Application of molecularly imprinted polymer nanoparticles for degradation of the bacterial autoinducer N-hexanoyl homoserine lactone.

A novel bacterial quorum quenching system is presented. For the first time the degradation of N-l-hexanoyl homoserine lactone (C6-AHL), a Gram-negative quorum sensing autoinducer, has been enhanced using molecularly imprinted nanoparticles (MIP NPs) which were prepared using transition state analogue of the γ-lactone ring hydrolysis as template

Development of a homogenous assay based on fluorescent imprinted nanoparticles for analysis of nitroaromatic compounds

Herein we describe the development of a homogeneous assay for the detection of 4-nitroaniline (4-NA) and 2,4-dinitroaniline (2,4-diNA). This assay relies on fluorescent molecularly imprinted nanoparticles (nanoMIPs) which, upon interaction with the target analytes, generate a reduction in fluorescence emission intensity (quenching). This is due to a responsive fluorescent monomer (N-2-propenyl-(5-dimethylamino)-1-naphthalene sulphonamide) employed in the manufacture of the nanoMIPs which, by virtue of the imprinting process, is capable of selective interaction with the target analyte, thus giving rise to a quenching effect. Selectivity experiments showed excellent recognition properties toward the target molecule. Under optimal conditions, the fluorescence intensity of these nanoMIPs decreased as the concentration of the imprinted analyte increased from 10 nM to 2.71 μM. A linear relation between the negative logarithm of 4-NA or 2,4-diNA concentrations and the fluorescence intensity for both nanosystems was found (R2 = 0.991 and R2 = 0.9895), with excellent sensitivity (limit of detection (LOD) = 7 and 6 nM, respectively). Furthermore, both nanosystems have been successfully applied for detection of 4-NA or 2,4-diNA in tap water, with recoveries between 90% to 100.6% and 92% to 100.3%, respectively. Thanks to the versatility of the imprinting process, this nanosystem holds the potential for further development of several optical sensors for many other compounds. [Figure not available: see fulltext.].</p

New protocol for optimisation of polymer composition for imprinting of peptides and proteins

We present here a novel screening tool for optimisation of polymerisation mixtures used in imprinting of peptides and proteins. To facilitate rapid synthesis and screening of a combinatorial library of polymers the solid-phase synthesis method developed by Piletsky and co-workers was scaled down to 50 mg of template-immobilised solid phase, allowing a single well of a 96-well microplate to function as an individual reaction vessel. In this way, 32 different polymer compositions containing N-isopropylacrylamide, acrylic acid, N-(3-aminopropyl)methacrylamide hydrochloride, and N-tert-butylacrylamide, were tested in imprinting of three peptides and three proteins. Utilising filtration microplates has allowed the elution and washing steps to be performed in a similar manner to the large-scale synthesis, whilst incorporation of a fluorescent monomer (N-fluoresceinylacrylamide) made it possible to analyse the binding of synthesised polymer nanoparticles to the solid phase with immobilised templates under different washing conditions. The experiment has proven that the variations in monomer compositions had an effect on the yield and affinity of synthesised molecularly imprinted polymers for the peptides, but not for the proteins. Imprinting in this way presents an ideal method for performing small-scale syntheses for testing polymerisation mixtures, as information regarding the molecularly imprinted polymers affinity can be assessed as part of the elution process, without a need for time-consuming analysis such as quartz crystal microbalance or surface plasmon resonance