AuNPs/CNF-modified DNA biosensor for early and quick detection of O. tsutsugamushi in patients suffering from scrub typhus

Abstract

A novel approach has been developed for the detection of 56 kDa tissue-specific antigen (TSA) gene of Orientia tsutsugamushi a causative agent of scrub typhus disease. The approach was developed by immobilization of 5′ NH2 labeled ssDNA probe selective to 56 kDa TSA gene, to the surface of AuNPs/CNF modified screen-printed electrode. An electrochemical response was recorded with single stranded genomic DNA (ssDNA) of O. tsutsugamushi isolated from patient sample, using cyclic voltammetry and electrochemical impedance spectroscopy. The electrode surface was characterized by Field-Emission Scanning electron microscope (FE-SEM), Fourier Transform Infrared Spectroscopy (FTIR) and Raman Spectroscopy at each step of fabrication. The DNA biosensor shows optimum response within 50-60 s at room temperature (25 ± 3 °C). The sensor shows higher sensitivity [7849 (µA/cm 2 )/ng DNA], fast response time (60 s), wider linear range (0.04-2.6 ng) with limit of detection of 0.02 ng/µl of ssDNA sample.

Leptospira interrogans Outer Membrane Protein-Based Nanohybrid Sensor for the Diagnosis of Leptospirosis

“…The electrode was characterized at a different phase of the sensor development, including the bare electrode and ssDNA probe-modified electrode, and after hybridization of the DNA sensor (DNA Probe) with ssGDNA of L. interrogans. Fourier-transform infrared spectroscopy (FTIR) and Raman spectroscopy were carried out to ensure each step of the DNA sensor development process [ 16 ]. FTIR studies revealed the functional groups imparted on the working electrode (AuN/CNF) after the modification with the ssDNA (probe) ( Figure 1 ).…”

“…The limit of detection (LOD) of the DNA sensor was determined as 0.0077 ng/µL, which was in agreement with the experimental value (minimum ssGDNA concentration). An increase in the Ip value with different concentrations of L. interrogans GDNA was due to the presence of guanine bases on the DNA sensor surface, which showed a binding affinity with methylene blue (MB) [ 16 ].…”

“…The emerging diagnostic methods, such as biosensors, are in demand because of their better performance in terms of onsite detection ability with less time and higher clinical sensitivity. An electrochemical DNA biosensor is becoming a need of ours due to its ability to lay bare the infection at the early stages with better sensitivity and accuracy [ 16 , 17 , 18 , 19 , 20 , 21 ]. It can create a point-of-care diagnostics facility even outside the laboratory settings and can be a replacement of the current diagnosis methods that require sophisticated instrument facilities and experts to carry out the tests [ 22 ].…”

“…The physical and chemical properties of carbon nanofibers (CNFs) make them a suitable nanomaterial for novel composites that can enhance the properties of composite materials due to the synergistic interactions. The graphitic and edge planes of CNFs have the potential for surface functionalization or modifications that can be useful in surface modifications for the binding of the bioreceptors [ 16 ] and also has great potential for biosensing applications due to the larger surface area, high conductivity, and electrocatalytic activity [ 24 ].…”

Graphene Oxide Nanoparticles Modified Paper Electrode as a Biosensing Platform for Detection of the htrA Gene of O. tsutsugamushi

“…The disease is highly prevalent in rural areas, where proper diagnosis facilities are not available to detect the infection at early stages resulting in higher mortalities. The clinical symptoms of the disease are very common and similar to the other infections that make it difficult to diagnose [ 1 , 3 ]. The bacteria spread through the infected larval mite that produces eschar at the biting site.…”