Enzyme-Free Amplification by Nano Sticky Balls for Visual Detection of ssDNA/RNA Oligonucleotides

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• 作者：Shan Chen ; Lok Ting Chu ; Pak Piu Yeung ; Zichen Zhao ; Yuanye Bao ; Miu Shan Chan ; Pik Kwan Lo ; Ting-Hsuan Chen
• 刊名：ACS Applied Materials & Interfaces
• 出版年：2015
• 出版时间：October 21, 2015
• 年：2015
• 卷：7
• 期：41
• 页码：22821-22830
• 全文大小：551K
• ISSN：1944-8252

文摘

Visual detection of nucleic acids provides simple and rapid screening for infectious diseases or environmental pathogens. However, sensitivity is the current bottleneck, which may require enzymatic amplification for targets in low abundance and make them incompatible with detection at resource-limited sites. Here we report an enzyme-free amplification that provides a sensitive visual detection of ssDNA/RNA oligonucleotides on the basis of nano 鈥渟ticky balls鈥? When target oligonucleotides are present, magnetic microparticles (MMPs) and gold nanoparticles (AuNPs) were linked together, allowing the collection of AuNPs after magnetic attraction. Subsequently, the collected AuNPs, which carry many oligonucleotides, were used as the sticky balls to link a second pair of MMPs and polymer microparticles (PMPs). Thus, because the magnetic field can attract the MMPs as well as the linked PMPs to the sidewall, the reduction of suspended PMPs yields a change of light transmission visible by the naked eye. Our results demonstrate that the limit of detection is 10 amol for ssDNAs (228 fM in 45 渭L) and 75 amol for ssRNAs (1.67 pM in 45 渭L). This method is also compatible with the serum environment and detection of a microRNA, miR-155, derived from human breast cancer cells. With significantly improved sensitivity for visual detection, it provides great potential for point-of-care applications at resource-limited sites.