Sub-attomolar HIV-1 DNA detection using surface-enhanced Raman spectroscopy

Abstract

A subattomolar HIV-1 DNA detection assay based on multilayer metal-molecule-metal nanojunctions (NJs) has been developed using surface-enhanced Raman spectroscopy (SERS). There is a two-step mechanism involved. First, label free target DNA facilitated the precipitation of Detection Unit I on the substrate through forming a sandwiched structure based on the capture probe, resulting in the first level amplification of target. Following that, the binding site on Detection probe I was further recognized by Detection Unit II. These two complementary probes acted as bricks to build up the multi-metal-molecule-metal NJs between Au nanoparticles (NPs) that not only created SERS "hot spots" by the conjugated Au NPs, but also obviously decreased the distance between Au NPs and Raman labels. Therefore, the Raman signal of the tag molecules on these detection probes was significantly enhanced due to the distance dependent electromagnetic enhancement (EM) of SERS. With regards to a HIV-1 DNA sequence, the platform could detect a concentration as low as 10(-19) M (approximately 10(-23) mol) with the ability of single base mismatch discrimination.

Surface-enhanced Raman spectroscopy at single-molecule scale and its implications in biology

“…Of these, one of the most promising applications of SM-SERS is in the rapid detection and identification of individual DNA bases with Raman structural specificity and characterization of individual base pairs in DNA fragments without the use of fluorescent or radioactive labels, as reported by Kneipp et al in 1998 [91], where adenine was detected by using silver colloid (label-free). Meanwhile, single HIV-1 DNA and single base extension reaction has been detected for DNA methylation analysis rstb.royalsocietypublishing.org Phil Trans R Soc B 368: 20120026 [92,93]. Ultrasensitive detection of proteins such as haemoglobin was also reported by using the aggregated silver colloid [94].…”

Gold Nanoparticles for DNA/RNA-Based Diagnostics

“…Hu et al developed a sensitive DNA-SERS biosensor based on multilayer metal-molecule-metal nanojunctions [70]. The sensor could detect as little as 0.1 atomolar of a HIV-1 DNA sequence.…”

An ultrasensitive method for the detection of gene fragment from transgenics using label-free gold nanoparticle probe and dynamic light scattering

“…The aggregation can be observed visually by color change or detected by ultraviolet visible (UV-vis) absorption spectroscopy, and the detection limit of the approach was about 1.0 × 10 −8 mol L −1 [18]. To improve the sensitivity, a variety of detection techniques have been exploited including scanometric method [19,20] and surfaceenhanced Raman spectroscopy (SERS) [21,22]. But these methods usually require labeling and immobilization procedures which make them complicated and time-consuming.…”