Abstract：
A novel construction strategy is introduced for an ultrasensitive dynamic light scattering (DLS) immunosensor targeting alpha fetoprotein (AFP). This approach relies on a self-assembled heptamer fusion protein (A1-C4bpα), incorporating the dual functions of multivalent recognition and crosslinking aggregation amplification due to the presence of seven AFP-specific A1 nanobodies on the A1-C4bpα heptamer. Leveraging antibody-functionalized magnetic nanoparticles for target AFP capture and DLS signal output, the proposed heptamer-assisted DLS immunosensor offers high sensitivity, strong specificity, and ease of operation. Under the optimized conditions, the designed DLS immunosensor demonstrates excellent linear detection of AFP in the concentration range 0.06 ng mL-1 to 512 ng mL-1, with a detection limit of 15 pg mL-1. The selectivity, accuracy, precision, practicability, and reliability of this newly developed method were further validated through an assay of AFP levels in spiked and actual human serum samples. This work introduces a novel approach for constructing ultrasensitive DLS immunosensors, easily extendable to the sensitive determination of other targets via simply replacing the nanobody sequence, holding great promise in various applications, particularly in disease diagnosis.
摘要：
介绍了一种针对甲胎蛋白（AFP）的超灵敏动态光散射（DLS）免疫传感器的新型构建策略。这种方法依赖于自组装的七聚体融合蛋白（A1-C4bpα），由于A1-C4bpα七聚体上存在七个AFP特异性A1纳米抗体，因此具有多价识别和交联聚集扩增的双重功能。利用抗体功能化的磁性纳米粒子捕获目标AFP和DLS信号输出，提议的七聚体辅助DLS免疫传感器提供高灵敏度，特异性强，和易于操作。在优化条件下,设计的DLS免疫传感器在0.06ngmL-1至512ngmL-1的浓度范围内具有出色的AFP线性检测能力，检测限为15pgmL-1。选择性,准确度,精度,实用性,通过测定加标和实际人血清样品中的AFP水平，进一步验证了这种新开发方法的可靠性。这项工作介绍了一种构建超灵敏DLS免疫传感器的新方法，通过简单地替换纳米体序列，可以轻松地扩展到其他目标的敏感确定，在各种应用中有着巨大的希望，特别是在疾病诊断中。
