Molecular Engineering of Fluorescent Penicillins for Molecularly Imprinted Polymer Assays
作者:Elena Benito-Peña、María C. Moreno-Bondi、Santiago Aparicio、Guillermo Orellana、Josefine Cederfur、Maria Kempe
DOI:10.1021/ac051939b
日期:2006.3.1
The interaction of seven novel fluorescent labeled β-lactams with a library of six polymer materials molecularly imprinted (MI) with penicillin G (PenG) has been evaluated using both radioactive and fluorescence competitive assays. The highly fluorescent competitors (emission quantum yields of 0.4−0.95) have been molecularly engineered to contain pyrene or dansyl labels while keeping intact the 6-aminopenicillanic acid moiety for efficient recognition by the cross-linked polymers. Pyrenemethylacetamidopenicillanic acid (PAAP) is the tagged antibiotic that provides the highest selectivity when competing with PenG for the specific binding sites in a MI polymer prepared with methacrylic acid and trimethylolpropane trimethacrylate (10:15 molar ratio) in acetonitrile in the presence of PenG. Molecular modeling shows that recognition of the fluorescent analogues of PenG by the MI material is due to a combination of size and shape selectivity and demonstrates how critical the choice of label and tether chain is. PAAP has been applied to the development of a fluorescence competitive assay for PenG analysis with a dynamic range of 3−890 μM in 99:1 acetonitrile−water solution. Competitive binding studies demonstrate various degrees of cross-reactivity for some antibiotics derived from 6-aminopenicillanic acid, particularly amoxicillin, ampicillin, and penicillin V (but not oxacillin, cloxacillin, dicloxacillin, or nafcillin). Other antibiotics, such as chloramphenicol, tetracycline, or cephapirin, do not compete with PAAP for binding to the imprinted polymer. The MI assay has successfully been tested for PenG analysis in a pharmaceutical formulation.
七种新型荧光标记的β-内酰胺与一种由青霉素G(PenG)分子印迹(MI)的六种聚合物材料库的相互作用,通过放射性和荧光竞争测定法进行了评估。这些荧光竞争者具有高荧光特性(发射量子产率为0.4−0.95),经过分子工程设计,含有芘或丹酰基标签,同时保持6-氨基青霉烷酸基团,以便能够有效被交联聚合物识别。芘甲基乙酰氨基青霉烷酸(PAAP)是标记的抗生素,在与PenG竞争在用丙烯酸和三羟甲基丙烷三甲基丙烯酸酯(10:15摩尔比)制备的MI聚合物的特定结合位点位竞争时,提供了最高的选择性,测试在含有PenG的乙腈中。分子模型表明,MI材料对PenG的荧光类似物的识别是由于尺寸和形状选择性的结合,并表明了标签和连接链选择的重要性。PAAP已被用于开发PenG分析的荧光竞争测定法,其动态范围为3−890 μM,在99:1乙腈−水溶液中。竞争结合研究表明,一些来源于6-氨基青霉烷酸的抗生素表现出不同程度的交叉反应性,特别是阿莫西林、氨苄西林和青霉素V(但非氧氟西林、克拉霉素、双克拉霉素或那福西林)。其他抗生素如氯霉素、四环素或头孢吡琳与PAAP在结合印迹聚合物时不发生竞争。该MI测定法已成功用于药物制剂中PenG的分析。