Proteins play vital roles in regulating a series of living activities and can be potentially considered to be useful indicators for diagnosing various diseases. Here, a target-triggered transcription cascade amplification strategy with the use of the fluorescence switch-on RNA aptamer is constructed for label-free and sensitive platelet-derived growth factor-BB (PDGF-BB) protein biomarker detection. The target molecule of PDGF-BB binds a rationally designed multifunctional hairpin probe to switch its structure and to expose a primer binding region. The primer sequence further binds such a region to initiate the target recycling and lighting-up RNA aptamer transcription cascade cycles to yield tremendous RNA aptamers. And, the fluorescence of the organic dye is substantially enhanced upon binding to these RNA aptamers for realizing highly sensitive and label-free PDGF-BB detection with the detection limit being lowered to 0.8 pM. Moreover, the developed strategy has superior selectivity and exhibits a promising potential to detect PDGF-BB spiked into serums with buffer dilution, which makes this method an attractive sensing system for detecting other biomarkers at trace levels.

蛋白质在调节一系列生命活动中起着至关重要的作用，并且可以潜在地被认为是诊断各种疾病的有用指标。在这里，构建了一种使用荧光开启 RNA 适体的靶触发转录级联扩增策略，用于无标记和敏感的血小板衍生生长因子-BB (PDGF-BB) 蛋白生物标志物检测。PDGF-BB的靶分子结合合理设计的多功能发夹探针，改变其结构并暴露引物结合区。引物序列进一步结合这样的区域以启动目标循环和点亮 RNA 适体转录级联循环以产生巨大的 RNA 适体。和，与这些RNA适配体结合后，有机染料的荧光显着增强，实现了高灵敏度、无标记的PDGF-BB检测，检测限降至0.8 pM。此外，所开发的策略具有卓越的选择性，并具有检测加入缓冲液稀释血清的 PDGF-BB 的潜力，这使得该方法成为检测其他痕量生物标志物的有吸引力的传感系统。