Sreenath Subrahmanyam

Analytical methods for determination of mycotoxins: a review.

Mycotoxins are small (MW approximately 700), toxic chemical products formed as secondary metabolites by a few fungal species that readily colonise crops and contaminate them with toxins in the field or after harvest. Ochratoxins and Aflatoxins are mycotoxins of major significance and hence there has been significant research on broad range of analytical and detection techniques that could be useful and practical. Due to the variety of structures of these toxins, it is impossible to use one standard technique for analysis and/or detection. Practical requirements for high-sensitivity analysis and the need for a specialist laboratory setting create challenges for routine analysis. Several existing analytical techniques, which offer flexible and broad-based methods of analysis and in some cases detection, have been discussed in this manuscript. There are a number of methods used, of which many are lab-based, but to our knowledge there seems to be no single technique that stands out above the rest, although analytical liquid chromatography, commonly linked with mass spectroscopy is likely to be popular. This review manuscript discusses (a) sample pre-treatment methods such as liquid-liquid extraction (LLE), supercritical fluid extraction (SFE), solid phase extraction (SPE), (b) separation methods such as (TLC), high performance liquid chromatography (HPLC), gas chromatography (GC), and capillary electrophoresis (CE) and (c) others such as ELISA. Further currents trends, advantages and disadvantages and future prospects of these methods have been discussed.

“Bite‐and‐Switch” Approach to Creatine Recognition by Use of Molecularly Imprinted Polymers

The detection of creatine is important in the analysis of athletes and body builders. Here is reported the preparation of a synthetic polymer using imprinting polymerization, which leaves the polym ...

The application of polythiol molecules for protein immobilisation on sensor surfaces

The immobilisation of bio-receptors on transducer surfaces is a key step in the development of biosensors. The immobilisation needs to be fast, cheap and most importantly should not affect the biorecognition activity of the immobilised receptor. The development of a protocol for biomolecule immobilisation onto a surface plasmon resonance (SPR) sensor surface using inexpensive polythiol compounds is presented here. The method used here is based on the reaction between primary amines and thioacetal groups, formed upon reaction of o-phthaldialdehyde (OPA) and thiol compounds. The self-assembled thiol monolayers were characterised using contact angle and XPS. The possibility to immobilise proteins on monolayers was assessed by employing BSA as a model protein. For the polythiol layers exhibiting the best performance, a general protocol was optimised suitable for the immobilisation of enzymes and antibodies such as anti-prostate specific antigen (anti-PSA) and anti Salmonella typhimurium. The kinetic data was obtained for PSA binding to anti-PSA and for S. typhimurium cells with a detection limit of 5x10(6) cells mL(-1) with minimal non-specific binding of other biomolecules. These findings make this technique a very promising alternative for amine coupling compared to peptide bond formation. Additionally, it offers opportunity for immobilising proteins (even those with low isoelectric point) on neutral polythiol layers without any activation step.

Application of molecularly imprinted polymers in sensors for the environment and biotechnology

Molecular imprinting is a generic technology, which introduces recognition properties into synthetic polymers using appropriate templates. Over the last two decades molecularly imprinted polymers (MIPs) have become a focus of interest for scientists engaged in the development of biological and chemical sensors. This is due to the many and considerable advantages they possess in comparison to natural receptors, enzymes and antibodies such as superior stability, low cost and ease of preparation. This brief review covers recent achievements and potential applications of imprinted sensors with specific reference to the environment and biotechnology.

A new reactive polymer suitable for covalent immobilisation and monitoring of primary amines

A new polymer capable of reacting with primary amines was synthesised from allyl mercaptan, o-phthalic dialdehyde and ethylene glycol dimethacrylate by radical polymerisation. Reactive hemithioacetal formed by allyl mercaptan and dialdehyde can bind primary amino groups without additional pre-activation forming the fluorescent isoindole complex. It gives a great opportunity to monitor binding and perform loading of the amino compounds onto the reactive surface. The reactive polymer is found to be an effective matrix for immobilisation of the proteins and other amino-containing compounds in affinity chromatography and could be used for their detection in solution

Computational Design of Molecularly Imprinted Polymers

Artificial receptors have been in use for several decades as sensor elements, in affinity separation, and as models for investigation of molecular recognition. Although there have been numerous publications on the use of molecular modeling in characterization of their affinity and selectivity, very few attempts have been made on the application of molecular modeling in computational design of synthetic receptors. This chapter discusses recent successes in the use of computational design for the development of one particular branch of synthetic receptors – molecularly imprinted polymers.

Computational Approaches in the Design of Synthetic Receptors

Artificial receptors have been employed in molecular recognition for a variety of biological applications. They have been used as materials for sensors, affinity separation, solid-phase extraction, and for research into biomolecular interaction. There have been a number of publications relating to the application of molecular modeling in the characterization of their affinity and selectivity; there are very few publications that discuss the application of molecular modeling to the computational design of artificial receptors. This chapter discusses recent successes in the use of computational design for the development of artificial receptors, and touches upon possible future applications, further emphasizing an exciting group of synthetic receptors—molecularly imprinted polymers.