Revolutionizing Tuberculosis Diagnostics: A Graphene Oxide-Based Biosensor for Enhanced Sensitivity and Selectivity in Cord Factor Detection

"Bovine tuberculosis is a chronic infectious disease which affects a broad range of mammalian hosts. The disease can be transmitted in several ways; for example, by direct contact, contact with the excreta of an infected animal, or inhalation of aerosols, depending on the species involved. The global burden of TB remains a significant public and animal health challenge whereby innovative techniques for early identification and successful management are required.

Next generation biosensor technology allows for SMART detection systems for disease detection.

Molecular techniques, particularly Polymerase Chain Reaction (PCR) and the revolutionary Xpert MTB/RIF test, have transformed TB detection, offering rapid and accurate results. Biosensors designed for the detection of various TB biomarkers are being developed, playing a crucial role

in the identification and management of the disease. Recent advancements in piezoelectric, magnetic, optical, and electrochemical biosensors have been notable. Graphene oxide (GO) is one of the most attributed materials for opening new possibilities in the development of next generation biosensors including biosensors based on fluorescence resonance energy transfer (FRET), laser desorption/ionization mass spectrometry (LDI-MS), surface-enhanced Raman spectroscopy (SERS), and electrochemical detection.

Due to the coexistence of hydrophobic domain from pristine graphite structure and hydrophilic oxygen containing functional groups, it exhibits biocompatibility, and high affinity for specific biomolecules as well as properties of graphene itself partly depending on preparation methods.

Nanomaterials such as graphene oxide (GO) nanoparticles have emerged as a versatile and promising platform and are characterized by various physicochemical properties, including nanoscale size, high surface area, and electrical charge. Reduced graphene oxide can be used in

(bio)sensors, biomedical applications, supercapacitors, membranes, catalysts, and water purification. GO nanoparticles will serve as the base material for the biosensor due to their exceptional biocompatibility, high surface area, and excellent electrical conductivity. One biomarker eg Cord factor (CF), is the most abundant glycolipid of the TB cell wall, is toxic to mammalian cells, and affects the host immune system by inhibiting the migration of polymorphonuclear neutrophils.

The detection of anti-cord factor (trehalose 6,6'-dimycolate) IgG antibody in TB samples is a useful serodiagnostic tool that can be used for early diagnosis of the disease. A highly specific antibody against CF will be immobilized on the GO nanoparticles. This antibody will selectively capture CF molecules from the sample.

GO nanoparticles can provide a large surface area for antibody immobilization, enhancing the sensitivity of the biosensor.

The CF-specific antibody will ensure that only CF molecules are detected, minimizing false positives. A signal transducer can provide rapid and real-time detection of CF. The proposed biosensor represents a novel approach due to its biological component integration with GO nanoparticles and its emphasis on real-time detection using a signal transducer coupled to a simple user interface and computing analysis. This will provide a SMART sensor for point of site detection.

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