Apolipoprotein A4 has a wide range of synaptic toxicity and can be used as a reliable molecular biomarker for the detection of depressive disorder. It has certain clinical requirements for simple, rapid and selective detection of apolipoprotein A4. Here, based on the DNA biped walker driven by DNAzyme, we designed a label-free surface-enhanced Raman scatting sensor for rapid detection of apolipoprotein A4. Compared with the typical DNA walker, the biped DNA walker has the advantages of large walking range and high magnification efficiency. The magnesium-dependent DNAzyme drives the DNA walker, which can cut the MBs sequentially. The resulting MBs fragments were then hybridized with AuNPs modified by repetitive adenine to make Au NPs proliferate on the substrate surface, resulting in a large number of cycles. Using 736 cm⁻¹ adenine as the internal marker, surface enhanced Raman scattering analysis showed that the linear detection range of human apolipoprotein A4 was 10∼1000 ng mL⁻¹, the detection limit was 4.7 pg/mL, and it had significant specificity, which could meet the needs of clinical detection and showed great application potential.

载脂蛋白A4具有广泛的突触毒性，可作为检测抑郁症的可靠分子生物标志物。对载脂蛋白A4的简单、快速、选择性检测具有一定的临床要求。在这里，基于DNAzyme驱动的DNA双足行走器，我们设计了一种无标记表面增强拉曼散射传感器，用于快速检测载脂蛋白A4。与典型的DNA步行机相比，双足DNA步行机具有行走范围大、放大效率高的优点。镁依赖性 DNAzyme 驱动 DNA walker，从而连续切割 MB。然后将所得的MBs片段与重复腺嘌呤修饰的AuNPs杂交，使Au NPs在基底表面增殖，从而产生大量的循环。以736 cm ^-1腺嘌呤为内标，表面增强拉曼散射分析表明，人载脂蛋白A4的线性检测范围为10∼1000 ng mL ^-1，检出限为4.7 pg/mL，具有显着的特异性。可以满足临床检测的需要，显示出巨大的应用潜力。