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, KB, of 9.28±1.6×105 M−1 and density of recognition sites, Bmax, of 11.9±0.8 nmol/g dried MIP. 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. Copyright © 2002 Elsevier Science B.V. All rights reserved.
CitationChow, C.-F., Lam, M. H. W., & Leung, M. K. P. (2002). Fluorescent sensing of homocysteine by molecular imprinting. Analytica Chimica Acta, 466(1), 17-30. doi: 10.1016/S0003-2670(02)00520-2
- Molecular imprinting
- Biomimetic sensing