Nanoresonator chip-based RNA sensor strategy for detection of circulating tumor cells: response using PCA3 as a prostate cancer marker

There is widespread interest in circulating tumor cells (CTCs) in blood. Direct detection of CTCs (often < 1/mL) is complicated by a number of factors, but the presence of ∼103 to 104 copies of target RNA per CTC, coupled with simple enrichments, can greatly increase detection capability. In this study we used resonance frequency shifts induced by mass-amplifying gold nanoparticles to detect a hybridization sandwich bound to functionalized nanowires. We selected PCA3 RNA as a marker for prostate cancer, optimized antisense binding sites, and defined conditions allowing single nucleotide mismatch discrimination, and used a hybrid resonator integration scheme, which combines elements of top-down fabrication with strengths of bottom-up fabrication, with a view to enable multiplexed sensing. Bound mass calculated from frequency shifts matched mass estimated by counting gold nanoparticles. This represents the first demonstration of use of such nanoresonators, which show promise of both excellent specificity and quantitative sensitivity.From the Clinical EditorCancer cell detection from blood is an emerging method for more sensitive screening for malignancies. In this work, RNA detection with nanoresonators is demonstrated to have high specificity and sensitivity, suggesting that such technology may be feasible for laboratory medicine-based cancer detection.

Graphical AbstractSandwich hybridization assay for DD3 RNA. A primary ASO (green) is covalently attached to the NW surface. Incubation with DD3 RNA (blue) results in hybridization. Subsequent hybridization with the ASO:Au NP (red) completes the sandwich. Formation of the sandwich hybridization complex adds mass to the anchored NW nanoresonator, which results in a shift in the resonance frequency of the NW, which is quantitatively proportional to the number of complexes bound. The resonance frequency shift is measured using laser interferometry.Figure optionsDownload high-quality image (157 K)Download as PowerPoint slide