Abstract: The feasibility of biomimetic molecular sensing of homocysteine, an independent risk factor for cardiovascular diseases, was studied. The sensing approach coupled fluorescent derivatization of DL-homocysteine by a thiol-specific fluoro- tagging agent, N-(1-pyrenyl)maleimide, with molecular recognition by a molecularly imprinted polymer (MIP) matrix. The non-covalent MIP was fabricated using the N-(1- pyrenyl)maleimide-DL-homocysteine (PM-H) adduct as template. The PM-H-MIP was found to possess outstanding analyte-specific affinity for PM-H with binding constant, K-B, of 9.28 +/- 1.6 x 10(5) M-1 and density of recognition sites, B-max, of 11.9 +/- 0.8 nmol/g dried MIR Following in situ fluorescent derivatization, luminescent response of the MIP was found to correlate linearly with concentration of DL-homocysteine in the range corresponding to realistic total homocysteine concentration in blood plasma. Besides being a passive recognition matrix for the binding of the fluoro-tagged analyte, the PM-H-MIP material was found to be able to specifically enhance the rate of derivatization reaction between DL-homocysteine and N-(1-pyrenyl)maleimide. In a sense, the MIP transformed a fluoro-tagging agent, which is generally reactive towards a broad spectrum of thiol-containing species, into a DL-homocysteine-specific derivatizing agent. The mechanism of such analyte-specific enhancement of derivatization rate and its advantages to the biomimetic molecular sensing are discussed. (C) 2002 Elsevier Science B.V. All rights reserved

Tweet