Ultrasensitive DNA detection based on two-step quantitative amplification on magnetic nanoparticles

作者：Jin, Mingliang; Liu, Xia; van den Berg, Albert; Zhou, Guofu; Shui, Lingling^*

来源：Nanotechnology, 2016, 27(33): 335102.

DOI：10.1088/0957-4484/27/33/335102

• ultrasensitive detection
• quantitative amplification
• DNA hybridyzation
• magnetic nanoparticle
• enzymatic reaction

Sensitive detection of a specific deoxyribo nucleic acid (DNA) sequence is important for biomedical applications. In this report, a two-step amplification strategy is developed based on magnetic nanoparticles (MNPs) to achieve ultrasensitive DNA fluorescence detection. The first level amplification is obtained from multiple binding sites on MNPs to achieve thousands of probe DNA molecules on one nanoparticle surface. The second level amplification is gained by enzymatic reaction to achieve fluorescence signal enhancement. MNPs functionalized by probe DNA (DNAp) are bound to target DNA (t-DNA) molecules with a ratio of 1:1 on a substrate with capture DNA (DNAc). After the MNPs with DNAp are released from the substrate, alkaline phosphatase (AP) is labelled to MNPs via hybridization reaction between DNAp on MNPs and detection DNAs (DNAd) with AP. The AP on MNPs catalyses non-fluorescent 4-methylumbelliferyl phosphate (4-MUP) to fluorescent 4-methylumbelliferone (4-MU) with high intensity. Finally, fluorescence intensity of the 4-MU is detected by a conventional fluorescence spectrophotometer. With this two-step amplification strategy, the limit of detection (LOD) of 2.8 x 10(-18) mol l(-1) for t-DNA has been achieved.

• 出版日期2016-8-19
• 单位华南师范大学