Maraldo David, Rijal Kishan, Campbell Gossett, Mutharasan Raj
Department of Chemical and Biological Engineering, Drexel University, Philadelphia, Pennsylvania 19104, USA.
Anal Chem. 2007 Apr 1;79(7):2762-70. doi: 10.1021/ac0621726. Epub 2007 Feb 20.
Rapid (approximately 10 min) measurement of very low concentration of pathogens (approximately 10 cells/mL) and protein (approximately fg/mL) has widespread use in medical diagnostics, monitoring biothreat agents, and in a broader context as a research method. For low-level pathogen, we currently use culture enrichment methods and, thus, rapid analysis is not possible. For low protein concentration, no direct method is currently available. We report here a novel macrocantilever design whose high-order resonant mode near 1 MHz exhibits mass detection sensitivity of 10 cells/mL for cells and 100 fg/mL for protein. The sensor is 1x3 mm and uses a piezoelectric layer for both actuation and sensing resonance. Sample is flowed (approximately 1 mL/min) past the antibody-immobilized sensor, and as antigen binds to the sensor, resonance frequency decreases in proportion to antigen concentration. The sensor showed selectivity to the pathogen even though copious nonpathogenic variant was simultaneously present.
对极低浓度病原体（约10个细胞/毫升）和蛋白质（约飞克/毫升）进行快速（约10分钟）测量在医学诊断、监测生物威胁制剂以及更广泛地作为一种研究方法中有着广泛应用。对于低水平病原体，我们目前使用培养富集方法，因此无法进行快速分析。对于低蛋白浓度，目前没有直接可用的方法。我们在此报告一种新型大悬臂梁设计，其接近1兆赫兹的高阶共振模式对细胞的质量检测灵敏度为10个细胞/毫升，对蛋白质为100飞克/毫升。该传感器尺寸为1×3毫米，使用压电层进行驱动和感应共振。样品以约1毫升/分钟的流速流过固定有抗体的传感器，当抗原与传感器结合时，共振频率会与抗原浓度成比例降低。即使同时存在大量非致病性变体，该传感器对病原体仍表现出选择性。
