State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Biology, College of Chemistry and Chemical Engineering, Key Laboratory for Bio-Nanotechnology and Molecule Engineering of Hunan Province, Hunan University, Changsha 410082, China.
Anal Chem. 2024 Sep 17;96(37):14775-14782. doi: 10.1021/acs.analchem.4c02077. Epub 2024 Sep 5.
Accurate and rapid imaging of tumor cells is of vital importance for early cancer diagnosis and intervention. Aptamer-based fluorescence sensors have become a potent instrument for bioimaging, while false positives and on-target off-tumors linked to single-biomarker aptasensors compromise the specificity and sensitivity of cancer imaging. In this paper, we describe a sequential response aptasensor for precise cancer cell identification that is based on a DNA "AND" logic gate. Specifically, the sensor consists of three single-stranded DNA, including the P-strand that can sensitively respond to an acid environment, the L-strand containing the ATP aptamer sequence, and the R-strand for target cell anchoring. These DNA strands hybridize with one another to create a Y-shaped structure (named Y-ALGN). The aptamer in the R-strand is utilized to anchor the sensor to the target cell membrane primarily. Responding to the extracellular acidic environment of the tumor (input 1), the I-motif sequence forms a tetramer structure so that the P-strand is released from the Y-shaped structure and exposes the ATP binding sites in the L-strand. Extracellular ATP, as input 2, continuously operates the DNA aptasensor to complete the logic computation. Upon the sequential response of both protons and ATP molecules, the aptasensor is activated with restored fluorescence on a particular cancer cell membrane. Benefiting from the precise computation capacity of the "AND" logic gate, the Y-ALGN aptasensor can distinguish between MCF-7 cells and normal cells with high accuracy. As a simple and dual-stimuli-responsive strategy, this nanodevice would offer a fresh approach for accurately diagnosing tumor cells.
准确快速地对肿瘤细胞成像对于癌症的早期诊断和干预至关重要。基于适配体的荧光传感器已成为生物成像的有力工具，然而，单一生物标志物适配体传感器与假阳性和靶外肿瘤相关，这会影响癌症成像的特异性和灵敏度。在本文中，我们描述了一种基于 DNA“与”逻辑门的用于精确癌细胞识别的顺序响应适配体传感器。具体来说，该传感器由三条单链 DNA 组成，包括能够对酸性环境敏感响应的 P 链、含有 ATP 适配体序列的 L 链和用于靶细胞锚定的 R 链。这些 DNA 链相互杂交形成 Y 形结构（命名为 Y-ALGN）。R 链中的适配体主要用于将传感器锚定到靶细胞膜上。响应肿瘤细胞外的酸性环境（输入 1），I 型发夹序列形成四聚体结构，从而使 P 链从 Y 形结构中释放出来，并暴露出 L 链中的 ATP 结合位点。细胞外的 ATP 作为输入 2，不断驱动 DNA 适配体传感器完成逻辑计算。在质子和 ATP 分子的顺序响应下，适配体传感器在特定的癌细胞膜上被激活并恢复荧光。得益于“与”逻辑门的精确计算能力，Y-ALGN 适配体传感器能够高精度地区分 MCF-7 细胞和正常细胞。作为一种简单的双刺激响应策略，这种纳米器件为准确诊断肿瘤细胞提供了一种新方法。
