Integrated system for cancer biomarker detection

描述(由申请人提供)： 有证据表明，下一代癌症筛查测试可能不只使用一个，而是一个不到十个生物标记物的小组，这些生物标记物加在一起，为特定癌症的检测增加了统计能力。虽然免疫分析方法(如ELISA法)已被很好地用于基于抗原的生物标记物的检测，但该分析的保真度主要取决于抗体-抗原复合体的解离常数Kd。如果抗原浓度显著低于Kd，则结合动力学缓慢，并且抗原-抗体复合体的读出精度因噪声而降低。 我们提出了一种改进免疫分析性能的一般方法。该方法基于一种纳米/微流控装置，该装置可控制地将生物标记物集中到KD附近。如果浓缩器的放大(或增益)是可调的，免疫分析的动态范围和检测下限最终将由浓缩器的属性而不是KD决定。 我们已经开发并验证了一种基于纳米通道的预浓缩器，它可以随着时间线性增加样品浓度，并可以在一小时内将初始样品浓度提高约10/7。由于浓缩物的总体积为10-100Pl，我们建议将预浓缩器与类似体积的检测器集成在一起，以避免稀释。该检测器在概念上类似于ELISA；然而，抗原-抗体结合的读出是基于在10pl体积内以皮卡分辨率直接检测生物标记物质量。因此，我们预计，结合浓缩器和SMR检测系统将允许以接近1pg/mL的分辨率检测特定的生物标志物。 为了增强生物标记物对癌症的预测能力，我们将用一个集成系统从单个样本中提取四种不同的生物标记物的丰度。该系统将通过传统的铸造级微加工工艺批量制造，以实现广泛和低成本的护理应用分配。

DESCRIPTION (provided by applicant): There is evidence to suggest that the next generation of cancer screening tests may employ not just one, but a small panel of less than ten biomarkers, that together add statistical power to the detection of specific cancers. While immunoassays such as ELISA are well established for antigen-based biomarker detection, the fidelity of the assay is primarily governed by the disassociation constant, Kd, of the antibody-antigen complex. If the antigen concentration is significantly below the Kd, then the binding kinetics are slow and read-out precision of the antigen-antibody complex is degraded by noise. We are proposing a general approach for improving the performance of immunoassays. The approach is based on a nano/microfluidic device that controllably concentrates biomarkers to the vicinity of the Kd. Provided the amplification (or gain) of the concentrator is adjustable, the dynamic range and detection limit of the immunoassay will ultimately be governed by the properties of the concentrator and not the Kd. We have developed and validated a nanochannel-based preconcentrator that increases sample concentration linearly with time and can enhance the initial sample concentration by approximately 10/7 in an hour. Since the total volume of the concentrate is 10-100 pL, we are proposing to integrate the preconcentrator with a detector of similar volume in order to avoid dilution. The detector is conceptually similar to ELISA; however, the read-out of the antigen-antibody binding is based on the direct detection of biomarker mass with picogram resolution within a 10 pL volume. Thus, we anticipate that the combined concentrator and SMR detection system will allow a specific biomarker to be detected at a resolution near 1 pg/mL. In order to enhance the predictive power of biomarkers for cancer, we will profile the abundance of four different biomarkers from a single sample with an integrated system. The system will be batch fabricated by conventional foundry-level micromachining processes to enable widespread and low-cost distribution for point-of-care applications.