the current and emerging nucleic acid based molecular approaches for the detection, discrimination andquantification ofmicrobes in environmental, food and clinical samples and includes reference to the recently developing areas of microfluidics and nanotechnology "Lab-on-a-chip".

Quantum dot-antibody conjugates via carbodiimide-mediated coupling for cellular imaging.

This chapter describes the processes of antibody (Ab) production, purification, conjugation to quantum dots (QDs), and the use of the conjugates produced in intracellular imaging of cell components and structures. Specifically, information is provided on the conjugation of carboxyl surface-terminated QDs to Abs via a one-step reaction using the water-soluble carbodiimide, 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide (EDC). The chapter details the process of conjugate optimization in terms of its final fluorescence and biological activity. The method described should guarantee the production of QD-Ab conjugates, which outperform classic organic fluorophore-Ab conjugates in terms of both image definition produced and the longevity of the imaging agent.

Novel and Improved Nanomaterials, Chemistries and Apparatus for Nanobiotechnology: the NACBO project.

This article outlines the nature and activities of the recently completed EU Framework Programme 6 Integrated Project, Novel and Improved Nanomaterials, Chemistries and Apparatus for Nanobiotechnology (NACBO). This project was designed to yield new nanomaterials, surface activation and synthetic nucleic acid chemistries, procedures and hardware for applications in forensics and diagnostics. It provides details on the project's structure and partnership along with its principal objectives and successes in terms of publications and commercial exploitation.

Silicon, silica and its surface patterning/activation with alkoxy- and amino-silanes for nanomedical applications.

Silica and silicates are widely used in nanomedicine with applications as diverse as medical device coatings to replacement materials in tissue engineering. Although much is known about silica and its synthesis, relatively few biomedical scientists fully appreciate the link that exists between its formulation and its resultant structure and function. This article attempts to provide insight into relevant issues in that context, as well as highlighting their importance in the material's eventual surface patterning/activation with alkoxy- and organo-silanes. The use of aminosilanes in that context is discussed at some length to permit an understanding of the specific variables that are important in the reproducible and robust aminoactivation of surfaces using such molecules. Recent investigative work is cited to underline the fact that although aminosilanization is a historically accepted mechanism for surface activation, there is still much to be explained about how and why the process works in the way it does. In the last section of this article, there is a detailed discussion of two classical approaches for the use of aminosilanized materials in the covalent immobilization of bioligands, amino-aldehyde and amino-carboxyl coupling. In the former case, the use of the homobifunctional coupler glutaraldehyde is explored, and in the latter, carbodiimides. Although these chemistries have long been employed in bioconjugations, it is apparent that there are still variables to be explored in the processes (as witnessed by continuing investigations into the chemistries concerned). Aspects regarding optimization, standardization and reproducibility of the fabrication of amino functionalized surfaces are discussed in detail and illustrated with practical examples to aid the reader in their own studies, in terms of considerations to be taken into account when producing such materials. Finally, the article attempts to remind readers that although the chemistry and materials involved are 'old hat', there is still much to be learnt about the methods involved. The article also reminds readers that although many highly specific and costly conjugation chemistries now exist for bioligands, there still remains a place for these relatively simple and cost-effective approaches in bioligand conjugate fabrication.

Fabrication of novel hierarchically ordered porous magnetic nanocomposites for bio-catalysis.

Novel hierarchically ordered porous magnetic nanocomposites with interconnecting macroporous windows and meso-microporous walls containing well dispersed magnetic nanoparticles have been fabricated and used as a support to immobilise lipase for the efficient hydrolysis of ester.

Mesoporous silica-magnetite nanocomposite: fabrication and applications in magnetic bioseparations.

Magnetic bioseparations such as adsorption and elution of nucleic acids by a mesoporous superparamagnetic silica-magnetite nanocomposite are reported.