Clinically Relevant Detection ofStreptococcus pneumoniaewith DNA-Antibody Nanostructures

Abstract

Streptococcus pneumoniae (SP) is a pathogenic bacterium and a major cause of community-acquired pneumonia that could be fatal if left untreated. Therefore, rapid and sensitive detection of SP is crucial to enable targeted treatment during SP infections. In this study, DNA tetrahedron (DNA TH) with a hollow structure is anchored on gold electrodes to construct an electrochemical immunosensor for rapid detection of pneumococcal surface protein A (PspA) peptide and SP lysate from synthetic and actual human samples. This DNA nanostructure-based immunosensor displays excellent electrochemical activity toward PspA with a sensitive linear region from 0 to 8 ng/mL of PspA peptide and a low limit of detection (LOD) of 0.218 ng/mL. In addition, this DNA-TH-based immunosensor exhibits good sensing performance toward SP lysate in a clinically relevant linear range from 5 to 100 CFU/mL with a LOD of 0.093 CFU/mL. Along with these attractive features, this electrochemical immunosensor is able to specifically recognize and detect the PspA peptide mixed with other physiologically relevant components like bovine serum albumin (BSA) and lipopolysaccharide. In addition, our sensor could detect SP lysate even when dispersed in BSA or Escherichia coli lysate. Lastly, uncultured samples from the nasal cavity, mouth, and axilla of a human subject could be successfully determined by this well-designed electrochemical immunosensor.

Sustainable, Alginate-Based Sensor for Detection of Escherichia coli in Human Breast Milk

“…As far as pathogen detection in biofluids across paper-based, microfluidic and electrochemical bioassays [38][39][40][41][42], the determined LOD of 10 2 CFU/mL and above is approximately two orders of magnitude higher than the reported 0.093 CFU/mL for electrochemical immunoassays [43]. Furthermore, amplification time and associated capital costs [34][35][36][37] are not required for the proposed hydrogel assay.…”

Rational design of multi-functional gold nanoparticles with controlled biomolecule adsorption: a multi-method approach for in-depth characterization

“…The AuNP-PEO-COOH system could also be used for conjugation to targeting antibodies. Compared to DNA-antibody nanostructures that have been recently developed for cancer cell targeting 38 and for detection of pathogens 39 the AuNP-PEO-COOH-antibody system would be less stoichiometrically and spatially controlled, while it could probably achieve the binding of more antibody molecules per nanoparticle.…”

Molecular Biosensors for Electrochemical Detection of Infectious Pathogens in Liquid Biopsies: Current Trends and Challenges

“…Nanomaterials such as CNTs and AuNPs have been used as electrode modifiers and advanced labels. Moreover, electrodes modified with tetrahedral surface DNA nanostructures have been reported in an electrochemical immunosensing strategy for S. pneumoniae determination [ 28 ].…”

“…Electrochemical biosensors described to date for bacterial infections [ 28 , 32 , 33 , 34 , 35 , 37 , 38 , 39 , 40 , 41 , 42 , 43 , 44 , 45 ] comprise a rather limited number of immunosensors using antibodies able to detect the whole bacteria ( Streptococcus pseudopneumoniae , Escherichia coli and Vibrio cholerae ) [ 36 , 37 , 38 ] or specific surface bacterial proteins (PspA peptide) [ 28 ], and a wide variety of nucleic acid sensors targeting specific bacterial genes used along with different nucleic acid and signal amplification strategies [ 32 , 33 , 34 , 35 , 39 , 40 , 41 , 42 , 43 , 44 , 45 ].…”

“…A sandwich electrochemical immunosensor for rapid detection of pneumococcal surface protein A (PspA) peptide was proposed by immobilizing the capture antibody onto a gold electrode nanostructured with a DNA tetrahedron (DNATH) and using the same antibody conjugated with ferrocene (FeC-Ab) as a detector (see Figure 2 ) [ 28 ]. The concentration of the antigen is followed by measuring the increase in the square wave voltammetric (SWV) signal corresponding to the oxidation of Fc in the FeC-AbC.…”