College of Chemistry and Pharmaceutical Sciences, Qingdao Agricultural University, Qingdao, 266109, People's Republic of China.
College of Plant Health & Medicine, Qingdao Agricultural University, Qingdao, 266109, People's Republic of China.
Talanta. 2024 Jan 1;266(Pt 1):125001. doi: 10.1016/j.talanta.2023.125001. Epub 2023 Jul 27.
Exosomes, involved in cancer-specific biological processes, are promising noninvasive biomarkers for early diagnosis of cancer. Herein, an immobilization-free dual-aptamer-based photoelectrochemical (PEC) biosensor was proposed for the enrichment and quantification of cancer exosome based on photoactive bismuch oxyiodide/gold/cadmium sulfide (BiOI/Au/CdS) composites, nucleic acid-based recognition and signal amplification. In this biosensor, the recognition of exosome by two aptamers would trigger the deoxyribonucleotidyl transferase (TdT) enzyme-aided polymerization, leading to the enrichment of alkaline phosphatase (ALP) on FeO surface. After magnetic separation, ALP could catalyze the generation of ascorbic acid (AA) as electron donor and initiate the following redox cycle reaction for further signal amplification. Furthermore, all the above processes were performed in solution, the recognition and signal amplification efficiency would be superior than the heterogeneous strategy owing to the avoidance of steric hindrance effect. As a result, the proposed PEC biosensor was capable of enriching and detecting of cancer exosomes with high sensitivity and selectivity. The linear range of the biosensor was from 1.0 × 10 particles·μL to 1.0 × 10 particles·μL and the detection limit was estimated to be 21 particles·μL. Therefore, the proposed PEC biosensor holds great promise in quantifying tumor exosome for nondestructive early clinical cancer diagnosis and various other bioassay applications.
外泌体参与癌症特异性生物过程，是癌症早期诊断有前途的非侵入性生物标志物。在此，提出了一种基于无固定化双适体的光电化学（PEC）生物传感器，用于基于光活性铋氧碘化物/金/硫化镉（BiOI/Au/CdS）复合材料、基于核酸的识别和信号放大，对癌症外泌体进行富集和定量。在该生物传感器中，两种适体对外泌体的识别会触发脱氧核糖核苷酸转移酶（TdT）酶辅助聚合，导致碱性磷酸酶（ALP）在 FeO 表面富集。磁分离后，ALP 可以催化抗坏血酸（AA）的生成，作为电子供体，并引发后续的氧化还原循环反应，以进一步放大信号。此外，所有上述过程均在溶液中进行，由于避免了空间位阻效应，识别和信号放大效率将优于异质策略。因此，所提出的 PEC 生物传感器能够以高灵敏度和选择性对癌症外泌体进行富集和检测。该生物传感器的线性范围为 1.0×10 个粒子·μL 至 1.0×10 个粒子·μL，检测限估计为 21 个粒子·μL。因此，该 PEC 生物传感器有望用于定量肿瘤外泌体，用于无损的早期临床癌症诊断和各种其他生物分析应用。
