E-DNA scaffold sensors and the reagentless, single-step, measurement of HIV-diagnostic antibodies in human serum

Abstract

The multiplexed, point-of-care measurement of specific antibodies could improve the speed with which diseases are diagnosed and their treatment initiated. To this end, we are developing E-DNA scaffold sensors, which consist of a rigid, nucleic acid “scaffold” attached on one end to an electrode and presenting both a redox reporter and an epitope on the other. In the absence of antibody, the reporter efficiently transfers electrons when interrogated electrochemically. Binding-induced steric hindrance limits movement, reducing electron transfer in a manner that is both easily measured and quantitatively related to target concentration. Previously we have used monoclonal antibodies to explore the analytical performance of E-DNA sensors, showing that they support the rapid, single-step, quantitative detection of multiple antibodies in small volume samples. Here, in contrast, we employ authentic human samples to better explore the platform’s clinical potential. Specifically, we developed E-DNA sensors targeting three HIV-specific antibodies and then compared the analytical and clinical performance of these against those of gold standard serological techniques. Doing so we find that, although the multistep amplification of an ELISA leads to a lower detection limits, the clinical sensitivity of ELISAs, E-DNA sensors and lateral-flow dipsticks are indistinguishable across our test set. It thus appears that, by merging the quantitation and multiplexing of ELISAs with the convenience and speed of dipsticks, E-DNA scaffold sensors could significantly improve on current serological practice.

An Overview on SARS-CoV-2 (COVID-19) and Other Human Coronaviruses and Their Detection Capability via Amplification Assay, Chemical Sensing, Biosensing, Immunosensing, and Clinical Assays

“…Up to now, various sensors have been advanced for the detection of diverse kinds of viruses such as human coronavirus [ 74 – 77 ], HIV [ 78 , 79 ], hepatitis B virus (HBV) [ 80 ], hepatitis C virus (HCV) [ 81 ], and Zika virus [ 82 , 83 ].…”

Beyond Sensitive and Selective Electrochemical Biosensors: Towards Continuous, Real-Time, Antibiofouling and Calibration-Free Devices

“…They can be classified as electrochemical DNA (E-DNA) [ 6 , 8 , 25 ] aptamer (E-AB) [ 2 , 3 , 7 , 9 , 10 , 26 ], and peptide (E-PB) [ 27 ] biosensors, and electrochemical biosensors for ion determination (E-ION) [ 28 ]. They have targeted the single or simultaneous determination [ 10 , 25 , 64 , 65 , 66 ] of a great number of significant analytes (DNAs, polymerase chain reaction amplification products, proteins, hormones, autoantibodies, drugs, toxins, adulterants, explosives, ions, and other biologically relevant molecules), and provide LODs as low as aM-fM for target DNAs [ 8 , 67 , 68 ], and pM for autoantibodies [ 69 ] and proteins [ 70 ], with compliance with threshold values and current regulations.…”

“…An illustrative example is shown in Figure 4 , where the scheme of a recently reported E-DNA sensor for the multidetermination of three HIV-diagnostic antibodies in human serum [ 25 ] is displayed. The comparison of the biosensor performance with those of gold standard serological techniques shows that this strategy merged the quantitation and multiplexing of ELISAs with the convenience and speed of dipsticks.…”

“…When the targeted antibody is not present, the DNA scaffold efficiently transfers electrons to the gold electrode, the electron transfer being reduced due to steric hindrance upon antibody binding ( a ); the square wave voltammetric signals obtained in the absence and in the presence of the targeted antibody ( b ). Reprinted and adapted from [ 25 ] with permission.…”

DNA‐Based Chemical Reaction Networks for Biosensing Applications

“…For example, Xia and coworkers developed an electrochemical DNA sensor (E‐DNA) based on the target‐driven DNA triplex formation which could generate an electrochemical output, thus supporting the continuous, real‐time measurement of melamine in flowing milk, [ 24 ] and HIV‐diagnostic antibodies in human serum. [ 25 ] Moreover, structure‐switchable aptamers have demonstrated promising performances in the real‐time detection of cytokines in vivo, [ 26 ] which is typically low abundances in physiological conditions and thus the aptasensing shows great value in biology and medicine. [ 27 ] Through decoration of graphene/methylene‐blue/Au nanocomposites with ferrocene‐labeled aptamer, Liu and coworkers successfully realized the real‐time detection of vascular endothelial growth factor in serum in a wide linear range (2–500 pg mL −1 ) with a much lower detection limit (0.1 pg mL −1 ).…”