Ultrasensitive Electrochemical Detection of Prostate-Specific Antigen by Using Antibodies Anchored on a DNA Nanostructural Scaffold

Abstract

The high occurrence of prostate cancer in men makes the prostate-specific antigen (PSA) screening test really important. More importantly, the recurrence rate after radical prostatectomy is high, whereas the traditional PSA immunoassay does not possess the sufficient high sensitivity for post-treatment PSA detection. In these assays, uncontrolled and random orientation of capture antibodies on the surface largely reduces their activity. Here, by exploiting the rapidly emerging DNA nanotechnology, we developed a DNA nanostructure based scaffold to precisely control the assembly of antibody monolayer. We demonstrated that the detection sensitivity was critically dependent on the nanoscale-spacing (nanospacing) of immobilized antibodies. In addition to the controlled assembly, we further amplified the sensing signal by using the gold nanoparticles, resulting in extremely high sensitivity and a low detection limit of 1 pg/mL. To test the real-world applicability of our nanoengineered electrochemical sensor, we evaluated the performance with 11 patients' serum samples and obtained consistent results with the "gold-standard" assays.

Synthesis of magnetic core-branched Au shell nanostructures and their application in cancer-related miRNA detection via SERS

“…The proposed B-GMNPs with improved SERS activities were further utilized as SERS-active magnetic capturer to assay cancer-related biomarker miRNA-21 in serum by a sandwich-structured strategy. In view of the remarkable advantages of DNA tetrahedrons, including good mechanical rigidity and structural stability, well controlled density and orientation of DNA capturers, enhanced accessibility of targets, as well as minimized nonspecific adsorption on the surface [35][36][37][38][39][40][41], tetrahedral DNAs containing the complementary sequence of target were structured first and then assembled onto the B-GMNPs to build SERS-active capturers with magnetic response. By using the tetrahedral DNA modified B-GMNPs as SERS-active capturers, sample separation and preconcentration operators, highly sensitive and specific detections of cancer-related biomarker miRNA-21 were conducted.…”

Electrochemical current rectification–a novel signal amplification strategy for highly sensitive and selective aptamer-based biosensor

“…(Hsieh et al, 2010) or the use of different kinds of multi-step nanomaterial assisted amplification through enhancing numerous binding units or electroactive probes (Chen et al, 2014a;Huang et al, 2014;Palchetti and Mascini, 2012). All these approaches require comparably expensive enzymes, stringent environmental conditions or complicated synthesis processes (Chen et al, 2014b;Cho et al, 2007;Hsieh et al, 2010;Huang et al, 2014;Lee et al, 2008;Liu et al, 2008). Therefore, there is still a strong demand for the Here, we report on the use of electrochemical current rectification (ECR) concept for the enhancement of redox signal of an electrochemical aptamer-based sensor.…”

Ultrasensitive electrochemical immunosensor based on dual signal amplification process for p16INK4a cervical cancer detection in clinical samples

“…Electrochemical detection platform has taken major contribution and have been proven to answer major challenges in particular for point-of-care cancer diagnostic. Highly sensitive immunosensor detections of biomarkers-including PSA (Chen et al, 2014;Mani et al, 2009;Yu et al, 2006), IL-6 (Malhotra et al, 2010), IL-8 (Munge et al, 2011), carcinoembryonic antigen (CEA) Lin et al, 2012;Qian et al, 2011), cancer antigens (e.g., CA-125, CA-153, CA-199) (Cui et al, 2014;Wilson and Nie, 2006), and α-feto-protein (AFP) (Liu et al, 2015;Du et al, 2010;Lai et al, 2009;) À have been reported employing different electrochemical methods and signal amplification techniques. Most of the system relied on sandwich-type reaction, which offers high selectivity and hence limited crosstalk and interfering signal.…”