Departamento de Química Analítica, Instituto Universitario de Investigación en Química Fina y Nanoquímica (IUNAN), Universidad de Córdoba, Campus de Rabanales, Edificio Anexo "Marie Curie", 14071, Córdoba, Spain.
Institut Für Analytische Chemie, Chemo- Und Biosensorik, Universität Regensburg, 93040, Regensburg, Germany.
Mikrochim Acta. 2024 Nov 13;191(12):739. doi: 10.1007/s00604-024-06829-9.
A method using pH gradient to modify the phospholipid dissociation has been developed using hybrid magnetoliposomes with encapsulated enzyme laccase, which has been immobilized on hydrophilic magnetic nanocrystals (PAA-MNCs) retained in the reaction/detection zone of a microfluidic system. The hybrid magnetoliposomes act as micro containers, providing the safe transfer of the enzyme to the reaction/detection site, where it is retained, and preconcentration of the enzyme in this place occurs, which improves the system's sensitivity. The use of pH change involves the lack of external molecules to release the encapsulated materials. The laccase-mediated redox oxidation of the fluorescent substrate 8-hydroxypyrene-1,3,6-trisulfonic acid (HPTS) to form its non-fluorescent oxide form has been used as the indicator reaction. The method was applied to determine potential laccase inhibitors in beverages and fruits. The study of the inhibitory effect has focused on compounds that follow different mechanisms: cysteine, malic acid, and fumaric acid. The dynamic ranges of the calibration graphs of these compounds were between 0.05-100, 0.02-100, and 0.1-100 μmol L, respectively. The detection limits have been established between 6 and 30 nmol L, and the precision expressed as the percent of relative standard deviation (RSD%) was between 2.5 and 5.1%. The overall microfluidic system showed a sampling frequency of 8 h. The method has been applied to determine fumaric acid as a laccase inhibitor in several juice samples (apple, pear, and grape), with recovery values between 85 and 101%. The results were comparable to those obtained using a LC reference method.
已经开发出一种使用 pH 梯度来修饰磷脂解吸的方法，该方法使用包封酶漆酶的杂交磁脂体，该酶固定在亲水性磁性纳米晶体 (PAA-MNC) 上，保留在微流控系统的反应/检测区。杂交磁脂体充当微容器，为酶安全转移到反应/检测部位提供了条件，在该部位酶被保留，并且在该部位发生酶的预浓缩，从而提高了系统的灵敏度。pH 值变化的使用涉及缺乏释放包封材料的外部分子。已将荧光底物 8-羟基芘-1,3,6-三磺酸 (HPTS) 的漆酶介导的氧化还原氧化作用用于形成其非荧光氧化物形式作为指示反应。该方法已用于测定饮料和水果中的潜在漆酶抑制剂。抑制作用的研究集中在遵循不同机制的化合物上：半胱氨酸、苹果酸和富马酸。这些化合物的校准曲线的动态范围分别为 0.05-100、0.02-100 和 0.1-100 μmol L，检测限分别为 6-30 nmol L，精密度表示为相对标准偏差 (RSD%) 的百分比在 2.5-5.1%之间。整个微流控系统的采样频率为 8 小时。该方法已用于测定苹果酸、梨和葡萄等几种果汁样品中的富马酸作为漆酶抑制剂，回收率在 85-101%之间。结果与使用 LC 参考方法获得的结果相当。
