Design and Fabrication of a Novel Biomass Sensor

目前，人们对新型生物传感器有着巨大的兴趣和需求，可以在越来越低的浓度下检测越来越多的不同分析物。本文首次提出了一种能够测量飞图级质量的超灵敏MEMS质量传感器。该传感器由一组运动悬臂梁环绕的旋转圆盘组成，这些运动悬臂梁通过固定的悬臂电极静电激励。该设备将用于检测甲胎蛋白（AFP），这是肝癌的一种生物标志物。肝癌是为数不多的细胞毒性化疗几乎没有效果的肿瘤之一，这证明了早期诊断可以提高生存率。确定该生物传感器的灵敏度、选择性和检出限。我们打算揭示潜在的非线性动力学，并减少该领域的知识差距。所提出的MEMS传感器/开关利用了平面内旋转运动，克服了传统悬臂式MEMS传感器的平面外运动的复杂性，因此与石英晶体微平衡技术相比，提高了灵敏度。此外，考虑到生物量与谐振腔质量的比例，生物量对悬臂梁的位置依赖性变得更加明显。由于所提出模型的独特结构，传感器的输出将独立于生物标志物的位置和受体的沉积，并且生物标志物不会改变传感器的刚度。因此，所提出的生物质传感器的灵敏度超过了现有的悬臂式生物质传感器，而不需要缩小到纳米级，这明显要求更高的制造成本和增加复杂性。这使得能够以超高灵敏度实时快速检测各种生物质（例如与不同疾病相关的生物标志物）。

Currently, there is immense interest and demand for novel biosensors to detect a growing number of diverse analytes at increasingly low concentrations. Here for the first time, a novel ultra-sensitive MEMS mass sensor is proposed capable of measuring masses in the order of femtogram. The sensor consists of a rotational disk surrounded by a group of moving cantilever beams which are electrostatically excited through the fixed cantilever electrodes. The proposed device will be tested for the detection of alphafetoprotein (AFP), which is a biomarker for liver cancer. The liver cancer is one of the few tumors for which cytotoxic chemotherapy has little effect and this justifies the early-stage diagnosis of it for more survival. The sensitivity, selectivity and detection limit of the biosensor will be determined. We intend to uncover the underlying nonlinear dynamics and reduce the knowledge gap in the field.The proposed MEMS sensor/switch takes advantage of the in-plane rotational motion to overcome the complications of the out-ofplane motion of traditional cantilever MEMS sensors and accordingly results in enhanced sensitivity in comparison with Quartz Crystal Microbalance technology. Furthermore, considering the ratio of the biomass to the resonator mass the position dependency of the biomass on the cantilever beam becomes more pronounced. Due to the unique architecture of the proposed model, the output of the sensor will be independent of the position of the biomarker and the deposition of the receptor, and the biomarker will not change the stiffness of the sensor. Therefore, the proposed biomass sensor offers a sensitivity beyond the available cantilever-based biomass sensors without the need to scale down to nano regime, which significantly demands higher fabrication costs and increases complexities. This enables the rapid detection of a wide range of biomasses (such as biomarkers associated with different diseases) in real-time and at ultra-high sensitivity.