近红外激发光电及荧光双模态循环肿瘤细胞传感及同步表型筛分

循环肿瘤细胞(CTC)是液体活检标志物，在外周血样中含量极微(<10个/mL)，异质化严重且易变，其含量及表型可体现肿瘤发生、发展、预后及疗效信息，具重要临床价值。传统单通道光电传感器需高能激发，光电转换效率低，传感性能受限，难以同步实现CTC高效能检测及表型筛分。本项目拟借鉴“轨道交通”之站点驻留原理，以单通道微流控集成具近红外光电响应并阵列式编码CTC识别子(适配体等)的稀土MOFs/ITO电极，利用空间效应筛分不同表型CTC，再经上转换荧光探针标记，基于光电响应实现高灵敏检测、荧光信号实现计数及表型判别，构建近红外激发光电及荧光双模态传感体系，实现临床样品分析。拟探究CTC分析效能与微流控通道物理特性、内壁修饰、识别子可控编码策略、近红外光电传感性能等的内在关联，获取近红外光电传感与材料特征(组成、形貌等)之构效关系、信号增强策略及转导机制，为肿瘤诊疗器件研发提供理论依据及技术支撑。

Circulating tumor cells (CTC) with high heterogeneity and complex phenotypes are crucial biomarkers in liquid biopsy for the diagnosis and the treatment of a malignant tumor. The quantity of CTCs is ultra-rare in the peripheral blood. CTCs are found in frequencies of 1 - 10 cells/mL in peripheral blood of patients with the primary tumor or the early-stage metastatic tumor. The tumor metastasis is the main reason for cancer deaths, and often causes undergoing an epithelial-to-mesenchymal transition process, leading circulating tumor cells varied from an epithelial phenotype to a mesenchymal phenotype. The detection of circulating tumor cells and the discrimination of their phenotypes can provide abundant information for tumorigenesis, tumor metastasis, tumor progression and the efficacy of therapies, and possess important significances for the clinical diagnosis and the treatment of tumors. Traditional photoelectrochemical sensors with a single detecting channel commonly employ high-energy light for the excitation of photoactive materials, providing weak photoelectric conversion efficiency and poor sensing performances. Thus, to simultaneously accomplish the detection of CTCs and the discrimination of their phenotypes turns out to be really difficult. .In this project, inspired by the principle of a closed rail transit system such as subway, we design a dual-modal photoelectrochemical and fluorometric sensing system based on near infra-red light excitation for detecting circulating tumor cell and identifying their phenotypes with a microfluidic device and encoded biorecognition elements for CTCs. The sensing system integration can be accomplished by following procedures: A near infra-red photoelectrochemical sensing platform (such as RE-MOFs/ITO) will be used as a substrate to immobilize biorecognition elements (such as aptamers) for CTCs with different phenotypes to form an encoded array. Then, a single microfluidic channel with desired patterns will be integrated with the aforementioned patterned working electrode to produce a track with tandem specific recognition sections. Meanwhile, a counter electrode and an auxiliary electrode will be embedded into the microfluidic channel along with the working electrode. CTCs can be selectively captured by encoded arrays, and thus to help to discriminate their phenotypes thorough spatial effect. Upon CTCs capturing, upconversion fluorescent nanoparticles functionalized with CTC aptamers will be used as fluorescent probes for CTCs labeling. Enumeration and identifying phenotypes of CTCs can be confirmed by fluorescence intensity or fluorescent imaging. Furthermore, the sensitive determination of CTCs can also be achieved by the near-infrared photoelectrochemical response. As a result, a dual-modal sensing platform has been successfully constructed and can be employed for assaying CTCs in real clinical samples. .Herein, the intrinsic connection between the sensing performances and the physical characteristics of the microfluidic channel, the inner surface modification, encoded strategy, and near-infrared photoelectrochemical sensing properties will be investigated thoroughly. In addition, the structure-activity relationship between the near-infrared photoelectrochemical sensing performances and the physical characteristics of photoactive materials (chemical composition, morphology and size etc.), strategies for signal amplification and mechanism for carrier transfer will also be investigated. All these investigations can provide valuable theoretical references and experimental database for improving performances of the sensing system for CTC detection and phenotype identification, thus providing theoretical and technical supports for designing the prototype devices for tumor diagnosis and treatment.