PO.PR02.02 · 预防研究
通过无创、无标记电化学免疫传感器探针检测早发性结直肠癌
Early-onset colorectal cancer detection through a non-invasive label-free electrochemical immunosensor probe
作者与单位 Authors & Affiliations
摘要 Abstract
中文摘要
早发性结直肠癌（CRC；<50岁）在美国正迅速增加，且对西班牙裔和非裔美国患者的影响尤为严重。由于生存率与早期检测呈正相关，针对年轻成人缺乏可靠且易获得的筛查工具仍是一项重大的未满足需求。液体活检诊断为侵入性检测提供了一种实用的替代方案；然而，假阴性的风险过高。利用基因表达数据集、cDNA阵列、组织微阵列以及CRC患者组织，我们已识别并验证了在西班牙裔早发性CRC患者中，与非西班牙裔白人相比，CCNB1和MCM10在转录本和蛋白水平的表达升高。我们正在开发一种用于即时检测（POC）这些早发性CRC生物标志物的无标记电化学免疫传感器。作为原型，我们设计了一种靶向早期CRC生物标志物CCSP-2的传感器。金工作电极（Au）用半胱氨酸修饰的重组Protein G进行功能化，Protein G选择性结合hIgG的Fc区域，从而在Au表面实现CCSP-2抗体（Ab）的可控取向。抗体固定后，使用牛血清白蛋白（BSA）作为封闭剂，每个修饰步骤均通过循环伏安法和电化学阻抗谱（EIS）进行表征。EIS通过相对电荷转移电阻的变化（ΔRct/Rcti）对CCSP-2抗原（Ag）进行定量。所得校准曲线（ΔRct/Rcti对Ag）在10-100 ng/µL范围内表现出很强的线性（R2 = 0.95），检测限为0.71 ng/µL。
为了进一步提高在复杂生物体液中的稳定性和抗污性能，我们正在将多孔BSA-戊二醛-金纳米线（BSA-GA-AuNW）水凝胶整合到Au叉指微电极上，随后进行抗体固定和早发性CRC生物标志物的检测。这种导电、亲水的基质有望提高灵敏度和特异性，同时实现可靠的血液检测。这种无创、低成本的电化学探针在扩大筛查范围和改善CRC早期检测方面具有巨大潜力，尤其是在年轻和服务不足的人群中，从而提高生存率。
查看英文原文 English abstract
Early-onset colorectal cancer (CRC; <50 years) is rapidly increasing in the United States and disproportionately affects Hispanic and African American patients. Since survival rates are positively associated with early detection, the absence of reliable and accessible screening tools for younger adults remains a significant unmet need. Liquid-biopsy diagnostics offer a practical alternative to invasive tests; however, the risk of false negatives is too high. Using gene-expression datasets, cDNA arrays, tissue-microarrays, and tissues from CRC patients, we have identified and validated the elevated expressions of CCNB1 and MCM10, at the transcript and protein levels, in Hispanic early-onset CRC patients when compared to their Non-Hispanic White counterparts. We are developing a label-free electrochemical immunosensor for point-of-care (POC) detection of these early-onset CRC biomarkers. As a prototype, we designed a sensor targeting the early CRC biomarker CCSP-2. A gold working electrode (Au) was functionalized with cysteine-modified recombinant Protein G, which selectively binds the Fc region of hIgG to achieve controlled orientation of CCSP-2 antibodies (Ab) on the Au surface. After Ab immobilization, bovine serum albumin (BSA) was used as a blocker, and each modification step was characterized by cyclic voltammetry and electrochemical impedance spectroscopy (EIS). EIS quantified CCSP-2 antigen (Ag) through changes in relative charge-transfer resistance (ΔR ct /R cti ). The resulting calibration curve (ΔR ct /R cti vs Ag) demonstrated strong linearity (R 2 = 0.95) from 10-100 ng/µL, with a detection limit of 0.71 ng/µL.
To further enhance stability and antifouling performance in complex biofluids, we are integrating a porous BSA-glutaraldehyde-gold nanowire (BSA-GA-AuNW) hydrogel onto Au interdigitated microelectrodes, followed by antibody immobilization and testing of early-onset CRC biomarkers. This conductive, hydrophilic matrix is expected to improve sensitivity and specificity while enabling reliable blood-based measurements. This non-invasive, low-cost electrochemical probe has strong potential to expand screening and improve early detection of CRC, especially among younger and underserved populations, thereby improving the survival rates.
利益披露 Disclosure
R. Paul, None..
A. Loya, None..
C. Cabrera, None.