Abstract：
A novel and highly sensitive colorimetric DNA sensor for determination of miRNA-155 at attomolar levelsis presented that combines the peroxidase-like activity of copper nanoparticles (CuNPs) with the hybridization chain reaction (HCR) . The utilization of CuNPs offers advantages such as strong interaction with double-stranded DNA, excellent molecular recognition, and mimic catalytic activity. Herein, a capture probe DNA (P1) was immobilized on carboxylated magnetic beads (MBs), allowing for amplified immobilization due to the 3D surface. Subsequently, the presence of the target microRNA-155 led to the formation of a sandwich structure (P2/microRNA-155/P1/MBs) when P2 was introduced to the modified P1/MBs. The HCR reaction was then triggered by adding H1 and H2 to create a super sandwich (H1/H2)n. Following this, Cu2+ ions were attracted to the negatively charged phosphate groups of the (H1/H2)n and reduced by ascorbic acid, resulting in the formation of CuNPs, which were embedded into the grooves of the (H1/H2)n. The peroxidase-like activity of CuNPs catalyzed the oxidation reaction of 3,3\',5,5\'-Tetramethylbenzidine (TMB), resulting in a distinct blue color measured at 630 nm. Under optimal conditions, the colorimetric biosensor exhibited a linear response to microRNA-155 concentrations ranging from 80 to 500 aM, with a detection limit of 22 aM, and discriminate against other microRNAs. It was also successfully applied to the determination of microRNA-155 levels in spiked human serum.
摘要：
提出了一种新颖且高灵敏度的比色DNA传感器，用于测定阿托摩尔水平的miRNA-155，该传感器将铜纳米颗粒（CuNPs）的过氧化物酶样活性与杂交链反应（HCR）相结合。CuNPs的利用提供了与双链DNA的强相互作用等优势，优秀的分子识别，模拟催化活性。在这里，将捕获探针DNA（P1）固定在羧化磁珠（MB）上，允许放大固定由于3D表面。随后，当P2被引入修饰的P1/MB时,靶微小RNA-155的存在导致夹心结构(P2/微小RNA-155/P1/MBs)的形成。然后通过添加H1和H2来触发HCR反应以产生超级夹心(H1/H2)n。在此之后,Cu2+离子被吸引到(H1/H2)n的带负电荷的磷酸基，并被抗坏血酸还原，导致CuNPs的形成，嵌入（H1/H2）n的凹槽中。CuNPs的过氧化物酶样活性催化3,3'，5,5'-四甲基联苯胺(TMB)，导致在630nm处测量的明显的蓝色。在最优条件下,比色生物传感器对80至500aM的microRNA-155浓度表现出线性响应，检测限为22aM，并歧视其他microRNA。它也成功地应用于测定加标人血清中的microRNA-155水平。
