New Surface-Enhanced Raman Sensing Chip Designed for On-Site Detection of Active Ricin in Complex Matrices Based on Specific Depurination

详细信息    查看全文

• 作者：Ji-jun Tang ; Jie-fang Sun ; Rui Lui ; Zong-mian Zhang ; Jing-fu Liu ; Jian-wei Xie
• 刊名：ACS Applied Materials & Interfaces
• 出版年：2016
• 出版时间：January 27, 2016
• 年：2016
• 卷：8
• 期：3
• 页码：2449-2455
• 全文大小：383K
• ISSN：1944-8252

文摘

Quick and accurate on-site detection of active ricin has very important realistic significance in view of national security and defense. In this paper, optimized single-stranded oligodeoxynucleotides named poly(21dA), which function as a depurination substrate of active ricin, were screened and chemically attached on gold nanoparticles (AuNPs, ～100 nm) via the Au–S bond [poly(21dA)–AuNPs]. Subsequently, poly(21dA)–AuNPs were assembled on a dihydrogen lipoic-acid-modified Si wafer (SH–Si), thus forming the specific surface-enhanced Raman spectroscopy (SERS) chip [poly(21dA)–AuNPs@SH–Si] for depurination of active ricin. Under optimized conditions, active ricin could specifically hydrolyze multiple adenines from poly(21dA) on the chip. This depurination-induced composition change could be conveniently monitored by measuring the distinct attenuation of the SERS signature corresponding to adenine. To improve sensitivity of this method, a silver nanoshell was deposited on post-reacted poly(21dA)–AuNPs, which lowered the limit of detection to 8.9 ng mL^–1. The utility of this well-controlled SERS chip was successfully demonstrated in food and biological matrices spiked with different concentrations of active ricin, thus showing to be very promising assay for reliable and rapid on-site detection of active ricin.