Ultra-sensitive detection of uranyl ions with a specially designed high-efficiency SERS-based microfluidic device

• 来源期刊: 中国科学:化学（英文版）
• 年，卷（期）: 2019,（8）
• 页码范围: 1064-1071
• 页数: 8页
• 语种: 英文

摘要

The uranyl ion (UO22+) poses high risks to human health and the environment,hence its detection and monitoring is of utmost significance.However,the development of an ultra-sensitive,high-efficiency and convenient approach for on-site detection of UO22+ remains a challenge.Herein,a reliable and reusable surface-enhanced Raman spectroscopy (SERS)-based microfluidic biosensor was developed for rapid detection of UO22+ in real samples.The detection protocol involved the reaction of 5'-Rhodamine B (RhB)-labeled double-stranded DNA for UO22+-specific DNAzyme-cleavage reaction in a U-shaped microchannel.Then,the reaction products were delivered into three parallel samples for high-throughput tests by SERS biochips,where 3D ZnO-Ag mesoporous nanosheet arrays (MNSs) were modified with a single-stranded DNA (ssDNA).The ssDNA was sequence-complementary with the 5'-RhB-labeled cleaved-stranded DNA (csDNA) from the reaction products.By the hybridization of ssDNA and csDNA,the signal probe RhB was fixed close to the surface of the ZnO-Ag MNSs to enhance the Raman signal.The limit of detection for UO22+ with the microfluidic-SERS biosensor was 3.71 × 10-15 M.An over 20,000-fold selectivity towards UO22+ response was also achieved in the presence of 15 other metal ions.The high-throughput microfluidicSERS biosensor operated well for practical UO22-detection,with excellent recoveries in contaminated river and tap water from 95.2％ to 106.3％ (relative standard deviation (RSD) ＜6.0％,n=6).Although the SERS-based microfluidic biosensor developed in this study was deployed for the detection of UO22+,the reusable and high-efficiency system may be expanded to the detection of other analytes on-site.