High-sensitivity terahertz scanner for detection of aflatoxins in nuts and nut products

项目摘要/摘要 太赫兹波具有独特的规格，这使得它们在非侵入性、无标签的领域非常有吸引力 生物传感技术。这是因为许多有机化合物对电磁波有独特的响应。 太赫兹频率。此外，太赫兹波可以穿透许多光学不透明的环境。 以及大多数包装材料，如塑料、纸等。这些巨大的潜力使太赫兹 成像/光谱分析系统是实现高灵敏度、高通量和无损检测的绝佳平台 黄曲霉毒素的检测，黄曲霉毒素可生长在各种农产品中，并导致各种慢性健康 如果食用会有问题，包括肝癌。黄曲霉毒素在太赫兹具有独特的光谱特性 然而，使用太赫兹波进行高通量和高灵敏度的黄曲霉毒素检测 由于传统太赫兹扫描仪的低灵敏度，食品以前似乎并不实用， 它们需要在信噪比(SNR)和测量时间之间进行权衡。例如, 实现足够灵敏的测量以检测黄曲霉毒素的最大允许污染水平 受食品和药物管理局(FDA)监管，使用传统的太赫兹扫描仪，超过1000 应对同一样本进行测量，以减少采集数据的噪声，这会增加 测量时间显著缩短。此外，大多数太赫兹光谱测量应该是 以非常细致的方式进行，这需要不适当的特定样品制备配方 用于字段设置。拟议的研究解决了传统太赫兹扫描系统的这些局限性。 并提供高通量、无损和高灵敏度的黄曲霉毒素扫描仪，该扫描仪不需要 熟练的用户操作。能够实现如此高性能黄曲霉毒素扫描仪的关键创新是：(1) 使用突破性的等离子体太赫兹源和探测器技术，提供几个数量级的 比传统太赫兹设备提供的信噪比水平高出一个数量级，(2)使用 先进的数据分析算法，能够直接计算黄曲霉毒素浓度，而不受 被测样品的类型和形状。因此，提出的太赫兹扫描仪提供了一个极好的 高通量、非破坏性、非接触式检测坚果及加工品中黄曲霉毒素的监管工具 坚果产品，将监管不合规风险降至最低，为公众提供优质产品。通过 第一阶段结束后，将完成对黄曲霉毒素片剂和黄曲霉毒素的全面实验分析。 用单像素太赫兹扫描仪原型评估受污染坚果的敏感性和特异性 建议使用扫描仪。在第二阶段，黄曲霉毒素扫描速度将通过使用焦平面探测器阵列和 开发的用于检测黄曲霉毒素的多像素扫描仪将扩展到更广泛的 农业食品，同时开发可用于现实领域/包装/分销的原型 设置。

Project Summary/Abstract Terahertz waves have unique specifications that make them very attractive for non-invasive, label-free biosensing. This is because many organic compounds have unique responses to the electromagnetic waves at terahertz frequencies. In addition, terahertz waves can penetrate through many optically-opaque environments as well as most of the packaging materials such as plastic, paper, etc. These great potentials make terahertz imaging/spectroscopy systems an excellent platform for high-sensitivity, high-throughput, and non-destructive detection of aflatoxins, which can grow in various agricultural food products and cause various chronic health problems if consumed, including liver cancer. Aflatoxins have unique spectral characteristics at terahertz frequencies, however the use of terahertz waves for high-throughput and high-sensitivity aflatoxin detection in food products did not seem practical before because of the low sensitivity of conventional terahertz scanners, which suffer from a trade-off between the signal-to-noise ratio (SNR) and the measurement time. For instance, to achieve a sufficiently sensitive measurement to detect the maximum allowed aflatoxin contamination level regulated by the Food and Drug Administration (FDA) with conventional terahertz scanners, more than thousand measurements should be taken on the same sample to reduce the noise of the acquired data, which increases the measurement time significantly. In addition, most of the terahertz spectroscopy measurements should be performed in very meticulous ways, which require specific sample preparation recipes that are not appropriate for field settings. The proposed research addresses these limitations of conventional terahertz scanning systems and offers a high-throughput, non-destructive, and highly-sensitive aflatoxin scanner that does not require a skilled user to operate. The key innovations that enable such a high-performance aflatoxin scanner are: (1) the use of a breakthrough plasmonic terahertz source and detector technology that offers several orders of magnitude higher SNR levels compared to those offered by conventional terahertz devices, (2) the use of an advanced data analysis algorithm that is capable of direct calculation of aflatoxin concentration regardless of the type and shape of the sample under test. As a result, the proposed terahertz scanner offers an excellent regulatory tool for high-throughput, non-destructive, non-contact detection of aflatoxins in nuts and processed nut products, minimizing regulatory non-compliance risks and providing high-quality products to the public. By the end of the Phase I, a thorough experimental analysis will be completed on aflatoxin tablets and aflatoxin- contaminated nuts with a single-pixel terahertz scanner prototype to assess the sensitivity and specificity of the proposed scanner. In Phase II, the aflatoxin scan rate will be boosted by using focal plane detector arrays and the use of the developed multi-pixel scanner for detection of aflatoxins will be extended to a wider range of agricultural food products, while developing a prototype that can be used in realistic field/packaging/distribution settings.