Direct Profiling of Cancer Biomarkers in Tumor Tissue Using a Multiplexed Nanostructured Microelectrode Integrated Circuit

Abstract

The analysis of panels of nucleic acid biomarkers offers valuable diagnostic and prognostic information for cancer management. A cost-effective, highly sensitive electronic chip would offer an ideal platform for clinical biomarker readout and would have maximal utility if it was (i) multiplexed, enabling on-chip assays of multiple biomarkers, and (ii) able to perform direct (PCR-free) readout of disease-related genes. Here we report a chip onto which we integrate novel nanostructured microelectrodes and with which we directly detect cancer biomarkers in heterogeneous biological samples-both cell extracts and tumor tissues. Coarse photolithographic microfabrication defines a multiplexed sensing array; bottom-up fabrication of nanostructured microelectrodes then provides sensing elements. We analyzed a panel of mRNA samples for prostate cancer related gene fusions using the chip. We accurately identified gene fusions that correlate with aggressive prostate cancer and distinguished these from fusions associated with slower-progressing forms of the disease. The multiplexed nanostructured microelectrode integrated circuit reported herein provides direct, amplification-free, sample-to-answer in under 1 h using the 10 ng of mRNA readily available in biopsy samples.

An electrochemical ELISA-like immunosensor for miRNAs detection based on screen-printed gold electrodes modified with reduced graphene oxide and carbon nanotubes

“…8 fM. Yang et al (2009) andFang et al (2009) have developed microelectrodes based on Pt nanostructures for immobilization of DNA-SH probes to detect miRNAs by SWV in phosphate buffer containing redox indicators [Ru (NH 3 ) 6 ] 3 þ or [Fe(CN) 6 ] 3-. These systems, which imply a reagent added in solution, can detect miRNAs at the aM level.…”

DNA sensing by electrocatalysis with hemoglobin

“…Most importantly, the sensitivity for MB-DNA reduction was demonstrated to be improved ≥100-fold upon electrocatalytic signal amplification. This enhanced sensitivity, which allows a high signal-to-noise ratio from an electrode assembled with femtomoles of MB-DNA, should provide the response necessary to detect the unlabeled cellular markers, both DNA and protein targets, at low concentrations (19,20). As electrocatalytic signal amplification with hemoglobin is a general means of enhancing the sensitivity of current DNA-modified electrode technologies, it should be applicable to many DNA electrochemical strategies based on redox reporting of MB.…”

“…Sensors based on DNA-mediated CT are exquisitely sensitive to structural perturbations caused by single-base mismatches, lesions, and DNA-binding proteins (2)(3)(4). Due to the high specificity, robust nature, and low cost of these DNA-based electrochemical sensors, they are being developed as new cancer diagnostics through the detection of transcription factors and low abundance microRNAs (4,5,19,20). Despite the intrinsic specificity of these devices, these DNA-CT sensors currently lack the required sensitivity to detect biologically relevant levels of cancer markers.…”

Electrochemical Detection of RNA

“…3b). The multiple redox cycles of Ru(III) amplify the reduction signal, thus reporting on the amount of hybridization at the electrode surface (Fang et al 2009). Recently, Lam et al (2012) presented an integrated platform for PCR-free bacterial detection with integrated cell lysis with a sampleto-answer time of 30 min.…”