Enhanced Sensitivity in Nanopore Sensing of Cancer Biomarkers in Human Blood via Click Chemistry

Abstract

Cancer biomarkers are expected to be indicative of the occurrence of certain cancer diseases before the tumors form and metastasize. However, many biomarkers can only be acquired in extremely low concentrations, which are often beyond the limit of detection (LOD) of current instruments and technologies. A practical strategy for nanopore sensing of cancer biomarkers in raw human blood down to the femtomolar level is developed here. This strategy first converts the detection of cancer biomarkers to the quantification of copper ions by conducting a sandwich assay involving copper oxide nanoparticles. The released Cu2+ is then taken to catalyze the “click” reaction which ligates a host–guest modified DNA probe. Finally, this DNA probe is subjected to single‐channel recordings to afford the translocation events that can be used to derive the concentrations of the original biomarkers. Due to the amplification effects of nanoparticle loadings and the “click” reaction, the LOD of this strategy can be as low as the subfemtomolar level. Further, the acid treatment step could effectively eliminate the interferences from plasma proteins in raw human blood and make the strategy highly suitable for the detection of cancer biomarkers in clinical samples.

Cucurbiturils in nucleic acids research

“…Since 2015, H.-C. Wu and co-workers are developing a versatile method for nanopore sensing of biologically related analytes based on DNA-CB [7] host-guest probes. [75][76][77][78][79][80][81][82][83] In the method developed by H.-C. Wu and co-workers, introduction of the analyte leads to the release or in situ formation of the single-stranded DNA (ssDNA) bearing a ferrocene-CB [7] or adamantane-CB [7] complex, referred to as a DNA probe. Threading of the DNA probe through the a-hemolysin (aHL) nanopore results in the dissociation of the host-guest complex and liberation of CB [7] (Fig.…”

“…Subsequent trapping and oscillation of free CB [7] in the vestibule of aHL produces a unique pattern of the current signature events that endows the detection with very high confidence at the single molecule level. The application of this strategy allowed to detect a large range of analytes of different size and nature, such as vascular endothelial growth factor (VEGF), thrombin, cocaine, 75 ssDNA, mono-/multivalent antibodies, 76 microRNA, 77 and cancer biomarkers, 78,79 with high levels of sensitivity. Selective epigenetic modification of 5-methylcytosine, 5-hydroxymethylcytosine 80 and 8-oxo-2 0 -deoxyguanosine 81 by attachment of the ferrocene-CB[7] 80 or adamantane-CB [7] 81 complexes allowed to apply the CB-based aHL nanopore sensing to detect the presence of these nucleobases in single-stranded DNA oligonucleotides.…”

Multiplex quantitative detection of SARS-CoV-2 specific IgG and IgM antibodies based on DNA-assisted nanopore sensing

“…constriction) in the pore. Based on DNA-assisted nanopore sensing ( Guo et al 2018 ; Guo et al 2020a ; Li et al 2015 ; Liu et al 2018 ; Wei et al 2020c ; You et al 2019 ; Zhang et al 2019 ), here we report a biosensing platform for accurate, multiplex, quantitative detection of SARS-CoV-2 specific antibodies with large dynamic ranges, and demonstrate its clinical utility by quantifying IgG and IgM against SARS-CoV-2 nucleocapsid (N) proteins in serum samples from confirmed and unconfirmed COVID-19 patients. The sensing principle of the assay involves: (1) capture of target antibodies with N protein functionalized magnetic beads (MBs); (2) labeling IgG or IgM antibodies with probe DNA modified gold nanoparticles (AuNPs); (3) thermal dehybridization of the probe DNAs from the AuNPs; (4) magnetic separation of probe DNAs from the sandwich structures; and (5) quantification of probe DNAs using the nanopore sensor ( Fig.…”

Insight into the effects of electrochemical factors on host-guest interaction induced signature events in a biological nanopore

“…Recently, the study of host-guest interactions through nanopore attracted increasing attention because of their wide application in the fields of functional materials and nanomedicine. 9 – 11 For example, the biomarkers in human bodily fluid can be quantified by establishing a correlation between the concentration of them and the frequency of unique signature signals generated by the host-guest interaction in the nanopore, 12 which is particularly important for clinical diagnostic uses (e.g. early diagnosis and precise prediction of treatment outcomes) as a way to prevent false positives.…”