Development and Validation of a Biosensor for Rapid TB Detection Nanotechnology
Tuberculosis (TB) is one of the world's deadliest infectious diseases (about 1.7 million people die annually) and is a leading cause of death among HIV positive patients. The standard test for diagnosing Mycobacterium tuberculosis (Mtb) is smear sputum microscopy, which is unable to identify one half of true infections. Several molecular based techniques have been examined for the rapid detection of Mtb but they require specialized equipment, are expensive and otherwise difficult to implement in primary health care settings. Therefore, there is a critical need for accurate, rapid and cost effective screening methods that are field deployable. Our objective for this research focuses on developing and validating a handheld field operable biosensor to quickly and cheaply detect Mtb infection in ethnically diverse highland populations in Chiapas, Mexico. For preliminary work, Mycobacterium smegmatis (Msm) is used as a surrogate for Mtb. Msm shares more than 2000 homologs with Mtb and shares the same unusual cell structure as Mtb. Like Mtb, it is also an acid fast bacterial species. The biosensor uses magnetic nanoparticles (MNPs) to non specifically extract bacterial cells from artificial sputum samples. Antibodies (Ab) specific to Mycobacterium species are conjugated to gold (Au) nanoparticles to form Ab Au NPs. These Ab Au NPs are then added to the MNP cells to form a MNP cell Ab Au complex. This complex is added to a screen printed carbon electrode chip that is connected to a handheld potentiostat. Differential pulse voltammetry is used to generate the signal. Preliminary results show that the biosensor can detect bacterial cells in the range of 10^1 10^6 cfu/ml. The whole process of sample preparation to detection is completed in less than one hour. Material cost for target extraction is about 2 cents per assay. Detection assay is about $1, making the whole extraction detection assay costing only about $2. The whole system is handheld, field portable, and operable by entry level health workers. This technology would be an alternative to other methods with comparable sensitivity, especially in point of care scenarios under scarce resources. Integration of genetically encoded molecular sensors into 3D microsensor materials by protein compatible photopolymerization Nanotechnology Biosensors Jenna Rickus, Purdue University, Leyla Nesrin Kahyaoglu, Purdue University, Rajtarun Madangopal, Purdue University (currently at the National Institutes of Health) Corresponding Author: Jenna Rickus, Purdue University, 225 S. University St, West Lafayette, Indiana 47907 USA