de la Rica Roberto, Baldi Antonio, Fernández-Sánchez César, Matsui Hiroshi
Department of Chemistry and Biochemistry, City University of New York-Hunter College, 695 Park Avenue, New York, New York 10065, USA.
Anal Chem. 2009 May 15;81(10):3830-5. doi: 10.1021/ac9001854.
Detection of physical changes of cells is emerging as a new diagnostic approach to determine their phenotypical features. One of such changes is related to their viability; live (viable) cells are more voluminous than the dead ones, and monitoring this parameter in tissue cells becomes essential in fields such as drug discovery and hazard evaluation. In the area of pathogen detection, an analytical system capable of specifically detecting viable cells with the simple sample preparation and detection process would be highly desirable since live microorganisms can rapidly increase their numbers even at extremely low concentration and become a severe health risk. However, current sensing strategies cannot clearly determine the viability of cells, and hence they are susceptible to false-positive signals from harmless dead pathogens. Here we developed a robust electronic immunoassay that uses a pair of polycrystalline silicon interdigitated electrodes for the rapid detection of pathogens with high specificity for live cells. After bacterial cells were specifically anchored to the surface of the antibody-modified electrode, the characteristic geometry of the transducer enables the selective detection of viable cells with a limit of detection of 3 x 10(2) cfu/mL and an incubation time of only 1 h. The CMOS compatible fabrication process of the chip along with the label-free, reagent-less electronic detection and the easy electrode regeneration to recycle for another impedance measurement make this approach an excellent candidate for oncoming economical in-field viable-cell detection systems, fully integrable with sophisticated signal processing circuits.
检测细胞的物理变化正在成为一种确定其表型特征的新诊断方法。其中一种变化与细胞活力有关；活细胞比死细胞体积更大，在药物发现和危害评估等领域，监测组织细胞中的这一参数变得至关重要。在病原体检测领域，一种能够通过简单的样品制备和检测过程特异性检测活细胞的分析系统将非常受欢迎，因为即使在极低浓度下，活微生物也能迅速增加其数量并带来严重的健康风险。然而，目前的传感策略无法明确确定细胞的活力，因此它们容易受到无害死病原体的假阳性信号影响。在此，我们开发了一种强大的电子免疫测定法，该方法使用一对多晶硅叉指电极快速检测对活细胞具有高特异性的病原体。细菌细胞特异性锚定在抗体修饰电极表面后，传感器的独特几何结构能够选择性检测活细胞，检测限为3×10(2) cfu/mL，孵育时间仅为1小时。芯片的CMOS兼容制造工艺，以及无标记、无试剂的电子检测和易于电极再生以循环进行另一次阻抗测量，使这种方法成为即将到来的经济现场活细胞检测系统的极佳候选方法，可与复杂的信号处理电路完全集成。
